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Cicchese Dissertation Final Copy.pdf (1.55 MB)

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Theta Oscillations Modulate Hippocampal Single-Unit Responses Across Subregions During Trace Eyeblink Classical Conditioning

Cicchese, Joseph John
http://orcid.org/0000-0003-2128-0702
http://rave.ohiolink.edu/etdc/view?acc_num=miami1466187297

Abstract Details

2016, Doctor of Philosophy, Miami University, Psychology.
Eyeblink classical conditioning (EBC) is a widely used model of associative learning that has been utilized in studies involving both human and non-human subjects. The hippocampus is critical in acquiring the trace form of this task, and modulates performance in the delay form. Our lab has used a brain-computer interface (BCI) during EBC to control for fluctuations in the hippocampal theta rhythm, an oscillation frequently tied to cognitive processes. Training in the presence of high theta power leads to an increase in learning rate, accompanied by modulation of cellular response direction in hippocampal area CA1. However, it is unknown how additional hippocampal subregions are affected by the presence of theta oscillations. In this study, Aim I utilized tetrode recordings and a brain-computer interface (BCI) to examine response profiles of single-units in CA3. Trace EBC trials were initiated in the presence (T+) or absence (T-) of hippocampal theta. Several interneuron subtypes were identified, showing unique theta-contingent response profiles across training. Pyramidal cells were more likely to increase their firing early in training in the T+ condition than the T- condition; however, that pattern was reversed during the late learning phase. Importantly, no difference was seen in the magnitude of response between T+ and T- pyramidals, suggesting theta is involved in the recruitment of cells rather than simply modulating firing rate. In Aim II, units were recorded during both T+ and T- triggered trials following asymptotic behavioral performance. Previous research has shown two classes of theta-responsive cells: Theta-On (increase firing during theta) and Theta-Off (increase in the absence of theta). Regardless of triggering theta-state, Theta-On cells were more likely to increase their firing in animals initially trained in T+ conditions, while Theta-Off cells increased at a higher rate in T- animals. These findings indicate that during acquisition, theta-state recruits specific types of cells that undergo conditioning-related changes in firing, but may not influence firing after conditioning has occurred. Taken together, these results expand our knowledge of how hippocampal subregions are involved in processing and provide insight into the cellular mechanisms underlying the increased learning rate in theta-contingent training.
Stephen Berry, Ph.D. (Committee Chair)
Jennifer Quinn, Ph.D. (Committee Member)
Barbara Oswald, Ph.D. (Committee Member)
Kathleen Killian, Ph.D. (Committee Member)
57 p.
Behavioral Sciences; Neurosciences; Psychobiology; Psychology
Theta; tetrodes; single-unit; hippocampus

Recommended Citations

Citations

  • Cicchese, J. J. (2016). Theta Oscillations Modulate Hippocampal Single-Unit Responses Across Subregions During Trace Eyeblink Classical Conditioning [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1466187297

    APA Style (7th edition)

  • Cicchese, Joseph. Theta Oscillations Modulate Hippocampal Single-Unit Responses Across Subregions During Trace Eyeblink Classical Conditioning. 2016. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1466187297.

    MLA Style (8th edition)

  • Cicchese, Joseph. "Theta Oscillations Modulate Hippocampal Single-Unit Responses Across Subregions During Trace Eyeblink Classical Conditioning." Doctoral dissertation, Miami University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1466187297

    Chicago Manual of Style (17th edition)

miami1466187297
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© 2016, all rights reserved.
This open access ETD is published by Miami University and OhioLINK.