The role of brain infarcts and hippocampal atrophy in subcortical ischaemic vascular dementia

The clinical profile of cerebral small vessel disease: Toward an evidence-based identification of cognitive markers

There is no consensus on which test is more suited to outline the cognitive deficits of cerebral small vessel disease (cSVD) patients. We explored the ability of eight cognitive tests, selected in a previous systematic review as the most commonly used in this population, to differentiate among cSVD patients, controls, and other dementing conditions performing a meta-analysis of 86 studies. We found that cSVD patients performed worse than healthy controls in all tests while data on the comparison to neurodegenerative diseases were limited. We outlined a lack of data on these tests' accuracy on the diagnosis. Cognitive tests measuring processing speed were those mostly associated with neuroimaging cSVD markers. There is currently incomplete evidence that a single test could differentiate cSVD patients with cognitive decline from other dementing diseases. We make preliminary proposals on possible strategies to gain information about the clinical definition of cSVD that currently remains a neuroimaging-based one.

Tamoxifen offers long-term neuroprotection after hippocampal silent infarct in male rats

Silent infarcts (SI) are a cerebral small vessel disease characterized by small subcortical infarcts. These occur in the absence of typical ischemia symptoms but are linked to cognitive decline and dementia. While there are no approved treatments for SI, recent results from our laboratory suggest that tamoxifen, a selective estrogen receptor modulator, is a viable candidate. In the present study, we induced SI in the dorsal hippocampal CA1 region of rats and assessed the effects of systemic administration of tamoxifen (5 mg/kg, twice) 21 days after injury on cognitive and pathophysiological measures, including cell loss, apoptosis, gliosis and estrogen receptors (ERs). We found that tamoxifen protected against the SI-induced cognitive dysfunction on the hippocampal-dependent, place recognition task, cell and ER loss, and increased apoptosis and gliosis in the CA1. Exploratory data analyses using a scatterplot matrix and principal component analysis indicated that SI-tamoxifen rats were indistinguishable from sham controls while they differed from SI rats, who were characterized by enhanced cell loss, apoptosis and gliosis, lower ERs, and recognition memory deficit. Supervised machine learning using support vector machine (SVM) determined predictors of progression from the early ischemic state to the dementia-like state. It showed that caspase-3 and ERα in the CA1 and exploration proportion were reliable and accurate predictors of this progression. Importantly, tamoxifen ameliorated SI-induced effects on all three of these variables, providing further evidence for its viability as a candidate treatment for SI and prevention of associated dementia.

The selective estrogen receptor modulator tamoxifen protects against subtle cognitive decline and early markers of injury 24 h after hippocampal silent infarct in male Sprague-Dawley rats

Silent infarcts (SI) are subcortical cerebral infarcts occurring in the absence of typical ischemia symptoms and are linked to cognitive decline and dementia development. There are no approved treatments for SI. One potential treatment is tamoxifen, a selective estrogen receptor modulator. It is critical to establish whether treatments effectively target the early consequences of SI to avoid progression to complete injury. We induced SI in the dorsal hippocampal CA1 of rats and assessed whether tamoxifen is protective 24 h later against cognitive deficits and injury responses including gliosis, apoptosis, inflammation and changes in estrogen receptors (ERs). SI led to subtle cognitive impairment on the object place task, an effect ameliorated by tamoxifen administration. SI did not lead to detectable hippocampal cell loss but increased apoptosis, astrogliosis, microgliosis and inflammation. Tamoxifen protected against the effects of SI on all measures except microgliosis. SI increased ERα and decreased ERβ in the hippocampus, which were mitigated by tamoxifen. Exploratory data analyses using scatterplot matrices and principal component analysis indicated that SI rats given tamoxifen were indistinguishable from controls. Further, SI rats were significantly different from all other groups, an effect associated with low levels of ERα and increased apoptosis, gliosis, inflammation, ERβ, and time spent with the unmoved object. The results demonstrate that tamoxifen is protective against the early cellular and cognitive consequences of hippocampal SI 24 h after injury. Tamoxifen mitigates apoptosis, gliosis, and inflammation and normalization of ER levels in the CA1, leading to improved cognitive outcomes after hippocampal SI.

Hippocampal silent infarct leads to subtle cognitive decline that is associated with inflammation and gliosis at twenty-four hours after injury in a rat model

Silent infarcts (SI) are subcortical cerebral infarcts that occur in the absence of clinical symptoms commonly associated with ischemia and are linked to dementia development. Little is known about the pathophysiology underlying the cognitive dysfunction associated with SI, and few studies have examined the early cellular responses and neurobiological underpinnings. We induced SI in adult male Sprague-Dawley rats using an infusion of endothelin-1 in the CA1 dorsal hippocampus. Twenty-four hours later, we assessed cognition using the hippocampal-dependent object place recognition task. We also examined whether the resulting cognitive effects were associated with common markers of ischemia, specifically cell and synapse loss, gliosis, and inflammation, using histology and immunohistochemistry. Hippocampal SI led to subtle cognitive impairment on the object place recognition task 24 -hs post-injury. This was characterized by a significant difference in exploration proportion relative to a pre-injury baseline and a positive association between time spent with both the moved and unmoved objects. SI did not result in any detectable cell or synaptophysin loss, but did increase apoptosis, gliosis and inflammation in the CA1. Principal component analysis indicated the main variables associated with hippocampal SI included increased time spent with the unmoved object, gliosis, apoptosis and inflammation as well as decreased exploration proportion and CA1 cells. Our data demonstrate that hippocampal SI can lead to cognitive dysfunction 24 -hs after injury. Further, this appears to be driven by early degenerative processes including apoptosis, gliosis and inflammation, suggesting that these may be targets for early interventions treating hippocampal SI and its cognitive consequences.

Alterations in the corticotropin-releasing hormone (CRH) neurocircuitry: Insights into post stroke functional impairments

Although it is well accepted that changes in the regulation of the hypothalamic-pituitary adrenal (HPA) axis may increase susceptibility to affective disorders in the general population, this link has been less examined in stroke patients. Yet, the bidirectional association between depression and cardiovascular disease is strong, and stress increases vulnerability to stroke. Corticotropin-releasing hormone (CRH) is the central stress hormone of the HPA axis pathway and acts by binding to CRH receptors (CRHR) 1 and 2, which are located in several stress-related brain regions. Evidence from clinical and animal studies suggests a role for CRH in the neurobiological basis of depression and ischemic brain injury. Given its importance in the regulation of the neuroendocrine, autonomic, and behavioral correlates of adaptation and maladaptation to stress, CRH is likely associated in the pathophysiology of post stroke emotional impairments. The goals of this review article are to examine the clinical and experimental data describing (1) that CRH regulates the molecular signaling brain circuit underlying anxiety- and depression-like behaviors, (2) the influence of CRH and other stress markers in the pathophysiology of post stroke emotional and cognitive impairments, and (3) context and site specific interactions of CRH and BDNF as a basis for the development of novel therapeutic targets. This review addresses how the production and release of the neuropeptide CRH within the various regions of the mesocorticolimbic system influences emotional and cognitive behaviors with a look into its role in psychiatric disorders post stroke.

Structural imaging biomarkers of Alzheimer's disease: predicting disease progression

Optimized magnetic resonance imaging (MRI)-based biomarkers of Alzheimer's disease (AD) may allow earlier detection and refined prediction of the disease. In addition, they could serve as valuable tools when designing therapeutic studies of individuals at risk of AD. In this study, we combine (1) a novel method for grading medial temporal lobe structures with (2) robust cortical thickness measurements to predict AD among subjects with mild cognitive impairment (MCI) from a single T1-weighted MRI scan. Using AD and cognitively normal individuals, we generate a set of features potentially discriminating between MCI subjects who convert to AD and those who remain stable over a period of 3 years. Using mutual information-based feature selection, we identify 5 key features optimizing the classification of MCI converters. These features are the left and right hippocampi gradings and cortical thicknesses of the left precuneus, left superior temporal sulcus, and right anterior part of the parahippocampal gyrus. We show that these features are highly stable in cross-validation and enable a prediction accuracy of 72% using a simple linear discriminant classifier, the highest prediction accuracy obtained on the baseline Alzheimer's Disease Neuroimaging Initiative first phase cohort to date. The proposed structural features are consistent with Braak stages and previously reported atrophic patterns in AD and are easy to transfer to new cohorts and to clinical practice.

Frontal lobe atrophy in depression after stroke

Background. Frontal lobe atrophy (FLA) is associated with late life depression. However, the role that FLA plays in the development of depression after stroke (DAS) remains unknown. This study thus examined the association between FLA and DAS. Methods. A convenience sample of 705 Chinese patients with acute ischemic stroke admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong participated in the study. A psychiatrist administered the Structural Clinical Interview for DSM-IV to all patients and made a diagnosis of DAS three months after the index stroke. Results. Eighty-five (12.1%) patients were diagnosed with DAS. In univariate analysis, the DAS patients were more likely to have severe FLA (14.1% versus 5.6%). Severe FLA remained an independent predictor of DAS in multivariate analysis, with an odds ratio of 2.6 (95% confidence intervals = 1.2–5.9). Conclusions. The results suggest that FLA may play a role in the pathogenesis of DAS, which supports the hypothesis that cumulative vascular burden may be important in predicting DAS. Further investigations are needed to clarify the impact of FLA on the clinical presentation, treatment response, and outcome of DAS in stroke survivors.

Determination of vascular dementia brain in distinct frequency bands with whole brain functional connectivity patterns

Recent studies have shown that multivariate pattern analysis (MVPA) can be useful for distinguishing brain disorders into categories. Such analyses can substantially enrich and facilitate clinical diagnoses. Using MPVA methods, whole brain functional networks, especially those derived using different frequency windows, can be applied to detect brain states. We constructed whole brain functional networks for groups of vascular dementia (VaD) patients and controls using resting state BOLD-fMRI (rsfMRI) data from three frequency bands - slow-5 (0.01 ≈ 0.027 Hz), slow-4 (0.027∼0.073 Hz), and whole-band (0.01 ≈ 0.073 Hz). Then we used the support vector machine (SVM), a type of MVPA classifier, to determine the patterns of functional connectivity. Our results showed that the brain functional networks derived from rsfMRI data (19 VaD patients and 20 controls) in these three frequency bands appear to reflect neurobiological changes in VaD patients. Such differences could be used to differentiate the brain states of VaD patients from those of healthy individuals. We also found that the functional connectivity patterns of the human brain in the three frequency bands differed, as did their ability to differentiate brain states. Specifically, the ability of the functional connectivity pattern to differentiate VaD brains from healthy ones was more efficient in the slow-5 (0.01 ≈ 0.027 Hz) band than in the other two frequency bands. Our findings suggest that the MVPA approach could be used to detect abnormalities in the functional connectivity of VaD patients in distinct frequency bands. Identifying such abnormalities may contribute to our understanding of the pathogenesis of VaD.

Memory after silent stroke: hippocampus and infarcts both matter

OBJECTIVE

Memory decline commonly occurs among elderly individuals. This observation is often attributed to early neurodegenerative changes in the hippocampus and related brain regions. However, the contribution of vascular lesions, such as brain infarcts, to hippocampal integrity and age-associated memory decline remains unclear.

METHODS

We studied 658 elderly participants without dementia from a prospective, community-based study on aging and dementia who received high-resolution structural MRI. Cortical and subcortical infarcts were identified, and hippocampal and relative brain volumes were calculated following standard protocols. Summary scores reflecting performance on tasks of memory, language, processing speed, and visuospatial function were derived from a comprehensive neuropsychological battery. We used multiple regression analyses to relate cortical and subcortical infarcts, hippocampal and relative brain volume, to measures of cognitive performance in domains of memory, language, processing speed, and visuospatial ability.

RESULTS

Presence of brain infarcts was associated with a smaller hippocampus. Smaller hippocampus volume was associated with poorer memory specifically. Brain infarcts were associated with poorer memory and cognitive performance in all other domains, which was independent of hippocampus volume.

CONCLUSIONS

Both hippocampal volume and brain infarcts independently contribute to memory performance in elderly individuals without dementia. Given that age-associated neurodegenerative conditions, such as Alzheimer disease, are defined primarily by impairment in memory, these findings have clinical implications for prevention and for identification of pathogenic factors associated with disease symptomatology.

Hippocampal atrophy in subcortical vascular dementia

BACKGROUND AND PURPOSE

New research criteria for subcortical vascular dementia (SVaD) have been suggested to define a more homogeneous subgroup of vascular dementia. Hippocampal (Hc) atrophy is a hallmark of Alzheimer's disease (AD), but it also occurs in other dementia disorders including vascular dementias. So far, it is unknown to which extent Hc atrophy is present in SVaD.

METHODS

From a larger consecutive referral population in a memory clinic, 11 patients fulfilling the research criteria for SVaD were carefully matched with comparison groups of healthy controls and patients with AD. To estimate the extent of Hc atrophy in SVaD, both Hc volumetry and visual rating of medial temporal lobe atrophy (MTA) were applied.

RESULTS

In SVaD, significant Hc atrophy occurred. The extent was intermediate between controls and patients with AD both on Hc volumetry and visual MTA ratings. At the same level of global cognition, Hc volumes were reduced by 11.6% in SVaD and 16.6% in AD, relative to controls.

CONCLUSIONS

Patient groups with AD and SVaD as identified by current research criteria appear to overlap considerably with regard to the feature of Hc atrophy. While contamination with AD is a likely cause, other mechanisms of Hc atrophy in SVaD also deserve consideration. The findings have implications for the design of future clinical trials of SVaD.

Frontal lobe atrophy is associated with small vessel disease in ischemic stroke patients

BACKGROUND

The pathogenesis of frontal lobe atrophy (FLA) in stroke patients is unclear. We aimed to ascertain whether subcortical ischemic changes were more associated with FLA than with parietal lobe atrophy (PLA) and temporal lobe atrophy (TLA).

METHODS

Brain magnetic resonance images (MRIs) from 471 Chinese ischemic stroke patients were analyzed. Lobar atrophy was defined by a widely used visual rating scale. All patients were divided into non-severe, mild-moderate, and severe atrophy of the frontal, parietal, and temporal lobe groups. The severity of white matter lesions (WMLs) was rated with the Fazekas' scale. Clinical and radiological features were compared among the groups. Subsequent logistic regressions were performed to determine the risk factors of atrophy and severe atrophy of the frontal, parietal and temporal lobes.

RESULTS

The frequency of FLA in our cohort was 36.9% (174/471). Severe FLA occurred in 30 (6.4%) patients. Age, previous stroke, and periventricular hyperintensities (PVH) (odds ratio (OR)=1.640, p=0.039) were independent risk factors of FLA. Age and deep white matter hyperintensities (DWMH) (OR=3.634, p=0.002) were independent risk factors of severe FLA. PVH and DWMH were not independent risk factors of PLA and TLA.

CONCLUSION

Frontal lobe atrophy in ischemic stroke patients may be associated with small vessel disease. The association between WMLs and FLA was predominant over atrophy of the parietal and temporal lobes, which suggests that the frontal lobe may be vulnerable to subcortical ischemic changes.

Influence of obstetric complication severity on brain morphology in schizophrenia: an MR study

INTRODUCTION

The purpose of this study was to determine if a causal relationship exists between obstetric complications (OCs) severity and linear magnetic resonance (MR) measurements of brain atrophy in patients with schizophrenia.

MATERIALS AND METHODS

Linear measurements of ventricular enlargement (bifrontal span, Evans ratio, and bicaudate ratio) and hippocampal atrophy (interuncal distance) were completed on MR images obtained in 47 patients with schizophrenia. Regression analysis was used to look at association with OCs severity, assessed by the "Midwife protocol" of Parnas and colleagues. The relationship between MR measurements and phenomenologic variables such as age at onset, illness duration, and exposure to antipsychotic medications was explored. The relationship between MR measurements, OCs severity, and symptom presentation was also investigated.

RESULTS

OCs severity was significantly associated with MR measurements of ventricular enlargement (bifrontal span, Evans ratio). As the severity of OCs increased, bifrontal span and Evans ratio increased. This effect was independent of age at onset, illness duration, or even antipsychotic treatment. Interestingly, bifrontal span, Evans ratio, and OCs severity score all showed a significant positive correlation with hallucinatory symptomatology.

CONCLUSION

Although confirmatory studies are needed, our findings would support the idea that environmental factors, in this case severe OCs, might partly contribute to ventricular abnormalities in schizophrenia.

Patterns of neuropsychological impairment in MCI patients with small subcortical infarcts or hippocampal atrophy

We investigated whether MCI patients with hippocampal atrophy or multiple subcortical infarcts demonstrate neuropsychological patterns and markers considered typical of Alzheimer's disease (AD) and of vascular dementia (VD), respectively. An extensive neuropsychological battery, including tests of memory, visual-spatial and executive functions, language, attention, praxis and psychomotor speed, was administered to 36 mild cognitive impairment (MCI) patients with hippocampal atrophy and 41 MCI patients with multiple subcortical infarcts. Both groups of MCI patients were very mildly impaired and well matched in terms of MMSE scores. A clear, disproportionately severe, episodic memory disorder was observed in MCI patients with hippocampal atrophy. A less specific neuropsychological profile, consisting of impairment on an Action Naming task that is sensitive to frontal lobe lesions, was observed in MCI patients with multiple subcortical infarcts. In MCI patients, a disproportionately severe episodic memory impairment strongly points to an Alzheimer's type brain pathology, whereas the prevalence of executive deficits and other frontal lobe symptoms are a much weaker diagnostic marker of small vessel subcortical disease.

Difference of the hippocampal and white matter microalterations in MCI patients according to the severity of subcortical vascular changes: neuropsychological correlates of diffusion tensor imaging

OBJECTIVES

Most imaging studies of mild cognitive impairment (MCI) have focused on gray matter alterations, although many MCI patients demonstrate subcortical vascular changes. We investigated the changes of the hippocampal area and various white matter areas in MCI patients with using diffusion tensor imaging (DTI), according to the severity of subcortical vascular changes, and we then correlated the DTI findings with the neuropsychological results.

PATIENTS AND METHODS

Among the 40 MCI patients, the 21 non-vascular MCI (nvMCI) and 19 vascular MCI (vMCI) patients were subdivided according to Erkinjuntti's imaging criteria. The mean diffusivity (MD) and fractional anisotropy (FA) were compared in the bilateral temporal, frontal, parietal and occipital white matter regions, as well as in the bilateral hippocampi, centrum semiovale, and the midline genu and splenum of the corpus callosum among the nvMCI and vMCI patients and the 17 controls. The neuropsychological findings were also compared between the subgroups.

RESULTS

All the MCI patients showed decreased FA and increased MD in all the regions except the occipital areas. In the parietal regions and centrum semiovale, the vMCI patients had a greater FA decrease than the nvMCI patients and controls. In the hippocampi, the FA was lowest in the nvMCI patients. The memory function in the nvMCI patients was more impaired than that in the vMCI patients. The vMCI patients showed impairment of the visuospatial and frontal executive functions.

CONCLUSION

We were able to correlate the microstructural alterations with the neuropsychological findings in the MCI subgroups.

Neurological soft signs and cerebral measurements investigated by means of MRI in schizophrenic patients

Neurophysiologic research has shown a Neurological Soft Sign (NSS) characteristic prevalence in schizophrenic patients, and correlations between NSS and the most frequently cerebral alterations. The aim of this study was to investigate, by means of MRI, the quantitative alterations of cortical and subcortical structures and their correlation with NSS in a sample of schizophrenic patients. Linear measures of lateral ventricular (Evans ratio), third ventricular (Third Ventricular Width), hippocampal (Interuncal Index) and cerebellar (Verm Cerebellar Atrophy) atrophy were made on magnified MR images of 33 patients with a DSM IV diagnoses of chronic schizophrenia. NSS were evaluated with the Buchanan and Heinrichs's Neurological Evaluation Scale (NES). Lateral ventricular enlargement showed to be correlated with right stereoagnosia item (p=0.001). Hippocampal atrophy, with right stereoagnosia item (p=0.023), with forefinger-right thumb opposition (p=0.004), forefinger-left thumb opposition (p=0.029 and face-hand extinction (0.26). Third ventricle enlargement showed to be correlated with forefinger-right thumb opposition (p=0.001), forefinger-left thumb opposition(p=0.021) and total sensorial integration (p=0.012). Cerebellar atrophy showed to be correlated with rhythmic drumming item (p=0.042), forefinger-right thumb opposition (p=0.007), forefinger-left thumb opposition (p=0.026), left specular movements (p=0.049), face-hand extinction (p=0.001), right-left confusion (p=0.005) and with left forefinger-nose index (p=0.032). Results obtained confirm the correlation between NSS and neuroanatomical alterations in schizophrenia.

Endovascular middle cerebral artery occlusion in rats as a model for studying vascular dementia

Vascular dementia (VaD), incorporating cognitive dysfunction with vascular disease, ranks as the second leading cause of dementia in the United States, yet no effective treatment is currently available. The challenge of defining the pathological substrates of VaD is complicated by the heterogeneous nature of cerebrovascular disease and coexistence of other pathologies, including Alzheimer's disease (AD) types of lesion. The use of rodent models of ischemic stroke may help to elucidate the type of lesions that are responsible for cognitive impairment in humans. Endovascular middle cerebral artery (MCA) occlusion in rats is considered to be a convenient and reliable model of human cerebral ischemia. Both sensorimotor and cognitive dysfunction can be induced in the rat endovascular MCA occlusion model, yet sensorimotor deficits induced by endovascular MCA occlusion may improve with time, whereas data presented in this review suggest that in rats this model can result in a progressive course of cognitive impairment that is consistent with the clinical progression of VaD. Thus far, experimental studies using this model have demonstrated a direct interaction of cerebral ischemic damage and AD-type neuropathologies in the primary ischemic area. Further, coincident to the progressive decline of cognitive function, a delayed neurodegeneration in a remote area, distal to the primary ischemic area, the hippocampus, has been demonstrated in a rat endovascular MCA occlusion model. We argue that this model could be employed to study VaD and provide insight into some of the pathophysiological mechanisms of VaD.

Medial temporal atrophy rather than white matter hyperintensities predict cognitive decline in stroke survivors

Stroke is an important risk factor for dementia, but the exact mechanisms involved in cognitive decline remain unclear. In this study, we related baseline MRI brain measures with later cognitive decline. Seventy-nine stroke survivors aged 75+ years without dementia were recruited 3-month post-stroke. They underwent yearly neuropsychological assessments and had an MRI at baseline and 2 years. Medial temporal lobe atrophy (MTA) was scored and volume of white matter hyperintensities (WMH) was measured at baseline. The rate of ventricular enlargement was measured by comparing the baseline and repeat images. Linear regression indicated that memory loss was related to both baseline memory and MTA (p=0.001; standardized regression coefficient beta=-0.35) but not WMH volume. The only independent predictor of ventricular enlargement was MTA (p=0.003; beta=0.47). However, no baseline MRI variable differed between those who did (18%) and did not (82%) develop dementia. The association of MTA but not WMH with subsequent cognitive decline and increasing brain atrophy suggests a greater role for Alzheimer type than vascular pathology in delayed cognitive impairment after stroke.

Neuroprotective effect of Coenzyme Q10 on ischemic hemisphere in aged mice with mutations in the amyloid precursor protein

This study was designed to test whether Coenzyme Q10 (CoQ10) supplementation has neuroprotective effect in aged, double-transgenic amyloid precursor protein (APP)/presenilin 1 (PS1), single transgenic APP and PS1 mice exposed to ischemic injury of the brain. Forty-eight mice (12 each of APP/PS1, APP, PS1 and wild-type) were studied. Half of each genotype groups (n=6 per group) was treated with CoQ10 (1200 mg/kg/day) after ischemic injury and the other half with placebo. Magnetic resonance (MR) images were used to measure the volume of induced infarction (IFV), as well as the volume of the hemispheres and hippocampi. Significantly greater volumes of infarction and lesser volumes of hemisphere/hippocampus on the ischemic side were observed in APP/PS1 and APP mice than in PS1 and wild-type mice. This is consistent with amplification of the effect of ischemia in APP carriers. After 28 days of CoQ10 treatment, APP/PS1 or APP mutations have smaller infarct volumes, while the volumes of hemisphere and hippocampus on the infarcted side were larger than those treated with placebo. No differences between CoQ10- and placebo-treated groups in volumes of infarct, hemisphere and hippocampus were observed in PS1 and wild-type mice. We conclude that CoQ10 has a protective effect on the brain from infarction and atrophy induced by ischemic injury in aged and susceptible transgenic mice.

Protective Effects of Breviscapine on Ischemic Vascular Dementia in Rats

Breviscapine, a traditional Chinese medicine, is extensively used in clinic to treat cardiovascular diseases and cerebrovascular injury. In this study, we demonstrated the effects of breviscapine on vascular dementia (VD) rats, which were mimicked by permanent occlusion of bilateral common carotid arteries. Breviscapine (2 mg/kg for 14 d) improved the performance of learning and memory of VD rats in Morris water maze, decreased the level of lipid peroxidation and free radicals, and attenuated the pathological alterations, such as nuclear shrink, cellular edema and irregular arrangement of pyramidal layer in the hippocampal CA(1) area. In vitro experiment, breviscapine (50 microg/l) protected cortical neuron from injury and decreased intracellular calcium overloading induced by H2O2 (10 mM). The results suggest that breviscapine has therapeutic effect on cerebral ischemia and vascular dementia.