Neural activity in readiness for incidental and explicitly timed actions

Voluntary, self-initiated actions are preceded by slowly increasing neural activity in pre-motor regions of the brain, beginning up to 2s before the onset of muscle movement. This activity is commonly seen in the scalp-recorded readiness potential, and is an index of movement preparation involving both motor programming and non-motor or cognitive processes such as attention. The specific contribution of cognitive processes, thought to occur during the earliest stage of planning, remains somewhat unclear. We suggest that attention to the timing of movement is a key voluntary process contributing to early-stage cortical activity. As a novel approach to examining this, we recorded EEG throughout a time reproduction task in which participants replicated the interval between two tones with two button-press actions. The first action, i.e. the beginning of the reproduced interval, was somewhat incidental to the task of time reproduction and required minimal attention to the time of initiation, while the second action required explicit attention to the time of initiation. Pre-movement neural activity preceding the first, relatively unattended movement was greatly reduced in amplitude and almost absent in the early stage, in contrast with readiness potentials typically seen prior to voluntary movement. Neural activity preceding explicitly timed movements was significantly larger, with effects emerging in the early component of pre-movement activity over frontal and right frontal scalp regions. We propose that attention to movement timing, i.e. the process of orienting attention in time towards the moment of movement initiation, is a key component of voluntary action preparation that is reflected in the early-stage neural activity we typically see prior to voluntary movement.     

Effects of Inhaled Rosemary Oil on Subjective Feelings and Activities of the Nervous System

Rosemary oil is one of the more famous essential oils widely used in aroma-therapy. However, the effects of rosemary oil on the human body, in particular the nervous system, have not been sufficiently studied. This study investigates the effects of the inhalation of rosemary oil on test subjects’ feelings, as well as its effects on various physiological parameters of the nervous system. Twenty healthy volunteers participated in the experiment. All subjects underwent autonomic nervous system (ANS) recording. This consisted of measurements of skin temperature; heart rate; respiratory rate; blood pressure; evaluations of the subjects’ mood states; and electroencephalography (EEG) recordings in the pre-, during treatment, and post-rosemary inhalation periods as compared with control conditions. Our results showed significant increases in blood pressure, heart rate, and respiratory rate after rosemary oil inhalation. After the inhalation treatments, subjects were found to have become more active and stated that they felt “fresher”. The analysis of EEGs showed a reduction in the power of alpha1 (8–10.99 Hz) and alpha2 (11–12.99 Hz) waves. Moreover, an increment in the beta wave (13–30 Hz) power was observed in the anterior region of the brain. These results confirm the stimulatory effects of rosemary oil and provide supporting evidence that brain wave activity, autonomic nervous system activity, as well as mood states are all affected by the inhalation of the rosemary oil.