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Identification of motor areas of the cat cerebral cortex based on studies of cortical stimulation and corticospinal connections
Author(s) -
Ghosh S.
Publication year - 1997
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19970407)380:2<191::aid-cne4>3.0.co;2-z
Subject(s) - forelimb , anatomy , biology , spinal cord , neuroscience , motor cortex , corticospinal tract , microstimulation , cerebral cortex , stimulation , cortex (anatomy) , hindlimb , central sulcus , medicine , magnetic resonance imaging , radiology , diffusion mri
The location and topography of motor areas in the cat cerebral cortex were studied by electrical stimulation of the cortex in five animals, and by the injection of retrograde tracers into the spinal cord of four animals. Movements evoked by intracortical microstimulation (ICMS) of the anterior, posterior and lateral sigmoid gyri, both banks of the cruciate sulcus and the dorsal bank of the presylvian sulcus were observed in anaesthetized cats. Fluorescent tracers (Fast Blue and/or Diamadino Yellow) were injected into the lateral funiculus in the second cervical segment, into the gray matter of cervical segments C3‐T1 and/or into the gray matter of lumbar segments L2‐S1. Contraction of the contralateral forelimb, hindlimb or facial muscles was observed following electrical stimulation of several cytoarchitectonic areas: 4γ, 4δ, 6aα, 6aγ, and 3a. These findings suggested representations of contralateral forelimb and hindlimb movements in areas 4γ and 4δ, and of the contralateral forelimb muscles in areas 6aα, and 6aγ. Corticospinal neurons were located in all the above cytoarchitectonic areas as well as in areas 3b, 1, 2, 2pri, and 5. Large numbers of neurons were labeled in areas 4γ and 4δ, and moderate labeling was observed in areas 6aγ and 6aα. Corticospinal neurons projecting to cervical and lumbar segments were located in areas 4γ and 4δ, while those projecting only to cervical segments were detected in areas 6aα, and 6aγ. Based on these findings it is proposed that within the motor cortex of the cat there are representations of limb movements in several cytoarchitectonic subdivisions. Many of these representations may be candidate secondary motor areas. J. Comp. Neurol. 380:191–214, 1997. © 1997 Wiley‐Liss, Inc.