Cortical and subcortical pathways and mechanisms underlying visual
perception and attention in animals; the role of the basal ganglia,
superior colliculus, and other subcortical structures in mediating
visual behaviors and the recovery of visual orienting in the cortically
blind cat; syndromes of visual attention and neglect.
Behavioral methods for assessing visual capacities in animals;
anatomical methods for studying neuronal connectivity; surgical,
and chemical methods for producing lesions in the brain; eye movement
recording in the awake behaving animal.
Our laboratory is interested in how cortical and subcortical visual
pathways and mechanisms mediate visual detection, orienting, and
attentional capacities. We are currently studying the role of
the superior colliculus, substantia nigra, and other brainstem
regions in mediating the recovery of visual detection and orienting
in the cortically blind cat. Reversible or permanent disinhibition
of the superior colliculus ipsilateral to a visual cortical lesion
results in a return of visual orienting behavior to the hemianopic
cat. Inhibition of one colliculus in the otherwise normal animal
results in a loss of visual detection and orienting in the contralateral
visual hemifield. We plan to continue our anatomical, pharmacological,
electrophysiological, and behavioral studies aimed at understanding
these phenomena and their relationship to syndromes of attention
and neglect.
KEY WORDS: Vision, attention, recovery of function, subcortical
visual pathways, superior colliculus, substantia nigra, GABA,
neglect, cortical blindness.
Ciaramitaro, V.M., Wallace, S.F., and Rosenquist, A.C. 1997 Ibotenic
acid lesions of the substantia nigra pars reticulata ipsilateral
to a visual cortical lesion fail to restore visual orienting responses
in the cat. Journal of Comparative Neurology 377: 596-
610.
Ciaramitaro, V.M., Todd, W.E., and Rosenquist, A.C. 1997 Disinhibition
of the superior colliculus restores orienting to visual stimuli
in the hemianopic field of the cat. Journal of Comparative
Neurology 387: 568-587.
Rosenquist, A.C., Ciaramitaro, V.M., Durmer, J.S., Wallace, S.F.,
and Todd, W.E. 1996 Ibotenic acid lesions of the superior colliculus
produce longer lasting deficits in visual orienting behavior than
aspiration lesions in the cat. Progress in Brain Research
112: 117-130.
