| dc.description.abstract | P300 is elicited in an oddball paradigm and associated with attention. In this study, we aim to establish a novel protocol using 3-D Virtual Reality technique to elicit the somatosensory P300 components.
Twelve healthy, right-handed subjects were instructed to perform a ball catch task using their dominant hand under a 3-D Virtual Reality scheme. The ball catch task has two conditions: standard (with force feedback) and target (without force feedback), with the 479 and 121 trials (i.e. 80% and 20% occurring rate), respectively. The feedback force in the standard condition was delivered to the subjects via a haptic feedback system. 32 channels electroencephalogram (EEG) were recorded with 250 Hz sampling rate during the task. The data were epoched from -500 to +2500 ms, and filtered with 0.1-59 Hz band-pass filter. The window of interest was set to be between +248 to +800 ms after ball catch. Independent Component Analysis (ICA) was employed to remove the electrooculogram (EOG) interference according to spatial and temporal criteria.
There is strong evidence suggesting that P300 components were elicited at Pz (p<0.001), P3 (P<0.001) and P4 (P<0.001) in all subjects. The mean peak amplitudes are 8.1±3.4, 7.2±3.8, and 6.5±3.2μV, and the mean peak latencies are 549±108, 617±125, and 563±129ms at Pz, P3 and P4, respectively. In addition, ICA could remove the EOG contamination effectively.
In conclusion, we have shown that 3-D Virtual Reality technique can be used to elicit the somatosensory P300 components reliably and Independent Component Analysis could increase the Signal-to-Noise Ratio of brain signals by removing the unwanted EOG components. It provides direct evidence that Virtual Reality technique is feasible for studying brain function. As VR technique can provide a simulated environment which is easy to manipulate and control, we believe that the outcome of this study could serve as a reference point of sensory P300 study and could most benefit the studies of motor recovery during rehabilitation after stroke in the future as in those studies, the control of task parameters is crucial.
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