Dynamic Encoding of Responses and Outcomes by Neurons in Medial Prefrontal Cortex

Abstract

Medial prefrontal cortex (MPFC) and lateral prefrontal cortex (LPFC) both contribute to goal-directed behavior, but their precise role remains unclear. Several lines of evidence suggest that MPFC is more important than LPFC for outcome-guided response selection. To examine this, we trained two subjects to perform a task that required them to monitor the specific outcome associated with a specific response on a trial-by-trial basis. While the subjects performed this task, we recorded the electrical activity of single neurons simultaneously from MPFC and LPFC. There were marked differences in the neuronal properties of these two areas. Neurons encoding the response were present in both areas, but in MPFC, there were also neurons that encoded the outcome. In particular, neurons encoded the subject's intended response and how preferable the received outcome was. Thus, only in MPFC was all the information necessary to solve the task encoded. In addition, largely separate populations of MPFC neurons encoded the response and the outcome. Neurons encoding the outcome were in the anterior parts of MPFC: posterior to the corpus callosum, there was a marked drop in their incidence. Our results suggest differences in the contribution of MPFC and LPFC to action control. MPFC neurons encode the desirability of the outcome produced by a specific response on a trial-by-trial basis. This capability may contribute to several of the functions of MPFC, such as action valuation, error detection, and decision making.

Treatment with Olanzapine is Associated with Modulation of the Default Mode Network in Patients with Schizophrenia

“…Olanzapine modulates default mode network in schizophrenia F Sambataro et al This brain region has an important role in decision making as well as in emotion and motivation associated with a cognitive task. Neurons in vmPFC encode the relative current value and the outcome of chosen options during decisions by comparing available options (Boorman et al, 2009;Luk and Wallis, 2009). In addition, vmPFC regulates both the emotional context and motivational milieu during a cognitive task (Groenewegen and Uylings, 2000) so that this region inhibits emotional processing that may interfere with cognitive performance in a 'dynamic interplay' with the regions of DMN anticorrelated network and specifically DLPFC (Longe et al, 2009).…”

Reward Prediction Error Computation in the Pedunculopontine Tegmental Nucleus Neurons

“…From where does the PPTN receive this motivational or reward prediction signal? The fixation target neurons may receive the signals of reward prediction from the orbitofrontal cortex (Tremblay & Schultz, 1999;Hikosaka & Watanabe, 2000;Roesch & Olson, 2004;Simmons & Richmond, 2008), prefrontal cortex (Kitazawa et al, 1998;Leon & Shadlen, 1999;Roesch & Olson, 2003;Kennerley & Wallis, 2009;Luk & Wallis, 2009), cingulated cortex (Cornwall et al, 1990), striatum (Mena-Segovia et al, 2004;Hikosaka et al, 2006;Winn, 2006) or hippocampus (Yang & Mogenson, 1987). We propose that the signals travel via 1) the ventral striatum-ventral pallidum pathway, which receives input mainly from the limbic cortex (Yang & Mogenson, 1987;Schultz et al, 1992;Brown et al, 1999), 2) the amygdala and the subthalamic nucleus (Semba & Fibiger, 1992), and 3) the cerebral cortices.…”

Frontal Oscillatory Dynamics Predict Feedback Learning and Action Adjustment

“…The importance of MFC for action-outcome learning is supported by single-cell recordings in monkey MFC. For example, MFC neurons seem to represent both desired outcomes and the responses to acquire them (Luk & Wallis, 2009;Matsumoto, Suzuki, & Tanaka, 2003). Activity of MFC neurons also differentiates to-be-learned from already-learned responses (Quilodran, Rothe, & Procyk, 2008;Matsumoto, Matsumoto, Abe, & Tanaka, 2007).…”