Prefrontal cortex influences behavior largely through its connections with other association cortices; however, the nature of the information conveyed by prefrontal output signals and what effect these signals have on computations performed by target structures is largely unknown. To address these questions, we simultaneously recorded the activity of neurons in prefrontal and posterior parietal cortices of monkeys performing a rule-based spatial categorization task. Parietal cortex receives direct prefrontal input, and parietal neurons, like their prefrontal counterparts, exhibit signals that reflect rule-based cognitive processing in this task. By analyzing rapid fluctuations in the cognitive information encoded by activity in the two areas, we obtained evidence that signals reflecting rule-dependent categories were selectively transmitted in a top-down direction from prefrontal to parietal neurons, suggesting that prefrontal output is important for the executive control of distributed cognitive processing.
Bibliographical noteFunding Information:
We thank A. Georgopoulos for fundamental intellectual contributions to, and longstanding support of, this work. We thank P. Goldman-Rakic for critical insights into the network basis of prefrontal cortex function that strongly influenced this study. We thank D. Evans and D. Boeff for excellent technical assistance. We thank J. Ortiz and S. Te Nelson for assistance in training of nonhuman primates. Supported by the US National Institutes of Health (grant R01 MH077779 and R24MH069675), the Department of Veterans Affairs and the American Legion Brain Sciences Chair. R.K. Blackman was supported by US National Institutes of Health grant T32 GM008244. The views and opinions expressed in this work are those of the authors solely and not those of the United States Federal Government.