Monitoring the visual world: hemispheric asymmetries and subcortical processes in attention

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Hemispheric specialization describes differing functions between the brain's left and right sides.
• Visual attention involves processes for selecting and prioritizing visual information.

Purpose of the Study:

• To investigate hemispheric specialization in visual attention.
• To explore subcortical contributions to visual attention in split-brain patients.

Main Methods:

• Utilized a spatial cuing paradigm with lateralized stimuli.
• Measured reaction times in callosotomy (split-brain) patients.

Main Results:

• Observed significant cuing effects for targets in the right hemisphere (left visual hemifield).
• No significant cuing effects were found for targets in the left hemisphere (right visual hemifield).
• Right hemisphere showed attention allocation to cued locations in both visual fields; left hemisphere predominantly to the right.

Conclusions:

• Suggests right hemisphere attention is more globally distributed across visual fields.
• Left hemisphere attention appears more restricted to the contralateral (right) visual field.
• Intact subcortical systems may mediate right hemisphere's ipsilateral visual attention.