It has long been known that attending to the right place at the right time can improve performance and reaction time in a wide variety of the tasks that humans engage in. If attention is defined as a general mechanism by which a nervous system’s economy of resources and information are distributed to enable a perceptual state that is well-aligned with the goals of the biological system, then changes in visual attention should emerge as changes in the distribution of resources and information in the visual cortex. A growing body of evidence supports this proposition in non-human primates, and suggests that visual spatial attention affects perceptual state through top-down signaling that refines the neural representation of the attended stimulus (Desimone and Duncan, Chelazzi and Reyonlds, Mayo). This refinement is correlated with, and often believed to cause, the change in behavioral performance accompanied by visual spatial attention. To test whether similar mechanisms of visual spatial attention affect perceptual state in mice (our central hypothesis), we recorded neuronal activity in the primary visual cortex while mice engaged in a contrast detection task. This task was designed to induce endogenous shifts in visual spatial attention by changing the probability that a stimulus would appear at a particular location on the monitor. We found that our subject’s contrast detection threshold did not depend on this manipulation, suggesting that either: our subject was unable to distinguish between different probability conditions, AND/OR there was no advantage in attending to the side of higher probability, AND/OR visual spatial attention does not affect perceptual state in mice in ways similar to that of non-human primates. Analyses of pupil recordings have helped us learn more about the subject’s strategy and the ways in which we can modify the task to encourage sizeable shifts in visual spatial attention.
In parallel with this experiment, a process was developed to aggregate neuronal data from the same population of neurons across days. Although difficult and time-consuming, this strategy enables analyses of individual neurons across many days and trial types. Once we are successful in designing a task to induce shifts in visual spatial attention, this routine will allow us to determine whether mice and non-human primates share a common mechanism of visual spatial attention. Doing so will elucidate whether the mouse model should be used to study the physiology and pathophysiology of visual spatial attention.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/30869 |
| Date | 03 July 2018 |
| Creators | Payne, Gregory |
| Contributors | Dominguez, Isabel |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution 4.0 International, http://creativecommons.org/licenses/by/4.0/ |
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