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Katydid's Site Index

Type Frequency (Hz) Location Normally Pathologically
Delta up to 4 frontally in adults, posteriorly in children; high amplitude waves adults slow wave sleep in babies Has been found during some continuous attention tasks (Kirmizi-Alsan et al. 2006) subcortical lesions diffuse lesions metabolic encephalopathy hydrocephalus deep midline lesions
Theta 4 7 Found in locations not related to task at hand young children drowsiness or arousal in older children and adults idling Associated with inhibition of elicited responses (has been found to spike in situations where a person is actively trying to repress a response or action) (Kirmizi-Alsan et al. 2006). focal subcortical lesions metabolic encephalopathy deep midline disorders some instances of hydrocephalus
Alpha 8 12 posterior regions of head, both sides, higher in amplitude on dominant side. Central sites (c3-c4) at rest . relaxed/reflecting closing the eyes Also associated with inhibition control, seemingly with the purpose of timing inhibitory activity in different locations across the brain (Klimesch, Sauseng, & Hanslmayr 2007; Coan & Allen 2008). coma
Beta 12 30 both sides, symmetrical distribution, most evident frontally; low amplitude waves alert/working active, busy or anxious thinking, active concentration benzodiazepines
Gamma 30 100+ Somatosensory cortex Displays during cross-modal sensory processing (perception that combines two different senses, such as sound and sight) (Kisley & Cornwell 2006; Kanayama, Sato, & Ohira 2007; Nieuwenhuis, Yeung, & Cohen 2004) Also is shown during short term memory matching of recognized objects, sounds, or tactile sensations (Herrmann, Frund, & Lenz 2009) A decrease in gamma band activity may be associated with cognitive decline, especially when related the theta band; however, this has not been proven for use as a clinical diagnostic measurement yet (Moretti et al. 2009).
Mu 8 13 Sensorimotor cortex. Shows rest state motor neurons (Gastaut, 1952).[15] Mu suppression could be indicative for motor mirror neurons working, and deficits in Mu suppression, and thus in mirror neurons, might play a role in autism. (Oberman et al., 2005)[16]
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