Unique and shared roles of the posterior parietal and dorsolateral prefrontal cortex in cognitive functions

Abstract

The dorsolateral prefrontal cortex (PFC) and posterior parietal cortex (PPC) are two parts of a broader brain network involved in the control of cognitive functions such as working-memory, spatial attention, and decision-making. The two areas share many functional properties and exhibit similar patterns of activation during the execution of mental operations. However, neurophysiological experiments in non-human primates have also documented subtle differences, revealing functional specialization within the fronto-parietal network. These differences include the ability of the PFC to influence memory performance, attention allocation, and motor responses to a greater extent, and to resist interference by distracting stimuli. In recent years, distinct cellular and anatomical differences have been identified, offering insights into how functional specialization is achieved. This article reviews the common functions and functional differences between the PFC and PPC, and their underlying mechanisms.

Keywords: attention; intraparietal sulcus; monkey; neuron; neurophysiology; persistent activity; principal sulcus.

Figure 1

Schematic diagrams of the lateral surface the macaque monkey. (A) Anterior half of monkey brain including the prefrontal cortex, adapted after Preuss and Goldman-Rakic [Preuss and Goldman-Rakic (1991)]. (B) Alternative map of prefrontal cortical areas, based on Petrides and Pandya [Petrides and Pandya (1994)]. (C) Posterior half of the monkey brain including the posterior parietal cortex. Inset depicts an unfolded view of the intraparietal sulcus Rawley and Constantinidis (2009). (D) Map of the posterior parietal cortex based on Pandya and Seltzer [Pandya and Seltzer (1982)]. Abbreviations: AIP, anterior intraparietal area; AS, arcuate sulcus; CIP, caudal intraparietal area; CS, central sulcus; DP, dorsal prelunate area; IPS, intraparietal sulcus; LIP, lateral intraparietal area; LS, lunate sulcus; MIP, medial intraparietal area; PS, principle sulcus; STS, superior temporal sulcus; VIP, ventral intraparietal area.

Figure 2

Neuronal activity representing a salient stimulus. Schematic illustration of a post-stimulus time histogram representing neuronal responses to two stimulus conditions. Insets depict the salient stimulus appearance in (red) or out (gray) of the neuron's receptive field (dotted line). Vertical arrow indicates the time of neuronal target discrimination. The diagram was constructed based on the results of Thompson and colleagues [Thompson et al. (1997)].

Figure 3

Schematic illustration of neuronal responses with persistent activity in the prefrontal and posterior parietal cortex. Gray bars indicate times of stimulus presentations. Red and blue lines represent the activity of the prefrontal cortex and the posterior parietal cortex, respectively. Insets above the gray bars illustrate examples of stimulus location relative to the receptive field depicted with dotted curve. (A) Sustained activity following appearance of the cue in the receptive field. Both the prefrontal and posterior parietal cortex continuously sustained activity higher than the baseline (horizontal dotted line) after the cue offset. (B) Anticipatory activity following appearance of the cue out of the receptive field. No activity was elicited by the stimulus; activity accelerated during the delay period. (C) Responses to the cue in the receptive field followed by a non-match stimulus out of the receptive field. Prefrontal neurons maintained activity during the delay period after the second stimulus (distractor) was presented whereas the activity of the posterior parietal went back to baseline. The diagrams were constructed based on the results of Qi and colleagues [Qi et al. (2010)].