Current Search:  Theta Rhythm (x)

View All Items

  • CSV Spreadsheet
(1 - 3 of 3)
supramammillary nucleus: Does it play a role in the mediation of hippocampal theta rhythm?
Title
The supramammillary nucleus: Does it play a role in the mediation of hippocampal theta rhythm?.
Creator
Thinschmidt, Jeffrey Scott., Florida Atlantic University, Vertes, Robert P.
Abstract/Description
Recent evidence suggests that the supramammillary nucleus (SUM) is an important link from the pontine reticular formation (PRF) to the septum-hippocampus in the generation of hippocampal theta rhythm. I proposed: (1) injections of WGA-HRP into the SUM would produce retrograde labeling in PRF cells; (2) lesions of the SUM would produce a reduction in the frequency and amplitude of hippocampal theta rhythm; (3) injections of procaine into the SUM would attenuate the amplitude and reduce the...
Show moreRecent evidence suggests that the supramammillary nucleus (SUM) is an important link from the pontine reticular formation (PRF) to the septum-hippocampus in the generation of hippocampal theta rhythm. I proposed: (1) injections of WGA-HRP into the SUM would produce retrograde labeling in PRF cells; (2) lesions of the SUM would produce a reduction in the frequency and amplitude of hippocampal theta rhythm; (3) injections of procaine into the SUM would attenuate the amplitude and reduce the frequency of reticular elicited theta rhythm. Although WGA-HRP injections in the SUM produced minimal labeling in the PRF, there were labeled cells in the central gray of the pons, and in the dorsal raphe and surrounding regions. I found that lesions of the SUM produced minimal changes in the frequency and amplitude of theta in the behaving animal but that injections of procaine attenuated both of these measures in the urethane anesthetized rat.
Show less
Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14919
Subject Headings
Theta rhythm, Hippocampus (Brain), Memory
Format
Document (PDF)
THE CAUSAL ROLE OF THETA OSCILLATIONS IN THE FRONTOPARIETAL NETWORK ON COGNITIVE FLEXIBILITY
Title
THE CAUSAL ROLE OF THETA OSCILLATIONS IN THE FRONTOPARIETAL NETWORK ON COGNITIVE FLEXIBILITY.
Creator
Yoon, Yosun, Hong, Sang Wook, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description
Cognitive flexibility is crucial for efficient goal-directed behavior, especially in rapidly changing environments. While recent studies have consistently shown enhanced theta power and synchronization in the frontoparietal network during flexible task-switching, direct evidence establishing a causal link between theta-rhythm brain oscillation and cognitive flexibility remains limited. In this study, we applied transcranial alternating current stimulation (tACS) to the frontoparietal network...
Show moreCognitive flexibility is crucial for efficient goal-directed behavior, especially in rapidly changing environments. While recent studies have consistently shown enhanced theta power and synchronization in the frontoparietal network during flexible task-switching, direct evidence establishing a causal link between theta-rhythm brain oscillation and cognitive flexibility remains limited. In this study, we applied transcranial alternating current stimulation (tACS) to the frontoparietal network at a theta frequency (6 Hz) with a phase difference of either 0° (inphase) or 180° (antiphase) to explore its impact on task-switching performance. The results showed no significant tACS modulation effects on switch costs or neural oscillatory synchronization in the frontoparietal network. However, a consistent negative correlation was observed between frontoparietal theta power in the early time window of cue-target interval and task switching performance, implying the close relationship between proactive control in task switching and frontoparietal theta activities.
Show less
Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014340
Subject Headings
Theta Rhythm, Cognition, Cognitive psychology
Format
Document (PDF)
Analysis of nucleus reuniens cell behavior during hippocampal theta rhythm
Title
Analysis of nucleus reuniens cell behavior during hippocampal theta rhythm.
Creator
Morales, George J., Florida Atlantic University, Morgera, Salvatore D., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Coherence estimates have been used to determine the presence of functional coupling between two signals. While direct projections from the nucleus reuniens (RE) to the hippocampus formation in the rat have been discovered, little is known about the possible functional influence of the RE on the hippocampus. This investigation makes use of MATLAB to create a set of specialized algorithms to investigate coherence function estimates between RE cell activity and hippocampal EEG. In addition,...
Show moreCoherence estimates have been used to determine the presence of functional coupling between two signals. While direct projections from the nucleus reuniens (RE) to the hippocampus formation in the rat have been discovered, little is known about the possible functional influence of the RE on the hippocampus. This investigation makes use of MATLAB to create a set of specialized algorithms to investigate coherence function estimates between RE cell activity and hippocampal EEG. In addition, error prevention considerations as well as shortcomings in current data acquisition software that ultimately lead to the necessity for additional software analysis tools are also discussed. An investigation into RE cell behavior requires the calculation of cell activity spike rates as well as the identification of action potential bursting phenomena. Isolation of individual cell activity, from a population recording channel, is needed in order to prevent erroneous effects associated with using unresolved multi-neuron recordings. Changes in spike rate activity and frequency of bursting occurrences are calculated as a means of gauging RE unit response to the presence of a stimulus (e.g., tail pinch). The relationship of RE units on hippocampal EEG by analysis of coherence function estimates between RE units and hippocampal EEG, as well as evaluated RE unit behavior in terms of changes in unit spike rate and bursting activity are established.
Show less
Date Issued
2006
PURL
http://purl.flvc.org/fcla/dt/13383
Subject Headings
Hippocampus (Brain), Electroencephalography, Neurosciences, Theta rhythm, Memory
Format
Document (PDF)