Whipple disease of the CNS

By the example of two cases that could only be cleared up by a postmortem examination the affection of the central nervous system by Whipple's disease is dealt with. The granulomatous inflammatory process which is almost exclusively localised in the grisea and shows a particular concentration in the diencephalon, in the cortex of the frontal, temporal and islet regions as well as in the deeper brain stem, had resulted in a variety of neurological-psychiatric symptoms, in most cases a systemic psychosyndrome, myoclonism and paresis of ocular movement. In both cases the diagnoses was verified by the electromicroscopic identification of the bacteria in the typical SPC cells.     

Motor Cortex Plasticity in Children With Spastic Cerebral Palsy: A Systematic Review

A review of the literature was performed to answer the following questions: Does motor cortex excitability correlate with motor function? Do motor cortex excitability and cortex activation change after a rehabilitation program that results in improvements in motor outcomes? Can the 10–20 electroencephalography (EEG) system be used to locate the primary motor cortex when employing transcranial direct current stimulation? Is there a bihemispheric imbalance in individuals with cerebral palsy similar to what is observed in stroke survivors? the authors found there is an adaptation in the geometry of motor areas and the cortical representation of movement is variable following a brain lesion. The 10–20 EEG system may not be the best option for locating the primary motor cortex and positioning electrodes for noninvasive brain stimulation in children with cerebral palsy.     

Clinical significance of sleep status following-large scale epileptic attacks (grand mal)

Certain clinical criteria of grand mal seizures, and particularly the post-convulsive sleep phase (PCS), appear to be manifestations of some more deep-rooted disturbance of the functional cerebral mechanisms. The symptoms of the chronic organic psychosyndrome were observed distinctly more often in patients with PCS than in those without it. The frequency of seizures is also important when considering the cause of chronic brain damage. Etiological aspects (genuinely-symptomatological) appear to be of secondary importance.     

Is there a "temporal psychosyndrome (Landolt)"?

With reference to features of two cases of grave traumatic temporal cerebral injury, where a "temporal psychosyndrome" as defined by Landolt was not ascertainable, the question is raised whether, apart from temporal-lobe epilepsy, such a syndrome really exists. Computed tomography offers an enhanced objective basis for an investigation embracing an extensive patient population.     

Differences in numeric,verbal, and spatial reasoning between engineering and literature students through a neurocognitive lens

This study used electroencephalography to investigate the brain activations of college students of various disciplines when they responded to questions in numeric, verbal, and spatial reasoning tasks. In total, 15 engineering students and 15 literature students were recruited in this experiment and were asked to respond to 12 intelligence test questions. The results were as follows: (i) the participants’ brain activations increased in the frontoparietal network during the numeric reasoning task, and the spectral power in the right anterior temporal cortex was generally higher in the literature students than in the engineering students. (ii) Activations of the language network were observed during the verbal reasoning task, and the spectral power in the right-biased posterior frontal cortex was generally higher in the literature students than in the engineering students; by contrast, the spectral power in the left lateral frontal cortex was generally higher in the engineering students than in the literature students. (iii) The participants’ brain activations increased in the spatial processing network during the spatial reasoning task, and the spectral power in the right posterior temporal cortex was generally higher in the literature students than in the engineering students.     

When is early visual cortex activated during visual mental imagery?

Although many neuroimaging studies of visual mental imagery have revealed activation in early visual cortex (Areas 17 or 18), many others have not. The authors review this literature and compare how well 3 models explain the disparate results. Each study was coded 1 or 0, indicating whether activation in early visual cortex was observed, and sets of variables associated with each model were fit to the observed results using logistic regression analysis. Three variables predicted all of the systematic differences in the probability of activation across studies. Two of these variables were identified with a perceptual anticipation theory, and the other was identified with a methodological factors theory. Thus, the variability in the literature is not random.     

Preliminary results of imurek treatment of multiple sclerosis]

The authors, after presenting a survey of the literature on the treatment of multiple sclerosis with immunosuppressants, report their experience with Imurek. Of 53 patients with a chronic and progressive course of the disease, objective improvement could be observed in 17. In 20 patients the symptomatology remained unchanged, although 4 of them reported subjective improvement. In 16 patients, progression of the disease could not be stopped. Better results of treatment could be obtained for those forms of the disease where the course was, first, in the form of what may be referred to as outbursts and, later, in a chronic and progressive form. -Possible side effects are pointed out.     

Side effects of bilateral electroconvulsive therapy--comparative clinico-computer tomographic study

The side effects of a five-times bilateral electric shock therapy were clinically and computer-tomographically investigated. A connection exists between the number of electric shock treatments which are carried out and the expression of a transitory organic psychosyndrome. However, no significant differences in relation to the initial findings were established a week after the completion of the treatment series despite great interindividual differentiation. Neither cerebral oedema or other signs of disturbances were computer-tomographically detectable as results of treatment. CT and clinic findings do not correspond to each other.     

Changes in plasma corticosterone and cerebral biogenic amines and their catabolites during training and testing of mice in passive avoidance behavior

Concentrations of cerebral biogenic amines and their catabolites, and of plasma corticosterone were determined 10 min after training and testing of passive avoidance behavior in mice. Training and testing of mice that had acquired the task well resulted in statistically significant increases of plasma corticosterone, of the DOPAC:DA ratio [an index of dopamine (DA) metabolism] in prefrontal cortex, and of MHPG:NE ratios [an index of norepinephrine (NE) metabolism] in hypothalamus and brain stem. There were also decreases of NE in hypothalamus and brain stem, and an increase of 5-HIAA:5-HT [an index of serotonin (5-HT) metabolism] and of tryptophan in brain stem. Some of these changes also occurred in mice merely exposed to the apparatus but not trained. Plasma corticosterone concentrations were significantly higher in mice that performed the task well compared to those that did not, and there were significant correlations between this measure and the avoidance performance. Although there was only one statistically significant correlation between a cerebral metabolite and the avoidance performance (a decrease in hypothalamic NE), there were indications of relationships between cerebral biogenic amine metabolism and the performance. The patterns of neurochemical and endocrine changes closely resemble those previously observed in response to various stressors. Thus, the changes could reflect stress responses, which may or may not be related directly to the performance of the avoidance task.     

Aspects of biochemical differentiation in the central nervous system

A demonstration of cell-specific patterns of development in the immature CNS is provided by examples of characteristic, cellspecific time-courses of enzyme development in different classes of brain cells isolated in highly purified form by bulk-separation from the cerebral and cerebellar cortex of the growing rat. The enzymatic analysis was carried out at the level of the nerve and glial cell lysosomes and mitochondria, two subcellular organelles crucial to the economy of all cells. The findings reveal rather similar developmental patterns for the lysosomal hydrolase N-acetyl-β-D-glucosaminidase in neurons and glial cells of the cerebral cortex as well as in two different cerebellar nerve cell types, the Purkinje and the granule cell. However, significant differences in the post-natal chronology of development of the mitochondrial enzyme α-glycerophosphate dehydrogenase were noted between cortical nerve and glial cells, the glial enzyme exhibiting 6-fold higher levels of activity than the neuronal one throughout the first month of postnatal life. The findings emphasize the feasibility as well as the necessity of studies aimed at the elucidation of the cell-specific aspects of the biochemistry of developing nerve and glial cells.     

Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.     

Associations between cortical thickness and general intelligence in children,adolescents and young adults

Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral performance correlates of normative gray matter thinning during adolescence.     

Conditioned interhemispheric transfer by cerebral tetanization

Electrodes were implanted over the motor and occipital cortex in both cerebral hemispheres of five dogs and also over the right ectosylvian cortex in one dog. Stimulation of these areas resulted mainly in contralateral movements opposite to the stimulated cortex. At appropriate voltages, stimulation of the occipital and ectosylvian cortex resulted in no movement at all. A non-motivated conditioned reflex (CR) was elaborated by coupling electrical stimulation of the occipital (CS) and the ipsilateral motor cortex (US). After long-term consolidation of this CR, electrical stimulations of the opposite hemisphere were performed again and a complete interhemispheric transfer was observed in all five dogs, i.e., stimulation of either right or left occipital cortex as well as stimulation of the right or left motor cortex constantly resulted in the same movement. The dynamics of the interhemispheric transfer were different in each individual dog. The transfer was limited to the symmetrical motor and occipital cortex. Stimulation of the ectosylvian cortex never resulted in any movement. This interhemispheric transfer is discussed as a function of the previous experience of the animal.     

Neurocognitive outcomes following pediatric brain injury: A developmental approach

Developmental neuropsychologists postulate that “immaturity” of the cerebral cortex should no longer be perceived as a protective factor. They argue that injury to the young brain may affect new learning by disrupting the skills in the midst of being acquired and skills that are yet to be developed. Cognitive deficits or weaknesses that are not detectable in the acute phase following a traumatic brain injury (TBI) may emerge over development as more complex skills are needed, thereby creating a developmental lag between children who sustained a pediatric TBI and typical age peers. This literature review was conducted to evaluate the developmental perspective on neurocognitive recovery/development following a TBI. Overall, the described findings support a developmental view and suggest that predictions of prognosis should be based on the child's remaining ability to learn.     

Functional maturity of brain structures in children aged 7-8 with differing levels of speech development

First graders (aged 7-8) in a public elementary school served as subjects for this study. The structural components of their speech were analyzed to determine speech maturity level; total EEG activity was analyzed to assess the functional maturity of brain structures. Results showed that children with levels of speech below the age norm exhibited abnormal EEG patterns suggesting immaturity of the cerebral cortex and fronto-thalamic regulatory system, as well as impairments in the functioning of the mesodiencephalic structures and nonspecific activation systems. Abnormalities in the functioning of brain regulatory systems and the presence of local abnormalities in EEG activity of deep origin are important factors in determining the severity of functional speech impairments.     

Brain abnormalities observed in childhood-onset schizophrenia: a review of the structural magnetic resonance imaging literature

Childhood-onset schizophrenia (COS) is a rare, severe form of schizophrenia in which there are structural brain abnormalities that may be related to the psychotic symptomatology and neurocognitive deficits found in these patients. While there are numerous structural imaging studies of the adult-onset variant of schizophrenia (with many conflicting findings), relatively few brain imaging studies of COS have been conducted. This paper summarizes the extant literature of magnetic resonance imaging (MRI) studies of structural brain abnormalities in COS, and compares findings to similar studies of adult-onset patients. Volumetric MRI studies of COS patients have consistently shown evidence for increased ventricular volume, reduced cerebral gray matter, and increased caudate volume, consistent with findings from adult-onset studies. Other volumetric brain abnormalities are observed in COS patients, such as reduced total brain volume, but not consistently across all studies. Voxel-based morphometric analyses have revealed abnormalities in the shape and spatial location of structures in COS such as the corpus callosum, caudate, and thalamus that could not be observed in the more traditional volumetric assessments. Similar findings also are observed in adult-onset patients. Progressive degenerative changes, such as ventricular enlargement, appear to occur in COS only until young adulthood where there is an apparent asymptote with no further degenerative changes. This is consistent with the lack of progressive changes noted in most longitudinal studies of adult-onset schizophrenia.     

Right-hemisphere reading in a case of developmental deep dyslexia

The right-hemisphere hypothesis of deep dyslexia has received support from functional imaging studies of acquired deep dyslexia following damage to the left cerebral hemisphere, but no imaging studies of cases of developmental deep dyslexia, in which brain damage is not suspected, have been reported. In this paper, we report the first evidence of right hyperactivation in an adult case of developmental deep dyslexia. Hyperactivation was observed in the right inferior frontal cortex during functional magnetic resonance imaging (fMRI) of the oral reading of imageable content words and nonwords to which imageable lexical responses were frequently made. No evidence of right hyperactivation was observed in the oral reading of function words, nor during the naming of imageable words in response to pictured objects. The results reveal strategic and selective use of right-hemisphere functions for particular types of written stimuli. We propose that children with developmental deep dyslexia compensate for their lack of phonological skills by accessing right-hemisphere imageable associations that provide a mnemonic for linking written forms to spoken names.     

Right-hemisphere reading in a case of developmental deep dyslexia

The right-hemisphere hypothesis of deep dyslexia has received support from functional imaging studies of acquired deep dyslexia following damage to the left cerebral hemisphere, but no imaging studies of cases of developmental deep dyslexia, in which brain damage is not suspected, have been reported. In this paper, we report the first evidence of right hyperactivation in an adult case of developmental deep dyslexia. Hyperactivation was observed in the right inferior frontal cortex during functional magnetic resonance imaging (fMRI) of the oral reading of imageable content words and nonwords to which imageable lexical responses were frequently made. No evidence of right hyperactivation was observed in the oral reading of function words, nor during the naming of imageable words in response to pictured objects. The results reveal strategic and selective use of right-hemisphere functions for particular types of written stimuli. We propose that children with developmental deep dyslexia compensate for their lack of phonological skills by accessing right-hemisphere imageable associations that provide a mnemonic for linking written forms to spoken names.     

Does taste or odor activate the same brain networks after retrieval of taste potentiated odor aversion?

When simultaneous presentation of odor and taste cues precedes illness, rats acquire robust aversion to both conditioned stimuli. Such a phenomenon referred to as taste-potentiated odor aversion (TPOA) requires information processing from two sensory modalities. Whether similar or different brain networks are activated when TPOA memory is retrieved by either the odor or the taste presentation remains an unsolved question. By means of Fos mapping, we investigated the neuronal substrate underlying TPOA retrieval elicited by either the odor or the taste conditioned stimulus. Whatever the sensory modality used to reactivate TPOA memory, a significant change in Fos expression was observed in the hippocampus, the basolateral nucleus of amygdala and the medial and the orbito-frontal cortices. Moreover, only the odor presentation elicited a significantly higher Fos immunoreactivity in the piriform cortex, the entorhinal cortex and the insular cortex. Lastly, according to the stimulus tested to induce TPOA retrieval, the BLA was differentially activated and a higher Fos expression was induced by the odor than by the taste in this nucleus. The present study indicates that even if they share some brain regions, the cerebral patterns induced by either the odor or the taste are different. Data are discussed in view of the relevance of each conditioned stimulus to reactivate TPOA memory and of the involvement of the different labeled brain areas in information processing and TPOA retrieval.