*Present address: F.C. Donders Centre for Cognitive Neuroimaging, PO Box 9101, NL-6500 HB Nijmegen, The Netherlands.
Frontal theta activity in humans increases with memory load in a working memory task
Version of Record online: 2 MAY 2002
European Journal of Neuroscience
Volume 15, Issue 8, pages 1395–1399, April 2002
How to Cite
Jensen, O. and Tesche, C. D. (2002), Frontal theta activity in humans increases with memory load in a working memory task. European Journal of Neuroscience, 15: 1395–1399. doi: 10.1046/j.1460-9568.2002.01975.x
- Issue online: 2 MAY 2002
- Version of Record online: 2 MAY 2002
- Received 4 September 2001, revised 19 February 2002, accepted 11 March 2002
- prefrontal cortex;
- short-term memory;
- Sternberg task
Recent theoretical work has suggested that brain oscillations in the theta band are involved in active maintenance and recall of working memory representations. To test this theoretical framework we recorded neuromagnetic responses from 10 subjects performing the Sternberg task. Subjects were required to retain a list of 1, 3, 5 or 7 visually presented digits during a 3-s retention period. During the retention period we observed ongoing frontal theta activity in the 7–8.5-Hz band recorded by sensors over frontal brain areas. The activity in the theta band increased parametrically with the number of items retained in working memory. A time–frequency analysis revealed that the task-dependent theta was present during the retention period and during memory scanning. Following the memory task the theta activity was reduced. These results suggest that theta oscillations generated in frontal brain regions play an active role in memory maintenance.