Prefrontal cortical (PFC) activity in the primate brain emerging from minicolumnar microcircuits plays a critical role in cognitive processes dealing with executive control of behavior. However, the specific operations of columnar laminar processing in prefrontal cortex (PFC) are not completely understood. Here we show via implementation of unique microanatomical recording and stimulating arrays, that minicolumns in PFC are involved in the executive control of behavior in rhesus macaque nonhuman primates (NHPs) performing a delayed-match-to-sample (DMS) task. PFC neurons demonstrate functional interactions between pairs of putative pyramidal cells within specified cortical layers via anatomically oriented minicolumns. Results reveal target-specific, spatially tuned firing between inter-laminar (layer 2/3 and layer 5) pairs of neurons participating in the gating of information during the decision making phase of the task with differential correlations between activity in layer 2/3 and layer 5 in the integration of spatial vs. object-specific information for correct task performance. Such inter-laminar processing was exploited by the interfacing of an online model which delivered stimulation to layer 5 locations in a pattern associated with successful performance thereby closing the columnar loop externally in a manner that mimicked normal processing in the same task. These unique technologies demonstrate that PFC neurons encode and process information via minicolumns which provides a closed loop form of “executive function,” hence disruption of such inter-laminar processing could form the bases for cognitive dysfunction in primate brain.
Keywords: prefrontal cortex, inter-laminar correlated firing, nonhuman primates, columnar correlates of target selection, columnar correlates of task difficulty, spatial vs. object tuning
Citation: Opris I, Fuqua JL, Huettl PF, Gerhardt GA, Berger TW, Hampson RE and Deadwyler SA (2012) Closing the loop in primate prefrontal cortex: inter-laminar processing. Front. Neural Circuits 6:88. doi: 10.3389/fncir.2012.00088
Received: 22 August 2012; Paper pending published: 21 September 2012;
Accepted: 30 October 2012; Published online: 22 November 2012.
Edited by:Steve M. Potter, Georgia Institute of Technology, USA
Reviewed by:Manuel Casanova, University of Louisville, USA
Copyright © 2012 Opris, Fuqua, Huettl, Gerhardt, Berger, Hampson and Deadwyler. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Ioan Opris, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA. e-mail: email@example.com
Sam A. Deadwyler, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA. e-mail: firstname.lastname@example.org