Student Prize Award Abstract 1996 Oral Paper Award
FUNCTIONAL HEMISPHERIC LATERALIZATION IN THE COMMON MARMOSET (Callithrix jacchus)
M.A. Hook-Costigan and L.J. Rogers
Department of Physiology, University of New England, Armidale, N.S.W. Australia, 2351.
We have found that the common marmoset (Callithrix
jacchus) displays lateralization of hand use for spontaneous
reaching for stationary food objects and for visuospatial
reaching, foot use, mouth and eye use, and asymmetry in
production of facial expressions. While lateralization of
hand, mouth and foot use was present at the individual level,
there was no evidence of a group bias for these behavioural
functions. Individuals had a division of function between
the hemispheres for these motor behaviours (eg. if the left
hand is preferred for spontaneous reaching the right hand is
preferred for visuospatial reaching). Eye preferences were
measured in a monocular viewing situation. Facial
expressions were induced by presentation of a fear-eliciting
visual stimulus. Lateralization of eye preference and
asymmetries in the production of facial expression were
present at both the individual and group level. Like humans
and rhesus monkeys, the marmosets displayed a right-eye
preference in monocular viewing situations and a left-side
bias when producing a fearful facial expression. In summary,
in marmosets there is a dissociation between hand preferences
and the lateralization of facial expression and eye
dominance. The group bias for the latter asymmetries may
indicate that the evolution of hemispheric specialization
originated for perception rather than for manual control, as
proposed by a number of authors. Hemispheric specializations
for perceptual and emotional/communicative functions may have
established a framework for the organization of later
evolving hemispheric specializations of manual function.
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