Genes influence the amplitude and timing of brain hemodynamic responses

- Heritability of the hemodynamic response function (HRF) was investigated using fMRI data from 558 twins.
- Genetic factors accounted for a significant proportion of the variation in HRF temporal profile and amplitude.
- Genetic influences on brain neurovascular coupling may be important in understanding disorders with abnormal hemodynamics.

In functional magnetic resonance imaging (fMRI), the hemodynamic response function (HRF) reflects regulation of regional cerebral blood flow in response to neuronal activation. The HRF varies significantly between individuals. This study investigated the genetic contribution to individual variation in HRF using fMRI data from 125 monozygotic (MZ) and 149 dizygotic (DZ) twin pairs. The resemblance in amplitude, latency, and duration of the HRF in six regions in the frontal and parietal lobes was compared between MZ and DZ twin pairs. Heritability was estimated using an ACE (Additive genetic, Common environmental, and unique Environmental factors) model. The genetic influence on the temporal profile and amplitude of HRF was moderate to strong (24%-51%). The HRF may be used in the genetic analysis of diseases with a cerebrovascular etiology.