Imaging the visual autokinetic illusion with fMRI.
During fixation of a stationary, dim light-emitting diode (LED) in complete darkness, a subtle, apparent motion is perceived which is called autokinesis. This autokinetic illusion increases with increasing fixation time. Eleven healthy subjects were examined by fMRI while fixating an LED in darkness for 35 s. BOLD signal changes of the first and the second half of the fixation period were compared. While the stimulus was the same for both periods, perception differed in that autokinesis was more pronounced in the second half. This second half of the period was associated with bilateral activations in the motion-sensitive middle occipito-temporal area known as MT/V5. Our finding suggests that area MT/V5 is involved in the mediation of autokinesis.
Riedel
Eva
E
Department of Neurology, Ludwig-Maximilians University, Klinikum Grosshadern, Marchioninistr. 15, D-81377 Munich, Germany. Eva.Riedel@nro.med.uni-muenchen.de
Stephan
Thomas
T
Deutschländer
Angela
A
Kalla
Roger
R
Wiesmann
Martin
M
Dieterich
Marianne
M
Brandt
Thomas
T
D000328:Adult; D001921:Brain / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007088:Illusions / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation
D010100:Oxygen