Short-term effects of unilateral lesion of the primary motor cortex (M1) on ipsilesional hand dexterity in adult macaque monkeys

Abstract

Although the arrangement of the corticospinal projection in primates is consistent with a more prominent role of the ipsilateral motor cortex on proximal muscles, rather than on distal muscles involved in manual dexterity, the role played by the primary motor cortex on the control of manual dexterity for the ipsilateral hand remains a matter a debate, either in the normal function or after a lesion. We, therefore, tested the impact of permanent unilateral motor cortex lesion on the manual dexterity of the ipsilateral hand in 11 macaque monkeys, within a time window of 60 days post-lesion. For comparison, unilateral reversible pharmacological inactivation of the motor cortex was produced in an additional monkey. Manual dexterity was assessed quantitatively based on three motor parameters derived from two reach and grasp manual tasks. In contrast to the expected dramatic, complete deficit of manual dexterity of the contralesional hand that persists for several weeks, the impact on the manual dexterity of the ipsilesional hand was generally moderate (but statistically significant) and, when present, lasted less than 20 days. Out of the 11 monkeys, only 3 showed a deficit of the ipsilesional hand for 2 of the 3 motor parameters, and 4 animals had a deficit for only one motor parameter. Four monkeys did not show any deficit. The reversible inactivation experiment yielded results consistent with the permanent lesion data. In conclusion, the primary motor cortex exerts a modest role on ipsilateral manual dexterity, most likely in the form of indirect hand postural control.

Role of primary motor cortex in the control of manual dexterity assessed via sequential bilateral lesion in the adult macaque monkey: A case study

“…The modified Brinkman board task has extensively been used in our laboratory (e.g. Liu and Rouiller, 1999;Schmidlin et al, 2004Schmidlin et al, , 2005Schmidlin et al, , 2011Freund et al, 2006Freund et al, , 2007Freund et al, , 2009Beaud et al, 2008Beaud et al, , 2012Wannier-Morino et al, 2008;Bashir et al, 2012;Hoogewoud et al, 2013;Kaeser et al, 2010Kaeser et al, , 2011Kaeser et al, , 2013Kaeser et al, , 2014Chatagny et al, 2013;Wyss et al, 2013). The modified Brinkman board task was performed daily, 5 days a week, except when alternated with ICMS days during the mapping periods and every two days -7 days a week -during the critical acute and recovery periods.…”

“…acute period and not plateau period). It has been suggested that bilateral manual control exerted by M1 depends on both the task complexity and the size of the cortical lesion (Shibasaki et al, 1993;Salmelin et al, 1995;Chen et al, 1997;Biernaskie et al, 2005;Bashir et al, 2012). Consequently, depending on the motor task, the role of the intact M1 in functional recovery may be either enhanced or masked.…”

“…Bashir et al, 2012;Freund et al, 2006Freund et al, , 2009Kaeser et al, 2010Kaeser et al, , 2011Kaeser et al, , 2013Kaeser et al, , 2014Liu and Rouiller, 1999;Schmidlin et al, 2004Schmidlin et al, , 2005Schmidlin et al, , 2011Wyss et al, 2013), derived from an early initial version (Brinkman and Kuypers, 1973;Brinkman, 1984); (ii) the modified Klu¨ver board task to assess various types of finger grip, ranging from power grip to precision grip (e.g. Nudo et al, 1992;Xerri et al, 1998;Murata et al, 2008;Milliken et al, 2013;Qi et al, 2013;Sugiyama et al, 2013).…”

Behavioral Assessment of Manual Dexterity in Non-Human Primates

“…The four behavioral tests illustrated above (Figure 1) have been used extensively in our laboratory in the context of studies aimed at investigating the functional recovery from lesion of the cervical spinal cord (Figure 2A) or of the motor cortex ( Figure 2B), in absence or in presence of a treatment applied to enhance the spontaneous recovery [12][13][14][15][16][17][18][19] .…”

“…The time interval is measured by replaying frame by frame the video sequence. The CT is measured for the first five vertical slots and the first five horizontal slots aimed by the monkey [16][17][18] . The graphs of the score illustrate the initial training phase, the pre-lesion plateau, the dramatic drop of score (usually to zero) immediately after the lesion, the progressive (spontaneous) functional recovery towards the post-lesion plateau.…”