7.1.398. balloonΒΆ

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References (please cite both):

THEORETICAL MODEL: RB Buxton, EC Wong, LR Frank. Dynamics of blood flow and oxygenation changes during brain activation: the balloon model. Magnetic Resonance in Medicine 39(6):855-864 (1998).

PRACTICAL IMPLEMENTATION: MK Belmonte. In preparation - for updated reference contact belmonte@mit.edu

USAGE: balloon TR N event_times [ t_rise t_sustain t_fall ] TR: scan repetition time in seconds

(the output curve will be sampled at this interval)

N: number of scans (the output curve will comprise this number of samples) event_times: The name of a file containing the event timings, in seconds, as

ASCII strings separated by white space, with time 0 being the time at which the initial scan occurred.

t_rise: haemodynamic rise time in seconds (typically between 4s and 6s) t_sustain: haemodynamic sustain in seconds (typically between 0s and 4s) t_fall: haemodynamic fall time in seconds (typically between 4s and 6s)

If t_rise, t_sustain, and t_fall aren’t specified on the command line, then the program will expect to find event-related values of these parameters to the right of each entry in the event file, separated by spaces: in this case each line of the event file must contain exactly four numbers - the event time, the haemodynamic rise time for this event, the haemodynamic sustain time for this event, and the haemodynamic fall time for this event. (These event-related values could for example be made to depend on a behavioural variable such as reaction time.)

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