I think Paul hit the nail on the head - so far as we know, a
deactivation simply reflects decreased synaptic activity. it's important
to mention that this could happen for two reasons: it could reflect an
active decrease during the task of interest, or it could reflect an
active increase during the baseline task. There are reasons to think
that both of these may occur in different situations. for example, the
decreases in e.g., auditory cortex seen during demanding visual tasks
may reflect an active decrease due to attentional de-modulation of the
auditory cortex. on the other hand, deactivations in some higher-order
regions may reflect the active engagement of conceptual processes during
the resting state.
cheers
russ
Li Tianhao wrote:
> Dear SPMers,
>
> Although I read some emails here, I am still confused by the question of
> deactivation. Who can give me any implication about the physiological
> basis
> of deactivation? Thanks a lot.
>
> tianhao
>
>
>
> _________________________________________________________________
> Join the world s largest e-mail service with MSN Hotmail.
> http://www.hotmail.com
--
Russell A. Poldrack, Ph.D.
Assistant Professor
UCLA Department of Psychology
Franz Hall, Box 951563
Los Angeles, CA 900095-1563
Phone: 310-794-1224
FAX: 310-206-5895
email: [log in to unmask]
web: http://www.poldracklab.org/
|