References (please cite both):

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).

MK Belmonte. In preparation - for updated reference contact

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