Impaired performance in verbal fluency tasks is a frequent observation in Parkinson’s disease. As to the nature of the underlying cognitive deficit, it is commonly attributed to a frontal-type dysexecutive syndrome due to nigrostriatal dopamine depletion. Whereas dopaminergic medication typically improves VF performance in PD, e.g., by ameliorating impaired lexical switching, its effect on semantic network activation is unclear. Data from priming studies suggest that dopamine causes a faster decay of semantic activation spread. The aim of the current study was (...) to examine the impact of dopaminergic medication on the dynamic change of word frequency during VF performance as a measure of semantic spreading activation. To this end, we performed a median split analysis of word frequency during phonemic and semantic VF task performance in a PD group tested while receiving dopaminergic medication as well as after drug withdrawal, and in a sample of age-matched healthy volunteers. Dopaminergic medication in the PD group significantly affected phonemic VF with improved word production as well as increased error-rates. The expected decrease of word frequency during VF task performance was significantly smaller in the PD group ON medication than in healthy volunteers across semantic and phonemic VF. No significant group-difference emerged between controls and the PD group in the OFF condition. The comparison between both treatment conditions within the PD group did not reach statistical significance. The observed pattern of results indicates a faster decay of semantic network activation during lexical access in PD patients on dopaminergic medication. In view of improved word generation, this finding is consistent with a concept of more focused neural activity by an increased signal-to-noise ratio due to dopaminergic neuromodulation. However, the effect of dopaminergic stimulation on VF output suggests a trade-off between these beneficial effects and increased error-rates. (shrink)

Theorists have found it difficult to reconcile the unity of inner speech as a mental state kind with the diversity of its manifestations. I argue that existing views concerning the content of inner speech fail to accommodate both of these features because they mistakenly assume that its content is to be found in the ‘speech processing hierarchy’, which includes semantic, syntactic, phonemic, phonetic, and articulatory levels. Upon rejecting this assumption, I offer a position on which the content of inner speech (...) is determined by voice processing, of which speech processing is but one component. The resulting view does justice to the idea that inner speech is a motley assortment of episodes that nevertheless form a kind. (shrink)

Recent scholarship emphasizes the scaffolding role of language for cognition. Language, it is claimed, is a cognition-enhancing niche (Clark, 2006), a programming tool for cognition (Lupyan and Bergen, 2016), even a neuroenhancement (Dove, 2019), and augments cognitive functions such as memory, categorization, cognitive control as well as meta-cognitive abilities (‘thinking about thinking’). Yet the notion that language enhances or augments cognition does not fit in with embodied approaches to language processing, or so we will argue. Accounts aiming to explain how (...) language enhances various cognitive functions often employ a notion of abstract representation. Yet embodied approaches to language processing have it that language processing crucially, according to some accounts even exclusively, involves embodied, modality-specific, i.e. non-abstract representations. In coming to understand a particular phrase or sentence, a prior experience has to be simulated or reenacted. The representation thus activated is embodied (modality-specific) as sensorimotor regions of the brain are thereby recruited. In the paper, we will first discuss the notion of representation, clarify what it takes for a representation to be embodied or abstract respectively, and distinguish between conceptual and (other) linguistic representations. We will then put forward a characterization of cognitive control and examine its representational infrastructure. The remainder of the paper will be devoted to arguing that language augments cognitive control. To that end, we will draw on two lines of research, which investigate how language augments cognitive control: i. research on the availability of linguistic labels, and ii. research on the active usage of a linguistic code, specifically in inner speech. Eventually, we will argue that the cognition-enhancing capacity of language can be explained once we assume that it provides us with a. abstract, non-embodied representations, and with b. abstract, sparse linguistic representations that may serve as easy-to-manipulate placeholders for fully embodied or otherwise more detailed representations. (shrink)