Neural control of quadrupedal and bipedal stance: Implications for the evolution of erect posture

D. C. Dunbar, Fay Horak, J. M. MacPherson, D. S. Rushmer

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The transition among hominids from quadrupedalism to bipedalism resulted in modifications in their musculoskeletal morphology. It is unclear, however, whether changes in the circuitry of the CNS were also necessary in order to accommodate the unique balance requirements of two-limb support. This study addresses the issue of modifications in control strategies by investigating the rapid, automatic postural responses of feline and human subjects to sudden disturbances of balance in the anteroposterior (AP) direction while they stand quadrupedally and bipedally on movable platforms. Postural responses are characterized in terms of segmental adjustments, generated AP shear forces, and electromyographic activity. Feline and human subjects correct posture similarly when standing quadrupedally. Furthermore, both species correct stance primarily with their hindlimbs and use their forelimbs as supportive struts. In contrast, both species use completely different correctional strategies when standing bipedally. Morphological restrictions, however, prevent cats from adopting the pillar-like plantigrade posture of human beings. Thus, the correctional strategies of bipedal cats are distinct from those of bipedal human subjects. It is concluded that 1) automatic postural response patterns of quadrupedal Felis and bipedal Homo reflect the different biomechanical characteristics of the initial postures rather than species differences in CNS circuitry controlling stance; 2) hindlimb-dominated posture control is probably a common and relatively ancient pattern; and 3) reorganization of hominid CNS circuitry was probably unnecessary because hindlimb control was already a feature of the system.

Original languageEnglish (US)
Pages (from-to)93-105
Number of pages13
JournalAmerican Journal of Physical Anthropology
Volume69
Issue number1
StatePublished - 1986
Externally publishedYes

Fingerprint

posture
Posture
Hominidae
Hindlimb
cats
Felidae
Cats
Felis
reorganization
Forelimb
Homo
forelimbs
limbs (animal)
interspecific variation
shears
human being
Extremities
hindlimbs

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Anthropology

Cite this

Neural control of quadrupedal and bipedal stance : Implications for the evolution of erect posture. / Dunbar, D. C.; Horak, Fay; MacPherson, J. M.; Rushmer, D. S.

In: American Journal of Physical Anthropology, Vol. 69, No. 1, 1986, p. 93-105.

Research output: Contribution to journalArticle

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