Character changes in epilepsy?]

There are no personality structures which are typical of epilepsies in the sense of a change in character that can be seen in cross and especially in longitudinal sections. Reported changes of character due to epilepsies cannot be exactly defined reproducibly for the forms of fits to be differentiated and cannot, therefore, be used operationally. There is no doubt, however, that several causal factors must be considered to be responsible for the manifestation of certain frequently observed peculiarities and characteristics, respectively. In addition to organic, psychodynamic, and socio-situational causes, long-time antiepileptic medication is an essential factor of changes in character due to diseases characterized by fits. A better understanding has now been obtained of the importance of this particular factor, and this allows to conclude that there can only be epileptic functioning and reacting.     

Story Recall and Narrative Coherence of High-Functioning Children with Autism Spectrum Disorders

Previous research has found few quantitative differences between children with high-functioning autism spectrum disorders (ASDs) and well-matched controls in the length, complexity, and structure of their narratives. Researchers have noted, however, that narratives of children with ASDs have an unusual and idiosyncratic nature. This study provides an analysis of narratives in 17 children with high-functioning ASDs and 17 typically developing children matched on age, gender, language abilities, and cognitive abilities. We examined story recall and narrative coherence. The study revealed no group differences in story length or syntactic complexity. Children with ASDs also did not differ from controls in their use of the gist of a story to aid recall, or in their sensitivity to the importance of story events. Children with ASDs did, however, produce narratives that were significantly less coherent than the narratives of controls. Children with ASDs appeared less likely to use the gist of the story to organize their narratives coherently. These findings are discussed with regard to their relationship to other cognitive and linguistic difficulties of children with ASDs.     

Brain dopamine and kinematics of graphomotor functions

Three experiments were performed in an attempt to achieve a better understanding of the effect of dopamine on handwriting. In the first experiment, kinematic aspects of handwriting movements were compared between healthy participants and patients with Parkinson's disease (PD) on their usual dopaminergic treatment and following withdrawal of dopaminergic medication. In the second experiment, the writing performance of healthy participants with a hyperechogenicity of the substantia nigra as detected by transcranial sonography (TCS) was compared with the performance of healthy participants with low echogenicity of the substantia nigra. The third experiment examined the effect of central dopamine reduction on kinematic aspects of handwriting movements in healthy adults using acute phenylalanine and tyrosine depletion (APTD). A digitising tablet was used for the assessment of handwriting movements. Participants were asked to perform a simple writing task. Movement time, distance, velocity, acceleration and measures of fluency of handwriting movements were measured. The kinematic analysis of handwriting movements revealed that alterations of central dopaminergic neurotransmission adversely affect movement execution during handwriting. In comparison to the automatic processing of handwriting movements displayed by control participants, participants with an altered dopaminergic neurotransmission shifted from an automatic to a controlled processing of movement execution. Central dopamine appears to be of particular importance with regard to the automatic execution of well-learned movements.     

The dental anxiety scale and effects of dental fear on salivary cortisol

Only a few studies have investigated use of the Dental Anxiety Scale in dental fear-induced neuroendocrine changes. The present study examined 19 female patients, each at two timepoints across an educational and a treatment session within periodontitis therapy. Subjective measures included a visual analogue scale, the STAI State scale, and the Dental Anxiety Scale. Salivary cortisol was measured in parallel across all four timepoints. Although patients were significantly more aroused and anxious prior to the treatment session, salivary cortisol remained unchanged. However, patients with high Dental Anxiety were significantly more aroused and anxious and showed significantly higher salivary cortisol during the educational session than those with low scores on Dental Anxiety. In conclusion, the Dental Anxiety Scale differentiated mean neuroendocrine change between patients scoring low and high for Dental Anxiety and its use as an accurate tool to identify patients with high dental anxiety should be further studied predictively.     

Amnestic effect of intrahippocampal AM251, a CB1-selective blocker, in the inhibitory avoidance, but not in the open field habituation task, in rats

CB1 is the most abundant metabotropic receptor of the brain, being found in areas classically involved in learning and memory and present at higher density at presynaptic terminals. Different sets of evidence support the idea that endogenous ligands (endocannabinoids) to the CB1 receptors act as modulators of neurotransmission. In hippocampus, endocannabinoids seem to act as retrograde messengers mediating down-regulation of GABA release. Previous reports have described a cognitive impairment effect of cannabinoid agonists, or facilitation by antagonists. The scope of the present study is to investigate the effect of intrahippocampal administration of the CB1-selective antagonist, AM251, in two behavioral tasks. One hundred and twelve male Wistar rats with bilateral cannulae implanted in the CA1 region of the dorsal hippocampus were trained in a step-down inhibitory avoidance task (IA, footshock, 0.5 mA) or an open field habituation task (OF). Immediately, after training, animals received an infusion of 0.55, 5.5, and 55.5 ng/side of AM251 (Tocris), or its vehicle (DMSO/saline), via these cannulae. Our results show that AM251 disrupted memory consolidation of the IA task, but not the OF task, an effect that seems to be purely mnemonic since the drug showed no motor performance effects. Only the intermediate dose (5.5 ng/side) of AM251 was effective in IA and the absence of effect with the larger dose may be the consequence of non-specific binding. The fact that OF was not affected raises the possibility that this endogenous system requires some degree of aversiveness to be recruited. We propose that increased levels of endogenous cannabinoids in the hippocampus, following a training session, contribute to facilitate memory consolidation, a process that may have been disrupted with AM251.     

Right Hemisphere Activation during Indirect Semantic Priming: Evidence from Event-Related Potentials

Healthy subjects performed a lexical decision task in a semantic priming paradigm while event-related potentials (ERPs) were recorded from 64 channels. Semantic distance between prime and target was varied by including directly, indirectly, and nonrelated word pairs. At centro-parietal electrodes an N400 to nonrelated pairs was elicited bilaterally which was sensitive only to direct, but not to indirect semantic priming. These N400 priming effects were mirrored by the RT data. At inferior fronto-temporal sites directly related words showed ERP priming effects over both hemispheres. However, indirectly related words only elicited ERP priming effects over the right hemisphere. These results support the hypothesis that the right hemisphere semantic system is involved in processing of remote semantic information.     

Limited translation invariance of human visual pattern recognition

Visual object recognition is considered to be largely translation invariant. An earlier study (Foster & Kahn, 1985), however, has indicated that recognition of complex novel stimuli is partially specific to location in the visual field: It is significantly easier to determine the identity of two briefly displayed random patterns if both stimuli are presented at the same, rather than at different, locations. In a series ofsame/different discrimination tasks, we characterize the processes underlying this “displacement effect”: Horizontal and vertical translations are equally effective in reducing performance. Making the task more difficult by increasing pattern similarity leads to even higher positional specificity. The displacement effect disappears after rotation or contrast reversal of the patterns, indicating that positional specificity depends on relatively low levels of processing. Control experiments rule out explanations that are independent of visual pattern memory, such as spatial attention, eye movements, or retinal afterimages. Positional specificity of recognition is found only forsame trials. Our results demonstrate that position invariance, a widely acknowledged property of the human visual system, is limited to specific experimental conditions. Normalization models involving mental shifts of an early visual representation or of a window of attention cannot easily account for these findings.     

Hegel und das Problem des Anfangs der griechischen Philosophie

Ohne Zusammenfassung