1,721,009 research outputs found
Small hippocampal size in cognitively normal subjects with coronary artery disease
No full textObjective: Hippocampal size reduction detected by three-dimensional structural magnetic resonance imaging (3D-MRI) represents an important hallmark of Alzheimer's disease (AD). Recently, epidemiological and neuropathological studies have associated coronary artery disease (CAD) and cardiovascular risk factors with AD. The present study aimed to assess whether small hippocampal size is also a feature of CAD. Methods: Hippocampal volumes were assessed in 20 men with CAD and 20 healthy matched control subjects by use of 3D-MRI. Subjects with a history of neurological or psychiatric disorder, or signs of cognitive impairment were rigorously excluded. Results: Compared with controls, subjects with CAD had significantly smaller (-14%) hippocampal volumes. Cardiovascular risk factors were not related to hippocampal volumes of CAD subjects. Conclusions: Our results demonstrate small hippocampal size in CAD subjects without any cognitive impairment. Future studies should clarify whether the annual rate of hippocampal volume loss of persons with CAD is greater than that of healthy individuals and predicts later cognitive decline or dementia. (c) 2004 Elsevier Inc. All rights reserved
Posterior parahippocampal gyrus lesions in the human impair egocentric learning in a virtual environment
No full textFunctional imaging studies have shown that the posterior parahippocampal gyrus (PHG) is involved in allocentric (world-centered) object and scene recognition. However, the putative role of the posterior PHG in egocentric (body-centered) spatial memory has received only limited systematic investigation. Thirty-one subjects with pharmacoresistant medial temporal lobe epilepsy (TLE) and temporal lobe removal were compared with 19 matched healthy control subjects on a virtual reality task affording the navigation in a virtual maze (egocentric memory). Lesions of the hippocampus and PHG of TLE subjects were determined by three-dimensional magnetic resonance imaging volumetric assessment. The results indicate that TLE subjects with right-sided posterior PHG lesions were impaired on virtual maze acquisition when compared with controls and TLE subjects with anterior PHG lesions. Larger posterior PHG lesions were significantly related to stronger impairments in virtual maze performance. Our results point to a role of the right-sided posterior PHG for the representation and storage of egocentric information. Moreover, access to both allocentric and egocentric streams of spatial information may enable the posterior PHG to construct a global and comprehensive representation of spatial environments
Emotional priming of facial affect identification in schizophrenia
No full textTwenty-three schizophrenia subjects were compared with healthy and clinical control subjects on an emotional priming task, Positive and negative emotional facial expressions were presented as primes, followed by a neutral pattern mask, then an emotionally neutral face as target. The prime-mask-target sequence was arranged to allow conscious perception of only the targets. Subjects had to judge if they had seen a pleasant or an unpleasant facial expression, All subjects judged the neutral target as significantly more unpleasant when negative emotional facial expressions were presented as primes as compared with positive or neutral facial expressions as primes, This judgment shift was significantly stronger in schizophrenia subjects than in control subjects. The stronger priming of schizophrenia subjects may reflect a stronger influence of automatically processed emotional stimuli on judgments. We suggest that increased spreading activation of emotional information might be related to low social/emotional functioning of the individual with schizophrenia
Enlarged amygdala volume and reduced hippocampal volume in young women with major depression
No full textBackground. Evidence is increasing that amygdala and hippocampus show significant structural abnormalities in affective disorders. Two previous studies found enlarged amygdala size in subjects with recent-onset major depression. Method. Amygdala and hippocampal volumes were assessed in 17 young women with major depressive disorder and 17 healthy matched control subjects by use of three-dimensional structural magnetic resonance imaging. The severity of depressive symptoms was assessed using the Hamilton Depression Scale and the Beck Depression Inventory. Results. Compared with control subjects, depressive subjects had significantly larger (+13%) amygdala volumes and significantly smaller (-12%) hippocampal volumes. Amygdala and hippocampal volumes were not significantly correlated with disorder-related variables. Conclusions. Our results are consistent with previous findings of structural abnormalities of amygdala and hippocampus in subjects with recent-onset major depression. It may be suggested that the size of the amygdala is enlarged in the first years of the disorder, and may decrease with prolonged disorder duration
Hippocampal volume in adult burn patients with and without posttraumatic stress disorder
No full textObjective: Increasing evidence suggests that posttraumatic stress disorder (PTSD) is associated with small hippocampal size. The authors compared trauma-exposed subjects with PTSD and trauma-exposed subjects without PTSD to clarify whether small hippocampal size is related to PTSD or to mere trauma exposure. Method: Three-dimensional structural magnetic resonance imaging was used to assess hippocampal volumes in 30 men who had recently been exposed to a severe burn trauma and 15 matched healthy comparison subjects. Results: Relative to the comparison subjects, the trauma-exposed subjects with PTSD (N=15) as well as the trauma-exposed subjects without PTSD (N=15) had significantly smaller volumes of the right hippocampus (subjects with PTSD: -12%; subjects without PTSD: -13%). Larger total areas of burned body surface were significantly related to smaller left hippocampal volumes. Use of analgesic/sedative treatment with the N-methyl-D-aspartic acid (NMDA) antagonist ketamine was significantly related to larger right hippocampal volumes and to stronger PTSD symptoms. Conclusions: PTSD is not a necessary condition for small hippocampal size in trauma-exposed individuals. Rather, the results provide evidence that smaller hippocampal size in trauma-exposed individuals is a result of traumatic stress. The posttraumatic application of NMDA antagonists may protect against hippocampal damage induced by traumatic stressors but increases the patient's risk of developing PTSD symptoms
Impaired facial affect recognition and emotional changes in subjects with transmodal cortical lesions
No full textThe present study attempts to identify cortical lesion sites associated with deficits in the decoding of emotional facial expressions and with changes of emotional states. A consecutive sample of 68 subjects with lesions caused by microsurgical tumor resection or by intracerebral hemorrhage were compared with 16 clinical and 15 healthy control subjects. A set of neuropsychological test measures - two experimental tasks requiring the sorting and rating of emotional facial expressions, and an adjective checklist as a measure of mood state - were administered. An analysis according to the functional properties of the areas with lesions revealed that subjects with combined lesions of heteromodal and limbic/paralimbic cortices of the right hemisphere showed the strongest deficits in the decoding of emotional facial expressions. In contrast, subjects with lesions of limbic/paralimbic cortices alone, or subjects with lesions of unimodal or primary motor or sensory cortices displayed only minor deficits. Subjects with combined lesions of heteromodal and limbic/paralimbic cortices of the left hemisphere showed the most negative mood states. Our results suggest that heteromodal and limbic/paralimbic, i.e. transmodal cortices may he viewed as 'bottleneck' structures for the decoding of emotional facial expressions and for the modulation of mood states. Lesions of transmodal cortices deprive limbic structures of one of their main sources of input and are therefore likely to produce deficits in various forms of complex human emotional-cognitive behaviors and emotional states
Impaired implicit learning and reduced pre-supplementary motor cortex size in early-onset major depression with melancholic features
No full textBackground: Major depression is a heterogeneous disorder. Biological markers and cognitive tasks have been employed to distinguish clinical subtypes but results have been inconclusive. Methods: The current study assessed implicit learning with the Serial Reaction Time Task (SRTT) known to be sensitive to frontostriatal dysfunctions and regional brain volumes of the anterior supplementary motor area (pre-SMA) in participants with early-onset major depression (MD) of either melancholic (n = 26) or non-melancholic (n = 9) subtype, and 26 matched controls. Results: Depressive subjects with melancholic features but not those with non-melancholic depression showed implicit learning deficits. This deficit could not be explained in terms of more severe depression or psychomotor retardation. Regional volumes of the right pre-SMA were reduced in depressive subjects with melancholic features. Limitations: Medication effects in depressive subjects and the small size of the non-melancholic sample should be taken into consideration when reviewing the implications of these results. Conclusions: Deficits in implicit motor sequence learning seem to be an additional characteristic of the melancholic subtype of depression. it might be linked to dysfunction within structural or functionally altered frontostriatal circuits. Use of implicit sequence learning tasks could offer useful diagnostic and aetiological cues for future research. (C) 2009 Elsevier B.V. All rights reserved.Deutsche Forschungsgemeinschaft (DFG) [IR15/6-3
Reduced size and abnormal asymmetry of parietal cortex in women with borderline personality disorder
No full textBackground: Evidence is accumulating that suggests borderline personality disorder(BPD) and posttraumatic stress disorder(PTSD) are related to small hippocampal size. Psychotic symptoms are frequent in both disorders. Psychotic spectrum disorders are known to be related to abnormalities of temporoparietal cortices. Methods: Using structural magnetic resonance imaging (3D-MRI), parietal cortex and hippocampal volumes were associated in 30 young women with BPD who had been exposed to severe childhood sexual and physical abuse and in 25 healthy control subjects. Results: Compared with control subjects, BPD subjects had significantly smaller right parietal cortex (-11%) and hippocampal (17%) volumes. The parietal cortex of borderline subjects showed a significantly stronger leftward asymmetry when compared with control subjects. Stronger psychotic symptoms and schizoid personality traits in borderline subjects were significantly related to reduced leftward asymmetry. Stronger trauma-related clinical symptoms and neuropsychologic deficits were significantly related to smaller hippocampal size. Conclusions: Our results are consistent with previous findings of small hippocampal size in BPD and PTSD. Reduced right parietal cortex size in individuals with BPD may reflect a neurodevelopmental deficit of the right hemisphere
Abnormal size of the amygdala predicts impaired emotional memory in major depressive disorder
No full textBackground: Amygdala and hippocampus show significant structural abnormalities in major depressive disorder (MDD). Individuals with MDD have difficulties in emotional memory. A relationship between emotional memory deficits and structural abnormalities of amygdala and hippocampus in MDD has been proposed but not shown, yet. Methods: The current study assessed memory for emotional faces in 21 young women with recent-onset MDD and 23 matched control subjects. All subjects underwent structural magnetic resonance imaging (3D-MRI) and a clinical and neuropsychological assessment. Results: Depressive subjects had significantly enlarged amygdala size and significantly reduced hippocampal size compared with controls. Depressive subjects were significantly impaired in leaming emotional facial expressions, with deficits being most pronounced for fearful, surprised and disgusted faces. Depressive subjects with amygdala volumes 1 SD or more above the mean of control subjects showed the strongest impairments. Correlation analyses revealed that larger left amygdala volumes were significantly related to worse memory performance and to higher anxiety scores of depressive subjects. Smaller left hippocampal volumes of depressive subjects were related to higher anxiety scores as well. Limitations: All MDD subjects were taking antidepressant medication at the time of the study. Longitudinal studies are needed to clarify whether the behavioral and/or volumetric abnormalities of MDD subjects can be attributed to medication or MDD or both. Conclusions: It might be speculated that amygdala enlargement in young MDD subjects is correlated with amygdalar overactivation and resolves with antidepressant treatment, as was shown for amygdalar over-activation. (c) 2006 Elsevier B.V. All rights reserved
Cerebellar lesions in the PICA but not SCA territory impair cognition
No full textThe authors sought to clarify whether lesions in different parts of the cerebellum result in differential cognitive and affective impairment. Six subjects with cerebellar lesions due to posterior inferior cerebellar artery ( PICA) infarction, five subjects with lesions in the SCA vascular territory, and 11 matched controls were administered a battery of standard neuropsychological tests. PICA lesions but not SCA lesions resulted in cognitive and affective deficits pointing to a dominant role of posterior cerebellar regions in cognitive and affective processing
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