Neuroanatomical characterization of inferior collicular seizure genesis: 2-deoxyglucose and stimulation mapping

Previous work has demonstrated that the cortical sub-division of the inferior colliculus is capable of seizure genesis, so the present studies delineated the neuroanatomical extent of this seizure genesis using two mapping techniques, [14C]2-deoxyglucose (2-DG) uptake and electrical stimulation. When 4 inferior collicular seizures were elicited over a 5 min period, the stimulated side of the brain showed highly selective increases in the [14C]2-DG uptake in comparison to the unstimulated side. Although the substantial change in [14C]2-DG uptake occurred over the entire inferior collicular cortex, electrical stimulation mapping delineated a specific area capable of seizure genesis within the inferior collicular cortex. The electrical stimulation also identified a number of regions that would support electrically dependent seizure behaviors: the cuneiform nucleus, the ventrolateral inferior colliculus, portions of the dorsal central gray, and the peripeduncular nucleus. In concert, marked unilateral increases in [14C]2-DG uptake were found on the stimulated side in the peripeduncular/substantia nigra lateralis area, the medial geniculate and a specific region of the dorsal central gray. These studies verify the asymmetric nature of inferior collicular seizure genesis, identify areas of seizure modulation, and delineate a region in the inferior collicular cortex that modulates sensory-motor integration.