Oscillatory activity is a candidate mechanism for providing frequency coding for the generation, storage and replay of sequential representations of events and episodes. We recorded local field potentials (LFPs) and spike activity in the striatum, a basal ganglia structure implicated in behavioral action-sequence learning and performance, as rats engaged in spontaneous and instructed behaviors ...

Working memory (WM) is known to be associated with synchronization of the theta and alpha bands observed in electroencephalograms (EEGs). Although frontal-posterior global theta synchronization appears in modality-specific WM, local theta synchronization in frontal regions has been found in modality-independent WM. How frontal theta oscillations separately synchronize with task-relevant sensory...

The phenomenon of disappearance of the theta rhythm after lesioning of the septum and fornix has in its time stimulated a series of reports describing attempts to understand the roles of various structures in determining the electrical activity of the hippocampus and the functional significance of the theta rhythm. In chronic experiments with rabbits have shown that electrical destruction of do...

The caudal cingulate motor area (CMAc) and the supplementary motor area (SMA) play important roles in movement execution. The present study examined the neural mechanisms underlying these roles by investigating local field potentials (LFPs) from these areas while monkeys pressed buttons with either their left or right hand. During hand movement, power increases in the high-gamma (80-120 Hz) and...

Mikulovic, S. 2016. On the Mechanisms Behind Hippocampal Theta Oscillations. The role of OLMα2 interneurons. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 1206. 47 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9542-8. Theta activity is one of the most prominent rhythms in the brain and appears to be conserved among mammals. These 4-12 Hz os...

LEUNG, L. S. Generation of theta and gamma rhythms in the hippocampus. NEUROSCI BIOBEHAV REV 22(2), 275–290, 1998.—In the behaving rat, theta rhythm was dominant during walking and rapid-eye-movement sleep, while irregular slow activity predominated during immobility and slow-wave sleep. Oscillatory evoked potentials of 20–50 Hz and spontaneous fast (gamma) waves were more prominent during thet...

Driven either by external landmarks or by internal dynamics, hippocampal neurons form sequences of cell assemblies. The coordinated firing of these active cells is organized by the prominent "theta" oscillations in the local field potential (LFP): place cells discharge at progressively earlier theta phases as the rat crosses the respective place field ("phase precession"). The faster oscillatio...

During social bargain, one has to both figure out the others' intentions and behave strategically in such a way that the others' behaviors will be consistent with one's expectations. To understand the neurobiological mechanisms underlying these behaviors, we used electroencephalography while subjects played as proposers in a repeated ultimatum game. We found that subjects adapted their offers t...