Motor and non‐motor projections from the cerebellum to rostrocaudally distinct sectors of the dorsal premotor cortex in macaques

Abstract

In the caudal part of the dorsal premotor cortex of macaques (area F2), both anatomical and physiological studies have identified two rostrocaudally separate sectors. The rostral sector (F2r) is located medial to the genu of the arcuate sulcus, and the caudal sector (F2c) is located lateral to the superior precentral dimple. Here we examined the sites of origin of projections from the cerebellum to F2r and F2c. We applied retrograde transsynaptic transport of a neurotropic virus, CVS-11 of rabies virus, in macaque monkeys. Three days after rabies injections into F2r or F2c, neuronal labeling was found in the deep cerebellar nuclei mainly of the contralateral hemisphere. After the F2r injection, labeled cells were distributed primarily in the caudoventral portion of the dentate nucleus, whereas cells labeled after the F2c injection were distributed in the rostrodorsal portion of the dentate nucleus, and in the interpositus and fastigial nuclei. Four days after rabies injections, Purkinje cells were densely labeled in the lateral part of the cerebellar cortex. After the F2r injection, Purkinje cell labeling was confined to Crus I and II, whereas the labeling seen after the F2c injection was located broadly from lobules III to VIII, including Crus I and II. These results have revealed that F2c receives inputs from broader areas of the cerebellum than F2r, and that distinct portions of the deep cerebellar nuclei and the cerebellar cortex send major projections to F2r and F2c, suggesting that F2c and F2r may be under specific influences of the cerebellum.

Deficient Use of Visual Information in Estimating Hand Position in Cerebellar Patients

“…This is much in line with the two body representations within the cerebellum, one in the anterior lobe (lobules III-V, with some extensions into VI) and one in the posterior lobe (lobule VIII) (Grodd et al, 2001). These lobules are primarily connected with MI, but also PM (Buckner et al, 2011;Glickstein et al, 2011).…”

“…In earlier work, we have found deficits in more anterior lobules to be associated with reaching adaptation tasks Donchin et al, 2012). In all of our studies, performance on motor tasks has been associated with more than one cerebellar area.…”

“…The overall impression from these studies is that increasingly caudal cerebellar areas are connected to increasingly higher levels of the motor hierarchy. For instance: Kelly and Strick (2003) see MI being connected to lobules IV-VI; Hashimoto et al (2010) find caudal PM connecting to these areas and also Crus I and rostral PM connecting to Crus I and Crus II; Prevosto et al (2010) find posterior parietal cortex being associated primarily with Crus II. In a review of the literature, Glickstein et al (2011) propose just such a gradient, at least for the cerebellar afferents.…”

“…As argued by Ashburner and Friston, the probability of being gray matter can be interpreted as a concentration of gray matter in that voxel (Ashburner and Friston, 2000). The gray matter that an individual subject has associated with a particular voxel in the SUIT template is the volume mapped onto that voxel (under the deformation map described above) multiplied by the concentration of gray matter in that volume as determined by the segmentation algorithm (Donchin et al, 2012). Mapping each patientЈs gray matter concentration map onto the SUIT template gave us a voxel-by-voxel assessment of gray matter associated with every voxel in the SUIT template.…”

Cerebellar fMRI Activation Increases with Increasing Working Memory Demands

“…Connectivity to the premotor, prefrontal, or parietal cortices has been shown in animal experiments for those cerebellar lobules that showed increasing activation following more executive demands in our study. The premotor cortex is target of cerebellar output from lobules V, VI, crus I, crus II, VII, and VIII [44], while the prefrontal cortex is targeted by crus II and-to a lesser degree-the vermis (lobules VII, X) [45]. The parietal cortex receives input primarily not only from lobules VI, crus II, and VIII but also from lobule IX and the posterior vermis (lobules VIII-X) [46].…”