Cortical afferent input to the principals region of the rhesus monkey

Abstract

Abstract-The sources of ipsilateral cortical afferent projections to regions along both banks of the principalis sulcus in the prefrontal cortex were studied with horseradish peroxidase in macaque monkeys. The principalis cortex receives a substantial proportion of its projections from neighboring prefrontal regions. However, differences were noted in the distribution of labeled cells projecting to the various principalis regions. These differences were most marked with respect to the relative proportion of cells originating in visual, auditory, somatosensory, premotor and limbic cortical areas. The findings indicate that the caudal ventral principalis region receives projections from both visual and visuomotor regions, whereas the anterior tip of the principalis appears to be the major target of projections from auditory association regions. The ventral bank at the middle extent of the principalis was the only case with a significant proportion of labeled cells in somatosensory association and premotor regions. There was a consistent increase in the proportion of labeled cells in limbic cortical areas projecting to more rostral principalis sites, irrespective of whether the injection was placed in the dorsal or ventral bank.These findings suggest that the caudal principalis region has a visual-visuomotor and the rostral, an auditorylimbic bias with respect to the long projections they receive.

Functional Connectivity Separates Switching Operations in the Posterior Lateral Frontal Cortex

“…As previous studies found taskswitching-related lateral frontal activity not only in the IFJ but also in more anterior prefrontal regions (Forstmann, Brass, Koch, & von Cramon, 2006;Braver et al, 2003), we predicted IFJ activity during abstract rule switching to be characterized by interactions with regions in anterior portions of the lateral PFC. Likewise, on the basis of previous reports of strong anatomical (Pandya & Barnes, 1987;Barbas & Mesulam, 1985) and functional (Rowe, Stephan, Friston, Frackowiak, & Passingham, 2005;Stephan et al, 2003) connectivity of frontal regions with more posterior motor-related regions during spatial and motor tasks, we expected functional connectivity of the IFJ with these posterior regions to be stronger during switching between motor responses. The finding of a differential connectivity pattern for the two types of switching would support the assumption that the IFJ mediates switching between specific contents (i.e., from one abstract rule to another or from one response mapping to another) via interactions with the relevant processing circuits for the newly relevant task set.…”

Organization of Multisynaptic Inputs from Prefrontal Cortex to Primary Motor Cortex as Revealed by Retrograde Transneuronal Transport of Rabies Virus

“…On the other hand, both ventral and dorsal area 46 neurons responded to delayed oculomotor tasks (Funahashi et al, 1990(Funahashi et al, , 1991. From an anatomical point of view, ventral area 46 and area 12 receive inputs mainly from the posterior parietal cortex (primarily area 7b) and the inferior temporal cortex, respectively (Barbas and Mesulam, 1985;Barbas, 1988;Cavada and Goldman-Rakic, 1989;Seltzer and Pandya, 1989;Carmichael and Price, 1995b). Moreover, it has been shown that posterior parietal neurons respond to forelimb movements as well as to somatosensory or visual stimuli (Dong et al, 1994;Calton et al, 2002).…”

“…On the other hand, located at the rostral pole of the frontal lobe is the prefrontal cortex that consists of multiple, anatomically distinct areas. These prefrontal areas receive inputs from the parietal association, temporal association, and limbic-related cortical areas (Barbas and Mesulam, 1985;Barbas, 1988;Pandya and Yeterian, 1990;Carmichael and Price, 1995a) and, in turn, send outputs to the frontal motorrelated areas (Barbas and Pandya, 1987;Luppino et al, 1993;Lu et al, 1994). It has been proposed that individual areas of the prefrontal cortex play differential roles in the control of voluntary actions according to distinct types of sensory and emotional information.…”

Prefrontal - Hippocampal Interaction: An Integrative Review and Model of the Think/No-Think Task with Implications for Psychiatric Conditions

“…These findings suggest a specific fiber bundle directly linking the MFG with regions of the posterior hippocampal complex [5,26]. Of note, these posterior regions of the hippocampal complex (i.e, retrosplenial cortex, presubiculum) send dense projections back to the MFG (BA9/46), suggesting these areas from a reciprocal neural network [5,26]. To demonstrate the function of this network, ablations to posterior regions of the hippocampal complex result in self-paced working memory (WM) deficits, while ablations to the anterior hippocampal complex (i.e., entorhinal cortex) yield no such deficit, therefore, suggesting that posterior areas are involved in output or retrieval processes of the hippocampus important for WM operations [26].Therefore, the medial pathway connecting the MFG and hippocampus may be of critical interest in the control over memory accessibility.…”

“…Retrograde tracers injected in various areas of the PFC indicate that the MFG (BA9/46) projects to the posterior hippocampal complex, whereas frontal-polar (BA10), posterior dorsolateral PFC (DLPFC; BA8) and ventrolateral PFC (VLPFC; BA44/45/47) do not. These findings suggest a specific fiber bundle directly linking the MFG with regions of the posterior hippocampal complex [5,26]. Of note, these posterior regions of the hippocampal complex (i.e, retrosplenial cortex, presubiculum) send dense projections back to the MFG (BA9/46), suggesting these areas from a reciprocal neural network [5,26].…”