Left Hippocampal Region Research Articles

Cross-sectional Study of Glutamate in the Anterior Cingulate and Hippocampus in Schizophrenia.

There has been growing support for dysfunctions of the excitatory glutamatergic system and its implications for the psychophysiology of schizophrenia. However, previous studies reported mixed results regarding glutamate concentrations in schizophrenia with varying deviations across brain regions. We used an optimized proton magnetic resonance spectroscopy procedure to measure absolute glutamate concentrations in the left hippocampal region and the anterior cingulate cortex (ACC) in 29 medicated patients with schizophrenia and in 29 control participants without mental disorder. The glutamate concentrations were significantly lower in the ACC but higher in the hippocampus of patients compared to controls. ACC and hippocampal glutamate concentrations correlated positively in patients but not in controls. ACC glutamate was weakly associated with Clinical Global Impression score and duration of illness in patients. Glutamate concentrations in schizophrenia deviate from controls and show associations with disease severity. A higher concentration of hippocampal glutamate in schizophrenia compared to controls is shown. The association between ACC and hippocampus glutamate concentrations in patients with schizophrenia suggests an abnormal coupling of excitatory systems compared to controls as predicted by previous glutamate models of schizophrenia.

Episodic Recollection Difficulties in ASD Result from Atypical Relational Encoding: Behavioral and Neural Evidence.

Memory functioning in Autism Spectrum Disorder (ASD) is characterized by impairments in the encoding of relational but not item information and difficulties in the recollection of contextually rich episodic memories but not in the retrieval of relatively context‐free memories through processes of familiarity. The neural underpinnings of this profile and the extent to which encoding difficulties contribute to retrieval difficulties in ASD remain unclear. Using a paradigm developed by Addis and McAndrews [2006; Neuroimage, 33, 1194–1206] we asked adults with and without a diagnosis of ASD to study word‐triplets during functional Magnetic Resonance Imaging (fMRI) scanning that varied in the number of category relations amongst component words. Performance at test confirmed attenuated recollection in the context of preserved familiarity based retrieval in ASD. The results also showed that recollection but not familiarity based retrieval increases as a function of category relations in word triads for both groups, indicating a close link between the encoding of relational information and recollection. This link was further supported by the imaging results, where blood oxygen level dependent (BOLD) signal responses in overlapping regions of the inferior prefrontal cortex were sensitive to the relational encoding manipulation as well as the contrast between recollection versus familiarity based retrieval. Interestingly, however, there was no evidence of prefrontal signal differentiation for this latter contrast in the ASD group for whom signal changes in a left hippocampal region were also marginally attenuated. Together, these observations suggest that attenuated levels of episodic recollection in ASD are, at least in part, attributable to anomalies in relational encoding processes. Autism Res 2015, 8: 317–327. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Identifying neural correlates of memory and language disturbances in herpes simplex encephalitis: a voxel-based morphometry (VBM) study.

Herpes simplex encephalitis (HSE) is a severe neurological disease that often leads to persistent cognitive deficits in survivors. Memory and naming impairments have been reported most, although direct association between memory and naming performance and disease-related atrophy has not yet been demonstrated in vivo for a larger sample of patients. In the present work, a voxel-based morphometry (VBM) analysis was conducted on 3T magnetic resonance imaging (MRI) of 13 HSE survivors. The gray matter density values were correlated with scores indicating verbal memory decline, as well as errors/omissions in picture naming; both were obtained through neuropsychological assessment. Analysis of individual lesion patterns revealed a considerable inter-individual variability, mainly with atrophy in the basal forebrain, adjacent frontal cortex, medial and lateral temporal cortex, insula and thalamus. The neuropsychological data analysis revealed correlation between verbal memory decline and atrophy especially in the left hippocampal region, whereas naming problems were associated with gray matter loss especially in the lateral temporal lobe, the thalamus and the left insula. These results confirm, for the first time, the assumptions of earlier studies about the considerable variability of individual lesion patterns in HSE in a whole-brain approach in vivo, and thus the anatomical validity of VBM.

Neural effects of cognitive–behavioural therapy on dysfunctional attitudes in depression

Dysfunctional attitudes are a feature of depression that has been correlated with receptor binding abnormalities in limbic and cortical regions. We sought to investigate the functional neuroanatomy of dysfunctional attitudes in major depressive disorder (MDD) and the effects of treatment with cognitive-behavioural therapy (CBT). Participants were 16 patients with unipolar depression in an acute depressive episode (mean age 40.0 years) and 16 matched healthy controls (mean age 39.9 years). Patients were medication free and received a course of treatment with CBT. All participants underwent functional magnetic resonance imaging (fMRI) scans at baseline and at week 16, prior to the initiation of therapy and following the course of CBT for patients. During each fMRI scan, participants indicated their attributions to statements from a modified Dysfunctional Attitudes Scale (mDAS-48). MDD patients in an acute depressive episode endorsed a greater number of extreme responses to DAS statements, which normalized following CBT treatment. Extreme attributions were associated with greater activation in the left hippocampal region, inferior parietal lobe and precuneus in MDD patients as compared with healthy controls as a main effect of group. An interaction effect was found in the left parahippocampal region, which showed less attenuation in MDD patients at the follow-up scan relative to healthy controls. Attenuation of activity in the parahippocampal region may be indicative of an improvement in dysfunctional thinking following CBT treatment in depression, while persistent engagement of regions involved in attentional processing and memory retrieval with extreme attributions reflects a trait feature of depression.

Cerebral microemboli increase β-amyloid protein deposition, MMP-9, and GFAP expression in the Alzheimer`s model of APP/PS1 double transgenic mice.

We investigated the effects of cerebral arterial microemboli on amyloid β protein (Aβ) deposition in the hippocampal region of amyloid precursor protein/presenilin 1 (APP/PS1) double transgenic mice and evaluated the role of cerebral arterial microemboli in Alzheimer's disease (AD) pathogenesis. The mice were divided into a wild-type sham surgery group (n = 15), a wild-type coupled with microemboli group (n =15), an APP/PS1 double transgenic sham surgery group (n =15) and an APP/PS1 double transgenic coupled with microemboli group (n =15). The microemboli mice were injected via the left internal carotid artery with 300 µL of a normal saline suspension containing 100 whole blood clot-derived microemboli (25-50 µm). The sham surgery mice were injected with equal volumes of saline. After the mouse model was established for 1, 2 or 4 weeks, the Aβ1-42 deposition in the left hippocampal region and the matrix metalloproteinase-9 (MMP-9) and glial fibrillary acidic protein (GFAP) expression levels were determined through immunohistochemical staining. The Aβ1-42 deposition level in the left hippocampi of transgenic microemboli group was significantly greater than in the transgenic sham group at week 1 and 2 (P<0.001) but not at week 4. No Aβ1-42 deposition was detected in the wild-type groups. Only sporadic MMP-9- and GFAP-positive cells were observed in the wild-type sham group. Significantly more MMP-9- and GFAP-positive cells were detected in the transgenic groups (P<0.001), particularly in the transgenic microemboli group. An intragroup analysis of the time factor for the microemboli groups showed significantly more MMP-9- and GFAP-positive cells at week 1 than at week 2 or 4 (P<0.001). No difference was detected between time points in the sham groups. Cerebral microemboli increased Aβ deposition in the hippocampal region of APP/PS1 double transgenic mice. MMP-9 and GFAP expression may play an important role in excess Aβ deposition, which is caused by an imbalance between the protein's synthesis and removal.

Comparison of associative recognition versus source recognition

The importance of the medial temporal lobe (MTL) for memory of arbitrary associations has been well established. However, the contribution of the MTL in concurrent retrieval of different classes of associations remains unclear. The present fMRI study investigated neural correlates of concurrent retrieval of associative and source memories. Participants studied a list of object pairs with two study tasks and judged the status and context of the pair during test. Associative retrieval was supported by neural activity in bilateral prefrontal cortex and left ventral occipito-temporal cortex, while source recognition was linked to activity in the right caudate. Both the hippocampus and MTL cortex showed retrieval activity for associative and source memory. Importantly, greater brain activity for successful associative recognition accompanied with successful source recognition was evident in left perirhinal and anterior hippocampal regions. These results indicate that the MTL is critical in the retrieval of different classes of associations.

Hippocampal Volume Is Decreased in Adults with Hypothyroidism

Thyroid hormones are important for the adult brain, particularly regions of the hippocampus including the dentate gyrus and CA1 and CA3 regions. The hippocampus is a thyroid hormone receptor-rich region of the brain involved in learning and memory. Consequently, alterations in thyroid hormone levels have been reported to impair hippocampal-associated learning and memory, synaptic plasticity, and neurogenesis. While these effects have been shown primarily in developing rats, as well as in adult rats, little is known about the effects in adult humans. There are currently no data regarding structural changes in the hippocampus as a result of adult-onset hypothyroidism. We aimed to establish whether hippocampal volume was reduced in patients with untreated adult-onset hypothyroidism compared to age-matched healthy controls. High-resolution magnetization-prepared rapid acquisition with gradient echo (MPRAGE) scans were performed on 11 untreated hypothyroid adults and 9 age-matched control subjects. Hypothyroidism was diagnosed based on increased levels of thyrotropin (TSH) and reduced levels of free thyroxine (fT4). Volumetric analysis of the right and left hippocampal regions, using functional magnetic resonance imaging of the brain (FMRIB) integrated registration and segmentation tool (FIRST), demonstrated significant volume reduction in the right hippocampus in the hypothyroid patients relative to the control group. These findings provide preliminary evidence that hypothyroidism results in structural deficits in the adult human brain. Decreases in volume in the right hippocampus were evident in patients with adult-onset overt hypothyroidism, supporting some of the findings in animal models.

A comparison of three brain atlases for MCI prediction

BackgroundAlthough previous voxel-based studies using features extracted by atlas-based parcellation produced relatively poor performances on the prediction of Alzheimer's disease (AD) in subjects with mild cognitive impairment (MCI), classification performance usually depends on features extracted from the original images by atlas-based parcellation. To establish whether classification performance differs depending on the choice of atlases, support vector machine (SVM)-based classification using different brain atlases was performed. New methodSeventy-seven three-dimensional T1-weighted MRI data sets of subjects with amnestic MCI, including 39 subjects who developed AD (MCI-C) within three years and 38 who did not (MCI-NC), were used for voxel-based morphometry (VBM) analyses and analyzed using SVM-based pattern recognition methods combined with a feature selection method based on the SVM recursive feature elimination (RFE) method. Three brain atlases were used for the feature selections: the Automated Anatomical Labeling (AAL) Atlas, Brodmann's Areas (BA), and the LONI Probabilistic Brain Atlas (LPBA40). ResultsThe VBM analysis showed a significant cluster of gray matter density reduction, located at the left hippocampal region, in MCI-C compared to MCI-NC. The SVM analyses with the SVM-RFE algorithm revealed that the best classification performance was achieved by LPBA40 with 37 selected features, giving an accuracy of 77.9%. The overall performance in LPBA40 was better than that of AAL and BA regardless of the number of selected features. ConclusionsThese results suggest that feature selection is crucial to improve the classification performance in atlas-based analysis and that the choice of atlases is also important.

Cerebral blood flow and metabolic changes in hippocampal regions of a modified rat model with chronic cerebral hypoperfusion

Chronic cerebral hypoperfusion (CCH) causes neurodegeneration which contributes to the cognitive impairment. This study utilized a modified rat model with CCH to investigate cerebral blood flow (CBF) and hippocampal metabolic changes. CBF was measured by laser Doppler flowmetry. Various metabolic ratios were evaluated from selective volumes of interest (VOI) in left hippocampal regions using in vivo proton magnetic resonance spectroscopy ((1)H-MRS). The ultrastructural changes with special respect to ribosomes in rat hippocampal CA1 neurons were studied by electron microscopy. CBF decreased immediately after CCH and remained reduced significantly at 1 day and 3 months postoperatively. (1)H-MRS revealed that CCH led to a significant decrease of N-acetyl aspartate/creatine (NAA/Cr) ratio in the hippocampal VOI in the model rats compared with the sham-operated control rats. However, no changes of myo-inositol/Cr, choline/Cr and glutamate and glutamine/Cr ratios between the model and control groups were observed. Under electron microscopy, most rosette-shaped polyribosomes were relatively evenly distributed in the hippocampal CA1 neuronal cytoplasms of the control rats. After CCH, most ribosomes were clumped into large abnormal aggregates in the model rats. Our data suggests that both permanent decrease of CBF and reduction of NAA/Cr ratio in the hippocampal regions may be related to the cognitive deficits in rats with CCH.

Differences in Brain Function and Changes with Intervention in Children with Poor Spelling and Reading Abilities

Previous fMRI studies in English-speaking samples suggested that specific interventions may alter brain function in language-relevant networks in children with reading and spelling difficulties, but this research strongly focused on reading impaired individuals. Only few studies so far investigated characteristics of brain activation associated with poor spelling ability and whether a specific spelling intervention may also be associated with distinct changes in brain activity patterns. We here investigated such effects of a morpheme-based spelling intervention on brain function in 20 children with comparatively poor spelling and reading abilities using repeated fMRI. Relative to 10 matched controls, children with comparatively poor spelling and reading abilities showed increased activation in frontal medial and right hemispheric regions and decreased activation in left occipito-temporal regions prior to the intervention, during processing of a lexical decision task. After five weeks of intervention, spelling and reading comprehension significantly improved in the training group, along with increased activation in the left temporal, parahippocampal and hippocampal regions. Conversely, the waiting group showed increases in right posterior regions. Our findings could indicate an increased left temporal activation associated with the recollection of the new learnt morpheme-based strategy related to successful training.

The neural correlates of maternal sensitivity: An fMRI study

Research on maternal neural response to infant distress highlights circuits that may underlie differences in quality of maternal behavior. However, it is far from clear which circuits are relevant to maternal sensitivity, as opposed to other maternal behavioral dimensions, particularly after the early postpartum. This study examined maternal sensitivity, intrusiveness, and mother-infant dyadic harmony as correlates of mothers' neural responses to the cries of their own infants. Twenty-two primiparous mothers were observed during an interaction with their infants at 18 months postpartum. In a separate functional neuroimaging session, mothers were exposed to their own infant's cry sound, as well as unfamiliar infant's cry and control sounds. Mothers who displayed more sensitive behaviors with their infant exhibited greater activation to their own infant's cry compared to that of an unfamiliar infant in the right frontal pole and inferior frontal gyrus. Mothers who displayed more intrusive behaviors with their infant showed greater activation in the left anterior insula and temporal pole, while mothers who had more harmonious interactions with their infant displayed greater activation in left hippocampal regions. The roles of these areas in the regulation of maternal emotion and stress, self and other awareness, and empathy are examined.

Obesity is associated with high serotonin 4 receptor availability in the brain reward circuitry

The neurobiology underlying obesity is not fully understood. The neurotransmitter serotonin (5-HT) is established as a satiety-generating signal, but its rewarding role in feeding is less well elucidated. From animal experiments there is now evidence that the 5-HT(4) receptor (5-HT(4)R) is involved in food intake, and that pharmacological or genetic manipulation of the receptor in reward-related brain areas alters food intake. Here, we used positron emission tomography in humans to examine the association between cerebral 5-HT(4)Rs and common obesity. We found in humans a strong positive association between body mass index and the 5-HT(4)R density bilaterally in the two reward ‘hot spots’ nucleus accumbens and ventral pallidum, and additionally in the left hippocampal region and orbitofrontal cortex. These findings suggest that the 5-HT(4)R is critically involved in reward circuits that regulate people's food intake. They also suggest that pharmacological stimulation of the cerebral 5-HT(4)R may reduce reward-related overeating in humans.

Rule and similarity in grammar: Their interplay and individual differences in the brain

Previous research on artificial grammar has indicated that the human ability to classify sentences or letter strings according to grammaticality relies on two types of knowledge. One is a superficial, familiarity-based understanding of a grammar the other is the knowledge of rules and critical features underlying a grammar. The fundamentally different characteristics of these systems permit an analysis of receiver-operating characteristics (ROC), which measures the extent to which each type of knowledge is used in grammaticality judgments. Furthermore, violations of a grammar can be divided into hierarchical and local violations. The present study is the first to combine the use of ROC analyses, fMRI and a grammaticality dichotomy. Based on previous neuroimaging studies, it was hypothesized that judgments based on rule knowledge, as extracted from individual ROC analyses, involve the left inferior frontal gyrus (IFG), whereas similarity would involve right IFG, as well as left hippocampal regions. With regards to violation types, it was hypothesized that hierarchical violations would recruit the opercular part of the left IFG as well as the posterior operculum, whereas local violations would bilaterally activate the premotor cortex (PMC). Results indicated that for greater reliance on rule knowledge, a ventral part of the left PMC was activated for ungrammatical items, whereas other PMC areas show a differentiated response for grammaticality for individuals less reliant on similarity. The right IFG was related to ungrammatical items as a function of similarity. Results are discussed with regards to possible error detection systems and differentiated efficiencies for respective classification strategies.

The effect of consequent exposure of stress and dermal application of low doses of chlorpyrifos on the expression of glial fibrillary acidic protein in the hippocampus of adult mice.

BackgroundChlorpyrifos (CPF), a commonly used pesticide worldwide, has been reported to produce neurobehavioural changes. Dermal exposure to CPF is common in industries and agriculture. This study estimates changes in glial fibrillary acidic protein (GFAP) expression in hippocampal regions and correlates with histomorphometry of neurons and serum cholinesterase levels following dermal exposure to low doses of CPF with or without swim stress.MethodsMale albino mice were separated into control, stress control and four treatment groups (n = 6). CPF was applied dermally over the tails under occlusive bandage (6 hours/day) at doses of 1/10th (CPF 0.1) and 1/5th dermal LD50 (CPF 0.2) for seven days. Consequent treatment of swim stress followed by CPF was also applied. Serum cholinesterase levels were estimated using spectroflurometric methods. Paraffin sections of the left hippocampal regions were stained with 0.2% thionin followed by the counting of neuronal density. Right hippocampal sections were treated with Dako Envision GFAP antibodies.ResultsCPF application in 1/10th LD50 did not produce significant changes in serum cholinesterase levels and neuronal density, but increased GFAP expression significantly (p < 0.001). Swim stress with CPF 0.1 group did not show increase in astrocytic density compared to CPF 0.1 alone but decreased neuronal density.ConclusionsFindings suggest GFAP expression is upregulated with dermal exposure to low dose of CPF. Stress combined with sub-toxic dermal CPF exposure can produce neurotoxicity.

Neural activity that predicts subsequent memory and forgetting: A meta-analysis of 74 fMRI studies

The present study performed a quantitative meta-analysis of functional MRI studies that used a subsequent memory approach. The meta-analysis considered both subsequent memory (SM; remembered>forgotten) and subsequent forgetting (SF; forgotten>remembered) effects, restricting the data used to that concerning visual information encoding in healthy young adults. The meta-analysis of SM effects indicated that they most consistently associated with five neural regions: left inferior frontal cortex (IFC), bilateral fusiform cortex, bilateral hippocampal formation, bilateral premotor cortex (PMC), and bilateral posterior parietal cortex (PPC). Direct comparisons of the SM effects between the studies using verbal versus pictorial material and item-memory versus associative-memory tasks yielded three main sets of findings. First, the left IFC exhibited greater SM effects during verbal material than pictorial material encoding, whereas the fusiform cortex exhibited greater SM effects during pictorial material rather than verbal material encoding. Second, bilateral hippocampal regions showed greater SM effects during pictorial material encoding compared to verbal material encoding. Furthermore, the left hippocampal region showed greater SM effects during pictorial-associative versus pictorial-item encoding. Third, bilateral PMC and PPC regions, which may support attention during encoding, exhibited greater SM effects during item encoding than during associative encoding. The meta-analysis of SF effects indicated they associated mostly with default-mode network regions, including the anterior and posterior midline cortex, the bilateral temporoparietal junction, and the bilateral superior frontal cortex. Recurrent activity oscillations between the task-positive and task-negative/default-mode networks may account for trial-to-trial variability in participants' encoding performances, which is a fundamental source of both SM and SF effects. Taken together, these findings clarify the neural activity that supports successful encoding, as well as the neural activity that leads to encoding failure.

Brain Function in Carriers of a Genome-wide Supported Bipolar Disorder Variant

The neural abnormalities underlying genetic risk for bipolar disorder, a severe, common, and highly heritable psychiatric condition, are largely unknown. An opportunity to define these mechanisms is provided by the recent discovery, through genome-wide association, of a single-nucleotide polymorphism (rs1006737) strongly associated with bipolar disorder within the CACNA1C gene, encoding the alpha subunit of the L-type voltage-dependent calcium channel Ca(v)1.2. To determine whether the genetic risk associated with rs1006737 is mediated through hippocampal function. Functional magnetic resonance imaging study. University hospital. A total of 110 healthy volunteers of both sexes and of German descent in the Hardy-Weinberg equilibrium for rs1006737. Blood oxygen level-dependent signal during an episodic memory task and behavioral and psychopathological measures. Using an intermediate phenotype approach, we show that healthy carriers of the CACNA1C risk variant exhibit a pronounced reduction of bilateral hippocampal activation during episodic memory recall and diminished functional coupling between left and right hippocampal regions. Furthermore, risk allele carriers exhibit activation deficits of the subgenual anterior cingulate cortex, a region repeatedly associated with affective disorders and the mediation of adaptive stress-related responses. The relevance of these findings for affective disorders is supported by significantly higher psychopathology scores for depression, anxiety, obsessive-compulsive thoughts, interpersonal sensitivity, and neuroticism in risk allele carriers, correlating negatively with the observed regional brain activation. Our data demonstrate that rs1006737 or genetic variants in linkage disequilibrium with it are functional in the human brain and provide a neurogenetic risk mechanism for bipolar disorder backed by genome-wide evidence.

Fronto‐temporal dysregulation in asymptomatic bipolar I patients: A paired associate functional MRI study

Bipolar disorder is associated with persistent declarative memory disturbances, but the neural basis of these deficits is not well understood. We used fMRI to investigate brain activity during performance on a face-name paired associate task, which allows for the dissociation of encoding and recall-related memory processes. Fifteen clinically remitted bipolar I disorder patients and 24 demographically matched healthy comparison subjects were scanned during task performance. At the voxel level, bipolar patients showed reduced cortical activation, relative to controls, in multiple task-related brain regions during encoding. During recognition, bipolar patients under-activated left hippocampal and parahippocampal regions, despite adequate task performance. Region of interest analyses indicated that, during encoding, bipolar patients had greater bilateral dorsolateral prefrontal (DLPFC) activity than healthy subjects. In contrast, during recognition patients showed hypo-activation relative to controls in the right, but not the left, DLPFC. Although hippocampal activity did not differ between groups during encoding, bipolar patients failed to activate hippocampal regions to the same extent as healthy subjects during recognition. Finally, while better task performance was associated with recognition-related hippocampal activity in healthy subjects, bipolar patients showed an inverse relationship between task performance and hippocampal activity. Remitted bipolar patients over-engaged dorsolateral prefrontal regions when learning face-name pairs, but relative hypoactivation in both prefrontal and medial temporal regions during recognition. These findings suggest a neural basis for the long-term memory deficits consistently observed in patients with bipolar disorder; further, as these patterns appear in symptomatically remitted patients, they are unlikely to be an artifact of mood symptoms.

1012 CORTICAL SUBSTRATE OF BLADDER CONTROL IN SCI AND THE EFFECT OF PERIPHERAL DORSAL GENITAL NERVE STIMULATION

You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Neurogenic Voiding Dysfunction1 Apr 20101012 CORTICAL SUBSTRATE OF BLADDER CONTROL IN SCI AND THE EFFECT OF PERIPHERAL DORSAL GENITAL NERVE STIMULATION Monika-Zita Zempleni, Lars Michels, Ulrich Mehnert, Brigitte Schurch, and Spyros Kollias Monika-Zita ZempleniMonika-Zita Zempleni More articles by this author , Lars MichelsLars Michels More articles by this author , Ulrich MehnertUlrich Mehnert More articles by this author , Brigitte SchurchBrigitte Schurch More articles by this author , and Spyros KolliasSpyros Kollias More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.2026AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES We investigated (i) the central representation of LUT control and (ii - iii) the acute and short-term central neuromodulatory effect of peripheral dorsal genital nerve (DGN) stimulation in incomplete SCI patients using functional magnetic resonance imaging (fMRI). METHODS After ethical approval, incomplete SCI subjects (ASIA B-C) were included. During a 1st fMRI (3-Tesla) session, the urinary bladder of the patients was repeatedly filled and emptied using a catheter (i). Subsequently, filling and emptying of the bladder was repeated with simultaneous peripheral DGN stimulation (ii). Following a two-week training of twice daily external electrical DGN stimulation (square wave, 0.2 ms, 20 Hz), a 2nd fMRI session was performed (iii). RESULTS 8 subjects completed the 1st fMRI session, showing supraspinal activation in the cerebellum, thalamus, putamen, left superior and middle frontal gyrus, insula, inferior frontal gyrus, anterior cingulated gyrus (ACG), and right precuneus (i). Compared to previously investigated healthy subjects, activations were less robust and showed a feft hemisheric dominance in frontal activation. Simultaneous DGN stimulation caused a reduction in activation in the right insula, left middle frontal gyrus, right temporal and hippocampal regions, and left cerebellum (ii). 6 subjects completed the 2 weeks stimulation training and the 2nd fMRI session, which showed an increase of activation in the caudate nuclei, left parahippocampal region, right middle temporal gyrus, right insula, right orbito-frontal, middle and superior frontal gyrus, right cerebellum, and right ACG (iii). 4 of the 6 subjects showed urodynamical improvements such as improved bladder sensibility, increased compliance, and improved voluntary voiding. CONCLUSIONS Our results suggest that the central representation of bladder filling sensation is partly preserved in the subacute stage of incomplete SCI (i). However, the decreased response in right prefrontal areas and the left hemispheric dominance, might indicate diminished inhibitory micturition control as well as, compensatory or decompensatory reorganization of bladder control. We also provide evidence for a neuromodulatory effect of acute DGN stimulation (ii). DGN stimulation training induced significant neuromodulation, predominantly signal increases in areas previously described as cortical network of bladder control in healthy (iii). Correlations with the patient's urological status indicate that this neuromodulatory effect may reflect the clinical improvement following training. Zurich, Switzerland© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e393-e394 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Monika-Zita Zempleni More articles by this author Lars Michels More articles by this author Ulrich Mehnert More articles by this author Brigitte Schurch More articles by this author Spyros Kollias More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The stress sensitization of adult rat Increased by stress in childhood and the neural mechanism

Objective To observe the influence of stress in childhood on adult rat's stress sensitization and the neural mechanism. Methods Sixty male Sprague-Dawley rats were randomly divided into stress group (thirty) and non-stress group(thirty). The rats in stress group were given 14 repeated daily forced swimming. The emotional behaviors were tested at the beginning of the experiment and when stress of forced swimming ended 8 weeks later. When the appraisal of behavior ended,the pyramidal neuron in the left hippocampal CA3 regions were counted under the light microscope, the pictures of synapses in the left hippocampal CA3 regions were got under the electromicroscope,and the morphological changes of synapses were analyzed with the automatic image analyzing system. Results (1) The score (1.20±0.60) of emotional behavior of stress group increased more than non-stress group(-0.13±0.83) (P<0.05). (2) The number of pyramidal neuron in the left hippocampal CA3 re-gions of stress group rats was small than that of non-stress group rats. (3) The number density [(1.01±0.15) N/ μm3 ], prosop density (0.20±0.04 )μm2/μm3], the average area of synaptic linkage [(0.05±0.02) μm2], the length of active areas [(314.78±46.32) nm], the curvatures (1.02±0.04), the thickness of postsynaptic dense material [(46.35±6.81) nm] in the left hippocampal CA3 regions of the stress group were small than those of non-stress group (P<0.05). Conclusion The stress in childhood could increase the stress sensitization of adult rats,and the decrease of synaptic plasticity might be the mechanism. Key words: Forced swimming test; Stress sensitization; Synapse; Pyramidal neuron; Rats

Specific hippocampal choline decrease in an animal model of depression

A decreased level of the hippocampal choline signal was found in patients with depression in previous proton magnetic resonance spectroscopy ((1)H-MRS) studies. The objective of this study is to compare choline levels before and after the forced swimming test (FST), an animal model of depression typically used for assessing antidepressant activity. (1)H-MRS spectra were obtained from both the left and right hippocampus. After the FST, rats showed a significant decrease of the choline/creatine (Cho/Cr, p = 0.037) and choline/N-acetylaspartate (Cho/NAA, p = 0.048) ratios in the left hippocampus, but not in the right hippocampus. This finding was analogous to results from patients with depression. It suggests that decreased Cho/Cr and Cho/NAA ratios in the left hippocampal regions might be considered to be biomarkers in rats with depression.