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NEURAL CORRELATES OF SIGNAL DETECTION UNDER NON-AROUSAL AND AROUSAL CONDITIONS
Title
NEURAL CORRELATES OF SIGNAL DETECTION UNDER NON-AROUSAL AND AROUSAL CONDITIONS.
Creator
CAEL, WILLIAM WARD, III., Florida Atlantic University
Abstract/Description
A signal detection experiment tested the assumption that the results of Hillyard, Squires, Bauer and Lindsay (1971), who found a significant late positive component (LFC) of the averaged evoked potential only in the hit category, were due to the response set of their Ss and not to any unique associations of the LPC with the hit category as interpreted by them. Phase 1 of the present study was basically a replication of Hillyard's study. In Phase 2 incorrect responses were punished by an...
Show moreA signal detection experiment tested the assumption that the results of Hillyard, Squires, Bauer and Lindsay (1971), who found a significant late positive component (LFC) of the averaged evoked potential only in the hit category, were due to the response set of their Ss and not to any unique associations of the LPC with the hit category as interpreted by them. Phase 1 of the present study was basically a replication of Hillyard's study. In Phase 2 incorrect responses were punished by an unpleasant feedback device designed to place more equal relevance on signal and non-signal trials. Significant LPCs appeared in both signal and non-signal brain waves under both phases indicating that the LPC is not contingent on any particular response category as Hillyard reported, but may instead reflect the relevance of the category to the experimental task as it is perceived by the S.
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Date Issued
1973
PURL
http://purl.flvc.org/fcla/dt/13605
Subject Headings
Evoked potentials (Electrophysiology), Arousal (Physiology)
Format
Document (PDF)
Behavioral and Electrophysiological Properties of Nucleus Reuniens: Role in Arousal, Spatial Navigation and Cognitive Processes
Title
Behavioral and Electrophysiological Properties of Nucleus Reuniens: Role in Arousal, Spatial Navigation and Cognitive Processes.
Creator
Viena, Tatiana Danela, Vertes, Robert P., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description
The hippocampal-medial prefrontal circuit has been shown to serve a critical role in decision making and goal directed actions. While the hippocampus (HF) exerts a direct influence on the medial prefrontal cortex (mPFC), there are no direct return projections from the mPFC to the HF. The nucleus reuniens (RE) of the midline thalamus is strongly reciprocally connected with the HF and mPFC and represents the major link between these structures. We investigated the role of RE in functions...
Show moreThe hippocampal-medial prefrontal circuit has been shown to serve a critical role in decision making and goal directed actions. While the hippocampus (HF) exerts a direct influence on the medial prefrontal cortex (mPFC), there are no direct return projections from the mPFC to the HF. The nucleus reuniens (RE) of the midline thalamus is strongly reciprocally connected with the HF and mPFC and represents the major link between these structures. We investigated the role of RE in functions associated with the hippocampus and the mPFC -- or their interactions. Using two different inactivation techniques (pharmacological and chemogenetic), we sought to further define the role of RE in spatial working memory (SWM) and behavioral flexibility using a modified delayed non-match to sample (DNMS) working memory task. We found that the reversible inactivation of RE with muscimol critically impaired SWM performance, abolished well-established spatial strategies and produced a profound inability to correct non-rewarded, incorrect choices on the T-maze (perseverative responding). We observed similar impairments in SWM following the chemogenetic (DREADDs) inactivation of RE or selective RE projections to the ventral HF. In addition, we showed that the inhibition of RE terminals to the dorsal or ventral HF altered task related behaviors by increasing or decreasing the time to initiate the task or reach the reward, respectively. Finally, we examined discharge properties of RE cells across sleep-wake states in behaving rats. We found that the majority of RE cells discharge at high rates of activity in waking and REM and at significantly reduced rates in SWS, with a subpopulation firing rhythmically in bursts during SWS. We identified five distinct subtypes of RE cells that discharged differently across vigilant states; those firing at highest rates in waking (W1, W2), in REM sleep (R1, R2) and SWS (S1). Given the differential patterns of activity of these cells, we proposed they may serve distinct functions in waking – and possibly in SWS/REM sleep. In sum, our findings indicate that RE is critically involved in mnemonic and executive functions and the heterogeneous activity of these cells support a role for RE in arousal/attention, spatial working memory and cognition.
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Date Issued
2018
PURL
http://purl.flvc.org/fau/fd/FA00013139
Subject Headings
Midline Thalamic Nuclei, Hippocampus, Prefrontal cortex, Neural pathways, Arousal (Physiology), Space Perception, Cognition
Format
Document (PDF)