The theta rhythm is the largest extracellular synchronous signal that can be recorded from the mammalian brain and has been strongly implicated in mnemonic processes of the hippocampus. We describe (a) ascending brain stem-forebrain systems involved in controlling theta and nontheta (desynchronization) states of the hippocampal electroencephalogram; (b) theta rhythmically discharging cells in several structures of Papez's circuit and their possible functional significance, specifically with respect to head direction cells in this same circuit; and (c) the role of nucleus reuniens of the thalamus as a major interface between the medial prefrontal cortex and hippocampus and as a prominent source of afferent limbic information to the hippocampus. We suggest that the hippocampus receives two main types of input: theta rhythm from ascending brain stem- diencephaloseptal systems and information bearing mainly from thalamocortical/cortical systems. The temporal convergence of activity of these two systems results in the encoding of information in the hippocampus, primarily reaching it from the entorhinal cortex and nucleus reuniens.
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http://dx.doi.org/10.1177/1534582304273594 | DOI Listing |
Hum Brain Mapp
January 2025
The Mind Research Network/Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA.
Evaluation of mechanisms of action of EEG neurofeedback (EEG-nf) using simultaneous fMRI is highly desirable to ensure its effective application for clinical rehabilitation and therapy. Counterbalancing training runs with active neurofeedback and sham (neuro)feedback for each participant is a promising approach to demonstrate specificity of training effects to the active neurofeedback. We report the first study in which EEG-nf procedure is both evaluated using simultaneous fMRI and controlled via the counterbalanced active-sham study design.
View Article and Find Full Text PDFBrain Behav
January 2025
Research Institute for Health Sciences and Technologies (SABITA), Neuroscience Research Center, Clinical Electrophysiology, Neuroimaging and Neuromodulation Lab, Istanbul Medipol University, Istanbul, Turkey.
Introduction: The neural substrates of reasoning, a cognitive ability we use constantly in daily life, are still unclear. Reasoning can be divided into two types according to how the inference process works and the certainty of the conclusions. In deductive reasoning, certain conclusions are drawn from premises by applying the rules of logic.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Airborne exists widely in the natural environment and is closely related to human health. Growing evidence indicates that environmental air pollution elevates the risk of depressive disorders. However, the potential role of airborne in the development of depression remains unclear.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of General Medicine, Shizuoka Saiseikai General Hospital, Shizuoka 422-8527, Japan.
(1) Background: Delirium is a serious condition in patients undergoing treatment for somatic diseases, leading to poor prognosis. However, the pathophysiology of delirium is not fully understood and should be clarified for its adequate treatment. This study analyzed the relationship between confusion symptoms in delirium and resting-state electroencephalogram (EEG) power spectrum (PS) profiles to investigate the heterogeneity.
View Article and Find Full Text PDFHippocampus
January 2025
Cognitive Science Program and Department of Psychology, University of Arizona, Tucson, Arizona, USA.
Numerous scientific advances and discoveries have arisen from research on the hippocampal formation. This special issue provides first-person historical descriptions of these advances and discoveries in hippocampal research, written by those directly involved in the research. This is the first section of a special issue that will also include future articles on this topic.
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