multiband networks; (vi) perception and action can proceed
in discrete ‘snapshots’ involving a-frequency band period-
icity [30,66,71,73,74]. This is natural or even mandatory if
a oscillations are involved in the GNW. Some predictions
associated with this framework are presented in Box 2.
In conclusion, an elucidation of the functional roles of a
oscillations seems to be mandatory to the understanding of
large-scale integration in the brain. Whether a oscillations
mediate idling, inhibition, attention, binding within the
GNW or any combination of these, remains a topic for years
This work was supported by the Academy of Finland and by the Ella and
Georg Ehrnrooth Foundation.
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Box 2. Hypotheses derived from the framework advanced in
Frontoparietal a synchrony should be found during focused
attention, WM and STM, as well as during conscious perception,
cognition and action, but it sho uld not phase lock to the stimulus
processing when the stimu li are subliminal, unattended or are not
consciously perceived for other reasons.
Those a-frequency band oscillations that are not phase locked to
the synchronous frontoparietal network do not belong to the
GNW and thereby might have different functional roles, such as
idling or inhibition.
The interaction between the GNW and the neuronal object
representations should influence the dynamic structure of these
representations according to variations in the cognitive context
(e.g. anaesthetized or awake; attended or ignored; one or multiple
a Oscillations and a–g interactions should be related to the
attentional enhancement of g-frequency band synchrony.
Cross-frequency phase synchrony between the frontoparietal a
network and locally synchronous g-frequency band assemblies
underlies the selection and inclusion of neuronal object repre-
sentations into the focus of attention and sensory awareness.
TRENDS in Neurosciences Vol.xxx No.x
TINS-503; No of Pages 9
Please cite this article in press as: Palva, S. and Palva, J.M., New vistas for a-frequency band oscillations, Trends Neurosci. (2007), doi:10.1016/j.tins.2007.02.001