Olivier Hardy, Jacques Mirenowicz, and Jocelyne Corvisier
- Published in print:
- 1993
- Published Online:
- March 2012
- ISBN:
- 9780198547853
- eISBN:
- 9780191724268
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198547853.003.0117
- Subject:
- Neuroscience, Sensory and Motor Systems
This chapter describes the experimental knowledge related to the possible feedback loops responsible for the control of eye and head movements. Anatomical, immunocytochemical, and physiological data ...
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This chapter describes the experimental knowledge related to the possible feedback loops responsible for the control of eye and head movements. Anatomical, immunocytochemical, and physiological data are reviewed in various species. These results point out that two possible feedback loops originating in the prepositus hypoglossi nucleus may act upon the superior colliculus. It seems that these two pathways are involved in two different functions. The direct pre-posito-collicular path is involved in the control of the saccade accuracy whereas the indirect pathway, relayed in the lateral mesencephalon, participates in switching strategies from a compensatory to an orienting stategy. A feedback signal is required to ensure the generation and the control of goal-directed eye movements; this signal is an efference copy of the motor command and, according to the model, should code either the position or the velocity of the eye movement. The superior colliculus most probably lies within the feedback loop even though local feedbacks could coexist. Whatever the nature (position or velocity) of the feedback signal, the displacement of a mountain of collicular activity would require a sophisticated organization of the feedback loop in order to operate a temporal to spatial transformation of the signal.Less
This chapter describes the experimental knowledge related to the possible feedback loops responsible for the control of eye and head movements. Anatomical, immunocytochemical, and physiological data are reviewed in various species. These results point out that two possible feedback loops originating in the prepositus hypoglossi nucleus may act upon the superior colliculus. It seems that these two pathways are involved in two different functions. The direct pre-posito-collicular path is involved in the control of the saccade accuracy whereas the indirect pathway, relayed in the lateral mesencephalon, participates in switching strategies from a compensatory to an orienting stategy. A feedback signal is required to ensure the generation and the control of goal-directed eye movements; this signal is an efference copy of the motor command and, according to the model, should code either the position or the velocity of the eye movement. The superior colliculus most probably lies within the feedback loop even though local feedbacks could coexist. Whatever the nature (position or velocity) of the feedback signal, the displacement of a mountain of collicular activity would require a sophisticated organization of the feedback loop in order to operate a temporal to spatial transformation of the signal.
