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Central pathway of photic reflex myoclonus
T Kanouchi1, T Yokota, T Kamata
1Department of Neurology, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Japan.
Journal of Neurology, Neurosurgery, and Psychiatry
|April 1, 1997
Summary
This study provides new evidence that photic reflex myoclonus originates in the cortex. Photic stimulation activates the occipital cortex, leading to myoclonic jerks in the contralateral limb.
Area of Science:
- Neuroscience
- Neurology
- Epileptology
Background:
- Photic reflex myoclonus is a neurological condition characterized by involuntary muscle jerks triggered by visual stimuli.
- The precise origin and central pathway of this reflex remain incompletely understood.
Observation:
- Photic stimulation in a patient with posterior cortical atrophy induced myoclonic jerks in the right upper limb.
- Neuroimaging revealed increased cerebral blood flow in the striate cortices and left premotor/motor areas during photic stimulation.
Findings:
- Transcranial magnetic stimulation over the left occipital cortex elicited motor evoked potentials in the right upper limb muscles.
- This suggests the left occipital cortex plays a crucial role in the photic reflex pathway.
Implications:
- The findings indicate that the cortical origin of photic reflex myoclonus involves activation of the contralateral occipital cortex.
- This activation propagates intrahemispherically to the primary motor cortex, initiating the myoclonic jerks.
- This study enhances our understanding of the neurophysiological mechanisms underlying reflex myoclonus.