In addition to perceptual processing, gamma-band activity accompanies also many other cognitive functions like attention [4,5], arousal [6], object recognition [7,8], and language perception [9,10].


4 Tiitinen, H. et al. (1993)
Selective attention enhances the auditory 40-Hz transient response in humans.
Nature 364, 59.60

5 Pantev, C. et al. (1991) 
Human auditory evoked gamma-band magnetic fields.
Proc. Natl. Acad. Sci. U. S. A. 88, 8996.9000

6 StruNber, D. et al. (2000) 
Reversal-rate dependant differences in the EEG gamma-band during multistable perception. 
Int. J. Psychophysiol. 38, 243.252

7 Basar, E. et al. (2000) 
Brain oscillations in perception and memory. 
Int. J. Psychophysiol. 35, 95.124

8 Keil, A. et al. (1999) 
Human gamma band activity and perception of a gestalt.
J. Neurosci. 19, 7152.7161

9 PulvermuN ller, F. et al. (1995) 
Spectral responses in the gamma-band: physiological signs of higher cognitive processes.
Neuroreport 6, 2059.2064

10 Eulitz, C. et al. (1996) 
Oscillatory neuromagnetic activity induced by language and non-language stimuli. 
Brain Res. Cogn. Brain Res. 4, 121.132

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"The same paradigm was also applied to human subjects and enhanced gamma activity was found for one coherently moving object [19]."

19 Muller, M.M. et al. (1996) 
Visually induced gamma-band responses in human electroencephalographic activity: a link to animal studies.
Exp. Brain Res. 112, 96.102

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These data show that coherent activity in the gamma-band is enhanced during attentional selection of sensory information.

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Based on computer simulations, cellular mechanisms have been suggested for how oscillatory synchronization of neurons could be used for attentional selection [27].


27 Niebur, E. et al. (1993) 
An oscillation-based model for the neuronal basis of attention.
Vision Res. 33, 2789.2802


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Therefore, it seems important to differentiate the processes of attention and binding when investigating their influence on gamma responses [30].

30 Herrmann, C.S. et al. (1999)
Gamma responses and ERPs in a visual classification task. 
Clin. Neurophysiol. 110, 636.642

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When testing which of the two modulations, binding or attention, is more relevant for gamma activity the latter seems to dominate over the former. If directly compared, attention towards targets leads to larger evoked gamma-band responses in human EEG than binding together illusory figures (Figure 1c) [31].