title: Visual-induced excitation leads to firing pauses in striatal cholinergic interneurons.
abstract: Tonically active neurons in the primate striatum, believed to be cholinergic interneurons (CINs), respond to sensory stimuli with a pronounced pause in firing. Although inhibitory and neuromodulatory mechanisms have been implicated, it is not known how sensory stimuli induce firing pauses in CINs in vivo. Here, we used intracellular recordings in anesthetized rats to investigate the effectiveness of a visual stimulus at modulating spike activity in CINs. Initially, no neuron was visually responsive. However, following pharmacological activation of tecto-thalamic pathways, the firing pattern of most CINs was significantly modulated by a light flashed into the contralateral eye. Typically, this induced an excitation followed by a pause in spike firing, via an underlying depolarization-hyperpolarization membrane sequence. Stimulation of thalamic afferents in vitro evoked similar responses that were independent of synaptic inhibition. Thus, visual stimulation likely induces an initial depolarization via a subcortical tecto-thalamo-striatal pathway, pausing CIN firing through an intrinsic afterhyperpolarization.
authors.affiliation: Department of Anatomy and Structural Biology, Brain Health Research Centre, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Schulz
authors.forename: Manfred J
authors.initials: MJ
authors.lastname: Oswald
authors.forename: John N J
authors.initials: JN
authors.lastname: Reynolds
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D018678:Cholinergic Agents / Q000378:metabolism*; D003342:Corpus Striatum / Q000166:cytology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007839:Functional Laterality; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007395:Interneurons / Q000187:drug effects / Q000502:physiology*; D008027:Light; D008297:Male; D008954:Models, Biological; D010721:Phosphinic Acids / Q000494:pharmacology; D010775:Photic Stimulation / Q000379:methods; D011412:Propanolamines / Q000494:pharmacology; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D013788:Thalamus / Q000502:physiology; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology; D014795:Visual Pathways / Q000502:physiology
chemical_list: D018678:Cholinergic Agents; D018691:Excitatory Amino Acid Antagonists; D058787:GABA-A Receptor Antagonists; D010721:Phosphinic Acids; D011412:Propanolamines; D011724:Pyridazines; C085075:CGP 55845A; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; C056639:2-amino-5-phosphopentanoic acid; C049853:gabazine; D014633:Valine; D001640:Bicuculline