Interactions of the mediodorsal thalamus and the prefrontal cortex support cognitive flexibility

Abstract

Cognitive control has long been a central problem of neuroscience. Recent experimental findings suggest that several subcortical regions are implicated in mediating brain function which is a significant shift from the cortico-centric paradigm. One of them, the mediodorsal thalamic nucleus, has been shown to influence prefrontal function. Yet, understanding of the function performed by this thalamocortical circuit and its place in the cognitive control system is limited and requires further investigation. A neural network model of mediodorsal-prefrontal function is used in a series of computational experiments to investigate the link between the topological properties of the brain connectivity and the function of the mediodorsal thalamus. The results of the present research are twofold. It began by further developing network theory methodology utilizing artificial neural networks. Accordingly, the encoding of the functional content of a brain region is facilitated by the connectivity and neurochemical properties of its neurons. Second, this methodology is used in the in silico investigation of recent phenomena related to the function of the mediodorsal thalamus. Computational modeling suggests that the function of the mediodorsal thalamus is primarily associated with the neuromodulatory properties of its efferent projections. Furthermore, computational experiments show how this function contributes to cognitive flexibility. Additionally, computational experiments suggest a link between suppression in the activity of the mediodorsal thalamus and disruption of prefrontal activity, one of the most common symptoms of schizophrenia.