QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, April 22, 2009, 29(16):5266-5275; doi:10.1523/JNEUROSCI.0661-09.2009

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kaku, Y. Articles by Iwamoto, Y. Search for Related Content PubMed PubMed Citation Articles by Kaku, Y. Articles by Iwamoto, Y.

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
Learning Signals from the Superior Colliculus for Adaptation of Saccadic Eye Movements in the Monkey

Yuki Kaku, Kaoru Yoshida, and Yoshiki Iwamoto

Department of Neurophysiology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, 305-8574, Japan

Correspondence should be addressed to Dr. Yoshiki Iwamoto, Department of Neurophysiology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, 305-8574, Japan. Email: iwamoto{at}md.tsukuba.ac.jp

Vital to motor learning is information about movement error. Using this information, the brain creates neural learning signals that instruct a plasticity mechanism to produce appropriate behavioral learning. Little is known, however, about brain structures that generate learning signals for voluntary movements. Here we show that signals from the superior colliculus (SC) can drive learning in saccadic eye movements in the monkey. Electrical stimulation of the SC deeper layers, subthreshold for evoking saccades, was applied immediately (60 ms) after the end of horizontal saccades in one or both directions. The target disappeared during saccades and remained invisible for 1 s to eliminate effects of postsaccadic visual information. Repetitive pairing of saccades with SC stimulation produced a marked, two-dimensional shift in movement endpoint relative to the target location. The elicited endpoint shift took a gradual, approximately exponential course over several hundred saccades as in visually induced saccade adaptation. The shift in movement endpoint remained nearly unchanged after stimulation was discontinued, indicating involvement of neuronal plasticity. When both rightward and leftward saccades were paired with stimulation, their endpoints shifted in similar directions. The endpoint shift was directed contralaterally to the stimulated SC. The direction and size of the endpoint shift depended on the stimulation site in the SC. We propose that the SC, a brainstem structure long known to be crucial for saccade execution, is involved in motor learning and sends signals that dictate the direction of adaptive shift in saccade endpoint.

---

Received Feb. 9, 2009; revised March 5, 2009; accepted March 26, 2009.

Correspondence should be addressed to Dr. Yoshiki Iwamoto, Department of Neurophysiology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, 305-8574, Japan. Email: iwamoto{at}md.tsukuba.ac.jp

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help