Physiology of the eyelid motor system.
The eyelid motor system represents an excellent experimental model for the study of reflex and learned motor responses. Eyelid responses can be recorded quantitatively with the search coil in a magnetic-field technique. Stimuli able to evoke reflex blinks (air puffs, flashes of light, tones) can also be controlled quantitatively. Eyelid movements can be classified as spontaneous, passive (such as those following eye saccades), reflex, and acquired with classical conditioning procedures. Information is available regarding the firing activity of brainstem motoneuronal pools (abducens, accessory abducens, and facial motoneurons) involved in these types of eyelid response. In particular, facial motoneurons present different encoding properties for the generation of reflex against learned eyelid responses. In cats, accessory abducens motoneurons are involved only in reflex (but not in learned) blinks. The recent description of the complete organization of premotoneuronal pathways related to eyelid motorics opens new experimental possibilities for the study of this particular motor system.
Delgado-García
José M
JM
División de Neurociencias, Laboratorio Andaluz de Biología, Universidad Pablo de Olavide, Sevilla 41013, Spain. jmdelgar@dex.upo.es
Gruart
Agnès
A
Trigo
José A
JA
D000010:Abducens Nerve / Q000502:physiology; D001767:Blinking / Q000502:physiology; D003215:Conditioning, Eyelid / Q000502:physiology; D005143:Eyelids / Q000294:innervation / Q000502:physiology*; D006801:Humans; D009046:Motor Neurons / Q000502:physiology*; D009799:Ocular Physiological Phenomena; D009801:Oculomotor Muscles / Q000294:innervation / Q000502:physiology; D011434:Proprioception / Q000502:physiology