Cytoarchitecture and cortical connections of the anterior cingulate and adjacent somatomotor fields in the rhesus monkey

Abstract

The cytoarchitecture and cortical connections of the anterior cingulate, medial and dorsal premotor, and precentral region are investigated using the Nissl and NeuN staining method and the fluorescent retrodgrade tract tracing technique. There is a gradual stepwise laminar change in the cytoarchitectonic organization from the proisocortical anterior cingulate region, through the lower and upper banks of the cingulate sulcus, to the dorsolateral isocortical premotor and precentral motor regions of the frontal lobe. These changes are characterized by a gradational emphasis on the lower stratum layers (V and VI) in the proisocortical cingulate region to the upper stratum layers (II and III) in the premotor and precentral motor region. This is accompanied by a progressive widening of layers III and VI, a poorly delineated border between layers III and V and a sequential increase in the size of layer V neurons culminating in the presense of giant Betz cells in the precentral motor region. The overall patterns of corticocortical connections paralleled the sequential changes in cytoarchitectonic organization. The proisocortical areas have connections with cingulate motor, supplementary motor, premotor and precentral motor areas on the one hand and have widespread connections with the frontal, parietal, temporal and multimodal association cortex and limbic regions on the other. The dorsal premotor areas have connections with the proisocortical areas including cingulate motor areas and supplementary motor area on the one hand, and premotor and precentral motor cortex on the other. Additionally, this region has significant connections with posterior parietal cortex and limited connections with prefrontal, limbic and multimodal regions. The precentral motor cortex also has connections with the proisocortical areas and premotor areas. Its other connections are limited to the somatosensory regions of the parietal lobe. Since the isocortical motor areas on the dorsal convexity mediate voluntary motor function, their close connectional relationship with the cingulate areas form a pivitol limbic-motor interface that could provide critical sources of cognitive, emotional and motivational influence on complex motor function.

A Variable Oscillator Underlies the Measurement of Time Intervals in the Rostral Medial Prefrontal Cortex during Classical Eyeblink Conditioning in Rabbits

“…Both of them receive a well defined projection from the medial half of the thalamic mediodorsal nucleus (Benjamin et al, 1978;Ray et al, 1992;Kronforst-Collins and Disterhoft, 1998;Leal-Campanario et al, 2007). The neurons recorded here are located in the rostral site of area 24 (anterior cingulate cortex) and the rostrodorsal part of area 32 (prelimbic cortex), but not in the area 24c involved in facial expression in monkeys (Buchanan et al, 1994;Morecraft et al, 2001Morecraft et al, , 2012.…”

“…In addition, caudal mPFC and dorsolateral PFC neurons present firing activities that persist during the CS-US interval in trace conditioning paradigms, helping in the generation of timed conditioned eyeblinks (Weiss and Disterhoft, 2011;Siegel and Mauk, 2013). Moreover, rmPFC neural signals can reach the hippocampus either directly or across the thalamic reuniens nucleus (McKenna and Vertes, 2004).…”

Connectivity reveals relationship of brain areas for reward-guided learning and decision making in human and monkey frontal cortex

“…A slightly more ventral area, d32, resembled the region active when decisions have to be made about whether rewards are worth the cost of foraging (10). Although it has been argued that no exact homolog of human d32 exists in the macaque (73), it was notable that its activity coupling pattern resembled that seen in the dorsal part of macaque area 32, which is in the anterior cingulate sulcus, a region sometimes called 32(s) (80). A region with a similar coupling pattern in the monkey has also been associated with cost-benefit decision making (11).…”

Selectivity for space and time in early areas of the auditory dorsal stream in the rhesus monkey

“…Connections of the caudal belt (and of neighboring areas of the posterior temporal lobe) with the dorsolateral regions of prefrontal, premotor, and posterior parietal cortex have been reported (Lewis and Van Essen 2000;Morecraft et al 2012;Romanski et al 1999aRomanski et al , 1999bSmiley et al 2007;Ward et al 1946). These regions are implicated in the proposed model of the auditory dorsal stream (Rauschecker 2011(Rauschecker , 2012.…”