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Long-term reversal of hemispheric specialization for visual memory in a split-brain macaque.
1Department of Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, NY 14642, USA. robert_doty@urmc.rochester.edu
Behavioural Brain Research
|July 14, 1999
Summary
Split-brain macaques showed shifting hemispheric dominance in visual tasks. Initially similar performance evolved, with the left hemisphere becoming superior after extensive training, altering fixation patterns.
Area of Science:
- Neuroscience
- Cognitive Science
- Primate Behavior
Background:
- Split-brain research investigates hemispheric specialization.
- Ocular fixations provide insights into visual processing and attention.
Purpose of the Study:
- To evaluate hemispheric performance in a continuous visual recognition task using ocular fixations.
- To explore the role of hemispheric dominance and its potential shifts with training.
Main Methods:
- Three split-brain macaques performed a visual recognition task (identifying 'NEW' or 'OLD' stimuli).
- Ocular fixations were recorded to analyze response accuracy and laterality.
- One animal experienced a cingulate gyrus lesion to confirm hemisphere-fixation relationships.
Main Results:
- Initially, hemispheres showed similar accuracy for images and human faces, but the right hemisphere excelled with macaque faces.
- Ocular fixations revealed hemispheric control over specific visual field processing.
- Extensive training led to a left hemisphere performance advantage and a reversal in fixation patterns.
Conclusions:
- Hemispheric dominance can shift with increased task familiarity and training in split-brain primates.
- Ocular fixation patterns correlate with performance accuracy and hemispheric specialization.
- The observed shift raises questions about hemispheric balance without forebrain commissures.