Increased neuronal firing in resting and sleep in areas of the macaque medial prefrontal cortex

Authors

  • Paul L. Gabbott,

    Corresponding author
    1. Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes, MK, UK
    2. Neural Architectonics Centre, Oxford, UK
    • Department of Experimental Psychology, University of Oxford, Oxford, UK
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  • Edmund T. Rolls

    1. Oxford Centre for Computational Neuroscience, Oxford, UK
    2. Department of Computer Science, University of Warwick, Coventry, UK
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Correspondence: Dr P. L. Gabbott, as above.

E-mail: p.l.gabbott@open.ac.uk

Abstract

The medial prefrontal cortex (mPFC) of humans and macaques is an integral part of the default mode network and is a brain region that shows increased activation in the resting state. A previous paper from our laboratory reported significantly increased firing rates of neurons in the macaque subgenual cingulate cortex, Brodmann area (BA) 25, during disengagement from a task and also during slow wave sleep [E.T. Rolls et al. (2003) J. Neurophysiology, 90, 134–142]. Here we report the finding that there are neurons in other areas of mPFC that also increase their firing rates during disengagement from a task, drowsiness and eye-closure. During the neurophysiological recording of single mPFC cells (n = 249) in BAs 9, 10, 13 m, 14c, 24b and especially pregenual area 32, populations of neurons were identified whose firing rates altered significantly with eye-closure compared with eye-opening. Three types of neuron were identified: Type 1 cells (28.1% of the total population) significantly increased (mean + 329%; P ≪ 0.01) their average firing rate with eye-closure, from 3.1 spikes/s when awake to 10.2 spikes/s when asleep; Type 2 cells (6.0%) significantly decreased (mean −68%; < 0.05) their firing rate on eye-closure; and Type 3 cells (65.9%) were unaffected. Thus, in many areas of mPFC, implicated in the anterior default mode network, there is a substantial population of neurons that significantly increase their firing rates during periods of eye-closure. Such neurons may be part of an interconnected network of distributed brain regions that are more active during periods of relaxed wakefulness than during attention-demanding tasks.

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