Philosophical and scientific investigations of the proprietary aspects of self—mineness or mental ownership—often presuppose that searching for unique constituents is a productive strategy. But there seem not to be any unique constituents. Here, it is argued that the “self-specificity” paradigm, which emphasizes subjective perspective, fails. Previously, it was argued that mode of access also fails to explain mineness. Fortunately, these failures, when leavened by other findings (those that exhibit varieties and vagaries of mineness), intimate an approach better suited to searching (...) for an explanation. Having an alternative in hand, one that shows promise of achieving explanatory adequacy, provides an additional reason to suspend the search for unique constituents. In short, a negative and a positive thesis are developed: we should cease looking for unique constituents and should seek to explain mineness in accord with the model developed here. This model rejects attempts to explain the phenomenon in terms of either a narrative or a minimal sense of self; it seeks to explain at a “molecular” level, one that appeals to multiple, interacting dimensions. The molecular-level model allows for the possibility that subjective perspective is distinct from a stark perspective (one that does not imply mineness). It proposes that the confounding of tacit expectations plays an important role in explaining mental ownership and its complement, disownership. But the confounding of tacit expectations is not sufficient. Because we are able to be aware of the existence of mental states that do not belong to self, we require a mechanism for determining degree of self-relatedness. One such mechanism is proposed here, and it is shown how this mechanism can be integrated into a general model of mental ownership. In the spirit of suggesting how this model might be able to help resolve outstanding problems, the question as to whether inserted thoughts belong to the patient who reports them is also considered. (shrink)

Sydney Shoemaker, developing an idea of Wittgenstein’s, argues that we are immune to error through misidentification relative to the first-person pronoun. Although we might be liable to error when “I” (or its cognates) is used as an object, we are immune to error when “I” is used as a subject (as when one says, “I have a toothache”). Shoemaker claims that the relationship between “I” as-subject and the mental states of which it is introspectively aware is tautological: when, say, we (...) judge that “I feel pain,” we are tautologically aware that feels pain is instantiated and that it is instantiated in oneself. Moreover, he contends that this relationship holds not just for bodily sensations, but also for the sense of agency and for visual perception. But we deny that this relationship is tautological; instead, we treat Shoemaker’s principle (IEM) as a hypothesis. We then proceed to show that certain pathological states and experimentally-induced illusions can be adduced to show that IEM describes not a necessary relationship but a contingent relationship, one that sometimes fails to obtain. That we are not immune to error in the way Shoemaker describes has grave consequences for many aspects of his ideas concerning the first-person perspective. In the course of arguing that these empirical phenomena count against IEM, we also show that not only can the content of conscious experience be misrepresented, so too can the subject: that is, not only can the what of conscious experience be misrepresented, so too can the who. (shrink)

Subjectivity theories of consciousness take self-reference, somehow construed, as essential to having conscious experience. These theories differ with respect to how many levels they posit and to whether self-reference is conscious or not. But all treat self-referencing as a process that transpires at the personal level, rather than at the subpersonal level, the level of mechanism. -/- Working with conceptual resources afforded by pre-existing theories of consciousness that take self-reference to be essential, several attempts have been made to explain seemingly (...) anomalous cases, especially instances of alien experience. These experiences are distinctive precisely because self-referencing is explicitly denied by the only person able to report them: those who experience them deny that certain actions, mental states, or body parts belong to self. The relevant actions, mental states, or body parts are sometimes attributed to someone or something other than self, and sometimes they are just described as not belonging to self. But all are referred away from self. -/- The cases under discussion here include somatoparaphrenia, schizophrenia, depersonalization, anarchic hand syndrome, and utilization behavior; the theories employed, Higher-Order Thought, Wide Intrinsicality, and Self-Representational. Below I argue that each of these attempts at explaining or explaining away the anomalies fails. Along the way, since each of these theories seeks at least compatibility with science, I sketch experimental approaches that could be used to adduce support for my position, or indeed for the positions of theorists with whom I disagree. -/- In a concluding section I first identify two presuppositions shared by all of the theorists considered here, and argue that both are either erroneous or misleading. Second, I call attention to divergent paths adopted when attempting to explain alienation experiences: some theorists choose to add a mental ingredient, while others prefer to subtract one. I argue that alienation from experience, action, or body parts could result from either addition or subtraction, and that the two can be incorporated within a comprehensive explanatory framework. Finally, I suggest that this comprehensive framework would require self-referencing of a sort, but self-referencing that occurs solely on the level of mechanism, or the subpersonal level. In adumbrating some features of this “subpersonal self,” I suggest that there might be one respect in which it is prior to conscious experience. (shrink)

Mental ownership concerns who experiences a mental state. According to David Rosenthal (2005: 342), the proper way to characterize mental ownership is: ‘being conscious of a state as present is being conscious of it as belonging to somebody. And being conscious of a state as belonging to somebody other than oneself would plainly not make it a conscious state’. In other words, if a mental state is consciously present to a subject in virtue of a higher-order thought (HOT), then the (...) HOT necessarily representsthe subject as the owner of the state. But, we contend, one of the lessons to be learned from pathological states like somatoparaphrenia is that conscious awareness of a mental state does not guarantee first-person ownership. That is to say, conscious presence does not imply mental ownership. (shrink)

For millennia self has been conjectured to be necessary for consciousness. But scant empirical evidence has been adduced to support this hypothesis. Inconsistent explications of “self” and failure to design apt experiments have impeded progress. Advocates of phenomenological psychiatry, however, have helped explicate “self,” and employed it to explain some psychopathological symptoms. In those studies, “self” is understood in a minimalist sense, sheer “for-me-ness.” Unfortunately, explication of the “minimal self” (MS) has relied on conceptual analysis, and applications to psychopathology have (...) been hermeneutic, allowing for many degrees of interpretive latitude. The result is that MS’s current scientific status is analogous to that of the “atom,” at the time when “atom” was just beginning to undergo transformation from a philosophical to a scientific concept. Fortunately, there is now an opportunity to promote a similar transformation for “MS.” Discovery of the brain’s Default Mode Network (DMN) opened the door to neuroimaging investigations of self. Taking the DMN and other forms of intrinsic activity as a starting point, an empirical foothold can be established, one that spurs experimental research and that enables extension of research into multiple phenomena. New experimental protocols that posit “MS” can help explain phenomena hitherto not thought to be related to self, thereby hastening development of a mature science of self. In particular, targeting phenomena wherein consciousness is lost and recovered, as in some cases of Unresponsive Wakefulness Syndrome (UWS), allow for design of neuroimaging probes that enable detection of MS during non-conscious states. These probes, as well as other experimental protocols applied to NREM Sleep, General Anesthesia (GA), and the waking state, provide some evidence to suggest that not only can self and consciousness dissociate, MS might be a necessary precondition for conscious experience. Finally, these findings have implications for the science of consciousness: it has been suggested that “levels of consciousness” (LoC) is not a legitimate concept for the science of consciousness. But because we have the conceptual and methodological tools with which to refine investigations of MS, we have the means to identify a possible foundation—a bifurcation point—for consciousness, as well as the means by which to measure degrees of distance from that foundation. These neuroimaging investigations of MS position us to better assess whether LoC has a role to play in a mature science of consciousness. (shrink)

Previous research has suggested that bodily signals from internal organs are associated with diverse cortical and subcortical processes involved in sensory-motor functions, beyond homeostatic reflexes. For instance, a recent study demonstrated that the preparation and execution of voluntary actions, as well as its underlying neural activity, are coupled with the breathing cycle. In the current study, we investigated whether such breathing-action coupling is limited to voluntary motor action or whether it is also present for mental actions not involving any overt (...) bodily movement. To answer this question, we recorded electroencephalography (EEG), electromyography (EMG), and respiratory signals while participants were conducting a voluntary action paradigm including self-initiated motor execution (ME), motor imagery (MI), and visual imagery (VI) tasks. We observed that the voluntary initiation of ME, MI, and VI are similarly coupled with the respiration phase. In addition, EEG analysis revealed the existence of readiness potential (RP) waveforms in all three tasks (i.e., ME, MI, VI), as well as a coupling between the RP amplitude and the respiratory phase. Our findings show that the voluntary initiation of both imagined and overt action is coupled with respiration, and further suggest that the breathing system is involved in preparatory processes of voluntary action by contributing to the temporal decision of when to initiate the action plan, regardless of whether this culminates in overt movements. -/- . (shrink)

According to Rosenthal’s Higher-Order Thought (HOT) theory of consciousness, first-order mental states become conscious only when they are targeted by HOTs that necessarily represent the states as belonging to self. On this view a state represented as belonging to someone distinct from self could not be a conscious state. Rosenthal develops this view in terms of what he calls the ‘thin immunity principle’ (TIP). According to TIP, when I experience a conscious state, I cannot be wrong about whether it is (...) I who I think is in that state. We first suggest that TIP is a direct consequence of the HOT theory. Next we argue that somatoparaphrenia—a pathology in which sensations are sometimes represented as belonging to other people—shows that TIP can be violated. This violation of TIP in turn shows that the HOT theory’s claim that conscious states are necessarily represented as belonging to self is in error. Rosenthal’s attempt to account for pathological cases is found to be inadequate when applied to somatoparaphrenia, and other possible defenses are also shown to be incapable of preserving TIP. We further conclude by suggesting that the HOT theory’s failing in this regard is not a failing that is peculiar to this theory of consciousness. (shrink)

In a recent Opinion article, Sui and Humphreys [1] argue that experimental findings suggest self is ‘special’, in that self-reference serves a binding function within human cognitive economy. Contrasting their view with other functionalist positions, chiefly Dennett's [2], they deny that self is a convenient fiction and adduce findings to show that a ‘core self representation’ serves as an ‘integrative glue’ helping to bind distinct types of information as well as distinct stages of psycho- logical processing. In other words, where (...) Dennett regards self as analogous to a center of gravity, a simplification posited by observers, Sui and Humphreys regard self as a function that modulates mental processes. In practice, however, the concept of ‘self’ they employ is not unlike Dennett's. We side with Sui and Humphreys in hold- ing that self-reference modulates mental processes: reference to self during a task can bind memory to source, increase perceptual integration, and link attention to decision making, among other things. What is more, these functions are not reducible to other factors such as semantic coding, familiarity, or reward [3]. But whereas Sui and Humphreys contribute important empirical detail, the binding functions they describe are compatible with Dennett's version of functionalism, which treats self as an artifact of social process. (shrink)

Currently, one of the most influential theories of consciousness is Rosenthal's version of higher-order-thought (HOT). We argue that the HOT theory allows for two distinct interpretations: a one-component and a two-component view. We further argue that the two-component view is more consistent with his effort to promote HOT as an explanatory theory suitable for application to the empirical sciences. Unfortunately, the two-component view seems incapable of handling a group of counterexamples that we refer to as cases of radical confabulation. We (...) begin by introducing the HOT theory and by indicating why we believe it is open to distinct interpretations. We then proceed to show that it is incapable of handling cases of radical confabulation. Finally, in the course of considering various possible responses to our position, we show that adoption of a disjunctive strategy, one that would countenance both one-component and two-component versions, would fail to provide any empirical or explanatory advantage. (shrink)

Recent studies have demonstrated neural overlap between resting state activity and self-referential processing. This “rest-self” overlap occurs especially in anterior cortical midline structures like the perigenual anterior cingulate cortex (PACC). However, the exact neurotemporal and biochemical mechanisms remain to be identified. Therefore, we conducted a combined electroencephalography (EEG)-magnetic resonance spectroscopy (MRS) study. EEG focused on pre-stimulus (e.g., prior to stimulus presentation or perception) power changes to assess the degree to which those changes can predict subjects’ perception (and judgment) of subsequent (...) stimuli as high or low self-related. MRS measured resting state concentration of glutamate, focusing on PACC. High pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power significantly correlated with both perception of stimuli judged to be highly self-related and with resting state glutamate concentrations in the PACC. In sum, our results show (i) pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power and resting state glutamate concentration to mediate rest-self overlap that (ii) dispose or incline subjects to assign high degrees of self-relatedness to perceptual stimuli. (shrink)

Sleep onset is associated with marked changes in behavioral, physiological, and subjective phenomena. In daily life though subjective experience is the main criterion in terms of which we identify it. But very few studies have focused on these experiences. This study seeks to identify the subjective variables that reflect sleep onset. Twenty young subjects took an afternoon nap in the laboratory while polysomnographic recordings were made. They were awakened four times in order to assess subjective experiences that correlate with the (...) (1) appearance of slow eye movement, (2) initiation of stage 1 sleep, (3) initiation of stage 2 sleep, and (4) 5 min after the start of stage 2 sleep. A logistic regression identified control over and logic of thought as the two variables that predict the perception of having fallen asleep. For sleep perception, these two variables accurately classified 91.7% of the cases; for the waking state, 84.1%. (shrink)

There is a distinctive form of existential anxiety, neuroexistential anxiety, which derives from the way in which contemporary neuroscience provides copious amounts of evidence to underscore the Darwinian message—we are animals, nothing more. One response to this 21st century existentialism is to promote Eudaimonics, a version of ethical naturalism that is committed to promoting fruitful interaction between ethical inquiry and science, most notably psychology and neuroscience. We argue that philosophical reflection on human nature and social life reveals that while working (...) to be and remain biologically fit, humans also seek meaning in a way that conforms to a pattern recognized by Plato. We argue that human beings should seek “the good,” “the true,” and “the beautiful”; moreover, the proper measure of human flourishing is the degree to which humans achieve these three, in a maximally harmonious way. One potential problem with this view, however, is that it might privilege the role of truth, such that if there is a conflict among these three, what is good or beautiful should yield to what is true. But this seems to conflict with evidence from neuroscience and psychology (e.g. the study of positive illusions) which suggests that people with a tendency to form and harbor certain false beliefs tend to more easily achieve eudaimonia than do those for whom truth takes precedence in all domains. We argue that this conflict is only apparent: the false beliefs in question are not literally beliefs; instead, they are an amalgam of belief and desire, an amalgam that we dub, tertullian beliefs (or, t-beliefs). Among other things, what is distinctive about t-beliefs is that they are able to change the world, in certain specific ways, such that, strictly speaking, it would be erroneous to say of them that they aim away from the truth. Paradoxically, it is because they seem to aim away from the truth, that they are sometimes able to succeed in changing the world so that it matches what we desire, or, what we t-believe. (shrink)

A cursory glance at the list of Nobel Laureates for Economics is sufficient to confirm Stanovich’s description of the project to evaluate human rationality as seminal. Herbert Simon, Reinhard Selten, John Nash, Daniel Kahneman, and others, were awarded their prizes less for their work in economics, per se, than for their work on rationality, as such. Although philosophical works have for millennia attempted to describe, explicate and evaluate individual and collective aspects of rationality, new impetus was brought to this endeavor (...) over the last century as mathematical logic along with the social and behavioral sciences emerged. Yet more recently, over the last several decades, propelled by the emergence of artificial intelligence, cognitive science, evolutionary psychology, neuropsychology, and related fields, even more sophisticated approaches to the study of rationality have emerged. (shrink)

Inducing the rubber hand illusion (RHI) requires that participants look at an imitation hand while it is stroked in synchrony with their occluded biological hand. Previous explanations of the RHI have emphasized multisensory integration, and excluded higher cognitive functions. We investigated the relationship between the RHI and higher cognitive functions by experimentally testing task switch (as measured by switch cost) and mind wandering (as measured by SART score); we also included a questionnaire for attentional control that comprises two subscales, attention-shift (...) and attention-focus. To assess experience of RHI, the Botvinick and Cohen (1998) questionnaire was used and illusion onset time was recorded. Our results indicate that rapidity of onset reliably indicates illusion strength. Regression analysis revealed that participants evincing less switch cost and higher attention-shift scores had faster RHI onset times, and that those with higher attention-shift scores experienced the RHI more vividly. These results suggest that the multi-sensory hypothesis is not sufficient to explain the illusion: higher cognitive functions should be taken into account when explaining variation in the experience of ownership for the rubber hand. (shrink)

Most mental disorders affect only a small segment of the population. On the reasonable assumption that minds or brains are prone to occasional malfunction, these disorders do not seem to pose distinctive explanatory problems. Depression, however, because it is so prevalent and costly, poses a conundrum that some try to explain by characterizing it as an adaptation—a trait that exists because it performed fitness-enhancing functions in ancestral populations. Heretofore, proposed evolutionary explanations of depression did not focus on thought processes; instead, (...) they emphasized that it facilitates navigation of adverse social circumstances or promotes immune response to infectious agents. According to a new hypothesis, the “analytical rumination hypothesis” (ARH), however, depression’s crucial adaptive trait is rumination—negative, intrusive thought. ARH holds that, (i) social dilemmas trigger depressed mood; (ii) depressed mood induces changes in body systems that facilitate ruminative analysis aimed at solving dilemmas; and, (iii) depressive rumination is a fitness-enhancing trait that was selected for in evolutionary time. Jointly, (i)~(iii) imply that we should not think of rumination as a disorder; instead, it is a trade-off, an eminently rational one. In the same way that fever solves a problem—coordination of the immune system in response to infection—so too does depressive rumination solve a problem, a social dilemma, albeit at the cost of inducing anhedonia and other maladies. But they argue that the cost is worthwhile, something that should be endured “until the problem is solved.” First, we argue that there are two distinct types of rumination, brooding and pondering; the former is associated with a disposition for depression, not the latter. But only the latter has the problem-solving capabilities that ARH requires. Second, recent brain imaging studies of depression reveal resting state hypoactivity in lateral regions and hyperactivity in paralimbic regions; this asymmetric pattern correlates with heightened levels of brooding, self-focused rumination. In other words, on the personal level, patients are trapped within self, isolated from the external world and suffused with negative affect; on the subpersonal level, this pattern is reflected by an asymmetric pattern of lateral vs. paralimbic resting state activity. Third, we proceed to conjecture that rational responses (e.g., pondering) to social dilemmas are those that strike a balance between internal and external considerations in the process of belief formation. Fourth, because the asymmetric resting state activity blocks those who suffer with depression from accessing and processing potentially positive stimuli from the external world, the capacity for rational, analytic response—hence, problem-solving—is constrained. Fifth, it follows that, although there might be conditions for which suffering should be endured rather than pharmacologically alleviated, depression is not one of those. Indeed, in view of the effects of the asymmetric resting state pattern, it is unlikely that depressive rumination would have been useful even for ancestral populations. (shrink)

According to Allen Wood’s “procedural principle” we should believe only that which can be justified by evidence, and nothing more. He argues that holding beliefs which are not justified by evidence diminishes our self-respect and corrupts us, both individually and collectively. Wood’s normative and descriptive views as regards belief are of a piece with the received view which holds that beliefs aim at the truth. This view I refer to as the Truth-Tracking View (TTV). I first present a modest version (...) of TTV, one which is sensitive to standard criticisms and one which is fully consistent with the procedural principle. I then raise some doubts about TTV by considering both anecdotal cases and empirical studies. These studies suggest that certain types of belief are designed to aim away from truth, in limited, carefully calibrated ways. Moreover, it seems to be the case that selectively aiming away from the truth is important for human well-being and performance. Beliefs that are designed to aim away I dub “Tertullian” beliefs (t-beliefs). I then limn the distinguishing characteristics of t-belief and proceed to evaluate the procedural principle in light of the evidence which suggests that t-belief plays an important role in our cognitive economy. Next I argue that t-beliefs might be essential to the maintenance of self-respect and that they do not corrupt in the way that Wood claims. Finally, I argue that the fate of Wood’s procedural principle will be determined by the results of further empirical research— sociological, psychological, and neuroscientific. (shrink)

Spontaneous activity levels prior to stimulus presentation can determine how that stimulus will be perceived. It has also been proposed that such spontaneous activity, particularly in the default-mode network (DMN), is involved in self-related processing. We therefore hypothesised that pre-stimulus activity levels in the DMN predict whether a stimulus is judged as self-related or not. Method: Participants were presented in the MRI scanner with a white noise stimulus that they were instructed contained their name or another. They then had to (...) respond with which name they thought they heard. Regions where there was an activity level difference between self and other response trials two seconds prior to the stimulus being presented were identified. Results: Pre-stimulus activity levels were higher in the right temporoparietal junction (RTPJ), the right temporal pole (RTP), and the left superior temporal gyrus in trials where the participant responded that they heard their own name than trials where they responded that they heard another. Conclusion: Pre-stimulus spontaneous activity levels in particular brain regions, largely overlapping with the DMN, predict the subsequent judgement of stimuli as self-related. This extends our current knowledge of self-related processing and its apparent relationship with intrinsic brain activity in what can be termed a rest-self overlap. (shrink)

Neural activity varies continually from moment to moment. Such temporal variability (TV) has been highlighted as a functionally specific brain property playing a fundamental role in cognition. We sought to investigate the mechanisms involved in TV changes between two basic behavioral states, namely having the eyes open (EO) or eyes closed (EC) in vivo in humans. To these ends we acquired BOLD fMRI, ASL, and [18F]-fluoro-deoxyglucose PET in a group of healthy participants (n = 15), along with BOLD fMRI and (...) [18F]-flumazenil PET in a separate group (n = 19). Focusing on an EO- vs EC-sensitive region in the occipital cortex (identified in an independent sample), we show that TV is constrained in the EO condition compared to EC. This reduction is correlated with an increase in energy consumption and with regional GABAA receptor density. This suggests that the modulation of TV by behavioral state involves an increase in overall neural activity that is related to an increased effect from GABAergic inhibition in addition to any excitatory changes. These findings contribute to our understanding of the mechanisms underlying activity variability in the human brain and its control. (shrink)

Disorders of consciousness (DoC)—that is, unresponsive wakefulness syndrome/vegetative state and minimally conscious state—are debilitating conditions for which no reliable markers of consciousness recovery have yet been identified. Evidence points to the GABAergic system being altered in DoC, making it a potential target as such a marker.

Neurovascular coupling (NVC), the transient regional hyperemia following the evoked neuronal responses, is the basis of blood oxygenation level-dependent techniques and is generally adopted across physiological conditions, including the intrinsic resting state. However, the possibility of neurovascular dissociations across physiological alterations is indicated in the literature. To examine the NVC stability across sleep–wake states, we used electroencephalography (EEG) as the index of neural activity and functional magnetic resonance imaging (fMRI) as the measure of cerebrovascular response. Eight healthy adults were recruited (...) for simultaneous EEG-fMRI recordings in nocturnal sleep. We compared the cross-modality (EEG vs. fMRI) consistency of functional indices (spectral amplitude and functional connectivity) among five states of wakefulness and sleep (state effect). We also segregated the brain into three main partitions (anterior, middle and posterior) for spatial assessments (regional effect). Significant state effects were found on δ, α and fMRI indices and regional effects on the α and fMRI indices. However, the cross-state EEG changes in spectral amplitude and functional connectivity did not consistently match the changes in the fMRI indices across sleep–wake states. In spectral amplitude, the δ band peaked at the N3 stage for all brain regions, while the fMRI fluctuation amplitude peaked at the N2 stage in the central and posterior regions. In regional connectivity, the inter-hemispheric connectivity of the δ band peaked at the N3 stage for all regions, but the bilateral fMRI connectivity showed the state changes in the anterior and central regions. The cross-modality inconsistencies across sleep–wake states provided preliminary evidence that the neurovascular relationship may not change in a linear consistency during NREM sleep. Thus, caution shall be exercised when applying the NVC presumption to investigating sleep/wake transitions, even among healthy young adults. (shrink)

Objective Manic and depressive phases of bipolar disorder (BD) show opposite psychomotor symptoms. Neuronally, these may depend on altered relationships between sensorimotor network (SMN) and subcortical structures. The study aimed to investigate the functional relationships of SMN with substantia nigra (SN) and raphe nuclei (RN) via subcortical-cortical loops, and their alteration in bipolar mania and depression, as characterized by psychomotor excitation and inhibition. -/- Method In this resting-state functional magnetic resonance imaging (fMRI) study on healthy (n = 67) and BD (...) patients (n = 100), (1) functional connectivity (FC) between thalamus and SMN was calculated and correlated with FC from SN or RN to basal ganglia (BG)/thalamus in healthy; (2) using an a-priori-driven approach, thalamus-SMN FC, SN-BG/thalamus FC, and RN-BG/thalamus FC were compared between healthy and BD, focusing on manic (n = 34) and inhibited depressed (n = 21) patients. -/- Results (1) In healthy, the thalamus-SMN FC showed a quadratic correlation with SN-BG/thalamus FC and a linear negative correlation with RN-BG/thalamus FC. Accordingly, the SN-related FC appears to enable the thalamus-SMN coupling, while the RN-related FC affects it favoring anti-correlation. (2) In BD, mania showed an increase in thalamus-SMN FC toward positive values (ie, thalamus-SMN abnormal coupling) paralleled by reduction of RN-BG/thalamus FC. By contrast, inhibited depression showed a decrease in thalamus-SMN FC toward around-zero values (ie, thalamus-SMN disconnection) paralleled by reduction of SN-BG/thalamus FC (and RN-BG/thalamus FC). The results were replicated in independent HC and BD datasets. -/- Conclusions These findings suggest an abnormal relationship of SMN with neurotransmitters-related areas via subcortical-cortical loops in mania and inhibited depression, finally resulting in psychomotor alterations. (shrink)

The neurotransmitters GABA and glutamate have been suggested to play a role in Major Depressive Disorder (MDD) through an imbalance between cortical inhibition and excitation. This effect has been highlighted in higher brain areas, such as the prefrontal cortex, but has also been posited in basic sensory cortices. Based on this, magnetic resonance spectroscopy (MRS) was used to investigate potential changes to GABA+ and glutamate+glutamine (Glx) concentrations within the occipital cortex in MDD patients (n = 25) and healthy controls (n (...) = 25). No difference in occipital GABA+ or Glx concentrations, nor in the GABA+/Glx ratio, was found between groups. An analysis of an extended MDD patient and unmatched control dataset (n = 90) found no correlation between metabolite concentrations and depressive symptoms. These results were integrated with prior studies through metabolite-specific meta-analyses, revealing no difference in occipital GABA and Glx concentrations between patients and controls. An effect of publication year on GABA group differences was found, suggesting that previously reported results may have been artifacts of measurement accuracy. Taken together, our results suggest that, contrary to some prior reports, MRS measurements of occipital GABA and Glx do not differ between MDD patients and controls. (shrink)

Background: Rumination, a tendency to focus on negative self-related thoughts, is a central symptom of depression. Studying the self-related aspect of such symptoms is challenging because of the need to distinguish self effects from the emotional content of task stimuli. This study employed an emotionally neutral self-related paradigm to investigate possible altered self-processing in depression and its link to rumination. Methods: People with major depressive disorder (n = 25) and controls (n = 25) underwent task-based electro-encephalogram recording. We studied late (...) event-related potentials, along with low-frequency oscillatory power. We compared electroencephalogram metrics between groups and correlated them with depressive symptoms and reported rumination. Results: Participants with major depressive disorder displayed a difference in late positive potentials across frontocentral electrodes between self-related and non-self-related conditions. We found no such difference in controls. The magnitude of this difference was positively correlated with depressive symptoms and reported rumination. Participants with major depressive disorder also had elevated theta oscillation power at central electrodes in self-related conditions, a finding that we did not see in controls. Limitations: Patients with major depressive disorder were medicated at the time of the study. The group studied was primarily female, so the observed effects may have been sex-specific. Conclusion: Rumination appears to be linked to altered self-related processing in depression, independent of stimuli-related emotional confounds. This connection between self-related processing and depression may point to a self disorder as a core component of depression. (shrink)

Time is an essential feature in bipolar disorder (BP). Manic and depressed BP patients perceive the speed of time as either too fast or too slow. The present article combines theoretical and empirical approaches to integrate phenomenological, psychological, and neuroscientific accounts of abnormal time perception in BP. Phenomenology distinguishes between perception of inner time, ie, self-time, and outer time, ie, world-time, that desynchronize or dissociate from each other in BP: inner time speed is abnormally slow (as in depression) or fast (...) (as in mania) and, by taking on the role as default-mode function, impacts and modulates the perception of outer time speed in an opposite way, ie, as too fast in depression and too slow in mania. Complementing, psychological investigation show opposite results in time perception, ie, time estimation and reproduction, in manic and depressed BP. Neuronally, time speed can be indexed by neuronal variability, ie, SD. Our own empirical data show opposite changes in manic and depressed BP (and major depressive disorder [MDD]) with abnormal SD balance, ie, SD ratio, between somatomotor and sensory networks that can be associated with inner and outer time. Taken together, our combined theoretical-empirical approach demonstrates that desynchronization or dissociation between inner and outer time in BP can be traced to opposite neuronal variability patterns in somatomotor and sensory networks. This opens the door for individualized therapeutic “normalization” of neuronal variability pattern in somatomotor and sensory networks by stimulation with TMS and/or tDCS. (shrink)

Reinterpretation of our data concerning sleep onset, motivated by the desire to pay close attention to “intra-individual regularities,” suggests that the experience of control might be a key factor in determining the subjective sense that sleep has begun. This loss of control seems akin to what Frith and others have described as “passivity experiences,” which also occur in schizophrenia. Although clearly sleep onset is not a schizophrenic episode, this similarity might help to explain other features of sleep onset. We further (...) speculate that we could build upon the discovery of various “intra-individual regularities” to construct a model of sleep onset and other forms of sleep mentation. (shrink)

We provide empirical examples to conceptually clarify some items on Firestone & Scholl’s (F&S’s) checklist, and to explain perceptual effects from an attentional and memory perspective. We also note that action and embodied cognition studies seem to be most susceptible to misattributing attentional and memory effects as perceptual, and identify four characteristics unique to action studies and possibly responsible for misattributions.

Patients with schizophrenia have a higher risk of cardiovascular diseases and higher mortality from them than does the general population; however, the underlying mechanism remains unclear. Impaired cerebral autoregulation is associated with cerebrovascular diseases and their mortality. Increased or decreased cerebral blood flow in different brain regions has been reported in patients with schizophrenia, which implies impaired cerebral autoregulation. This study investigated the cerebral autoregulation in 21 patients with schizophrenia and 23 age- and sex-matched healthy controls. None of the participants (...) had a history of cardiovascular diseases, hypertension, or diabetes. All participants underwent 10-min blood pressure and cerebral blood flow recording through finger plethysmography and Doppler ultrasonography, respectively. Cerebral autoregulation was assessed by analyzing two autoregulation indices: the mean blood pressure and cerebral blood flow correlation coefficient (Mx), and the phase shift between the waveforms of blood pressure and cerebral blood flow determined using transfer function analysis. Compared with the controls, the patients had a significantly higher Mx (0.257 vs. 0.399, p = 0.036) and lower phase shift (44.3° vs. 38.7° in the 0.07–0.20 Hz frequency band, p = 0.019), which indicated impaired maintenance of constant cerebral blood flow and a delayed cerebrovascular autoregulatory response. Impaired cerebral autoregulation may be caused by schizophrenia and may not be an artifact of coexisting medical conditions. The mechanism underlying impaired cerebral autoregulation in schizophrenia and its probable role in the development of cerebrovascular diseases require further investigation. (shrink)

It is becoming increasingly difficult for those who engage in ethical analysis to ignore evolution and neuroscience. The kind of creature that we are and that we have evolved to be matters when determining how we ought to live. There is still a need to aim for a reflective equilibrium that includes reflection over not straightforwardly empirical issues. It would, for example, be inaccurate to say that "good" just means "highly evolved." But it does turn out to be the case (...) that many questions pivotal to ethical theorizing are straightforwardly empirical. And, to a large extent, ethics can be treated as a kind of applied science, one that aims to encourage personal and social flourishing. Of course just what counts as "flourishing" is a matter that will also require a healthy dose of reflective equilibrium. Be that as it may, the best philosophers of the 21st century do what the best philosophers of previous centuries did: they draw upon the resources available to them during the era in which they work. In this era that includes evolutionary biology and neuroscience. (shrink)

意識是如此不可捉摸又抽象的概念，「測量」意識簡直就像科幻小說情節。科學家近年來在這方面已大有進展，藉由各項腦造影技術和實驗手法，能夠分析不同意識狀態下的大腦活動型態。.

It is not necessarily the case that we ever have experiences of self, but human beings do regularly report instances for which self is experienced as absent. That is there are times when body parts, mental states, or actions are felt to be alien. Here I sketch an explanatory framework for explaining these alienation experiences, a framework that also attempts to explain the “mental glue” whereby self is bound to body, mind, or action. The framework is a multi-dimensional model that (...) integrates personal and sub-personal components, psychological and neural processes. I then proceed to show how this model can be applied to explain the action-related passivity experiences of persons suffering from schizophrenia. I argue that a distinctive phenomenological mark of these experiences is that they are vividly felt, unlike ordinary actions (those taken to belong to self), and I seek to explain these heightened sensory experiences from within the proposed framework. I also propose hypotheses concerning such phenomena as thought insertion and anarchic hand syndrome that are motivated by this framework. Finally, I argue that the proposed model and view of self-experiences is consistent with several aspects of and theories of consciousness, especially theories which indicate that consciousness is more likely to be engaged when we are dealing with novelty or error—e.g. when self seems to have gone missing. I conclude by recommending that if we wish to learn about self, we would be well advised to attend closely to those times when it seems absent. -/- . (shrink)

Objective: To evaluate the potential of arterial spin labeling (ASL) as an alternative to FDG-PET in the diagnosis of disorders of consciousness (DOC), we conducted a comparative study of the two modalities. Methods: A total of 36 DOC patients (11 female; mean age = 49.67 ± 14.54 years) and 17 healthy control (HC) participants (9 female; mean age = 31.9 ± 9.6 years) underwent both FDG-PET scans that measure metabolism via glucose uptake and ASL scans that measure cerebral blood flow (...) (CBF). CBF and metabolism in DOC and HC were compared, globally and for seven functional networks. Comparability of the two modalities was estimated using Spearman partial correlation for both global and network levels. Furthermore, a support vector machine (SVM) algorithm was used to train two classifiers to distinguish DOC patients from HC with normalized CBF or metabolism values from the seven networks. Performance of these classifiers was first evaluated through leave-one-subject-out (LOSO) cross-validation within their respective modalities. Subsequently, cross-modal validation was conducted: testing the ASL-trained classifier with PET data (ASL-to-PET validation) and vice versa (PET-to-ASL validation). Performance of each classifier was assessed using receiver operating characteristic (ROC) analysis, with area under the curve (AUC) as the metric. Results: Both modalities showed agreement in decreased CBF and metabolism in DOC patients compared to HC, at both global and network levels. The global brain and most networks showed significant positive partial correlation between CBF and metabolism. SVM classifiers, utilizing activity from seven networks as features, performed well in the both LOSO cross-validation (ASL-trained classifier: accuracy = 83.02%, AUC = 0.95; PET-trained classifier: accuracy = 98.12%, AUC = 0.98) and cross-modal validation (ASL-to-PET validation: accuracy = 84.90%, AUC =0.92; PET-to-ASL validation: accuracy = 73.58%, AUC = 0.93). Conclusion: Our results demonstrate that ASL provides information comparable to FDG-PET for DOC patients; moreover, classifiers trained on ASL data perform comparably well to those trained on FDG-PET data. Therefore, ASL could be a valuable alternative to FDG-PET in the clinical diagnosis of DOC, especially in light of its advantages: ease of acquisition, avoidance of radiation exposure, brevity of scanning time, and lower-cost. (shrink)

Even when brain scans fail to detect a striate lesion, functional evidence for blindsight can be adduced. In the aftermath of an automobile accident, JK became blind. Results of ophthalmic exams indicated that the blindness must be cortical. Nevertheless, multiple MRI scans failed to detect structural damage to the striate cortex. Prior to the accident JK had been an athlete; after the accident he retained some athletic abilities, arousing suspicions that he might be engaged in fraud. His residual athletic abilities—e.g., (...) hitting a handball or baseball, or catching a Frisbee—coupled with his experienced blindness, suggested blindsight. But due to the apparent absence of striate lesions, we designed a series of tasks for temporal and spatial dimensions in an attempt to detect functional evidence of his disability. Indeed, test results revealed compelling neural evidence that comport with his subjective reports. This spatiotemporal task-related method that includes contrasts with healthy controls, and detailed understanding of the patient's conscious experience, can be generalized for clinical, scientific and forensic investigations of blindsight. -/- . (shrink)

Invited Commentary On: Graziano, M. S. A., Guterstam, A., Bio, B. J., Wilterson, A. I. (2019). Toward a standard model of consciousness: Reconciling the attention schema, global workspace, higher order thought, and illusionist theories. Cognitive Neuropsychology.

Resting state networks comprise several brain regions that exhibit complex patterns of interaction. Switching from eyes closed (EC) to eyes open (EO) during the resting state modifies these patterns of connectivity, but precisely how these change remains unclear. Here we use functional magnetic resonance imaging to scan healthy participants in two resting conditions (viz., EC and EO). Seven resting state networks were chosen for this study: salience network (SN), default mode network (DMN), central executive network (CEN), dorsal attention network (DAN), (...) visual network (VN), motor network (MN) and auditory network (AN). We performed functional connectivity (FC) analysis for each network, comparing the FC maps for both EC and EO. Our results show increased connectivity between most networks during EC relative to EO, thereby suggesting enhanced integration during EC and greater modularity or specialization during EO. Among these networks, SN is distinctive: during the transition from EO to EC it evinces increased connectivity with DMN and decreased connectivity with VN. This change might imply that SN functions in a manner analogous to a circuit switch, modulating resting state relations with DMN and VN, when transitioning between EO and EC. (shrink)

Subjective perception of sleep is not necessarily consistent with electroencephalography (EEG) indications of sleep. The mismatch between subjective reports and objective measures is often referred to as “sleep state misperception.” Previous studies evince that this mismatch is found in both patients with insomnia and in normal sleepers, but the neurophysiological mechanism remains unclear. The aim of the study is to explore the neurophysiological basis of this mechanism, from the perspective of both EEG power and functional magnetic resonance imaging (fMRI) fluctuations. (...) Thirty-six healthy young adults participated in the study. Simultaneous EEG and fMRI recordings were conducted while the participants were trying to fall asleep in an MRI scanner at approximately 9:00 pm. They were awakened after achieving stable N1 or N2 sleep, or after 90 min without falling into stable sleep. Next they were asked to recall their conscious experiences from the moment immediately prior to awakening. Sixty-one instances of scheduled awakenings were collected: 21 of these after having achieved stable stage N2 sleep; 12, during stage N1 sleep; and, 20 during the waking state. Relative to those awakenings without subjective–objective discrepancy (n = 27), these awakenings with discrepancy (n = 14) were associated with lower θ power, as well as higher α, β, and γ power. Moreover, we found that participants who exhibited the discrepancy, compared with those who did not, evinced a higher amplitude of low-frequency fluctuation levels in the prefrontal cortex. These results lend support to the conjecture that the subjective–objective discrepancy is associated with central nervous system hyperarousal. (shrink)

Nonrapid eye movement (NREM) sleep is associated with fading consciousness in humans. Recent neuroimaging studies have demonstrated the spatiotemporal alterations of the brain functional connectivity (FC) in NREM sleep, suggesting the changes of information integration in the sleeping brain. However, the common stationarity assumption in FC does not satisfactorily explain the dynamic process of information integration during sleep. The dynamic FC (dFC) across brain networks is speculated to better reflect the time-varying information propagation during sleep. Accordingly, we conducted simultaneous EEG-fMRI (...) recordings involving 12 healthy men during sleep and observed dFC across sleep stages using the sliding-window approach. We divided dFC into two aspects: mean dFC (dFCmean) and variance dFC (dFCvar). A high dFCmean indicates stable brain network integrity, whereas a high dFCvar indicates instability of information transfer within and between functional networks. For the network-based dFC, the dFCvar were negatively correlated with the dFCmean across the waking and three NREM sleep stages. As sleep deepened, the dFCmean decreased (N0~N1 > N2 > N3), whereas the dFCvar peaked during the N2 stage (N0~N1 < N3 < N2). The highest dFCvar during the N2 stage indicated the unstable synchronizations across the entire brain. In the N3 stage, the overall disrupted network integration was observed through the lowest dFCmean and elevated dFCvar, compared with N0 and N1. Conclusively, when the network specificity (dFCmean) breaks down, the consciousness dissipates with increasing variability of information exchange (dFCvar). (shrink)

The brain’s intrinsic activity plays a fundamental role in its function. In normal conditions this activity is responsive to behavioural context, changing as an individual switches between directed tasks and task‐free conditions. A key feature of such changes is the movement of the brain between corresponding critical and sub‐critical states, with these dynamics supporting efficient cognitive processing. Breakdowns in processing efficiency can occur, however, in brain disorders such as depression. It was therefore hypothesised that depressive symptoms would be related to (...) reduced intrinsic activity responsiveness to changes in behavioural state. This was tested in a mixed group of major depressive disorder patients (n = 26) and healthy participants (n = 37) by measuring intrinsic EEG activity temporal structure, quantified with detrended fluctuation analysis (DFA), in eyes‐closed and eyes‐open task‐free states and contrasting between the conditions. The degree to which DFA values changed between the states was found to be negatively correlated with depressive symptoms. DFA values did not differ between states at all in those with higher symptom levels, meaning that the brain remained in a less flexible sub‐critical condition. This sub‐critical condition in the eyes‐closed state was further found to correlate with levels of maladaptive rumination. This may reflect a general cognitive inflexibility resulting from a lack in neural activity reactivity that may predispose people to overly engage in self‐directed attention. These results provide an initial link between intrinsic activity reactivity and psychological features found in psychiatric disorders. (shrink)

Sertraline is one of the most commonly prescribed antidepressants. Major depressive disorder (MDD) is characterized by spontaneous thoughts that are laden with negative affect-a "malignant sadness". Prior neuroimaging studies have identified abnormal resting-state functional connectivity (rsFC) in the spontaneous brain networks of MDD patients. But how antidepressant medication acts to relieve the experience of depression as well as adjust its associated spontaneous networks and mood-regulation circuits remains an open question. In this study, we recruited 22 drug-naïve MDD patients along with (...) 35 normal controls and investigated whether the functional integrity of cortical networks associated with spontaneous thoughts is modulated by sertraline treatment. We attempted to predict post-treatment effects based upon what we observed in the pre-treatment rsFC of drug-naïve MDD patients. In the result, we demonstrated that (1) after the sertraline treatment, the medial temporal lobe of default network (DNMTL) and mood regulation pathway-the fronto-parietal control network (FPCN), the thalamus, and the salience network (SN)-were restored to normal connectivity, relative to the pre-treatment condition; however, the altered connections of FPCN-core DN (DNCORE), FPCN-SN, and intra-FPCN among MDD patients remained impaired; (2) thalamo-prefrontal connectivity provides moderate predictive power (r2 = 0.63) for the effectiveness of sertraline treatment. In summary, our findings contribute to a body of evidence that suggests salubrious effects of sertraline treatment primarily involve the FPCN-thalamus-SN pathway. The pre-treatment rsFC in this pathway could serve as a predictor of sertraline treatment outcome. (shrink)

Some theories of consciousness emphasize its relationship to language, its emergent quality, and its causal role. Prominent among these theories is the one that Dennett has been developing for nearly four decades. According to Dennett’s most recent version, consciousness is a kind of cerebral clout. But consideration of examples of pain—arguably the best candidate on offer for a paradigm of consciousness—reveals that clout is neither necessary nor sufficient for consciousness. Moreover, pain doesn’t necessarily have the aftermath that is predicted by (...) Dennett’s Clout Theory (CT); pain cannot always be accommodated by Dennett’s methodology; and, pain does not always conform to Dennett’s proposed ontology. Dennett might wish to substitute episodic memory as a preferred paradigm for consciousness, but episodic memory is shown to be non-essential. And, were it to be treated as a paradigm of consciousness, it would create new explanatory problems for CT. Rather than abandoning CT, because it does seem to help explain some pain phenomena and because it does comport well with certain views of language, I propose that some of its more intriguing proposals be retained and treated as hypotheses to guide further empirical inquiry. Finally, I recommend some specific empirical cases wherein relevant research might be pursued. (shrink)

Cerebrospinal fluid (CSF) is a fluidic part of the brain’s microenvironment that isolates the brain from the rest of the body. CSF dilutes metabolites from neuronal activities and removes them from the brain. Its production and resorption are regulated dynamically and are central to maintaining brain homeostasis. We discovered that the major CSF source, the choroid plexus (CP), harbors the brain’s strongest circadian clock. Here, we consider some implications of the CP circadian clock for metabolite clearance in the brain. If (...) the circadian clock contributes to timed production of the CSF, its synchronization with sleep timing can maximize clearance efficiency and help prevent neurodegenerative diseases such as Alzheimer’s disease. (shrink)

Patient suffering of major depressive disorder (MDD) often complain that subjective time seems to “drag” with respect to physical time. This may point toward a generalized dysfunction of temporal processing in MDD. In the present study, we investigated temporal preparation in MDD. “Temporal preparation” refers to an increased readiness to act before an expected event; consequently, reaction time should be reduced. MDD patients and age-matched controls were required to make a saccadic eye movement between a central and an eccentric visual (...) target after a variable duration preparatory period. We found that MDD patients produced a larger number of premature saccades, saccades initiated prior to the appearance of the expected stimulus. These saccades were not temporally controlled; instead, they seemed to reflect reduced inhibitory control causing oculomotor impulsivity. In contrast, the latency of visually guided saccades was strongly influenced by temporal preparation in controls; significantly less so, in MDD patients. This observed reduced temporal preparation in MDD was associated with a faster decay of short-term temporal memory. Moreover, in patients producing a lot of premature responses, temporal preparation to early imperative stimuli was increased. In conclusion, reduced temporal preparation and short-term temporal memory in the oculomotor domain supports the hypothesis that temporal processing was altered in MDD patients. Moreover, oculomotor impulsivity interacted with temporal preparation. These observed deficits could reflect other underlying aspects of abnormal time experience in MDD. (shrink)

Susceptibility to the rubber hand illusion (RHI) varies. To date, however, there is no consensus explanation of this variability. Previous studies, focused on the role of multisensory integration, have searched for neural correlates of the illusion. But those studies have failed to identify a sufficient set of functionally specific neural correlates. Because some evidence suggests that frontal α power is one means of tracking neural instantiations of self, we hypothesized that the higher the frontal α power during the eyes-closed resting (...) state, the more stable the self. As a corollary, we infer that the more stable the self, the less susceptible are participants to a blurring of boundaries—to feeling that the rubber hand belongs to them. Indeed, we found that frontal α amplitude oscillations negatively correlate with susceptibility. Moreover, since lower frequencies often modulate higher frequencies, we explored the possibility that this might be the case for the RHI. Indeed, some evidence suggests that high frontal α power observed in low-RHI participants is modulated by δ frequency oscillations. We conclude that while neural correlates of multisensory integration might be necessary for the RHI, sufficient explanation involves variable intrinsic neural activity that modulates how the brain responds to incompatible sensory stimuli. (shrink)

Objective: Alterations in psychomotor dimension cut across different psychiatric disorders, such as schizophrenia (SCZ) and bipolar disorder (BD). This preliminary study aimed to investigate the organization of intrinsic brain activity in the subcortical-cortical sensorimotor system in SCZ (and BD) as characterized according to psychomotor dimension. -/- Method: In this resting-state functional magnetic resonance imaging (fMRI) study, functional connectivity (FC) between thalamus and sensorimotor network (SMN), along with FC from substantia nigra (SN) and raphe nuclei (RN) to basal ganglia (BG) and (...) thalamic regions, were investigated by using an a-priori-driven and dimensional approach. This was done in two datasets: SCZ patients showing inhibited psychomotricity (n = 18) vs. controls (n = 19); SCZ patients showing excited psychomotricity (n = 20) vs. controls (n = 108). Data from a third dataset of BD in inhibited depressive or manic phases (reflecting inhibited or excited psychomotricity) were used as control. -/- Results: SCZ patients suffering from psychomotor inhibition showed decreased thalamus-SMN FC toward around-zero values paralleled by a concomitant reduction of SN-BG/thalamus FC and RN-BG/thalamus FC (as BD patients in inhibited depression). By contrast, SCZ patients suffering from psychomotor excitation exhibited increased thalamus-SMN FC toward positive values paralleled by a concomitant reduction of RN-BG/thalamus FC (as BD patients in mania). -/- Conclusions: These findings suggest that patients exhibiting low or high levels of psychomotor activity show distinct patterns of thalamus-SMN coupling, which could be traced to specific deficit in SN- or RN-related connectivity. Notably, this was independent from the diagnosis of SCZ or BD, supporting an RDoC-like dimensional approach to psychomotricity. (shrink)