How and when plume zonation appeared during the 132 Myr evolution of the Tristan Hotspot

Increasingly, spatial geochemical zonation, present as geographically distinct, subparallel trends, is observed along hotspot tracks, such as Hawaii and the Galapagos. The origin of this zonation is currently unclear. Recently zonation was found along the last B70 Myr of the Tristan-Gough hotspot track. Here we present new Sr–Nd–Pb–Hf isotope data from the older parts of this hotspot track (Walvis Ridge and Rio Grande Rise) and re-evaluate published data from the Etendeka and Parana flood basalts erupted at the initiation of the hotspot track. We show that only the enriched Gough, but not the less-enriched Tristan, component is present in the earlier (70–132 Ma) history of the hotspot. Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle

Intractable reflex audiogenic seizures in Aicardi syndrome.

Aicardi syndrome (AS) is a rare disorder which includes the triad of total or partial agenesis of the corpus callosum, infantile spasms, and chorioretinal anomalies. Seizures and electroencephalogram findings observed in AS are polymorphic with both focal and generalized seizures. We first report on a patient affected by AS who presented with reflex audiogenic seizures specifically triggered by the starting tune of a popular television news. No other type of stimuli, either simple or complex, were able to precipitate the seizures in the patient. The severe cortical-subcortical lesions commonly observed in AS are associated with hyperexcitability of the cortices and may well account for the broad electroclinical patterns noted in this group of patients. From our report, the context of these patterns should be extended to include reflex audiogenic seizures

Hot water epilepsy and focal malformation of the parietal cortex development.

Hot water epilepsy (HWE) refers to a specific type of reflex epilepsy precipitated by the stimulus of bathing in hot water. HWE is considered to be a geographically specific epileptic syndrome since it mainly occurs in the Indian community. Spontaneous seizures may also occur later in life. The seizure pattern includes complex partial attacks. Although the pathogenesis of HWE is still unknown, temporal lobe has been thought to take part in the epileptogenesis. This paper reports on a 4-year-old girl who, at the age of 6 months, experienced complex partial seizures triggered by bathing in hot water. Non-provoked seizures intercritical EEG showed isolated spikes and spike-and-waves in the left parietal region. Brain MRI detected a left parietal focal cortical dysplasia. This is the second patient with HWE in whom a cortical malformation has been observed. The observation present here and data reported in the literature seem to indicate that the sensory cortex might also be involved in triggering seizures precipitated by a bath in hot water. Moreover, the authors believe that MRI examination should be considered for this group of patients