Long-term motor cortical map changes following unilateral lesion of the hand representation in the motor cortex in macaque monkeys showing functional recovery of hand functions

Abstract

Purpose: How are motor maps modified within and in the immediate vicinity of a damaged zone in the motor cortex of non-human primates? Methods: In eight adult macaque monkeys subjected to a restricted chemical lesion of the hand area in the primary motor cortex (M1), motor maps were established using intracortical micro-stimulation (ICMS) techniques. The monkeys were subdivided into five animals without treatment, whereas three monkeys received an anti-Nogo-A antibody treatment. Results: Following permanent M1 injury, the lesion territory became largely non micro-excitable several months post-lesion, in spite of some recovery of hand function. Few sites within the lesion territory remained excitable, though irrespective to the degree of functional recovery. Around the lesion in M1, there was no reallocation of proximal shoulder/arm territories into distal hand functions. However, ICMS delivered at supra-threshold intensities in these proximal territories elicited digit movements. Post-lesion ICMS thresholds to elicit movements of forelimb muscle territories increased, independently from the degree of functional recovery. Further behavioural evidence for an enhancement of functional recovery promoted by the anti-Nogo-A antibody treatment is provided. Conclusion: The degree of functional recovery is not related to a reorganization of motor maps within, and in the vicinity of, a M1 lesion.

Changes of motor corticobulbar projections following different lesion types affecting the central nervous system in adult macaque monkeys

“…All 13 animals were also involved in behavioural tasks, as previously reported (see Badoud et al, 2017;Bashir et al, 2012;Freund et al, 2006Freund et al, , 2009Hamadjida et al, 2012;Hoogewoud et al, 2013;Kaeser et al, 2010Kaeser et al, , 2011Schmidlin et al, 2011;Wyss et al, 2013). All surgical and experimental procedures, animal care were conducted in accordance to the Guide and Care and Use of Laboratory animals (ISBN 0-309-05377-3, 1996) and were authorized by both the local (Canton of Fribourg) and federal (Switzerland) veterinary offices (authorizations FR-157-03; FR-157-04; FR-157e-04; FR-156-04; FR-156-06; FR-185-08; FR-17-09; FR-2012-01; FR-2012-01E).…”

“…Manual dexterity data in MPTP monkeys will be published later. Functional recovery data are taken from previous studies (Freund et al, 2009;Wannier-Morino et al, 2008;Beaud et al, 2008Beaud et al, , 2012Wyss et al, 2013;Borgognon et al, 2017) . The percentage of recovery is to some extent related to the lesion volume (see lesion volume data in Table 1).…”

“…There is still incomplete understanding of the precise role played by brainstem-descending pathways in motor recovery from lesion, as well as by corticobulbar pathways. Although previous reports speculated that corticobulbar projections may play an important role in motor recovery after lesion of the CNS (Beaud et al, 2008;Hoogewoud et al, 2013;Mosberger et al, 2017;Wyss et al, 2013;Zörner & Schwab, 2010), this descending tract still remains mysterious for the most part, possibly due in part to its location and the difficult access to the corresponding target nuclei in the brainstem. The present study is original as it represents a unique study in nonhuman primates quantitatively investigating the rearrangement of the corticobulbar projections onto the PMRF following different pathologies affecting the CNS, such as motor cortex lesion, PD or SCI.…”

“…l-1,2,3,6-tetrahydropyridine (MPTP) intoxication to produce Parkinson's disease-like lesions of the nigro-striatal dopaminergic system (PD). Previous reports derived from these experiments concerned specifically behavioural data Bashir et al, 2012;Freund et al, 2006Freund et al, , 2009Hamadjida et al, 2012;Hoogewoud et al, 2013;Kaeser et al, 2010Kaeser et al, , 2011Wyss et al, 2013), imaging of dopaminergic function or tracing data on the CS tract (Beaud et al, 2008;Freund et al, 2007), the rubrospinal projection (Wannier-Morino et al, 2008) or callosal projection . In the present study, this rich collection of monkeys subjected to one of these pathologies (MCI, SCI, PD; n = 13) was analysed here in order to compare their corticobulbar projections to PMRF with that of a cohort of intact monkeys (n = 7) recently reported .…”

Corticobulbar projections from distinct motor cortical areas to the reticular formation in macaque monkeys

“…After completion of tracer injections and a survival period of 20-29 days for BDA, around 5 days for CB, to allow transport of the tracers to the region of interest, the animals were euthanized under deep anaesthesia (lethal dose of pentobarbital sodium 90 mg/kg body weight; i.p.) and perfused transcardially as previously reported (Rouiller et al, 1994Hamadjida et al, 2012;Wyss et al, 2013). The brainstem was cut in the frontal plane in 50 lm (40 lm for SC-1 only) thick sections with a freezing microtome, collected in 5-7 series (see Table 1).…”