Fig. 1From: Insomniacs show greater prefrontal activation during verbal fluency task compared to non-insomniacs: a functional near-infrared spectroscopy investigation of depression in patientsThe VFT protocol used for near-infrared spectroscopy. Each trial consisted of a 30Â s pre-task rest period, a 60Â s task period subdivided into four 15Â s blocks and finally a 60Â s post-task rest periodBack to article page