Directional responses of basal optic neurons are modulated by the nucleus lentiformis mesencephali in pigeons.
The nucleus lentiformis mesencephali (nLM) and the nucleus of the basal optic root (nBOR) in pigeons are both involved in optokinetic nystagmus. They are reciprocally connected and thus may interact with each other. The present study injected lidocaine into nLM and then examined the effects of nLM blockade on visual responses of nBOR neurons to target motion. The results indicate that nLM could modulate nBOR activity in two ways. First, nLM enhances visual responses of 70% of nBOR cells to motion in the preferred directions, sharpening their directional tuning. Second, nLM reduces visual responses of 13% of nBOR cells to motion in the preferred directions, broadening their directional tuning. The remaining 17% of nBOR cells are not affected by drug application. Taken together with the previous results that nBOR could modulate nLM activity (Gu et al., Neuroscience, 104 (2001) 153), it suggests that both nuclei can mutually modulate each other in generating optokinetic nystagmus.
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Laboratory for Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, 100101, Beijing, China.
Gu
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Wang
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D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D010856:Columbidae / Q000033:anatomy & histology / Q000502:physiology*; D008012:Lidocaine / Q000494:pharmacology; D009039:Motion Perception / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D017120:Nystagmus, Optokinetic / Q000187:drug effects / Q000502:physiology; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D013028:Space Perception / Q000502:physiology; D013477:Superior Colliculi / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D014795:Visual Pathways / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D000779:Anesthetics, Local; D008012:Lidocaine