Multisensory information facilitates reaction speed by enlarging activity difference between superior colliculus hemispheres in rats

Hirokawa, J., Sadakane, O., Sakata, S., Bosch, M., Sakurai, Y., Yamamori, T. (September 2011) Multisensory information facilitates reaction speed by enlarging activity difference between superior colliculus hemispheres in rats. PLoS ONE, 6 (9). ISSN 1932-6203 (Electronic)

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Abstract

Animals can make faster behavioral responses to multisensory stimuli than to unisensory stimuli. The superior colliculus (SC), which receives multiple inputs from different sensory modalities, is considered to be involved in the initiation of motor responses. However, the mechanism by which multisensory information facilitates motor responses is not yet understood. Here, we demonstrate that multisensory information modulates competition among SC neurons to elicit faster responses. We conducted multiunit recordings from the SC of rats performing a two-alternative spatial discrimination task using auditory and/or visual stimuli. We found that a large population of SC neurons showed direction-selective activity before the onset of movement in response to the stimuli irrespective of stimulation modality. Trial-by-trial correlation analysis showed that the premovement activity of many SC neurons increased with faster reaction speed for the contraversive movement, whereas the premovement activity of another population of neurons decreased with faster reaction speed for the ipsiversive movement. When visual and auditory stimuli were presented simultaneously, the premovement activity of a population of neurons for the contraversive movement was enhanced, whereas the premovement activity of another population of neurons for the ipsiversive movement was depressed. Unilateral inactivation of SC using muscimol prolonged reaction times of contraversive movements, but it shortened those of ipsiversive movements. These findings suggest that the difference in activity between the SC hemispheres regulates the reaction speed of motor responses, and multisensory information enlarges the activity difference resulting in faster responses. © 2011 Hirokawa et al.

Item Type: Paper
Subjects: organism description > animal behavior
organism description > animal > mammal > rodent > rat
organism description > animal > mammal > rodent > rat
organs, tissues, organelles, cell types and functions > tissues types and functions > superior colliculus
CSHL Authors:
Communities: CSHL Post Doctoral Fellows
CSHL labs > Kepecs lab
Depositing User: CSHL Librarian
Date: 26 September 2011
Date Deposited: 09 Nov 2011 19:17
Last Modified: 02 May 2013 15:57
PMCID: PMC3180293
Related URLs:
URI: https://repository.cshl.edu/id/eprint/15644

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