Motion and pattern cortical potentials in adults with high-functioning autism spectrum disorder

Purpose: Autism spectrum disorder (ASD) is a condition in which visual perception to both static and moving stimuli is altered. The aim of this study was to investigate the early cortical responses of subjects with ASD to simple patterns and moving radial rings using visual evoked potentials (VEPs). Methods: Male ASD participants (n = 9) and typically developing (TD) individuals (n = 7) were matched for full, performance and verbal IQ (p > 0.263). VEPs were recorded to the pattern reversing checks of 50′ side length presented with Michelson contrasts of 98 and 10 % and to the onset of motion—either expansion or contraction of low-contrast concentric rings (33.3 % duty cycle at 10 % contrast). Results: There were no significant differences between groups in the VEPs elicited by pattern reversal checkerboards of high (98 %) or low (10 %) contrast. The ASD group had a significantly larger N160 peak (1.85 x) amplitude to motion onset VEPs elicited by the expansion of radial rings (p = 0.001). No differences were evident in contraction VEP peak amplitudes nor in the latencies of the motion onset N160 peaks. There was no evidence of a response that could be associated with adaptation to the motion stimulus in the interstimulus interval following an expansion or contraction phase of the rings. Conclusion: These data support a difference in processing of motion onset stimuli in this adult high-functioning ASD group compared to the TD group

Hippocampal-Dependent Spatial Memory in the Water Maze is Preserved in an Experimental Model of Temporal Lobe Epilepsy in Rats

Cognitive impairment is a major concern in temporal lobe epilepsy (TLE). While different experimental models have been used to characterize TLE-related cognitive deficits, little is known on whether a particular deficit is more associated with the underlying brain injuries than with the epileptic condition per se. Here, we look at the relationship between the pattern of brain damage and spatial memory deficits in two chronic models of TLE (lithium-pilocarpine, LIP and kainic acid, KA) from two different rat strains (Wistar and Sprague-Dawley) using the Morris water maze and the elevated plus maze in combination with MRI imaging and post-morten neuronal immunostaining. We found fundamental differences between LIP- and KA-treated epileptic rats regarding spatial memory deficits and anxiety. LIP-treated animals from both strains showed significant impairment in the acquisition and retention of spatial memory, and were unable to learn a cued version of the task. In contrast, KA-treated rats were differently affected. Sprague-Dawley KA-treated rats learned less efficiently than Wistar KA-treated animals, which performed similar to control rats in the acquisition and in a probe trial testing for spatial memory. Different anxiety levels and the extension of brain lesions affecting the hippocampus and the amydgala concur with spatial memory deficits observed in epileptic rats. Hence, our results suggest that hippocampal-dependent spatial memory is not necessarily affected in TLE and that comorbidity between spatial deficits and anxiety is more related with the underlying brain lesions than with the epileptic condition per se

Guidelines for diagnosis and management of the cobalamin-related remethylation disorders cblC, cblD, cblE, cblF, cblG, cblJ and MTHFR deficiency

BACKGROUND: Remethylation defects are rare inherited disorders in which impaired remethylation of homocysteine to methionine leads to accumulation of homocysteine and perturbation of numerous methylation reactions. OBJECTIVE: To summarise clinical and biochemical characteristics of these severe disorders and to provide guidelines on diagnosis and management. DATA SOURCES: Review, evaluation and discussion of the medical literature (Medline, Cochrane databases) by a panel of experts on these rare diseases following the GRADE approach. KEY RECOMMENDATIONS: We strongly recommend measuring plasma total homocysteine in any patient presenting with the combination of neurological and/or visual and/or haematological symptoms, subacute spinal cord degeneration, atypical haemolytic uraemic syndrome or unexplained vascular thrombosis. We strongly recommend to initiate treatment with parenteral hydroxocobalamin without delay in any suspected remethylation disorder; it significantly improves survival and incidence of severe complications. We strongly recommend betaine treatment in individuals with MTHFR deficiency; it improves the outcome and prevents disease when given early

Lithium/pilocarpine status epilepticus-induced neuropathology of piriform cortex and adjoining structures in rats is agedependent

Summary Distribution of LiCl/pilocarpine status epilepticus-induced neuronal damage was studied in the piriform cortex and in adjoining structures in 12-day-old, 25-day-old and adult rats. No distinct structural and neuronal alterations were detected in the basal telencephalon in 12-day-old rats surviving status epilepticus (SE) for one week or two months. In 25-day-old rats a decrease in Nissl staining was evident. There was also cell loss and gliosis in the caudal 2/3 of the piriform cortex, in the superficial amygdaloid nuclei, in the dorsal and ventral endopiriform nucleus and in the rostrolateral part of the entorhinal cortical area. In adult animals, the topography of neuropathological changes in the basal telencephalon was comparable to those in 25-day-old rats. The damage in the caudal 2/3 or caudal half of the piriform cortex in adult rats with survival times one week or two months was characterized by a marked loss of neurons and striking glial infiltration. The thickness of the piriform cortex and superficial amygdaloid nuclei was significantly reduced. In 25-day-old and in adult animals the sublayer IIb and layer III of the piriform cortex was more affected, while sublayer IIa was less damaged. Parvalbumin (PV) immunocytochemistry revealed a significant decrease in the number of PV-immunoreactive neurons in the rostral piriform cortex and in the dorsal claustrum in animals surviving for two months

Differences in expression of calcium binding proteins in the perirhinal and retrosplenial cortex of the rat

The main aim was to describe interneuronal population expressing calcium binding proteins calretinin (CR) and parvalbumin (PV) in the perirhinal (PRC) and retrosplenial (RSC) cortex of the rat. These two cortical areas differ strikingly in their connectivity and function, which could be caused also by different structure of the interneuronal populations. Having a precise knowledge of the cellular composition of any cerebral area forms one of the basic input parameters and tenets for computational modelling of neuronal networks and for understanding some pathological conditions, like generating and spreading of epileptic activity. PRC possesses higher absolute and relative densities of CR+ and PV+ neurons than RSC, but the CR : PV ratio is higher in the RSC, which is similar to the neocortex. The bipolar/bitufted neurons are most common type of CR+ population, while the majority of PV+ neurons show multipolar morphology. Current results indicate that main difference between analysed areas is in density of CR+ neurons, which was significantly higher in the PRC. Our results coupled with works of other authors show that there are significant differences in the interneuronal composition and distribution of heretofore seemingly similar transitional cortical areas. These results may contribute to the better understanding of the mechanism of function of this cortical region in normal and diseased states

Effects of lamotrigine on cortically-elicited phenomena in adult rats: differences between acute application and late consequences of early postnatal administration

Lamotrigine (LTG) is increasingly used in pediatric epileptology but there are no experimental data on delayed consequences of early life administration of LTG on epileptic phenomena. Therefore we used cortically induced epileptic phenomena to study these possible effects and compared the results with data on acute administration of LTG in adult rats. Naïve adult rats as well as animals with a history of LTG administration in early postnatal period (daily from postnatal day 7 to 11 in a dose of 10 and/or 20 mg/kg i.p.) were implanted with cortical stimulation and recording electrodes. Cortical interhemispheric responses and epileptic afterdischarges (ADs) were elicited by stimulation of sensorimotor area in both groups. Acute administration of LTG (10 and/or 20 mg/kg i.p.) did not affect cortical interhemispheric evoked responses but increased thresholds for elicitation of movements elicited by stimulation, spike-and-wave ADs and accompanying clonic seizures. On the contrary, duration of ADs was increased. Animals injected with LTG postnatally exhibited increased thresholds for transition of ADs into a limbic type (mixed ADs), decreased incidence of the limbic type and suppression of recurrent ADs. Evoked responses exhibited a steeper input-output curve in a group receiving the 20 mg/kg dose of LTG during early development. Our results demonstrated a specific anticonvulsant effect as a delayed consequence of early-life administration of LTG; it differed from effects of acute administration of LTG to adult rats