A pilot study for investigating cortical binocularity in humans using fMRI adaptation.
Disrupted stereovision is a feature that accompanies strabismus. This study uses an fMRI adaptation paradigm to assess the amount of cortical binocularity in subjects with normal or impaired stereopsis. We present data from a pilot study of two normally-sighted and one stereodeficient subject with alternating fixation. We adapted one eye to diagonally oriented sinusoidal gratings and tested either the same (monocular test) or the other eye (interocular transfer), using either the same or an orthogonal orientation. In normally-sighted subjects, we observed monocular adaptation but only weak interocular transfer in the striate cortex, whereas in the extrastriate cortex we found strong monocular as well as interocular adaptation. In the stereodeficient subject, monocular adaptation but no interocular transfer was obtained in the extrastriate cortex. These results suggest that impaired stereopsis is related to reduced interocular transfer of adaptation at higher levels of the cortical visual pathway.
Jurcoane
Alina
A
Department of Neurophysiology, Max Planck Institute for Brain Research, Johann Wolfgang Goethe-University, Frankfurt/M., Germany.
Choubey
Bhaskar
B
Muckli
Lars
L
Sireteanu
Ruxandra
R
D000221:Adaptation, Ocular / Q000502:physiology*; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010468:Perceptual Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D010775:Photic Stimulation; D010865:Pilot Projects; D012720:Severity of Illness Index; D013285:Strabismus / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D015349:Vision, Monocular / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*