Patterns of afferent input to the caudal and rostral areas of the dorsal premotor cortex (6DC and 6DR) in the marmoset monkey

Abstract

Corticocortical projections to the caudal and rostral areas of dorsal premotor cortex (6DC and 6DR, also known as F2 and F7) were studied in the marmoset monkey. Both areas received their main thalamic inputs from the ventral anterior and ventral lateral complexes, and received dense projections from the medial premotor cortex. However, there were marked differences in their connections with other cortical areas. While 6DR received consistent inputs from prefrontal cortex, area 6DC received few such connections. Conversely, 6DC, but not 6DR, received major projections from the primary motor and somatosensory areas. Projections from the anterior cingulate cortex preferentially targeted 6DC, while the posterior cingulate and adjacent medial wall areas preferentially targeted 6DR. Projections from the medial parietal area PE to 6DC were particularly dense, while intraparietal areas (especially the putative homolog of LIP) were more strongly labeled after 6DR injections. Finally, 6DC and 6DR were distinct in terms of inputs from the ventral parietal cortex: projections to 6DR originated preferentially from caudal areas (PG and OPt), while 6DC received input primarily from rostral areas (PF and PFG). Differences in connections suggest that area 6DR includes rostral and caudal subdivisions, with the former also involved in oculomotor control. These results suggest that area 6DC is more directly involved in the preparation and execution of motor acts, while area 6DR integrates sensory and internally driven inputs for the planning of goal-directed actions. They also provide strong evidence of a homologous organization of the dorsal premotor cortex in New and Old World monkeys.

Thalamic projections to visual and visuomotor areas (V6 and V6A) in the Rostral Bank of the parieto-occipital sulcus of the Macaque

“…Area V6A receives important input from the VL complex, which is regarded as having a primarily motor function, sending fibres to the primary and secondary motor areas (Ilinsky and Kultas-Ilinsky 2002;Kultas-Ilinsky et al 2003;Burman et al 2014). The strong input from VL to V6Ad is in line with the proposed involvement of V6Ad in the on-line control of motor acts .…”

The cortical motor system of the marmoset monkey (Callithrix jacchus)

“…The dorsal premotor region differentiates in caudal (6DC) and rostral (6DR) areas, which show many similarities with areas F2 and F7 of the macaque, respectively (Matelli et al, 1985). The rostral sector of macaque F7 is likely to contain a supplementary eye field (Schlag and SchlagRey, 1987), and a similar organization has been proposed in the marmoset (Burman et al, 2014b).…”

Representation of central and peripheral vision in the primate cerebral cortex: Insights from studies of the marmoset brain

“…Another example of an anatomical gradient which is likely to have functional implications was described by Schall et al (1995), who reported that information from the central and peripheral visual fields converges on different segments of the macaque frontal eye field, which in turns mediate different types of eye movements. In the marmoset, projections from visual areas to prefrontal and premotor areas also tend to originate in representations of peripheral vision (Reser et al, 2013;Burman et al, 2014).…”