fNIRS measure of transitive and intransitive gesture execution, observation and imagination in ecological setting: A pilot study

To explore the presence of differential cortical hemodynamic activations related to cognitive components of actions, we performed a fNIRS (functional Near-Infrared Spectroscopy) study during Observation (O), Execution (E) and Imagination (I) of complex and meaningful (transitive and intransitive) gestures in ecological setting. A pilot sample of 5 healthy adults underwent an event-related study consisting of these 3 different conditions, with O set as first and followed by a randomized presentation of E or I. fNIRS measurements were performed using a 24 channel array of optodes (8 light injectors and 8 detectors) placed over the contralateral central, centro-parietal, parietal and temporal areas. Results showed that the premotor (PMC) and the sensory-motor cortices (SM1) were recruited selectively during E, with levels of oxygenated hemoglobin (oxy-Hb) higher than the other conditions, while the posterior parietal cortex (PPC) showed increased oxy-Hb levels for both E and O. These data suggest that variations in hemodynamic responses can be attributed to different neural processes underpinning these tasks, with PMC and SM1 being more involved in action preparation and performance, and PPC prevalently dedicated to attentive processes related to the execution and observation of limb movements.