theta rhythm

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.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

the′ta rhythm`

a pattern of brain waves (the′ta waves`) with a frequency of 4 to 7 hertz, occurring during light sleep.

[1945–50]

ThesaurusAntonymsRelated WordsSynonymsLegend:

Noun

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

theta wave

brain wave, brainwave, cortical potential - (neurophysiology) rapid fluctuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph

Mentioned in

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.

Status of Noninvasive Brain Stimulation in the Therapy of Alzheimer's Disease

(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.

Assessment of serotonergic system in formation of memory and learning/ Avaliacao do sistema serotonergico na formacao de memoria e aprendizagem

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].

Electroacupuncture Treatment Alleviates the Remifentanil-Induced Hyperalgesia by Regulating the Activities of the Ventral Posterior Lateral Nucleus of the Thalamus Neurons in Rats

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.

Odor-induced modulation of electroencephalogram waves in healthy controls

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].

A Consistent Definition of Phase Resetting Using Hilbert Transform

In the awakened stage the brain has only minimal amount of theta activity and no organized theta rhythm.

EEG based wheelchair navigation for paralysis patients

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).

Frontal electroencephalographic (EEG) activity and mediumship: a comparative study between spiritist mediums and controls