Cortical spreading edema in persistent visual migraine aura.

We present imaging evidence of the spreading of cortical edema with reversibly restricted water diffusion from the left occipital to the temporoparietal cortex in persistent visual migraine aura in a 58-year-old man. The right-sided visual field defect lasting for 15 days was associated with discoupling of glucose metabolism and blood flow and the decreased apparent diffusion coefficient also suggested cytotoxic edema. At 8 weeks no signs were present, and magnetic resonance imaging became normal; therefore, long-lasting restricted cortical water diffusion, even if coupled with hypometabolism and edema, can be reversible in persistent visual migraine aura.

Synaptic targets of commissural interneurons in the lumbar spinal cord of neonatal rats.

There is strong evidence that commissural interneurons, neurons with axons that extend to the contralateral side of the spinal cord, play an important role in the coordination of left/right alternation during locomotion. In this study we investigated the projections of commissural interneurons to motor neurons and other commissural interneurons on the other side of the spinal cord in neonatal rats. To establish whether there are direct contacts between axons of commissural interneurons and motor neurons, we carried out two series of experiments. In the first experiment we injected biotinylated dextran amine (BDA) into the lateral motor column to retrogradely label commissural interneurons that may have direct projections to motor neurons. Stained neurons were recovered in the ventromedial areas of the contralateral gray matter in substantial numbers. In the second experiment BDA was injected into the ventromedial gray matter on one side of the lumbar spinal cord, whereas motor neurons were simultaneously labeled on the opposite side by applying biocytin onto the ventral roots. BDA injections into the ventromedial gray matter labeled a strong axon bundle that arose from the site of injection, crossed the midline in the ventral commissure, and extensively arborized in the contralateral ventral gray matter. Many of these axons made close appositions with dendrites and somata of motor neurons and also with commissural interneurons retrogradely labeled with BDA. The results suggest that commissural interneurons may establish monosynaptic contacts with motor neurons on the opposite side of the spinal cord. Our findings also indicate that direct reciprocal connections between commissural interneurons on the two sides of the spinal cord may also exist.