One of the best kept secrets in neuroscience, and in the relation of neuronal activity to behavior (and mental experience), is that the brain exists in duplicate. The two cerebral hemispheres are each endowed with full human capability, as evidenced by cases of hemispherectomy or human “split-brain” patients. In normal life the hemispheres are seamlessly coordinated by massive interconnections via the forebrain commissures, and a variety of subcortical systems. Because of the arrangement of fibers in the optic chiasm, it is quite easy to direct visual input to each hemisphere individually. The question thus arises as to how long it takes to shift attention from an object in one visual field/hemisphere to that in the other; and whether there is any difference in time required for the shift between hemispheres versus that within a hemisphere. Infrared monitoring of eye position with computer control makes it possible to present stimuli, or cues (false or true) as to probable location of stimuli, precisely as to position and timing. Differences in reaction time of the subjects decisively delineate any temporal differences, as a function of true position versus expectation, thus measuring how long it takes to shift attention from one to another locus. Defining this time will delimit the nature of the underlying neuronal processes or circuitry. Embedded in such research are two other features: the characteristics of “expectation”, which this laboratory has shown, unexpectedly, to take time to disassemble; and, since each hemisphere has somewhat differing propensities, the opportunity to examine hemispheric differences in regard to allocation of attention, its mobility, and relation to visual material presented. Furthermore, the various paradigms in such experiments offer diagnostic and/or prognostic tests for individual differences, normal or pathological.

Pub Med Citations

Bartlett, J.R., DeYoe, E.A., Doty, R.W., Lee, B.B., Lewine, J.D., Negrao, N. and Overman, W.H., Jr. Psychophysics of electrical stimulation of striate cortex in macaques. J Neurophysiol 94: 3430-3442, 2005.

DeYoe, E.A., Lewine, J. and Doty, R.W. Laminar variation in threshold for detection of electrical excitation of striate cortex by macaques. J Neurophysiol. 94:.3443-3450, 2005.

Doty, R.W. Review of: Principles of Brain Evolution, by Georg F. Striedter. Quartely Review of Biology 80:264, 2005.
 
Doty, R. W. 2001, Memory,Brain, and Belief. Quarterly Rev. Biol.:113.

Doty, R.W. 2001, Autobiography. In: Squire, L., ed., The History of Neuroscience in Autobiography. pp 214-244, San Diego, Academic.

Kavcic, V., Fei R., Doty, R.W. 2000, Hemispheric interaction, metacontrol, and mnemonic processing in split-brain macaques. Behav. Brain Res., 111: 71-82.

Kavcic, V. Krar, F.J. and Doty, R.W. 2000, Temporal cost of switching between kinds of visual stimuli in a memory task. Cognitive Brain Res. 9:199-203.

Doty, R.W. 1999, Two brain, one person. Brain Res Bull Special Issue: Highlights in Twentieth Century Neuroscience, December Issue.

Doty, R.W., Fei, R., Hu, S., Kavcic, V. 1999, Long-term reversal of hemispheric specialization for visual memory in a split-brain macaque. Behav Brain Res.

Doty, R.W. 1998, Five Mysteries of the Mind, and their Consequences. Neuropsychologia 36:1069-1076

Doty, R.W., Savakis, A.E. 1997, Commonality of processes underlying visual and verbal recognition memory. Cognitive Brain Res. 5: 283-294.

Doty, R.W., Ringo, J.L., Lewine, J.D. 1994, Interhemispheric sharing of visual memory in macaques. Behav. Brain Res. 64: 79-84.

Doty, R.W. 1990, Forebrain commissures and the unity of mind. In: John, E.R., ed. Machinery of the Mind, pp 3-13. Boston: Birkhäuser.

Doty, R.W. 1989, Schizophrenia: A disease of interhemispheric processes at forebrain and brainstem levels? Behav. Brain Res. 34:1-33.