theta rhythm


Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.

theta rhythm

n.
A waveform on an electroencephalogram having a frequency of 4 to 8 hertz, recorded chiefly in the hippocampus of carnivorous mammals when they are alert or aroused. Also called theta wave.

the′ta rhythm`


n.
a pattern of brain waves (the′ta waves`) with a frequency of 4 to 7 hertz, occurring during light sleep.
[1945–50]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.theta rhythm - the normal brainwave in the encephalogram of a person who is awake but relaxed and drowsy; occurs with low frequency and low amplitude
brain wave, brainwave, cortical potential - (neurophysiology) rapid fluctuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph
References in periodicals archive ?
Additionally, in behaving animals, long-term potentiation is preferentially induced at the peak of local theta rhythm in hippocampi, and long-term depression is induced in response to stimulation at the trough.[30] Therefore, novel devices need to be developed to stimulate in a closed-loop pattern and controlled by behavioral feedback and brain signals.
(1994) showed that lesions in fornix, fimbria, as well as on medial septal nuclei, might affect theta rhythm in the hippocampus and also memory impairment.
Theta oscillation also plays a crucial network-level role in hippocampal learning and memory; thus, suppression of the theta rhythm impairs learning and memory [61].
However, in general, the theta rhythm index is higher for a three-dimensional than for a two-dimensional perception, especially in the right hemisphere.
Odor 1 and 2 both elicited diffuse slowing, focal slowing, and sharp waves mainly in temporal region and partly in centro-parietal and frontotemporal region, with more right hemispherical involvement, and increased theta rhythm. Odor 2 also produced left hemisphere dominant asymmetry.
During stable anesthesia, changes in the delta and theta rhythm of the parietal cortex were monitored, showing the level of intoxication.
Buzsaki, "Theta rhythm of navigation: link between path integration and landmark navigation, episodic and semantic memory," Hippocampus, vol.
A strong correlation between the phase of theta rhythm and the amplitude of gamma oscillations is also believed to be related to visual stimuli processing and learning [1, 8, 9] and fear-related information processing [10,11].
In the awakened stage the brain has only minimal amount of theta activity and no organized theta rhythm.
Likewise, no group effect was noted for percent time in which each frequency band was observed, except for a significantly greater percent of theta rhythm in the non-medium controls' group compared to MG (p = 0.035), at the post-communication phase (Table 4).