Cholinergic depletion reduces plasticity of barrel field cortex.
This experiment examines the impact of the cholinergic input from the basal forebrain on the plasticity of the vibrissa-related somatosensory cortex. Newborn rat pups received intraventricular injections of the cholinergic immunotoxin IgG192-saporin, after bilateral removal of the C-line whisker follicles. Compared with saline-injected control animals, unilateral injections of 0.1 microg IgG192-saporin decreased the number of cholinergic neurons on the toxin injected side by 78% in the basal nucleus of Meynert and the vertical limb of the diagonal band of Broca, 80% in the magnocellular preoptic nucleus and the horizontal limb of the diagonal band of Broca, and 54% in the medial septal nucleus. Neuronal loss contralateral to the toxin was approximately half that on the ipsilateral side. The size of the C and D row barrels were compared from tangential sections through the barrel field. In control animals, D row barrels expanded into C row territory, giving a ratio of areas for D/C barrels of 2.03. Depletion of the cholinergic neurons reduced the expansion of D row barrels and hence decreased the D/C ratio, with a greater reduction on the toxin-treated side (1.43, P <0.005) compared with the contralateral side (1.64, P <0.05). This study implicates the basal forebrain cholinergic projection in somatosensory cortical plasticity.
Zhu
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School of Anatomy, University of New South Wales, Sydney, Australia.
Waite
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PM
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal; D001835:Body Weight / Q000502:physiology; D007150:Immunohistochemistry; D000922:Immunotoxins; D009699:N-Glycosyl Hydrolases; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D009929:Organ Size / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000166:cytology / Q000502:physiology*; D016548:Prosencephalon / Q000033:anatomy & histology / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D054789:Ribosome Inactivating Proteins, Type 1; D000076985:Saporins; D013003:Somatosensory Cortex / Q000502:physiology*; D014738:Vibrissae / Q000294:innervation* / Q000502:physiology
C085696:192 IgG-saporin; D000911:Antibodies, Monoclonal; D000922:Immunotoxins; D054789:Ribosome Inactivating Proteins, Type 1; D000110:Acetylcholinesterase; D009699:N-Glycosyl Hydrolases; D000076985:Saporins