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Sequential operation of disconnected cerebral hemispheres in split-brain patients
H Pashler1, S J Luck, S A Hillyard
1Department of Psychology, University of California, San Diego, La Jolla 92093-0109.
Neuroreport
|November 21, 1994
Summary
Patients with severed corpus callosum still show dual-task interference. Subcortical structures are critical for response selection, not just the corpus callosum.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neuropsychology
Background:
- Concurrent sensorimotor tasks requiring separate responses typically cause response selection interference.
- The corpus callosum is a major forebrain commissure facilitating interhemispheric communication.
Purpose of the Study:
- To investigate the role of subcortical structures in dual-task interference after forebrain commissure transection.
- To determine if the corpus callosum is essential for the 'dual-task bottleneck' phenomenon.
Main Methods:
- Examined dual-task performance in four patients who had undergone surgical transection of forebrain commissures, including the corpus callosum.
- Presented sequential light flashes to each visual field, with ipsilateral hand responses to confine tasks to separate hemispheres.
Main Results:
- All patients exhibited dual-task interference comparable to normal individuals.
- Response selection for the second task was delayed, indicating a bottleneck effect.
Conclusions:
- Intact subcortical structures are crucial for sequencing response selection processes.
- Confirms a distinction between attentional limitations in action planning versus perceptual analysis.