Lee, Chi-Yu;
(2022)
The role of primary visual cortex in visual discrimination.
Masters thesis (M.Phil), UCL (University College London).
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Abstract
Visual discrimination is important for visually guided behaviours. Previous research has suggested the importance of primary visual cortex (V1), among other regions, in visual discrimination. Nevertheless, the role V1 plays in visual discrimination remains largely unclear. Recent advances in techniques such as optogenetics and DREADD (designer receptor exclusively activated by a designer drug), which allow manipulation of a particular region or neuronal population, open opportunities for a better understanding of the role of V1 in visual discrimination. Here I used hM4Di, an inhibitory DREADD, to ask what role V1 plays in mouse visual discrimination, for ethologically valid stimuli. We virally expressed hM4Di in V1 and examined efficacy of hM4Di manipulation in vivo by recording local field potential while presenting a battery of visual stimuli. We found that hM4Di manipulation enhances low-frequency oscillation and visual- evoked responses to slowly flickering grating stimuli. I then performed behavioural experiments after expressing hM4Di, to test if V1 is required for visual discrimination in mice. We found no evidence for an influence of hM4Di on the probability of responding to sweeping (a latent visual threat), or looming (an imminent visual threat) stimuli. In addition, I developed a new visual object recognition (VOR) assay to study spontaneous visual discrimination. Both hM4Di and control groups showed neophilia over novel objects, indicating that hM4Di manipulation in V1 did not disrupt the visual discrimination between novel and familiar objects. These finding suggests that hM4Di manipulation in V1 does influence activity in V1 but does not disrupt (a) visual detection of visual threats; (b) visual discrimination. V1’s involvement in visual discrimination of ethologically valid stimuli therefore remains to be determined.
| Type: | Thesis (Masters) |
|---|---|
| Qualification: | M.Phil |
| Title: | The role of primary visual cortex in visual discrimination |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10146200 |
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