Thalamocortical synapses and intrinsic inhibition: The primary cholinergic effectors in macaque V1. [microform]
- Bib ID:
- 3664891
- Format:
- Book and Microform
- Author:
- Disney, Anita A
- Description:
- 349 p.
- ISBN:
- 049690261X
- Summary:
-
Acetylcholine is a neurotransmitter and neuromodulator that has been implicated in processes that underlie development, synaptic plasticity, neuroprotection, sleep and arousal, learning and memory, attention and a number of cognitive neuropathologies, including Alzheimer's disease. Despite its ubiquity, acetylcholine---particularly as a neuromodulator in the central nervous system---is not well understood. The cortical mantle in mammals receives a diffuse, loosely topographic cholinergic innervation from the basal forebrain. Cholinergic axons ramify over minimally overlapping cortical volumes and usually release ACh by non-synaptic, or volume, transmission. The system, on the basis of this anatomy of release, appears to have a limited capacity for specific signalling, and yet previous data are suggestive of specific effects.
Might the specificity of physiological responses be derived from a precise localization pattern of cholinergic receptors, rather than of the cholinergic axons? While the anatomy of the cholinergic innervation of cortex is well understood, little is known about the localisation of cholinergic receptors in cortex. We need data on the types of receptors expressed by cortical neurons and where on these neurons the receptors are located. The body of work described in this thesis uses quantitative confocal microscopy, tract tracing and immuno-electron microscopy to localise m1 and m2 muscarinic receptors and the beta2 subunit of nicotinic receptors in the primary visual area (V1) of the macaque monkey.
Data on the cholinergic modulation of this area are important in understanding mechanisms that underlie visual attention. These experiments showed that cholinergic receptor expression is enriched in the inhibitory interneurons of V1 and that the most strongly modulated population were neurons immunoreactive for parvalbumin. In addition, the tract-tracing/immuno-electron microscopy experiments showed that beta2 subunit-containing nicotinic receptors are located pre-synaptically at thalamocortical synapses onto spiny neurons in layer 4C, but not at thalamocortical synapses onto aspiny neurons. These data are used to build circuit models upon which predictions are made regarding the effect acetylcholine release will have on early visual processing. Preliminary experiments testing these hypotheses in vivo using single unit physiology combined with microiontophoresis of cholinergic agonists are also described.
- Notes:
-
- (UnM)AAI3157821
- Source: Dissertation Abstracts International, Volume: 65-12, Section: B, page: 6211.
- Advisers: Chiye Aoki; Michael J. Hawken.
- Thesis (Ph.D.)--New York University, 2005.
- Reproduction:
- Microfiche. Ann Arbor, Mich. : University Microfilms International.
- Subject:
- Biology, Neuroscience
- Other authors/contributors:
- New York University
- Copyright:
-
In Copyright
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Copyright status was determined using the following information:
- Material type:
- Literary Dramatic Musical
- Published status:
- Unpublished
- Creation date:
- 2005
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