1
Abteilung Neurophysiologie, Max-Planck-Institut für Hirnforschung, Frankfurt/M, Germany
2
Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Frankfurt/M, Germany
3
University of Maryland School of Medicine, Maryland Psychiatric Research Center, Baltimore, MD, USA
4
Department of Psychology, University of Glasgow, Centre for Cognitive Neuroimaging, Glasgow, UK
5
Brain Imaging Center Frankfurt, Johann Wolfgang Goethe Universität, Frankfurt/M, Germany
6
Department of Cognitive Neuroscience, Faculty of Psychology, Universiteit Maastricht, Maastricht, The Netherlands
7
Abteilung Physiologie kognitiver Prozesse, Max-Planck-Institute für biologische Kybernetik, Tübingen, Germany
Short-term memory requires the coordination of sub-processes like encoding, retention, retrieval and comparison of stored material to subsequent input. Neuronal oscillations have an inherent time structure, can effectively coordinate synaptic integration of large neuron populations and could therefore organize and integrate distributed sub-processes in time and space. We observed field potential oscillations (14–95 Hz) in ventral prefrontal cortex of monkeys performing a visual memory task. Stimulus-selective and performance-dependent oscillations occurred simultaneously at 65–95 Hz and 14–50 Hz, the latter being phase-locked throughout memory maintenance. We propose that prefrontal oscillatory activity may be instrumental for the dynamical integration of local and global neuronal processes underlying short-term memory.