Dear Andreas,
>Looking for a good MRI atlas of the brain (to identify functional
>activations), I found Nowinskis and Thirunavuukarasuus software "Brain
>Atlas for functional Imaging", which contains the Talairach-Tournoux
>brain atlas and allows anatomical and functional images to be warped and
>coregistered with the atlas and which, by this, allows the user to
>identify the activation loci.
Im afraid this is not strictly speaking correct. There are only very
approximate spatial relationships between the atlas of Talairach and
Tournoux and the ICBM /MNI space to which we normalise our images. The
atlas is now only appropriate to gain a 'very general' idea of where
activations are. The experiences of many imagers has proved that the
exclusive use of this atlas will often result mislocalisation. Brains in
ICBM space that are normalised to the MNI template are basically of a
different shape to the brain in the Talairach and Tournoux atlas. This is a
debate that has gone on (and on and on...) for the last few years and I
wont bore you with all the details (search for 'Talairach' in the SPM
archives).
There is no method that can localise activity with total accuracy, but one
could be much more confident of a method that superimposes the functional
data in ICBM space onto structural T1 data also in ICBM space, and then use
a 'proper' anatomical atlas to localise the activations based on
sulcal/gyral/other anatomical landmarks. A very suitable atlas is by
Duvernoy (1991) ('The human brain : surface, three-dimensional sectional
anatomy and MRI'; Wien : Springer-Verlag).
Best wishes,
Narender Ramnani
***************************************************
Dr Narender Ramnani
Sensorimotor Control Group,
Department of Physiology,
University of Oxford,
Parks Road,
Oxford OX1 3TP,
United Kingdom.
Oxford University Centre for
Functional Magnetic Resonance Imaging of the Brain,
John Radcliffe Hospital,
Headington,
Oxford OX3 9DU,
United Kingdom.
Tel. 01865 222704 (Direct)
01865 222729 (Admin)
mob. 0771 2632785
Fax. 01865 222717
email [log in to unmask]
*****************************************************
|