Description
- Abstract:
- The perirhinal cortex (PER) has a well-established role in identification and recognition of objects. Our lab previously provided evidence that neuronal activity in PER may signal novelty and familiarity through synchronous activity at specific frequencies, with novelty signaled at 30 Hz. Medial prefrontal cortex (mPFC) is also known to be involved in processing information about novelty. Secondary motor cortex (MOs) in the rodent prefrontal cortex plays an important role in processing sensory information in order to guide appropriate goal-directed behavior. MOs and mPFC have strong anatomical connections to PER. Based on this evidence, we suggest that PER interacts directly with mPFC and MOs to provide the necessary cognitive control over novelty exploration. In this study we employed optogenetic techniques to address the hypotheses that PER-PFC interaction is necessary for novelty guided exploration and that these interactions are modulated by synchronous neuronal activity in the low gamma (30-40 Hz) frequency domain. We tested a model in which information about novelty is transmitted from PER to the infralimbic (IL) area of mPFC and subsequent exploratory behavior is modulated by an MOs projection to PER. Rats were bilaterally injected with viral vectors containing channelrhodopsin (ChR2) and implanted with optical fibers in either MOs or IL. During a spontaneous object recognition (SOR) task, rats underwent optical stimulation of 30 Hz, 8 Hz, 20 Hz, and a no-stimulation control. When rats were presented with one novel and one familiar image and exploration of the familiar image was paired with 30 Hz stimulation of either MOs or IL, the rats increased exploration of the familiar image, as if it were also novel. When rats were presented with two identical familiar images, rats treated the familiar image paired with 30 Hz stimulation of MOs as novel, but this did not happen with 30 Hz stimulation of IL. This suggests that novelty is signaled by synchronous activity in a particular frequency band, and that the function of the signal differs for MOs and IL. Our data provides evidence that novelty is communicated through a new type of temporal code in a circuit that includes PER, MOs, and IL.
- Notes:
- Thesis (Sc. M.)--Brown University, 2019
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- Collection is open for research.
Citation
Ioannou, Alexia Evgenia,
"Control of Perirhinal-dependent Novelty Exploration in Rats by Optogenetic Modulation of Prefrontal Cortex"
(2019).
Biomedical Engineering Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.26300/4vcy-p878
Relations
Collection:
-
Biomedical Engineering Theses and Dissertations
Theses and Dissertations for the Biomedical Engineering department....