Abstract
Changes in alpha band power (8-13Hz) with eye state has been well documented (i.e., closing or opening the eyes; Berger, 1939), with closing increasing alpha power (synchronization) and opening decreasing alpha (desynchronization). With increased cognitive load, similar changes have been demonstrated for motor imagery, with alpha desynchronization in recruited areas and synchronization in task-irrelevant areas (Pfurtscheller et al., 1999). However, the interaction of eye state and cognitive load on alpha power has never been examined in a single study. In a sample of n=30 subjects trained to move to music (dance, figure skating, and gymnastics), continuous electroencephalography (EEG) activity was recorded during three tasks: (i) baseline accompanied by music, (ii) observational learning of a brief dance sequence, and (iii) kinesthetic motor imagery (KMI) of the newly learned dance. KMI involves imagining oneself performing movement from a first-person internal perspective, and was examined in two conditions dependent on eye state. Our results confirm a main effect of higher alpha power with eyes closed (F(1,29)=36.2, P<0.001, η2=0.56) and an interaction with eye state and cognitive load (F(5,145)=9.4, P<0.001, η2=0.24): alpha power was lower during KMI relative to baseline when eyes are closed in occipital and right parietal recording sites (P<0.05), but was significantly greater during KMI in the eyes open condition in all but left temporal recording sites (P<0.01). Most importantly, subjective ratings of clarity and vividness of KMI were significantly reduced during the eyes open condition (P<0.01). Together, these results suggest that both alpha power and the ability to effectively engage in KMI are modulated by eye state. We provide evidence for alpha synchronization and diminished KMI ability relative to baseline when eyes are open, and that this trend is reversed when eyes are closed. This may explain why people will usually close their eyes during mental rehearsal.
Meeting abstract presented at VSS 2014