The mediodorsal nucleus of the thalamus (MD) is reciprocally connected with the prefrontal cortex (PFC), and although the MD has been implicated in a range of PFC-dependent cognitive functions (Watanabe and Funahashi, 2012; Mitchell and Chakraborty, 2013; Parnaudeau et al., 2018), little is known about how MD neurons in the primate participate specifically in cognitive control, a capability that reflects the ability to use contextual information (such as a rule) to modify responses to environmental stimuli. To learn how the MD-PFC thalamocortical network is engaged to mediate forms of cognitive control that are selectively disrupted in schizophrenia, we trained male monkeys to perform a variant of the AX continuous performance task, which reliably measures cognitive control deficits in patients (Henderson et al., 2012) and used linear multielectrode arrays to record neural activity in the MD and PFC simultaneously. We found that the two structures made clearly different contributions to distributed processing for cognitive control: MD neurons were specialized for decision-making and response selection, whereas prefrontal neurons were specialized to preferentially encode the environmental state on which the decision was based. In addition, we observed that functional coupling between MD and PFC was strongest when the decision as to which of the two responses in the task to execute was being made. These findings delineate unique contributions of MD and PFC to distributed processing for cognitive control and characterized neural dynamics in this network associated with normative cognitive control performance.
Bibliographical noteFunding Information:
This work was supported by the National Institutes of Health (R01MH107491, F31MH109238, and T32GM847121), Minnesota’s Discovery, Research, and Innovation Economy Neuromodulation Fellowship (Mn-DRIVE), and the American Brain Sciences Chair. This material is the result of work supported with resources and the use of facilities at the Veteran’s Affairs Medical Center in Minneapolis, MN. We thank David Redish and Sophia Vinogradov for their important insights regarding the relation of this work to state representation and cognitive
Copyright © 2020 the authors
Copyright 2020 Elsevier B.V., All rights reserved.
- Cognitive control
- MD thalamus