Task switching

…perform perceptual decision-making tasks that involve different underlying computations and vary in complexity. However, the circuit mechanisms enabling such large-scale activity reorganization remain unknown. An interesting possibility is that they depend on neuromodulatory input to the cortex. In particular, cholinergic neurons in the basal forebrain project widely across cortical areas while exhibiting topographical and functional heterogeneity. They are therefore well equipped to serve as an orchestrator

Schizophrenia is a complex disorder known for its positive symptoms: delusions and hallucinations. However, the impact of schizophrenia on function is mostly due to its executive dysfunction. Mechanistically, it is known that the prefrontal cortex (PFC) is dysfunctional in this disorder and that there is a general excitatory/inhibitory (E/I) imbalance in the schizophrenia brain. However, whether schizophrenia executive dysfunction can be specifically attributed to prefrontal E/I imbalance is unknown. Here, through a series of experiments across schizophrenia-relevant mouse models, we show the

Cognitive flexibility is a function of the prefrontal cortex (PFC) that allows shifting strategies to adjust performance in changing environments. The dorsal raphe nucleus (DRN) provides most of the serotonergic inputs to the PFC. Clinical and pharmacological evidence suggests that prefrontal impairments or serotonergic alterations affect cognitive flexibility. However, the neuronal correlates of cognitive flexibility are largely unknown, and whether modulation of the neuronal activity in the DRN affects flexible behaviors remains unclear. We investigated how projections from the DRN modulate

Flexibly switching between tasks is crucial for goal-directed adaptive behavior. Task switches require inhibition of the no-longer relevant and updating of the newly relevant task set, resulting in lower performance on trials requiring a task switch vs. repetition (i.e., switch costs). While children show greater switch costs than adults, theorized to be partly due to less distinct task-set representations, age differences can be mitigated by training. Studies in adults suggest that neural task-set representations become more distinct with training, enabling more effective processing in the la

The Default Mode Network (DMN) is a task-negative network composed of mainly cortical areas with elevated activity during ‘autopilot’ states and decreased activity during goal-directed behavior. Work from our laboratory implicates a basal forebrain node, the ventral pallidum (VP), in the regulation of DMN, suggesting that it dramatically impacts transitions between internally and externally guided behaviors. While VP activation has been shown to positively correlate with DMN upregulation and vice versa, it remains unclear which efferent VP neural pathways mediate these effects. We examine this

…a range of visual executive function tasks (working memory, task switching, planning, inhibition) show that deaf individuals specifically recruit superior temporal “auditory” regions during task switching. Neural activity in auditory regions predicts behavioural performance during task switching in deaf individuals, highlighting the func

To survive in the uncertain world, humans and animals must pick the right task to perform in each situation and flexibly switch between tasks when they infer that the environment has changed. Yet such flexibility comes at a cost. Task performance decreases when the relevance of the task is uncertain. Here we present multiple lines of evidence from monkey electrophysiology, human psychophysics, and artificial neural networks demonstrating a neuronal mechanism that inflicts a cost of flexibility. In a behavioral paradigm designed to measure and manipulate subjects’ belief about the relevance of

…of control facilitate flexible task switching at the expense of the stability needed to support goal-directed behavior in face of distraction. We formulate this problem in a dynamical system, in which control signals are represented as attractors and in whic