Topographic organization of baboon primary motor cortex

Face, hand, forelimb, and shoulder representation

Robert Waters, Donald D. Samulack, Robert W. Dykes, Patricia A. Mckinley

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

(1) The fine details of the motor organization of the forelimb, face, and tongue representation of the baboon (Papio h. anubis)primary motor cortex were studied in four adult animals, using intracortical microstimulation (ICMS). (2) A total of 293 electrode penetrations were made. ICMS was delivered to 10,052 sites, and of these, 6,186 sites were verified to have been located within the grey matter. Motor effects were evoked from 30% of these sites. (3)The baboon motor cortex is confined, in large part, to the cortical tissue lying along the anterior bank of the central sulcus. When the electrode penetrations were confined to the precentral gyrus, few sites were capable of evoking movement when stimulated by currents of 40 μA or less. (4)The details of the motor maps varied among the four animals; nonetheless, a general topographic organization existed, with the tongue musculature being represented most laterally, followed by a medial progression of the face, digits, wrist, forearm, and shoulder. Within the representation of a given body part, the muscles were organized as a mosaic, wherein the same muscle was multiply represented. (5) A zone of unresponsive cortex was observed to lie consistently between the face and forelimb representation in all four animals. Repeated electrode penetrations within the unresponsive zone failed to elicit muscle contractions even with stimulating currents as high as 80 μA. (6) Our results suggest that the baboon motor cortex is topographically organized; however, embedded within this overall pattern lies a fine-grained mosaic incorporating multiple representations of the same muscle.

Original languageEnglish (US)
Pages (from-to)485-514
Number of pages30
JournalSomatosensory & Motor Research
Volume7
Issue number4
DOIs
StatePublished - Jan 1 1990

Fingerprint

Forelimb
Papio
Motor Cortex
Electrodes
Hand
Tongue
Muscles
Papio anubis
Frontal Lobe
Muscle Contraction
Wrist
Human Body
Forearm
Organizations

All Science Journal Classification (ASJC) codes

  • Physiology
  • Sensory Systems

Cite this

Topographic organization of baboon primary motor cortex : Face, hand, forelimb, and shoulder representation. / Waters, Robert; Samulack, Donald D.; Dykes, Robert W.; Mckinley, Patricia A.

In: Somatosensory & Motor Research, Vol. 7, No. 4, 01.01.1990, p. 485-514.

Research output: Contribution to journalArticle

Waters, Robert ; Samulack, Donald D. ; Dykes, Robert W. ; Mckinley, Patricia A. / Topographic organization of baboon primary motor cortex : Face, hand, forelimb, and shoulder representation. In: Somatosensory & Motor Research. 1990 ; Vol. 7, No. 4. pp. 485-514.
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