Diffusion tensor imaging of the hippocampus and verbal memory performance: the RUN DMC study

Background: Cerebral small vessel disease (SVD) and hippocampal atrophy are related to verbal memory failures and may ultimately result in Alzheimer's disease. However, verbal memory failures are often present before structural changes on conventional MRI appear. Changes in microstructural integrity of the hippocampus, which cannot be detected with conventional MRI, may be the underlying pathological substrate. With diffusion tensor imaging (DTI), we investigated the relation between the microstructural integrity of the hippocampus and verbal memory performance in 503 nondemented elderly with SVD. Methods: The Radboud University Nijmegen Diffusion tensor and Magnetic resonance imaging Cohort study is a prospective cohort study among 503 nondemented elderly with cerebral SVD aged between 50 and 85 years. All participants underwent T1 MPRAGE, fluid‐attenuated inversion recovery, DTI scanning and the Rey Auditory Verbal Learning Test. After manual segmentation of the hippocampi, we calculated the mean diffusivity (MD) and fractional anisotropy in both hippocampi. The relation between memory performance and hippocampal DTI parameters was adjusted for age, sex, education, depressive symptoms, hippocampal, and white‐matter lesions volume and lacunar infarcts. Results: We found inverse relations between hippocampal MD and verbal memory performance (β = ?0.22; P < 0.001), immediate recall (β = ?0.22; P < 0.001), delayed recall (β = ?0.20; P < 0.001), and forgetting rate (β = ?0.13; P = 0.025), most pronounced in participants with a normal hippocampal volume. Conclusion: Microstructural integrity of the hippocampus assessed by DTI is related to verbal memory performance in elderly with SVD, also in participants with an intact appearing hippocampus. Changes in hippocampal microstructure may be an early marker of underlying neurodegenerative disease, before macrostructural (i.e., volumetric) changes occur. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.     

Differential hippocampal shapes in posterior cortical atrophy patients: A comparison with control and typical AD subjects

Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by predominant visual deficits and parieto‐occipital atrophy, and is typically associated with Alzheimer's disease (AD) pathology. In AD, assessment of hippocampal atrophy is widely used in diagnosis, research, and clinical trials; its utility in PCA remains unclear. Given the posterior emphasis of PCA, we hypothesized that hippocampal shape measures may give additional group differentiation information compared with whole‐hippocampal volume assessments. We investigated hippocampal volume and shape in subjects with PCA (n = 47), typical AD (n = 29), and controls (n = 48). Hippocampi were outlined on MRI scans and their 3D meshes were generated. We compared hippocampal volume and shape between disease groups. Mean adjusted hippocampal volumes were ～8% smaller in PCA subjects (P < 0.001) and ～ 22% smaller in tAD subject (P < 0.001) compared with controls. Significant inward deformations in the superior hippocampal tail were observed in PCA compared with controls even after adjustment for hippocampal volume. Inward deformations in large areas of the hippocampus were seen in tAD subjects compared with controls and PCA subjects, but only localized shape differences remained after adjusting for hippocampal volume. The shape differences observed, even allowing for volume differences, suggest that PCA and tAD are each associated with different patterns of hippocampal tissue loss that may contribute to the differential range and extent of episodic memory dysfunction in the two groups. Hum Brain Mapp 36:5123–5136, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.     

Hippocampal Volume and Memory Performance in Children With Perinatal Stroke

BackgroundPediatric neurologists and neonatologists often are asked to predict cognitive outcome after perinatal brain injury (including likely memory and learning outcomes). However, relatively few data exist on how accurate predictions can be made. Furthermore, although the consequences of brain injury on hippocampal volume and memory performance have been studied extensively in adults, little work has been done in children.MethodsWe measured the volume of the hippocampus in 27 children with perinatal stroke and 19 controls, and measured their performance on standardized verbal and non-verbal memory tests.ResultsWe discovered the following: (1) As a group, children with perinatal stroke had smaller left and right hippocampi compared with control children. (2) Individually, children with perinatal stroke demonstrated 1 of 3 findings: no hippocampal loss, unilateral hippocampal loss, or bilateral hippocampal volume loss compared with control children. (3) Hippocampal volume inversely correlated with memory test performance in the perinatal stroke group, with smaller left and right hippocampal volumes related to poorer verbal and non-verbal memory test performance, respectively. (4) Seizures played a significant role in determining memory deficit and extent of hippocampal volume reduction in patients with perinatal stroke.ConclusionsThese findings support the view that, in the developing brain, the left and right hippocampi preferentially support verbal and nonverbal memory respectively, a consistent finding in the adult literature but a subject of debate in the pediatric literature. This is the first work to report that children with focal brain injury incurred from perinatal stroke have volume reduction in the hippocampus and impairments in certain aspects of declarative memory.     

The overall pathological status of the left hippocampus determines preoperative verbal memory performance in left mesial temporal lobe epilepsy

Studies on hippocampal cell loss in epilepsy have produced diverging evidence as to which subfields are specifically related to memory. This may be due to rather small and often heterogeneous samples, or to different memory measures. Therefore, the current study examined hippocampal cell densities and memory in a large sample of patients with solely mesial temporal lobe epilepsy (mTLE), employing measures with proven sensitivity to mesiotemporal pathology. In 104 patients who had undergone epilepsy surgery for mTLE, we evaluated the role of segmental hippocampal cell loss and its underlying factor structure with regard to presurgical verbal and figural memory while controlling for side‐of‐surgery and hemispheric dominance. First of all, patients showed material‐specific memory impairment concordant with the lateralization of epilepsy. Factor analysis of segmental cell loss revealed a single factor reflecting the overall integrity of the hippocampus. The overall pathological status of the left hippocampus correlated with verbal memory parameters (r = 0.33–0.34, P < 0.05), especially when controlling for atypical hemispheric dominance (r = 0.50–0.57, P < 0.01), and explained up to 33% of the observed variance. Further analyses revealed no superior role of a single subfield or cell loss pattern for memory performance. No systematic relations between neuronal cell densities of the right hippocampus and memory function were found, nor did left or right hippocampal pathology explain figural memory parameters. The results suggest that the overall pathological status of the left hippocampus – rather than a specific subfield pathology – is predictive for verbal memory in mTLE. The finding that figural memory parameters, although sensitive to right mTLE, were not related to neuronal cell densities of the right hippocampus, puts the left/right hippocampus verbal/nonverbal memory dichotomy into perspective. © 2014 Wiley Periodicals, Inc.     

不同半球脑梗死记忆障碍的研究

目的本文通过对不同半球脑梗死所致记忆障碍进行研究,明确记忆障碍与脑损害部位是否有必然联系,探索不同的记忆障碍在脑部相应区域的定位。方法将《临床记忆量表》[13]与《WMSCR》[6]两种量表结合起来并加用Rey复杂图形以检测视空间记忆能力,脑梗死组与对照组各40例用上述记忆量表测验,对不同脑损害的记忆功能进行较为全面的评价。结果脑梗死组记忆成绩无论临床记忆量表、韦氏记忆量表测验均明显低于对照组(P<0.05),其中部分分测验(言语记忆)的差别非常显著(P<0.01)。脑梗死组记忆成绩明显低于对照组(P<0.01),脑梗死组左半球与右半球病变不同的记忆内容比较也有显著性差异。结论不同的记忆功能在大脑的分工是有区别的,左半球主要对语文记忆起作用,右半球对非语文记忆起作用。在图形、空间记忆方面右半球起主导地位,而在短时记忆中左半球占优势。     

The canonical semantic network supports residual language function in chronic post‐stroke aphasia

Current theories of language recovery after stroke are limited by a reliance on small studies. Here, we aimed to test predictions of current theory and resolve inconsistencies regarding right hemispheric contributions to long‐term recovery. We first defined the canonical semantic network in 43 healthy controls. Then, in a group of 43 patients with chronic post‐stroke aphasia, we tested whether activity in this network predicted performance on measures of semantic comprehension, naming, and fluency while controlling for lesion volume effects. Canonical network activation accounted for 22%–33% of the variance in language test scores. Whole‐brain analyses corroborated these findings, and revealed a core set of regions showing positive relationships to all language measures. We next evaluated the relationship between activation magnitudes in left and right hemispheric portions of the network, and characterized how right hemispheric activation related to the extent of left hemispheric damage. Activation magnitudes in each hemispheric network were strongly correlated, but four right frontal regions showed heightened activity in patients with large lesions. Activity in two of these regions (inferior frontal gyrus pars opercularis and supplementary motor area) was associated with better language abilities in patients with larger lesions, but poorer language abilities in patients with smaller lesions. Our results indicate that bilateral language networks support language processing after stroke, and that right hemispheric activations related to extensive left hemispheric damage occur outside of the canonical semantic network and differentially relate to behavior depending on the extent of left hemispheric damage. Hum Brain Mapp 38:1636–1658, 2017. © 2016 Wiley Periodicals, Inc.     

Serotonin 1A receptors, depression, and memory in temporal lobe epilepsy

Purpose: Memory deficits and depression are common in patients with temporal lobe epilepsy (TLE). Previous positron emission tomography (PET) studies have shown reduced mesial temporal 5HT1A‐receptor binding in these patients. We examined the relationships among verbal memory performance, depression, and 5HT1A‐receptor binding measured with 18F‐trans‐4‐fluoro‐N‐2‐[4‐(2‐methoxyphenyl)piperazin‐1‐yl]ethyl‐N‐(2‐pyridyl) cyclohexane carboxamide (18FCWAY) PET in a cross‐sectional study. Methods: We studied 40 patients (24 male; mean age 34.5 ± 10.7 years) with TLE. Seizure diagnosis and focus localization were based on ictal video–electroencephalography (EEG) recording. Patients had neuropsychological testing with Wechsler Adult Intelligence Score III (WAIS III) and Wechsler Memory Score III (WMS III) on stable antiepileptic drug (AED) regimens at least 24 h since the last seizure. Beck Depression Inventory (BDI) scores were obtained. We performed interictal PET with 18FCWAY, a fluorinated derivative of WAY 100635, a highly specific 5HT1A ligand, and structural magnetic resonance imaging (MRI) scans to estimate partial volume and plasma free fraction corrected 18FCWAY volume of distribution (V/f1). Key Findings: Hippocampal V/f1 was significantly lower in area ipsilateral than contralateral to the epileptic focus (73.7 ± 27.3 vs. 95.4 ± 28.4; p < 0.001). We found a significant relation between both left hippocampal 18FCWAY V/f1 (r = 0.41; p < 0.02) and left hippocampal volume (r = 0.36; p < 0.03) and delayed auditory memory score. On multiple regression, there was a significant effect of the interaction of left hippocampal 18FCWAY V/f1 and left hippocampal volume on delayed auditory memory, but not of either alone. High collinearity was present. In an analysis of variance including the side of the seizure focus, the effect of left hippocampal 18FCWAY V/f1 but not focus laterality retained significance. Mean BDI was 8.3 ± 7.0. There was a significant inverse relation between BDI and 18FCWAY V/f1 ipsilateral to the patient’s epileptic focus (r = 0.38 p < 0.02). There was no difference between patients with a right or left temporal focus. There was no relation between BDI and immediate or delayed auditory memory. Significance: Our study suggests that reduced left hippocampal 5HT1A‐receptor binding may play a role in memory impairment in patients with TLE.     

Cognitive state following mild stroke: A matter of hippocampal mean diffusivity

The hippocampus is known to play a vital role in learning and memory and was demonstrated as an early imaging marker for Alzheimer's disease (AD). However, its role as a predictor for mild cognitive impairment and dementia following stroke is unclear. The main purpose of this study was to examine the associations between hippocampal volume, mean diffusivity (MD) and connectivity and cognitive state following stroke. Eighty three consecutive first ever mild to moderate stroke or transient ischemic attack (TIA) survivors from our ongoing prospective TABASCO (Tel Aviv Brain Acute Stroke Cohort) study underwent magnetic resonance imaging scans within 7 days of stroke onset. Hippocampal volume was measured from T1 weighted images, hippocampal mean diffusivity was calculated from diffusion tensor imaging and connectivity was calculated from resting state fMRI. Global cognitive assessments were evaluated during hospitalization and 6 and 12 months later using a computerized neuropsychological battery. Multiple linear regression analysis was used to test which of the hippocampi measurements best predict cognitive state. All three imaging parameters were significantly correlated to each other (|r's| >0.3, P's < 0.005), and with cognitive state 6 and 12 months after the event. Multiple regression analyses demonstrated the predictive role of hippocampal mean diffusivity (β = ?0.382, P = 0.026) on cognitive state, above and beyond that of volume and connectivity of this structure. To our knowledge, the combination of hippocampal volume, mean diffusivity and connectivity in first ever post stroke or TIA patients has not yet been considered in relation to cognitive state. The results demonstrate the predictive role of hippocampal mean diffusivity, suggesting that these changes may precede and contribute to volumetric and connectivity changes in the hippocampi, potentially serving as a marker for early identification of patients at risk of developing cognitive impairment or dementia. © 2015 Wiley Periodicals, Inc.     

Bilateral reductions of hippocampal volume, glucose metabolism, and Wada hemispheric memory performance are related to the duration of mesial temporal lobe epilepsy

In refractory temporal lobe epilepsy (TLE) temporal lobe structures and functions are continuously or intermittently affected by abnormal brain electrical events, noxious neurochemical agents, and metabolic disturbances. There is conflicting evidence regarding the relationship between the duration of refractory mesial TLE and quantitative measures of temporal lobe functions and volumes of the hippocampi. Twenty patients (aged 28 ± 7 years, 14 males) with an initial precipitating injury before the age of 5 years were subjected to high-resolution magnetic resonance imaging, fluoro-2-deoxy-d-glucose positron-emission tomography (PET), and the Wada test. We investigated whether the duration of unilateral refractory TLE (12 left, 8 right) affects hippocampal volume, glucose metabolism, or Wada hemispheric memory performance. Ipsilateral to the epileptogenic zone the hippocampal volume, metabolism, and Wada hemispheric memory performance were reduced compared to the corresponding contralateral measures. The duration of epilepsy controlled for age at investigation, side of seizure origin, underlying cause, and sex were negatively correlated with ipsi- and contralateral hippocampal volume, hippocampal metabolism, and Wada hemispheric memory performance. Moreover, ipsilateral Wada hemispheric memory performance and contralateral hippocampal glucose metabolism were correlated with the frequency of habitual seizures. Refractory TLE seems to be associated with a slow but ongoing bilateral temporal lobe damage. These cross-sectional results require verification by longitudinal studies carried out over a period of more than two decades. Received: 30 July 1998 Received in revised form: 16 March 1999 Accepted: 24 April 1999     

Impact of PICALM and CLU on hippocampal degeneration

PICALM and CLU are two major risk genes of late‐onset Alzheimer's disease (LOAD), and there is strong molecular evidence suggesting their interaction on amyloid‐beta deposition, hence finding functional dependency between their risk genotypes may lead to better understanding of their roles in LOAD development and greater clinical utility. In this study, we mainly investigated interaction effects of risk loci PICALM rs3581179 and CLU rs11136000 on hippocampal degeneration in both young and elderly adults in order to understand their neural mechanism on aging process, which may help identify robust biomarkers for early diagnosis and intervention. Besides volume we also assessed hippocampal shape phenotypes derived from diffeomorphic metric mapping and nonlinear dimensionality reduction. In elderly individuals (75.6 ± 6.7 years) significant interaction effects existed on hippocampal volume (P < 0.001), whereas in young healthy adults (19.4 ± 1.1 years) such effects existed on a shape phenotype (P = 0.01) indicating significant variation at hippocampal head and tail that mirror most AD vulnerable regions. Voxel‐wise analysis also pointed to the same regions but lacked statistical power. In both cohorts, PICALM protective genotype AA only exhibited protective effects on hippocampal degeneration and cognitive performance when combined with CLU protective T allele, but adverse effects with CLU risk CC. This study revealed novel PICALM and CLU interaction effects on hippocampal degeneration along aging, and validated effectiveness of diffeomorphometry in imaging genetics study. Hum Brain Mapp 37:2419–2430, 2016. © 2016 Wiley Periodicals, Inc.     

Functional and structural changes in the memory network associated with left temporal lobe epilepsy

Understanding functional plasticity in memory networks associated with temporal lobe epilepsy (TLE) is central to predicting memory decline following surgery. However, the extent of functional reorganization within memory networks remains unclear. In this preliminary study, we used novel analysis methods assessing network‐level changes across the brain during memory task performance in patients with TLE to test the hypothesis that hippocampal functions may not readily shift between hemispheres, but instead may show altered intra‐hemispheric organization with unilateral damage. In addition, we wished to relate functional differences to structural changes along specific fibre pathways associated with memory function. Nine pre‐operative patients with intractable left TLE and 10 healthy controls underwent functional MRI during complex scene encoding. Diffusion tensor imaging was additionally performed in the same patients. In our study, we found no evidence of inter‐hemispheric shifts in memory‐related activity in TLE using standard general linear model analysis. However, tensor independent component analysis revealed significant reductions in functional connectivity between bilateral MTL, occipital and left orbitofrontal regions among others in left TLE. This altered orbitofrontal activity was directly related to measures of fornix tract coherence in patients (P < 0.05). Our results suggest that specific fibre pathways, potentially affected by MTL neurodegeneration, may play a central role in functional plasticity in TLE and highlight the importance of network‐based analysis approaches. Relative to standard model‐based methods, novel objective functional connectivity analyses may offer improved sensitivity to subtle changes in the distribution of memory functions relevant for surgical planning in TLE. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.     

Smaller hippocampal volumes predict lower antidepressant response/remission rates in depressed patients: A meta-analysis

Objectives: Whether hippocampal volume predicts response and/or remission after antidepressant treatment of major depressive episodes (MDE) in major depressive disorder (MDD) remains unclear. We meta-analysed prospective studies comparing baseline hippocampal volume in patients with or without response/remission after antidepressant treatment.

Methods: Pubmed, Embase and Google Scholar were searched for studies of patients with current MDE in MDD, with hippocampal volume assessments at baseline, initiation of antidepressant drug treatment, and prospective assessment of response/remission after treatment.

Results: Six studies (374 patients), of which two were positive and four negative, were meta-analysed. Compared to responders/remitters, patients who failed to achieve response/remission had smaller total hippocampus volumes at baseline (mean volume difference?=?260?mm³, 95% CI [93; 427], P?=?0.002). These results remained significant in patients under 60 years of age (P?=?0.02), in those over 60 years old (P?=?0.04), and for right (P?=?0.006) and left (P?=?0.02) hippocampi. The probability of non-response/non-remission was 68.6% for patients with a total hippocampal volume at least 10% lower than the average, and 47.1% for patients with a total hippocampal volume 10% higher than the average.

Conclusions: In depressed patients treated with antidepressant drugs, smaller hippocampal volumes predict lower response/remission rates.     

Brain development of very preterm and very low-birthweight children in childhood and adolescence: a meta-analysis

Aim The aim of this article was to clarify the impact and consequences of very preterm birth (born <32wks of gestation) and/or very low birthweight ([VLBW], weighing <1500g) on brain volume development throughout childhood and adolescence. Method The computerized databases PubMed, Web of Knowledge, and EMBASE were searched for studies that reported volumetric outcomes during childhood or adolescence using magnetic resonance imaging and included a term‐born comparison group. Fifteen studies were identified, encompassing 818 very preterm/VLBW children and 450 term‐born peers. Average reductions in the total brain volume, white matter volume, grey matter volume, and in the size of the cerebellum, hippocampus, and corpus callosum were investigated using meta‐analytic methods. Results Very preterm/VLBW children were found to have a significantly smaller total brain volume than the comparison group (d=?0.58; 95% confidence interval [CI] ?0.43 to ?0.73; p<0.001), smaller white matter volume (d=?0.53; CI ?0.40 to ?0.67; p<0.001), smaller grey matter volume (d=?0.62; CI ?0.48 to ?0.76; p<0.001), smaller cerebellum (d=?0.74; CI ?0.56 to ?0.92; p<0.001), smaller hippocampus (d=?0.47; CI ?0.26 to ?0.69; p<0.001), and smaller corpus callosum (d=?0.71; CI ?0.34 to ?1.07; p<0.001). Reductions have been associated with decreased general cognitive functioning, and no relations with age at assessment were found. Interpretation Very preterm/VLBW birth is associated with an overall reduction in brain volume, which becomes evident in equally sized reductions in white and grey matter volumes, as well as in volumes of diverse brain structures throughout childhood and adolescence.     

Frontotemporoparietal asymmetry and lack of illness awareness in schizophrenia

Introduction: Lack of illness awareness or anosognosia occurs in both schizophrenia and right hemisphere lesions due to stroke, dementia, and traumatic brain injury. In the latter conditions, anosognosia is thought to arise from unilateral hemispheric dysfunction or interhemispheric disequilibrium, which provides an anatomical model for exploring illness unawareness in other neuropsychiatric disorders, such as schizophrenia. Methods: Both voxel‐based morphometry using Diffeomorphic Anatomical Registration through Exponentiated Lie Algebra (DARTEL) and a deformation‐based morphology analysis of hemispheric asymmetry were performed on 52 treated schizophrenia subjects, exploring the relationship between illness awareness and gray matter volume. Analyses included age, gender, and total intracranial volume as covariates. Results: Hemispheric asymmetry analyses revealed illness unawareness was significantly associated with right < left hemisphere volumes in the anteroinferior temporal lobe (t = 4.83, P = 0.051) using DARTEL, and the dorsolateral prefrontal cortex (t = 5.80, P = 0.003) and parietal lobe (t = 4.3, P = 0.050) using the deformation‐based approach. Trend level associations were identified in the right medial prefrontal cortex (t = 4.49, P = 0.127) using DARTEL. Lack of illness awareness was also strongly associated with reduced total white matter volume (r = 0.401, P < 0.01) and illness severity (r = 0.559, P < 0.01). Conclusion: These results suggest a relationship between anosognosia and hemispheric asymmetry in schizophrenia, supporting previous volume‐based MRI studies in schizophrenia that found a relationship between illness unawareness and reduced right hemisphere gray matter volume. Functional imaging studies are required to examine the neural mechanisms contributing to these structural observations. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.     

Inverse correspondence between hippocampal perfusion and verbal memory performance in older adults

Understanding physiological changes that precede irreversible tissue damage in age‐related pathology is central to optimizing treatments that may prevent, or delay, cognitive decline. Cerebral perfusion is a tightly regulated physiological property, coupled to tissue metabolism and function, and abnormal (both elevated and reduced) hippocampal perfusion has been reported in a range of cognitive disorders. However, the size and location of the hippocampus complicates perfusion quantification, as many perfusion techniques acquire data with spatial resolution on the order of or beyond the size of the hippocampus, and are thus suboptimal in this region (especially in the presence of hippocampal atrophy and reduced flow scenarios). Here, the relationship between hippocampal perfusion and atrophy as a function of memory performance was examined in cognitively normal healthy older adults (n = 20; age=67 ± 7 yr) with varying genetic risk for dementia using a custom arterial spin labeling acquisition and analysis procedure. When controlling for hippocampal volume, it was found that hippocampal perfusion correlated inversely (P = 0.04) with memory performance despite absent hippocampal tissue atrophy or white matter disease. The hippocampal flow asymmetry (left hippocampus perfusion–right hippocampus perfusion) was significantly (P = 0.04) increased in APOE‐?4 carriers relative to noncarriers. These findings demonstrate that perfusion correlates more strongly than tissue volume with memory performance in cognitively normal older adults, and furthermore that an inverse trend between these two parameters suggests that elevation of neuronal activity, possibly mediated by neuroinflammation and/or excitation/inhibition imbalance, may be closely associated with minor changes in memory performance. © 2012 Wiley Periodicals, Inc.     

Visual rating of the hippocampus in non‐demented elders: Does it measure hippocampal atrophy or other indices of brain atrophy? The SMART‐MR study

Visual rating of hippocampal atrophy is often used to differentiate between normal aging and Alzheimer's disease. We investigated whether two visual rating scales of hippocampal atrophy were related to hippocampal volumes, and if visual rating was related to global, cortical and subcortical brain atrophy in persons without dementia. Within the SMART‐MR study, a prospective cohort study among patients with manifest arterial disease, medial temporal lobe atrophy was qualitatively rated in 95 participants without dementia (mean age 62 ± 10 years) using two visual rating scales: the medial temporal lobe (MTA) score was rated on coronal oriented images and the perihippocampal cerebrospinal fluid (HCSF) score was rated on axial oriented images. Hippocampal volume assessed by manual segmentation on a 3‐dimensional FFE T1‐weighted MR image. Automated segmentation was used to quantify volumes of brain tissue and cerebrospinal fluid. Total brain volume, gray matter volume, and ventricular volume were divided by intracranial volume to obtain brain parenchymal fraction (BPF), gray matter fraction (GMF) and ventricular fraction (VF). Using ANOVA, crude hippocampal volumes were smaller with increasing MTA and HSCF scores as were hippocampal volumes normalized for intracranial volume (P < 0.05). However, hippocampal volumes normalized for total brain size were not smaller with increasing MTA or HSCF scores (P = 0.33 and P = 0.49). Also, with increasing visual rating scores, BPF was smaller and VF was larger (P < 0.001), and the GMF decreased with increasing HCSF score (P = 0.008). In this nondemented population, visual rating of the medial temporal lobe reflects hippocampal atrophy as well as global and subcortical atrophy. © 2009 Wiley‐Liss, Inc.     

Asymmetry analysis of deformable hippocampal model using the principal component in schizophrenia

The hippocampus is thought to play an important role in learning and memory processing, and impairments in memory, attention, and decision making are found commonly in schizophrenia. Although many studies have reported decreases in hippocampal volume in the left hemisphere in schizophrenia, regionally specific hippocampal volume loss has not been revealed consistently using volume analysis. Recently, many studies have analyzed shape asymmetry using 3-D models; however, inconsistent results have been reported, mainly due to methodologic differences. We therefore used an active, flexible, deformable shape model for surface parameterization, and compared shape asymmetry based on principal component analysis (PCA) in the hippocampi of schizophrenic patients with those of the normal controls. Although the overall pattern of the statistical results did not change according to the number of principal components, the reconstructed results based on six major components were much more distinguishable. Although the left hemispheric hippocampal volume was larger than the right hemispheric was in this study, the difference was not significant. In shape asymmetry analysis, the right hemisphere hippocampus was bilaterally larger than the left hemisphere hippocampus was in the head of the superior CA1 and smaller in the tail and head of the inferior CA1. The asymmetry in the schizophrenia group was statistically smaller than that in the control group through reduction of the left hemisphere hippocampus volume.     

Clinical and imaging correlates of amyloid deposition in dementia with Lewy bodies

Background : Amyloid deposition is common in dementia with Lewy bodies, but its pathophysiological significance is unclear. Objective : The objective of this study was to investigate the relationship between amyloid deposition and clinical profile, gray matter volume, and brain perfusion in dementia with Lewy bodies. Methods : Dementia with Lewy bodies (n = 37), Alzheimer's disease (n = 20), and controls (n = 20) underwent a thorough clinical assessment, 3T MRI, and early‐ and late‐phase ¹⁸F‐Florbetapir PET‐CT to assess cortical perfusion and amyloid deposition, respectively. Amyloid scans were visually categorized as positive or negative. Image analysis was carried out using statistical parametric mapping (SPM) 8. Results : There were no significant differences between amyloid‐positive and amyloid‐negative dementia with Lewy bodies cases in age (P = .78), overall cognitive impairment (P = .83), level of functional impairment (P = .80), or any other clinical or cognitive scale. There were also no significant differences in hippocampal or gray matter volumes. However, amyloid‐positive dementia with Lewy bodies cases had lower medial temporal lobe perfusion (P = .03) than amyloid‐negative cases, although a combination of medial temporal lobe perfusion, hippocampal volume, and cognitive measures was unable to accurately predict amyloid status in dementia with Lewy bodies. Conclusions : Amyloid deposition was not associated with differences in clinical or neuropsychological profiles in dementia with Lewy bodies, but was associated with imaging evidence of medial temporal lobe dysfunction. The presence of amyloid in dementia with Lewy bodies cannot be identified on the basis of clinical and other imaging features and will require direct assessment via PET imaging or CSF. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.     

Memory complaints in patients with normal cognition are associated with smaller hippocampal volumes

Abstract. We aimed to investigate volumetry of the medial temporal lobe in patients with subjective memory complaints without any cognitive impairment. This study included 20 patients with subjective memory complaints and normal cognitive function and 28 controls without memory complaints. Volumes of the hippocampus and parahippocampal gyrus (PHG) were measured using coronal T1-weighted MR images. Cognitive functions were assessed using the Cambridge Cognitive Examination. Depressive symptoms were assessed using the Geriatric Depression Scale. Differences between groups were analysed using t-tests. Patients with subjective memory complaints had a higher education and more depressive symptoms than controls (p < 0.01). Moreover, they had smaller left hippocampal volumes than controls (p < 0.01). There were no differences between groups in the volume of the right hippocampus or PHG. There was a moderate association between the volume of left hippocampus and left PHG and memory-score (r = 0.32, p = 0.03; r = 0.34, p = 0.02). We concluded that memory complaints in patients without any cognitive impairment were associated with smaller left hippocampal volumes and more depressive symptoms. These preliminary results suggest that memory complaints may reflect minimal brain deficits associated with impending dementia, depression or a combination of both disorders.     

Pathway to neural resilience: Self‐esteem buffers against deleterious effects of poverty on the hippocampus

Human neuroimaging studies have shown that people living in poverty tend to suffer hippocampal atrophy, which leads to impaired memory and learning throughout life. However, behavioral studies demonstrate that poor people with high self‐esteem are often exempt from the deleterious effect of poverty and instead possess a happy and successful life. Here we investigated whether high self‐esteem can buffer against the deleterious effects of poverty, as indicated by low subjective socioeconomic status (SSS), on the hippocampal gray matter volume (GMV) in a large cohort of young participants (N = 280). As expected, findings revealed that although low (vs. high) SSS was linked with a smaller hippocampal GMV, the deleterious effect of low SSS on hippocampal GMV was alleviated when the participants have high self‐esteem. Commonality analyses further confirmed this observation. The current study suggests that positive psychological resources such as self‐esteem may provide protection for the hippocampal atrophy in adversity. Hum Brain Mapp 37:3757–3766, 2016. © 2016 Wiley Periodicals, Inc .