RESEARCH INTEREST

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.


RESEARCH TECHNIQUES

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.


RESEARCH SUMMARY

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.


KEY REFERENCES

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.