Dear Patrick,
the HRF function consists of two parts (gamma functions) with
delay patameter (default)
p(1) - delay of response (relative to onset) 6
p(2) - delay of undershoot (relative to onset) 16
This results in a fuction with peak at about 5 seconds
corresponding to experimental findings e.g. from optical recordings.
(Vanzetta and Grinvald, Science 1999; 286:1555-1558)
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Dr. Michael Erb
Sektion f. experimentelle Kernspinresonanz des ZNS
Abteilung Neuroradiologie
Universitaetsklinikum
Hoppe-Seyler_Str. 3, D-72076 Tuebingen
Tel.: +49(0)7071/2985398 priv. +49(0)7071/61559
Fax.: +49(0)7071/294371
e-mail: <[log in to unmask]>
www: http://www.medizin.uni-tuebingen.de/nrad/sektion
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