Summary:Purpose: A nonhuman primate model of generalized absence status epilepticus was developed for use in functional magnetic resonance imaging (f MRI) experiments to elucidate the brain mechanisms underlying this disorder.Methods: Adult male marmoset monkeys (Callithrix jacchus) were treated with γ -butyrolactone (GBL) to induce prolonged absence seizures, and the resulting spike-wave discharges (SWDs) were analyzed to determine the similarity to the 3-Hz SWDs that characterize the disorder. In addition, bloodoxygenation-level-dependent (BOLD) f MRI was measured at 4.7 Tesla after absence seizure induction with GBL.Results: Electroencephalographic recordings during imaging showed 3-Hz SWDs typical of human absence seizures. This synchronized EEG pattern started within 15 to 20 min of drug administration and persisted for >60 min. In addition, pretreatment with the antiepileptic drug, ethosuximide (ESM), blocked the behavioral and EEG changes caused by GBL. Changes in BOLD signal intensity in the thalamus and sensorimotor cortex correlated with the onset of 3-Hz SWDs. The change in BOLD signal intensity was bilateral but heterogeneous, affecting some brain areas more than others. No significant negative BOLD changes were seen.Conclusions: The BOLD f MRI data obtained in this marmoset monkey model of absence status epilepticus shows activation within the thalamus and cortex. Key Words: Absence seizuref MRI-Epilepsy-Marmoset-Monkey.Absence epilepsy consists of seizures causing multiple, brief impairments of consciousness with characteristic bilaterally synchronous 3-Hz spike-and-wave discharges (SWDs) on electroencephalography (EEG). A typical absence seizure is manifested behaviorally as a "staring spell" and can be accompanied by atonic postures and/or automatisms (1).Nonhuman primate models of generalized epilepsy have been used for many years to study convulsive seizures (2-6). A few studies have demonstrated that nonhuman primates mimic the behavior and characteristic EEGs of childhood absence epilepsy, producing SWDs with a frequency of 3 Hz (7,8). Because rodent models of absence seizures produce SWDs of 7 to 11 Hz, the nonhuman primates are better suited to study the pathophysiology of the disorder.γ -Hydroxybutyric acid (GHB) is a naturally occurring metabolite of the inhibitory neurotransmitter γ -aminobutyric acid (GABA). Primates and rodents given GHB show behavioral and EEG changes consistent with

Cerebral arterial infarction is a more common cause of neonatal seizures than has been previously appreciated. In 50 full-term newborns with seizures studied, 7 had cerebral infarction which was the second most common definable cause of seizures. We describe these 7 full-term infants with cerebrovascular accidents who presented with focal or generalized seizures. Obstetrical histories were normal in 5 of these patients. Their neurological examinations demonstrated lethargy and generalized hypotonia. Electroencephalograms demonstrated focal abnormalities in 4 infants. Computed tomographic scans in the first week of life showed infarctions in 6 newborns and in another at age 6 months. Neonatal stroke should be considered as a cause of seizures in a full-term newborn in spite of a normal obstetrical history and a nonfocal neurological examination.

No abstract

An 8-year-old boy presented in coma and was found to have a massive posterior fossa hemorrhage on computed tomographic scan. Autopsy disclosed a large cerebellar hematoma within a mixed glioma containing both juvenile pilocytic astrocytoma and oligodendroglioma. It is postulated that the hemorrhage originated from the oligodendroglial component of the tumor.

The principal neuropathologic abnormality observed in three autopsy cases of Menkes steely hair syndrome was widespread nerve cell loss and gliosis, especially severe in the cerebral and cerebellar cortex and in the relay nuclei of the thalamus. Granular stellate cells of neocortical layer IV and the granule cells of the cerebellum are cell classes which were particularly severely depopulated. The degree of reduction of myelinated axons is consistent with axonal degeneration secondary to nerve cell loss. There are also prominent abnormalities in the patterns of dendritic arborization of surviving cortical pyramids and cerebellar Purkinje cells as seen in Golgi impregnations. The deviant neuronal forms are probably due, in part, to failure of innervation by afferent fiber systems during the fetal as well as postnatal epochs.