"While meditation formerly
has been understood to comprise mainly passive relaxation states,
recent EEG findings suggest that meditation
is associated with active states which involve cognitive
restructuring and learning."
"Furthermore, the authors describe
that the amplitude of gamma band activity in meditators
was higher than any other gamma band activity previously observed
in healthy human subjects. They speculate that the level
of meditative training can alter the spectral distribution of the
EEG in terms of possible permanent baseline changes. Of course,
further studies are needed to corroborate this interpretation. In
the framework of our hypotheses, these changes are closely related
to an expert level of meditation practice.
In the next chapter, we will describe the relevance of gamma
activity for cortical plasticity and the formation of neural circuits.
We will discuss, how these functions may contribute to the goal
of meditative practice: the development of new states of
consciousness."
"The required delay times for effective Hebbian modification of
synaptic connections by correlated firing of the pre- and postsynaptic
neurons are of the order of less than ±10 ms [81]. Synchronized
high frequency EEG rhythms like gamma activity thus could provide
an optimal condition for the establishment and modification of
Hebbian neural assemblies and therefore may be a crucial mechanism
in associative learning and memory formation. This view is
supported by several recent memory studies [47,82–86].
To conclude, these data suggest that synchronized gamma
activity is highly relevant for neural plasticity and the implementation
of new processing circuits (for a review see e.g. [87]). The
findings of strongly increased synchronized gamma activity in
meditation experts may thus be related to processes of cortical
restructuring and learning. These processes may provide a permanent
neural basis facilitating specific meditation-related states of
consciousness, as well as altered perception and cognition outside
meditation practice."
From alpha to gamma: Electrophysiological correlates of meditation-
related
states of consciousness
Juergen Fell *, Nikolai Axmacher, Sven Haupt
Department of Epileptology, University of Bonn, Sigmund-Freud Str.
25, D-53105 Bonn, Germany
21 February 2010
