Show simple item record

dc.contributor.authorTan, Can Ozanen_US
dc.contributor.authorBullock, Danielen_US
dc.date.accessioned2011-11-14T18:20:40Z
dc.date.available2011-11-14T18:20:40Z
dc.date.issued2006-10en_US
dc.identifier.urihttp://hdl.handle.net/2144/2048
dc.description.abstractThe giant cholinergic interneurons of the striatum are tonically active neurons (TANs) that respond with characteristic pauses to novel events and to appetitive and aversive conditioned stimuli. Fluctuations in acetylcholine release by TANs modulate performance- and learning-related dynamics in the striatum. Whereas tonic activity emerges from intrinsic properties of these neurons, glutamatergic inputs from thalamic centromedian-parafascicular nuclei, and dopaminergic inputs from midbrain, are required for the generation of pause responses. No prior computational models encompass both intrinsic and synaptically-gated dynamics. We present a mathematical model that robustly accounts for behavior-related electrophysiological properties of TANs in terms of their intrinsic physiological properties and known afferents. In the model, balanced intrinsic hyperpolarizing and depolarizing currents engender tonic firing, and glutamatergic inputs from thalamus (and cortex) both directly excite and indirectly inhibit TANs. If the latter inhibition, presumably mediated by GABAergic interneurons, exceeds a threshold, its effect is amplified by a KIR current to generate a prolonged pause. In the model, the intrinsic mechanisms and external inputs are both modulated by learning-dependent dopamine (DA) signals and our simulations revealed that many learning-dependent behaviors of TANs are explicable without recourse to learning-dependent changes in synapses onto TANs. The "teaching signal" that modulates reinforcement learning at cortico-striatal synapses may be a sequence composed of an adaptively scaled DA burst, a brief ACh burst, and a scaled ACh pause. Such an interpretation is consistent with recent data on cholinergic control of LTD of cortical synapses onto striatal spiny projection neurons.en_US
dc.description.sponsorshipNational Science Foundation (SBE-354378); Higher Education Council of Turkey; Canakkale Onsekiz Mart University of Turkeyen_US
dc.publisherBoston University Center for Adaptive Systems and Department of Cognitive and Neural Systemsen_US
dc.relation.ispartofseriesBU CAS/CNS Technical Reports;CAS/CNS-TR-2006-006en_US
dc.rightsCopyright 2008 Boston University. Permission to copy without fee all or part of this material is granted provided that: 1. The copies are not made or distributed for direct commercial advantage; 2. the report title, author, document number, and release date appear, and notice is given that copying is by permission of BOSTON UNIVERSITY TRUSTEES. To copy otherwise, or to republish, requires a fee and / or special permission.en_US
dc.subjectTonically active neuronen_US
dc.subjectBasal gangliaen_US
dc.subjectThalamostriatalen_US
dc.subjectReinforcement learningen_US
dc.subjectDopamineen_US
dc.subjectAcetylcholineen_US
dc.titleSimulating Effects of Learning and Lesions with a Model of Intrinsic and Synaptically Gated Responses of Striatal Cholinergic Interneuronsen_US
dc.typeTechnical Reporten_US
dc.rights.holderBoston University Trusteesen_US


Files in this item

This item appears in the following Collection(s)

Show simple item record