Friday, October 30, 2009

The Electroencephalographer's Couch

BRAIN WAVE SOFA, by lucas maassen
The Brain Wave Sofa is a representation of a 3 second wave of Alpha brain activity captured with a 3d EEG.
It shows the 3 seconds when the eyes closed.

From the 3d-EEG the file got directly milled in faom by a 3d milling machine and then upholstred in felt by hand.

in cooperation with Dries Verbruggen (Unfold)
Close your eyes and relax...

However, information aesthetics was a bit wrong when they said the purpose of alpha waves (in the EEG frequency band of 8-12 Hz) is only "to prepare the brain for the large input of signals when one opens the eyes." According to Başar et al. (1997), their function is much more complex:
The old concept stating that EEG alpha (10-Hz) activity reflects passive or idling states of the brain is giving way to modern views of 10-Hz oscillations in relation to diverse brain functions comprising sensory, motor, and memory processes: (1) Spontaneous alpha activity is not pure noise as shown by methods of chaos analysis. (2) Evoked alpha oscillations patterns (precisely time-locked to a stimulus; duration approx. 200-300 ms) depend on the modality of stimulation and the recording site. (3) Induced alpha oscillations are initiated by, but not closely time-locked to a stimulus. (4) 10-Hz oscillations are recorded in nervous systems of different complexities, from the human brain to isolated ganglia of invertebrates. The neural origins of 10-Hz oscillations are demonstrated by recordings at the cellular level. (5) Rather than trying to locate a unique alpha generator, it is preferable to assume that a 'diffuse and distributed alpha system' exists. A particular support for this hypothesis is given by stimulus-dependent hippocampal alpha responses in the cat brain. (6) The major physiological meaning of 10-Hz oscillations may be comparable to the putative universal role of gamma responses in brain signaling.

From Fig. 1A (Hughes & Crunelli, 2007).


Başar E, Schürmann M, Başar-Eroglu C, Karakaş S. (1997). Alpha oscillations in brain functioning: an integrative theory. Int J Psychophysiol. 26:5-29.

Hughes SW, Crunelli V. (2007). Just a phase they're going through: the complex interaction of intrinsic high-threshold bursting and gap junctions in the generation of thalamic alpha and theta rhythms. Int J Psychophysiol. 64:3-17.

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