thetafrequency

Theta frequency, often called theta rhythm or theta waves, refers to neural oscillations primarily in the theta band of the brain’s electrical activity. In humans this band is typically defined as about 4 to 8 Hz, though some studies use a slightly broader range such as 3 to 7 Hz or up to 8 Hz. In rodents, hippocampal theta tends to occur at somewhat higher frequencies, commonly around 6 to 10 Hz. Theta activity can be measured with electroencephalography ( EEG), magnetoencephalography (MEG), intracranial EEG, or other analyses of local field potentials, and is identified by spectral power in the theta range or by phase relationships across brain regions.

Neural sources and regional distribution vary by species and context. In rodents, the hippocampus and related structures generate robust theta during locomotion and exploration. In humans, theta power is often observed in frontal and temporal regions during memory tasks and cognitive control, with the hippocampus contributing to memory processing. Theta can co-occur with other rhythms such as gamma, and interactions like theta–gamma coupling are proposed to support timing and organization of neural spiking during information processing.

Functions and significance. Theta activity is associated with learning, memory encoding and retrieval, spatial navigation, and planning. It is modulated by task demands and behavioral state, with increases linked to memory processing and navigational computation in certain tasks. Theta–gamma coupling is one hypothesis for how the brain coordinate neural assemblies to encode and retrieve information.

Measurement and relevance. Theta frequency and power are common targets in cognitive neuroscience and clinical research, with individual and regional variability across tasks and populations. Abnormalities in theta-related dynamics have been reported in various neurological and psychiatric conditions, though interpretations depend on context and methodology.