This paper compares the free energy neuroscience now advocated by Karl Friston and his colleagues with that hypothesised by Freud, arguing that Freud's notions of conflict and trauma can be understood in terms of computational complexity. It relates Hobson and Friston's work on dreaming and the reduction of complexity to contemporary accounts of dreaming and the consolidation of memory, and advances the hypothesis that mental disorder can be understood in terms of computational complexity and the mechanisms, including synaptic pruning, that (...) have evolved to reduce it. (shrink)

The main concepts of the free energy (FE) neuroscience developed by Karl Friston and colleagues parallel those of Freud's Project for a Scientific Psychology. In Hobson et al. ( 2014 ) these include an innate virtual reality generator that produces the fictive prior beliefs that Freud described as the primary process. This enables Friston's account to encompass a unified treatment—a complexity theory—of the role of virtual reality in both dreaming and mental disorder. In both accounts the brain operates to minimize (...) FE aroused by sensory impingements—including interoceptive impingements that report compliance with biological imperatives—and constructs a representation/model of the causes of impingement that enables this minimization. In Friston's account (variational) FE equals complexity minus accuracy, and is minimized by increasing accuracy and decreasing complexity. Roughly the brain (or model) increases accuracy together with complexity in waking. This is mediated by consciousness-creating active inference—by which it explains sensory impingements in terms of perceptual experiences of their causes. In sleep it reduces complexity by processes that include both synaptic pruning and consciousness/virtual reality/dreaming in REM. The consciousness-creating active inference that effects complexity-reduction in REM dreaming must operate on FE-arousing data distinct from sensory impingement. The most relevant source is remembered arousals of emotion, both recent and remote, as processed in SWS and REM on “active systems” accounts of memory consolidation/reconsolidation. Freud describes these remembered arousals as condensed in the dreamwork for use in the conscious contents of dreams, and similar condensation can be seen in symptoms. Complexity partly reflects emotional conflict and trauma. This indicates that dreams and symptoms are both produced to reduce complexity in the form of potentially adverse (traumatic or conflicting) arousals of amygdala-related emotions. Mental disorder is thus caused by computational complexity together with mechanisms like synaptic pruning that have evolved for complexity-reduction; and important features of disorder can be understood in these terms. Details of the consilience among Freudian, systems consolidation, and complexity-reduction accounts appear clearly in the analysis of a single fragment of a dream, indicating also how complexity reduction proceeds by a process resembling Bayesian model selection. (shrink)

Emotion regulation (i.e. either up- or down-regulating affective responses to emotional stimuli) has been shown to modulate long-term emotional memory formation. Further, research has demonstrated that the emotional aspects of scenes are preferentially remembered relative to neutral aspects (known as the emotional memory trade-off effect). This trade-off is often enhanced when sleep follows learning, compared to an equivalent period of time spent awake. However, the interactive effects of sleep and emotion regulation on emotional memory are poorly understood. We presented 87 (...) participants with pictures of neutral or negative objects on neutral backgrounds paired with instructions to either increase or decrease their emotional response by altering personal relevance, or to passively view the stimuli. Following a 12 h period of sleep or wakefulness, participants were tested for their memory of objects and backgrounds separately. Although we replicated the emotional memory trade-off effect, no differences in the magnitude of the trade-off effect were observed between regulation conditions. Sleep improved all aspects of memory, but it did not preferentially benefit memory for emotional components of scenes. Irrespective of a period of sleep or wake following encoding, findings suggest emotion regulation during encoding did not influence memory for emotional items at a 12-hour delay. (shrink)