Mixed selectivity morphs population codes in prefrontal cortex

Abstract

The prefrontal cortex maintains working memory information in the presence of distracting stimuli. It has long been thought that sustained activity in individual neurons or groups of neurons was responsible for maintaining information in the form of a persistent, stable code. Here we show that, upon the presentation of a distractor, information in the lateral prefrontal cortex was reorganized into a different pattern of activity to create a morphed stable code without losing information. In contrast, the code in the frontal eye fields persisted across different delay periods but exhibited substantial instability and information loss after the presentation of a distractor. We found that neurons with mixed-selective responses were necessary and sufficient for the morphing of code and that these neurons were more abundant in the lateral prefrontal cortex than the frontal eye fields. This suggests that mixed selectivity provides populations with code-morphing capability, a property that may underlie cognitive flexibility.

Inhibition in selective attention

“…Fine‐tuning of the target template in relation to distractor features may take place in the lateral prefrontal cortex due to the abundance of neurons with mixed selectivity in this area. A recent study demonstrated that information in working memory in monkey's lateral prefrontal cortex reorganized into a different pattern of activity upon distractor presentation, whereas the same code remained stable in frontal eye fields (FEFs) …”

“…A recent study demonstrated that information in working memory in monkey's lateral prefrontal cortex reorganized into a different pattern of activity upon distractor presentation, whereas the same code remained stable in frontal eye fields (FEFs). 63 A challenge for future work will be to establish how such code morphing or template-to-distractor distinctiveness 17 may help, albeit indirectly, the suppression of distractor processing, especially when targets and distractors are highly similar at the feature level. In particular, it is still unclear whether only the target representation is adjusted, or whether the representation of both targets and distractors can be adapted.…”

Emergence of Chimera-like States in Prefrontal-Cortex Macaque Intracranial Recordings

“…The macaque was trained to perform a delayed saccade task [7]. Electrode arrays of 16-and 32-channels (256 in total), were implanted in the monkey's brain (see fig.…”

“…In this paper, building on these previous works, we seek to study the emergence of spatio-temporal coexisting patterns of synchronized and desynchronized behavior, termed chimeralike states, in neurophysiological signals from a macaque monkey and particularly, from prefrontal-cortex intracranial recordings [7].…”

“…prefrontal-cortex intracranial recordings) when performing a delayed saccade task for 240 successful trials [7], and compute the corresponding phase synchronization among the brain subregions with implanted electrode arrays. In this context, a trial is successful if the monkey remembered correctly the location of the target in which case it received food as a reward.…”