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SUMMARY:Continuous control of brain computer interfaces based on a covert 
 spatial attention paradigm - Ali Bahramisharif (Radboud University Nijmege
 n)
DTSTART:20100914T100000Z
DTEND:20100914T110000Z
UID:TALK26190@talks.cam.ac.uk
CONTACT:Zoubin Ghahramani
DESCRIPTION:While brain-computer interfaces (BCIs) can be used for control
 ling external devices\, they also hold the promise of providing a new tool
  of studying the working brain. In this work we investigated whether modul
 ations of brain activity by changes in covert attention can be used as a c
 ontinuous control signal for BCI. Covert attention is the act of mentally 
 focusing on a peripheral sensory stimulus without changing gaze direction.
  The ongoing brain activity was recorded using magnetoencephalography in s
 ubjects while they covertly attended to a moving cue while maintaining fix
 ation. Based on posterior alpha power alone\, the direction to which subje
 cts were attending could be recovered using circular regression. Results s
 how that the angle of attention could be predicted with a mean absolute de
 viation of 51 degrees in our best subject. Averaged over subjects\, the me
 an deviation was approximately 70 degrees. In terms of information transfe
 r rate\, the optimal data length used for recovering the direction of atte
 ntion was determined to be 1700 ms which resulted in a mean absolute devia
 tion of 60 degrees for the best subject. The results were obtained without
  any subject-specific feature selection and did not require prior subject 
 training. Our findings demonstrate that modulations of posterior alpha act
 ivity due to the direction of covert attention has potential as a control 
 signal for continuous control in a BCI setting. Our approach will have sev
 eral applications\, including a brain-controlled computer mouse and improv
 ed methods for neuro-feedback that allow direct training of subjects’ ab
 ility to modulate posterior alpha activity.\n
LOCATION:Engineering Department\, CBL Room 438
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