Gamma Oscillations Correlate with Working Memory Load in Humans

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 13; no. 12; pp. 1369 - 1374
• Main Authors: Howard, Marc W., Rizzuto, Daniel S., Caplan, Jeremy B., Madsen, Joseph R., Lisman, John, Aschenbrenner-Scheibe, Richard, Schulze-Bonhage, Andreas, Kahana, Michael J.
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.12.2003; Oxford Publishing Limited (England)
• Subjects: Brain Mapping - methods; Cerebral Cortex - physiopathology; Child; Epilepsy - physiopathology; Female; gamma oscillations; Humans; iEEG; Male; Memory, Short-Term; Neurons; Statistics as Topic; working memory
• ISSN: 1047-3211; 1460-2199; 1460-2199
• DOI: 10.1093/cercor/bhg084

Functional imaging of human cortex implicates a diverse network of brain regions supporting working memory — the capacity to hold and manipulate information for short periods of time. Although we are beginning to map out the brain networks supporting working memory, little is known about its physiological basis. We analyzed intracranial recordings from two epileptic patients as they performed a working memory task. Spectral analyses revealed that, in both patients, gamma (30–60 Hz) oscillations increased approximately linearly with memory load, tracking closely with memory load over the course of the trial. This constitutes the first evidence that gamma oscillations, widely implicated in perceptual processes, support the maintenance of multiple items in working memory.