Half-cosine HRF

Segments: 0->f1 (h1), f1->1 (h2), 1->f2 (h3), f2->0 (h4). Negative f1 gives an initial dip; negative f2 gives an undershoot. Peak is at t = h1 + h2 (amplitude 1 by construction).

Usage

hrf_half_cosine(t, h1 = 1, h2 = 5, h3 = 7, h4 = 7, f1 = 0, f2 = 0)

Arguments

t

Numeric vector of times (s)

h1, h2, h3, h4

Segment durations (s). Must be > 0.

f1

Initial dip level (default 0), typically in [-0.2, 0]

f2

Undershoot level (default 0), typically in [-0.3, 0]

Value

Numeric vector same length as t

Examples

t <- seq(0, 30, by = 0.1)
y <- hrf_half_cosine(t)