Whitford, Andrew
(2016)
Patterns of population activity associated with the intentional control of single neuron firing rates in primate motor cortex.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Although it is firmly established that the primate motor cortex contributes to intentional behavior, the exact relationship between patterns of cortical activity and effected action is not well-understood. A particular matter of controversy is the degree to which such patterns subserve a singular function in the control of behavior, and are constrained by this specific role. The reported capability of nearby motor cortical neurons to vary independently of one another -- and to be dissociated from overt movement -- has often been cited as evidence that patterns of cortical activity are rather labile; that they are readily adjusted to suit varied behavioral demands. Such claims are rooted in evidence from neurophysiology experiments that entail direct reinforcement of variation in the firing rates of single cortical neurons -- that is, single unit operant conditioning experiments. However, such investigations have largely been limited to the consideration of relationships among neurons recorded on the same electrode, or among small populations (N<5) of nearby neurons. Here, we explore cortical flexibility by characterizing patterns of population (N>20) activity as single neurons are targeted for conditioning. We find that a substantial percentage of the populations tend to co-vary, even though behavioral goals (i.e., reward) depend only on the activity of single neurons. Further, stable patterns of covariation can change with those goals. We conclude that cortical activity can be reshaped to suit behavioral demands, but that intrinsic structure -- perhaps due to network connectivity patterns -- likely constrains the flexibility of population activity.
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Details
Item Type: |
University of Pittsburgh ETD
|
Status: |
Unpublished |
Creators/Authors: |
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ETD Committee: |
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Date: |
16 September 2016 |
Date Type: |
Publication |
Defense Date: |
13 July 2016 |
Approval Date: |
16 September 2016 |
Submission Date: |
26 July 2016 |
Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
Number of Pages: |
90 |
Institution: |
University of Pittsburgh |
Schools and Programs: |
Swanson School of Engineering > Bioengineering |
Degree: |
PhD - Doctor of Philosophy |
Thesis Type: |
Doctoral Dissertation |
Refereed: |
Yes |
Uncontrolled Keywords: |
motor cortex, behavioral neurophysiology, brain interface, operant conditioning, behavior |
Date Deposited: |
16 Sep 2016 16:59 |
Last Modified: |
15 Nov 2016 14:34 |
URI: |
http://d-scholarship.pitt.edu/id/eprint/28927 |
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