BOLD correlations to force in precision grip: an event-related study.

The introduction of functional neuroimaging has resulted in a profusion of knowledge on various topics, including how blood oxygenation level dependent (BOLD) signal in the brain is related to force. To date, studies that have explicitly examined this relationship have used block designs. To gain a better understanding of the networks involved in human motor control, analyses sensitive to temporal relationships, such as Granger Causality or Dynamic Causal Modeling, require event-related designs. Therefore the goal of this experiment was to examine whether similar or even better relationships between BOLD and force during precision grip could be determined with an event-related design. Five healthy subjects exerted forces at 10%, 20% and 30% of maximum voluntary force, along with an observation condition. We report that the BOLD signal was linearly correlated with precision grip force in primary sensorimotor cortex and cerebellum, showing slightly better correlations than previous work. The results provide a clearer picture regarding the sensitivity of BOLD signal to force and show that event-related designs can be more appropriate than block designs in motor tasks.