Cognitive Control Signals in Posterior Cingulate Cortex

David V Smith,Benjamin Y Hayden,Michael L Platt

doi:10.3389/fnhum.2010.00223

Abstract

Efficiently shifting between tasks is a central function of cognitive control. The role of the default network – a constellation of areas with high baseline activity that declines during task performance – in cognitive control remains poorly understood. We hypothesized that task switching demands cognitive control to shift the balance of processing toward the external world, and therefore predicted that switching between the two tasks would require suppression of activity of neurons within the posterior cingulate cortex (CGp). To test this idea, we recorded the activity of single neurons in CGp, a central node in the default network, in monkeys performing two interleaved tasks. As predicted, we found that basal levels of neuronal activity were reduced following a switch from one task to another and gradually returned to pre-switch baseline on subsequent trials. We failed to observe these effects in lateral intraparietal cortex, part of the dorsal fronto-parietal cortical attention network directly connected to CGp. These findings indicate that suppression of neuronal activity in CGp facilitates cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain.

Highlights

The ability to switch efficiently between different tasks in the behavioral repertoire is a critical component of cognitive flexibility
These observations suggest that neural activity in CGp, and perhaps the default network more generally, reflects processes that compete with cognitive control processes elsewhere in the brain
Posterior cingulate cortex and task switching region that is directly connected to CGp, but outside the default network. These findings indicate that suppression of neuronal activity in CGp contributes to cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain

Summary

Introduction

The ability to switch efficiently between different tasks in the behavioral repertoire is a critical component of cognitive flexibility. We know almost nothing about the role of the complementary default network in task switching and cognitive control. Because monkeys appear to have a default network homologous with that of humans (Vincent et al, 2006; Hayden et al, 2009), these neuronal effects likely extend to humans as well. These observations suggest that neural activity in CGp, and perhaps the default network more generally, reflects processes that compete with cognitive control processes elsewhere in the brain

Methods

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Conclusion