Intracortical sensorimotor projections in the rodent: Patterns of connectivity and functional dynamics within the vibrissa sensorimotor system.
Item
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Title
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Intracortical sensorimotor projections in the rodent: Patterns of connectivity and functional dynamics within the vibrissa sensorimotor system.
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Identifier
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AAI3325404
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identifier
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3325404
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Creator
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Donovan, Mary Rocco.
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Contributor
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Adviser: Joshua C. Brumberg
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Date
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2008
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological | Biology, Neuroscience
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Abstract
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The reciprocal connections between primary motor cortex (M1) and primary somatosensory cortex (S1) are hypothesized to play a crucial role in an animal's ability to update its motor plan in response to changes in the sensory periphery. These interactions provide the motor cortex with information about the sensory environment which in turn provides the sensory cortex with anticipatory knowledge of ongoing motor plans. In the mouse neocortex there are representations of the body surface within both M1 and S1. Utilizing physiologically targeted micro injections of biotinylated dextran amine into either the whisker representation of M1 or S1, we characterized the axonal pathways connecting these two areas and demonstrated that the homotopic areas of the two representations were preferentially connected to each other. We then used this data to determine a plane of section that contained both whisker M1 and whisker S1 and maintained a functional axonal pathway between these two areas. To examine the synaptic mechanism of the feedforward (S1 to M1) and feedback (M1 to S1) connections directly, we utilized whole-cell recordings within the in vitro sensorimotor slice. Our findings indicate that these regions are connected through a reciprocal axonal pathway that transverses the infragranular layers in both directions (FF and FB). Direct synaptic connections are observed following stimulation of both pathways. Larger responses are observed in the feedforward direction, while the feedback responses occur at a shorter latency. The morphology as well as the intrinsic firing properties indicates that differences exist in the synaptic organization within each of these circuits. The results of these studies suggest that the sensorimotor slice is a valuable method for the investigation of sensorimotor processing.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
