FUNCTIONAL VALUE AND SPATIAL ATTENTION SIGNALS OCCUPY TOPOGRAPHICAL HUBS IN THE MACAQUE FRONTO-CINGULATE CORTEX

For behaviourally relevant choices to be made a variety of bottom-up sensory cues from the environment and top-down signals from the brain must integrate in a context dependent manner in order to optimize behaviour. Of these signals the location and value of potential stimuli are of critical importance. We tested the hypothesis that the neural correlates of these signals are present and integrate in cortical hubs across the fronto-cingulate axis. Furthermore we postulated that failure of this recruitment of information would result in suboptimal performance (errors). We recorded from 811 single cells across the fronto- cingulate cortex in areas, 24a/b/c, 32, 10, 8, 8b, 9 and 46 from two male rhesus macaques. Using a variant of a well-established paradigm eliciting specific rule guided behaviour we were able to independently analyze and map the neural correlates of spatial attention and reward value. We discovered four functional clusters that convey attentional rule signals in the lateral prefrontal cortex (IPFC) and anterior cingulate cortex (ACC). We also found that clusters of neurons coding value intersected with spatial attention signals in the ACC when value was high and in the IPFC when value of the cued target was low. Absence of neural activity in these clusters during periods of shifting attention was associated with errors. Therefore we concluded that reward value-expectancy and spatial attention selection signals, which are part of a larger cognitive control network, exist and are integrated in confined functional hubs of the fronto-cingulate cortex