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Lobe Structures (lobe + structure)

Distribution by Scientific Domains
Medical Sciences40%
Life Sciences40%

Kinds of Lobe Structures

  • temporal lobe structure
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    Selected Abstracts

    Temporal lobe epilepsy surgery and the quest for optimal extent of resection: A review

    EPILEPSIA, Issue 8 2008
    Johannes Schramm
    Summary The efficacy of surgery to treat drug-resistant temporal lobe epilepsy (TLE) has been demonstrated in a prospective randomized trial. It remains controversial which resection method gives best results for seizure freedom and neuropsychological function. This review of 53 studies addressing extent of resection in surgery for TLE identified seven prospective studies of which four were randomized. There is considerable variability between the intended resection and the volumetrically assessed end result. Even leaving hippocampus or amygdalum behind can result in seizure freedom rates around 50%. Most authors found seizure outcome in selective amygdalohippocampectomy (SAH) to be similar to that of lobectomy and there is considerable evidence for better neuropsychological outcome in SAH. Studies varied in the relationship between extent of mesial resection and seizure freedom, most authors finding no positive correlation to larger mesial resection. Electrophysiological tailoring saw no benefit from larger resection in 6 of 10 studies. It must be concluded that class I evidence concerning seizure outcome related to type and extent of resection of mesial temporal lobe structures is rare. Many studies are only retrospective and do not use MRI volumetry. SAH appears to have similar seizure outcome and a better cognitive outcome than TLR. It remains unclear whether a larger mesial resection extent leads to better seizure outcome. [source]

    Functional (GT)n polymorphisms in promoter region of N -methyl- d -aspartate receptor 2A subunit (GRIN2A) gene affect hippocampal and amygdala volumes

    GENES, BRAIN AND BEHAVIOR, Issue 3 2010
    H. Inoue
    The glutamate system including N -methyl- d -aspartate (NMDA) affects synaptic formation, plasticity and maintenance. Recent studies have shown a variable (GT)n polymorphism in the promoter region of the NMDA subunit gene (GRIN2A) and a length-dependent inhibition of transcriptional activity by the (GT)n repeat. In the present study, we examined whether the GRIN2A polymorphism is associated with regional brain volume especially in medial temporal lobe structures, in which the NMDA-dependent synaptic processes have been most extensively studied. Gray matter regions of interest (ROIs) for the bilateral amygdala and hippocampus were outlined manually on the magnetic resonance images of 144 healthy individuals. In addition, voxel-based morphometry (VBM) was conducted to explore the association of genotype with regional gray matter volume from everywhere in the brain in the same sample. The manually measured hippocampal and amygdala volumes were significantly larger in subjects with short allele carriers (n = 89) than in those with homozygous long alleles (n = 55) when individual differences in intracranial volume were accounted for. The VBM showed no significant association between the genotype and regional gray matter volume in any brain region. These findings suggest that the functional GRIN2A (GT)n polymorphism could weakly but significantly impact on human medial temporal lobe volume in a length-dependent manner, providing in vivo evidence of the role of the NMDA receptor in human brain development. [source]

    Bilateral medial temporal lobe damage does not affect lexical or grammatical processing: Evidence from amnesic patient H.M.

    HIPPOCAMPUS, Issue 4 2001
    Elizabeth A. Kensinger
    Abstract In the most extensive investigation to date of language in global amnesia, we acquired data from experimental measures and examined longitudinal data from standardized tests, to determine whether language function was preserved in the amnesic patient H.M. The experimental measures indicated that H.M. performed normally on tests of lexical memory and grammatical function, relative to age- and education-matched control participants. Longitudinal data from four Wechsler subtests (Information, Comprehension, Similarities, and Vocabulary), that H.M. had taken 20 times between 1953 (preoperatively) and 2000, indicated consistent performance across time, and provided no evidence of a lexical memory decrement. We conclude that medial temporal lobe structures are not critical for retention and use of already acquired lexical information or for grammatical processing. They are, however, required for acquisition of lexical information, as evidenced in previous studies revealing H.M.'s profound impairment at learning new words. Hippocampus 2001;11:347,360. © 2001 Wiley-Liss, Inc. [source]

    Development of pro, and antisaccades in children with attention,deficit hyperactivity disorder (ADHD) and healthy controls

    PSYCHOPHYSIOLOGY, Issue 1 2003
    C. H. Klein
    To date, the investigation of the antisaccade task, a simple test of "executive functions," in children with ADHD has yielded inconsistent results. The present study aimed at contributing to this issue by (a) the investigation of a large sample of carefully diagnosed ADHD patients aged 7,15 years, and (b) the analyses of differential age effects in patients and controls. Healthy control children were pairwise matched with patients (N=46; age=136±24 months) for age and gender, and did not significantly differ in IQ. Horizontal pro, and antisaccades were elicited under the 200,ms gap and overlap conditions (blocks of 100 trials each). Overall, patients exhibited (a) augmented pro, and antisaccadic reaction times, (b) augmented error rates (antitasks), (c) augmented proportions of early responses (all conditions), and (d) reduced proportions of express saccades under the prosaccadic gap condition. The greater decline in anti, as compared to pro,SRT with increasing age that characterized controls was missing in patients. Confirming Barkley's (1997) neuropsychological theory of ADHD, these results altogether point to alterations in "executive Functions" in ADHD patients that are presumably supported by frontal lobe structures, in particular the lateral prefrontal cortex and the frontal eye fields. [source]

    Memory with emotional content, brain amygdala and Alzheimer's disease

    ACTA NEUROLOGICA SCANDINAVICA, Issue 2 2009
    R. R. Schultz
    Objectives,,, A highly adaptive aspect of human memory is the enhancement of explicit, consciously accessible memory by emotional stimuli. We studied the performance of Alzheimer's disease (AD) patients and elderly controls using a memory battery with emotional content, and we correlated these results with the amygdala and hippocampus volume. Methods,,, Twenty controls and 20 early AD patients were subjected to the International Affective Picture System (IAPS) and to magnetic resonance imaging-based volumetric measurements of the medial temporal lobe structures. Results,,, The results show that excluding control group subjects with 5 or more years of schooling, both groups showed improvement with pleasant or unpleasant figures for the IAPS in an immediate free recall test. Likewise, in a delayed free recall test, both the controls and the AD group showed improvement for pleasant pictures, when education factor was not controlled. The AD group showed improvement in the immediate and delayed free recall test proportional to the medial temporal lobe structures, with no significant clinical correlation between affective valence and amygdala volume. Conclusion,,, AD patients can correctly identify emotions, at least at this early stage, but this does not improve their memory performance. [source]