The theta rhythm organizes neural activity across hippocampus and entorhinal cortex. A role for theta oscillations in spatial navigation is supported by half a century of research reporting that theta frequency encodes running speed linearly so that displacement can be estimated through theta frequency integration. We show that this relationship is an artifact caused by the fact that the speed of freely moving animals could not be systematically disentangled from acceleration. Using an experimental procedure that clamps running speed at pre-set values, we find that the theta frequency of local field potentials and spike activity is linearly related to positive acceleration, but not negative acceleration or speed. The modulation by positive-only acceleration makes rhythmic activity at theta frequency unfit as a code to compute displacement or any other kinematic variable. Temporally precise variations in theta frequency may instead serve as a mechanism for speeding up entorhinal-hippocampal computations during accelerated movement.
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http://dx.doi.org/10.1016/j.neuron.2021.01.017 | DOI Listing |
Hum Brain Mapp
January 2025
FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Turku, Finland.
The brain develops most rapidly during pregnancy and early neonatal months. While prior electrophysiological studies have shown that aperiodic brain activity undergoes changes across infancy to adulthood, the role of gestational duration in aperiodic and periodic activity remains unknown. In this study, we aimed to bridge this gap by examining the associations between gestational duration and aperiodic and periodic activity in the EEG power spectrum in both neonates and toddlers.
View Article and Find Full Text PDFUnlabelled: While visual working memory (WM) is strongly associated with reductions in occipitoparietal 8-12 Hz alpha power, the role of 4-7 Hz frontal midline theta power is less clear, with both increases and decreases widely reported. Here, we test the hypothesis that this theta paradox can be explained by non-oscillatory, aperiodic neural activity dynamics. Because traditional time-frequency analyses of electroencephalopgraphy (EEG) data conflate oscillations and aperiodic activity, event-related changes in aperiodic activity can manifest as task-related changes in apparent oscillations, even when none are present.
View Article and Find Full Text PDFAlzheimers Res Ther
January 2025
Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, Pozuelo de Alarcón, 28223, Spain.
Background: Changes in amyloid beta (Aβ) and phosphorylated tau brain levels are known to affect brain network organization but very little is known about how plasma markers can relate to these measures. We aimed to address the relationship between centrality network changes and two plasma pathology markers: phosphorylated tau at threonine 231 (p-tau231), a proxy for early Aβ change, and neurofilament light chain (Nfl), a marker of axonal degeneration.
Methods: One hundred and four cognitively unimpaired individuals were divided into a high pathology load (33 individuals; HP) group and a low pathology (71 individuals; LP) one.
J Affect Disord
January 2025
Center for Functional Neurosurgery, Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Electronic address:
Background: Parkinson's disease (PD) is primarily characterized by motor symptoms, but patients also experience a relatively high prevalence of non-motor symptoms, including emotional and cognitive impairments. While the subthalamic nucleus (STN) is a common target for deep brain stimulation to treat motor symptoms in PD, its role in emotion processing is still under investigation. This study examines the subthalamic neural oscillatory activities during facial emotion processing and its association with affective characteristics.
View Article and Find Full Text PDFEpilepsia
January 2025
Brain and Mind Electrophysiology Laboratory, Multimedia Systems Department, BioTechMed Center, Gdansk University of Technology, Gdansk, Poland.
Objective: Cognitive deficits are one of the most debilitating comorbidities in epilepsy and other neurodegenerative, neuropsychiatric, and neurodevelopmental brain disorders. Current diagnostic and therapeutic options are limited and lack objective measures of the underlying neural activities. In this study, electrophysiological biomarkers that reflect cognitive functions in clinically validated batteries were determined to aid diagnosis and treatment in specific brain regions.
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