Preoperative Acute Sleep Deprivation Causes Postoperative Pain Hypersensitivity and Abnormal Cerebral Function

Preoperative sleep loss can amplify post-operative mechanical hyperalgesia. However, the underlying mechanisms are still largely unknown. In the current study, rats were randomly allocated to a control group and an acute sleep deprivation (ASD) group which experienced 6 h ASD before surgery. Then the variations in cerebral function and activity were investigated with multi-modal techniques, such as nuclear magnetic resonance, functional magnetic resonance imaging, c-Fos immunofluorescence, and electrophysiology. The results indicated that ASD induced hyperalgesia, and the metabolic kinetics were remarkably decreased in the striatum and midbrain. The functional connectivity (FC) between the nucleus accumbens (NAc, a subregion of the ventral striatum) and the ventrolateral periaqueductal gray (vLPAG) was significantly reduced, and the c-Fos expression in the NAc and the vLPAG was suppressed. Furthermore, the electrophysiological recordings demonstrated that both the neuronal activity in the NAc and the vLPAG, and the coherence of the NAc-vLPAG were suppressed in both resting and task states. This study showed that neuronal activity in the NAc and the vLPAG were weakened and the FC between the NAc and the vLPAG was also suppressed in rats with ASD-induced hyperalgesia. This study highlights the importance of preoperative sleep management for surgical patients.

Tibetan medicine Ru-yi-Zhen-bao Pills exhibits anti-migraine effect through mediating PAG anti-nociceptive channel

ETHNOPHARMACOLOGICAL RELEVANCE

Migraine is a disabling neurovascular disorder, which increases risk of cardiovascular events and is a social burden worldwide. The present first-line anti-migraine medications can cause overwhelming side-effects, of which one includes the onset of cardiovascular disease. As one of the marketed Tibetan drugs, Ru-yi-Zhen-bao Pills (RYZBP) have been clinically used to treat cardiovascular disorders and as anti-migraine medication. However, there is currently no research exploring the anti-migraine actions of RYZBP.

AIM OF THE STUDY

The current research was designed to assess the anti-migraine roles of RYZBP and explore the underlying mechanisms in a nitroglycerin (NTG)-induced migraine rat model trial.

MATERIALS AND METHODS

120 rats were randomly divided into the following six groups of 20 rats each: normal control group, model control group, positive control group, and RYZBP high/medium/low-dose groups (Ru-yi-Zhen-bao Pills; TH 1.00 g/kg, TM 0.50 g/kg and TL 0.25 g/kg). All rats were administered intragastrically for 7 consecutive days, which were subcutaneously injected with the NTG (10 mg/kg) after the last gavage (except in the normal control group). 3min after NTG treatment, 30 rats (5 rats from each group) were anesthetized and devoted to electroencephalogram(EEG) testing, which was used to evaluate the analgesic effect of RYZBP. One hour after NTG treatment, the rest of the 90 rats (15 rats from each group) were anesthetized and midbrain tissue sample was dissected. The dissection was then washed with physiological saline and collected. The histopathological changes in the periaqueductal gray(PAG) of 5 tissue samples were determined by aematoxylin-eosin (H&E) staining, as well as an estimation of substance P (SP) and neurokinin 1 receptor (NK1R) expression through immunohistochemically staining(IHC). Another 5 midbrain preparations were carried out to evaluate calcitonin gene-related peptide (CGRP), proenkephalin (PENK), SP, and cholecystokinin (CCK) expressions by real-time quantitative polymerase chain reaction (RT-qPCR). The rest of the 5 brainstem tissues were then used to measure CCK, CGRP, and opioid peptide receptor (DORR) levels by western blotting(WB).

RESULTS

In the EEG test, RYZBP (TM 0.50 g / kg) treatment transformed the EEG pain-wave of the NTG-induced migraine model rats in different time period. In the mechanism assay, compared with the model control group, RYZBP pretreatment reduced inflammatory cell infiltration, fibrosis and vacuolation of neuronal cells of PAG tissue seen by HE staining. IHC experiments further showed that RYZBPTM up-regulated SP expression levels and enhanced NK1R levels in the NTG-induced migraine rats (P < 0.05). Therapeutic administration of RYZBP also increased PENK mRNA expression and DORR protein level. Both RT-qPCR and western blotting trials indicated that RYZBP treatment significantly decreased CCK and CGRP expression levels (P < 0.01 or P < 0.05) in the NTG-induced migraine rats.

CONCLUSIONS

RYZBP has the potential to be an effective anti-migraine treatment through suppressing the EEG pain-wave, increasing the levels of SP, PENK, DORR and reducing expression of CCK and CGRP. Mediating the PAG anti-nociceptive channel and inhibiting central sensitization were the two potential mechanisms, which offers further evidence for clinical therapy.

Stress induces analgesia via orexin 1 receptor-initiated endocannabinoid/CB1 signaling in the mouse periaqueductal gray

The orexin system consists of orexin A/hypocretin 1 and orexin B/hypocretin 2, and OX1 and OX2 receptors. Our previous electrophysiological study showed that orexin A in the rat ventrolateral periaqueductal gray (vlPAG) induced antinociception via an OX1 receptor-initiated and endocannabinoid-mediated disinhibition mechanism. Here, we further characterized antinociceptive effects of orexins in the mouse vlPAG and investigated whether this mechanism in the vlPAG can contribute to stress-induced analgesia (SIA) in mice. Intra-vlPAG (i.pag.) microinjection of orexin A in the mouse vlPAG increased the hot-plate latency. This effect was mimicked by i.pag. injection of WIN 55,212-2, a CB1 agonist, and antagonized by i.pag. injection of the antagonist of OX1 (SB 334867) or CB1 (AM 251), but not OX2 (TCS-OX2-29) or opioid (naloxone), receptors. [Ala(11), D-Leu(15)]-orexin B (i.pag.), an OX2 selective agonist, also induced antinociception in a manner blocked by i.pag. injection of TCS-OX2-29, but not SB 334867 or AM 251. Mice receiving restraint stress for 30 min showed significantly longer hot-plate latency, more c-Fos-expressing orexin neurons in the lateral hypothalamus and higher orexin levels in the vlPAG than unrestrained mice. Restraint SIA in mice was prevented by i.pag. or intraperitoneal injection of SB 334867 or AM 251, but not TCS-OX2-29 or naloxone. These results suggest that during stress, hypothalamic orexin neurons are activated, releasing orexins into the vlPAG to induce analgesia, possibly via the OX1 receptor-initiated, endocannabinoid-mediated disinhibition mechanism previously reported. Although activating either OX1 or OX2 receptors in the vlPAG can lead to antinociception, only OX1 receptor-initiated antinociception is endocannabinoid-dependent.

[An update on the conceptual and classification issues of anxiety, its neuroanatomy and problems of anxiolytic drug discovery]

Anxiety disorders are highly prevalent psychiatric diseases. In this short review we provide an overview of concepts of fear, anxiety and anxiety disorders. In addition, based on the recent literature, neuroanatomical structures involved in anxiety and functional/structural changes of these structures in anxiety disorders are also discussed. Furthemore, the pitfalls of anxiolytic drug discovery is also concerned in the paper.

The nucleus accumbens as a potential target for central poststroke pain

Although deep brain stimulation (DBS) has been found to be efficacious for some chronic pain syndromes, its usefulness in patients with central poststroke pain (CPSP) has been disappointing. The most common DBS targets for pain are the periventricular gray region (PVG) and the ventralis caudalis of the thalamus. Despite the limited success of DBS for CPSP, few alternative targets have been explored. The nucleus accumbens (NAC), a limbic structure within the ventral striatum that is involved in reward and pain processing, has emerged as an effective target for psychiatric disease. There is also evidence that it may be an effective target for pain. We describe a 72-year-old woman with a large right hemisphere infarct who subsequently experienced refractory left hemibody pain. She underwent placement of 3 electrodes in the right PVG, ventralis caudalis of the thalamus, and NAC. Individual stimulation of the NAC and PVG provided substantial improvement in pain rating. The patient underwent implantation of permanent electrodes in both targets, and combined stimulation has provided sustained pain relief at nearly 1 year after the procedure. These results suggest that the NAC may be an effective DBS target for CPSP.

Resting-state functional connectivity bias of middle temporal gyrus and caudate with altered gray matter volume in major depression

Magnetic resonance imaging (MRI) studies have indicated that the structure deficits and resting-state functional connectivity (FC) imbalances in cortico-limbic circuitry might underline the pathophysiology of MDD. Using structure and functional MRI, our aim is to investigate gray matter abnormalities in patients with treatment-resistant depression (TRD) and treatment-responsive depression (TSD), and test whether the altered gray matter is associated with altered FC. Voxel-based morphometry was used to investigate the regions with gray matter abnormality and FC analysis was further conducted between each gray matter abnormal region and the remaining voxels in the brain. Using one-way analysis of variance, we found significant gray matter abnormalities in the right middle temporal cortex (MTG) and bilateral caudate among the TRD, TSD and healthy controls. For the FC of the right MTG, we found that both the patients with TRD and TSD showed altered connectivity mainly in the default-mode network (DMN). For the FC of the right caudate, both patient groups showed altered connectivity in the frontal regions. Our results revealed the gray matter reduction of right MTG and bilateral caudate, and disrupted functional connection to widely distributed circuitry in DMN and frontal regions, respectively. These results suggest that the abnormal DMN and reward circuit activity might be biomarkers of depression trait.

EP1 receptor within the ventrolateral periaqueductal grey controls thermonociception and rostral ventromedial medulla cell activity in healthy and neuropathic rat

The aim of this study was to investigate the expression of prostaglandin EP1 receptor within the ventrolateral periaqueductal grey (VL PAG). The role of VL PAG EP1 receptor in controlling thermonociception and rostral ventromedial medulla (RVM) activity in healthy and neuropathic rats was also examined. EP1 receptor was indeed found to be expressed within the VL PAG and co-localized with vesicular GABA transporter. Intra-VL PAG microinjection of ONO-DI-004, a selective EP1 receptor agonist, dose-dependently reduced tail flick latency as well as respectively increasing and decreasing the spontaneous activity of ON and OFF cells. Furthermore, it increased the ON cell burst and OFF cell pause. Intra-VL PAG prostaglandin E2 (PGE2) behaved similarly to ONO-DI-004. The effects of ONO-DI-004 and PGE2 were antagonized by intra-VL PAG L335677, a selective EP1 receptor antagonist. L335677 dose-dependently increased the tail flick latency and ongoing activity of the OFF cells, while reducing the ongoing ON cell activity. It also decreased the ON cell burst and OFF cell pause. In neuropathic rats using spare nerve injury (SNI) of the sciatic nerve model, EP1 receptor expression decreased in the VL PAG. However, ONO-DI-004 and L335677 were able to alter pain responses and ON and OFF cell activity, as they did in healthy animals. Collectively, these data show that within the VL PAG, EP1 receptor has a facilitatory effect on the nociceptive response and consistently affects RVM neuron activity. Thus, the blockade of EP1 receptor in the VL PAG leads to antinociception in neuropathic pain conditions, despite its down-regulation. The expression of EP1 receptor on GABAergic neurons is consistent with an EP1 receptor blockade-induced disinhibition of the antinociceptive descending pathway at VL PAG level.

Neuroanatomy of anxiety

The evolutionary approach to human anxiety is based on the defensive responses that nonhuman animals show to fear-provoking stimuli. Studies performed mostly on rodents have related areas such as the medial prefrontal cortex, amygdaloid and hypothalamic nuclei, hipoccampal formation, and midbrain central gray to these responses. It is clear, however, that animals show different and sometimes opposite responses according to the threatening stimulus. These responses include immediate reactions such as freezing or flight, behavioral inhibition or avoidance, which are organized by at least partially distinct brain systems. As discussed in this chapter, several pieces of evidence indicate that these brain systems are similar in rodents and primates. In addition, recent neuroimaging studies also suggest dysfunctions in these systems are probably related to anxiety disorders in humans.

Hypocretin-2 saporin lesions of the ventrolateral periaquaductal gray (vlPAG) increase REM sleep in hypocretin knockout mice

Ten years ago the sleep disorder narcolepsy was linked to the neuropeptide hypocretin (HCRT), also known as orexin. This disorder is characterized by excessive day time sleepiness, inappropriate triggering of rapid-eye movement (REM) sleep and cataplexy, which is a sudden loss of muscle tone during waking. It is still not known how HCRT regulates REM sleep or muscle tone since HCRT neurons are localized only in the lateral hypothalamus while REM sleep and muscle atonia are generated from the brainstem. To identify a potential neuronal circuit, the neurotoxin hypocretin-2-saporin (HCRT2-SAP) was used to lesion neurons in the ventral lateral periaquaductal gray (vlPAG). The first experiment utilized hypocretin knock-out (HCRT-ko) mice with the expectation that deletion of both HCRT and its target neurons would exacerbate narcoleptic symptoms. Indeed, HCRT-ko mice (n = 8) given the neurotoxin HCRT2-SAP (16.5 ng/23nl/sec each side) in the vlPAG had levels of REM sleep and sleep fragmentation that were considerably higher compared to HCRT-ko given saline (+39%; n = 7) or wildtype mice (+177%; n = 9). However, cataplexy attacks did not increase, nor were levels of wake or non-REM sleep changed. Experiment 2 determined the effects in mice where HCRT was present but the downstream target neurons in the vlPAG were deleted by the neurotoxin. This experiment utilized an FVB-transgenic strain of mice where eGFP identifies GABA neurons. We verified this and also determined that eGFP neurons were immunopositive for the HCRT-2 receptor. vlPAG lesions in these mice increased REM sleep (+79% versus saline controls) and it was significantly correlated (r = 0.89) with loss of eGFP neurons. These results identify the vlPAG as one site that loses its inhibitory control over REM sleep, but does not cause cataplexy, as a result of hypocretin deficiency.

Gray matter deficits in young adults with narcolepsy

OBJECTIVES

The aim of this study was to investigate gray matter volume changes in narcolepsy.

MATERIALS AND METHODS

An optimized voxel-based morphometry was conducted for 17 young adults with a sole diagnosis of human leukocyte antigen DQB(1) 0602 positive narcolepsy with cataplexy (26.6 +/- 5.2 years old) and 17 comparison subjects (24.6 +/- 4.9 years old) using 3 Tesla scanner. Gray matter volumes in the bilateral hypothalamic voxel of interests (VOI) were also calculated.

RESULTS

Compared with the comparison subjects, narcoleptic patients had gray matter volume decrease in the right hypothalamus and other regions including subcortical, prefrontal, limbic and occipital areas. Narcoleptic patients also had lower gray matter volume on predefined VOI at the bilateral hypothalamus, which correlated with the Ullanlinna Narcolepsy Scale score.

CONCLUSIONS

Current findings suggest that narcoleptic patients have structural abnormalities in hypothalamus, which might be related to the clinical manifestation of narcolepsy with cataplexy.

Diffusion tensor imaging demonstrates brainstem and cerebellar abnormalities in congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS) patients show reduced breathing drive during sleep, decreased hypoxic and hypercapnic ventilatory responses, and autonomic and affective deficits, suggesting both brainstem and forebrain injuries. Forebrain damage was previously described in CCHS, but methodological limitations precluded detection of brainstem injury, a concern because genetic mutations in CCHS target brainstem autonomic nuclei. To assess brainstem and cerebellar areas, we used diffusion tensor imaging-based measures, namely axial diffusivity, reflecting water diffusion parallel to fibers, and sensitive to axonal injury, and radial diffusivity, measuring diffusion perpendicular to fibers, and indicative of myelin injury. Diffusion tensor imaging was performed in 12 CCHS and 26 controls, and axial and radial diffusivity maps were compared between groups using analysis of covariance (covariates; age and gender). Increased axial diffusivity in CCHS appeared within the lateral medulla and clusters with injury extended from the dorsal midbrain through the periaqueductal gray, raphé, and superior cerebellar decussation, ventrally to the basal-pons. Cerebellar cortex and deep nuclei, and the superior and inferior cerebellar peduncles showed increased radial diffusivity. Midbrain, pontine, and lateral medullary structures, and the cerebellum and its fiber systems are injured in CCHS, likely contributing to the characteristics found in the syndrome.

Extrahippocampal gray matter atrophy and memory impairment in patients with medial temporal lobe epilepsy

Memory impairment observed in patients with medial temporal lobe epilepsy (MTLE) is classically attributed to hippocampal atrophy. The contribution of extrahippocampal structures in shaping memory impairment in patients with MTLE is not yet completely understood, even though atrophy in MTLE extends beyond the hippocampus. We aimed to evaluate the neuropsychological profile of patients with MTLE focusing on memory, and to investigate whether gray matter concentration (GMC) distribution within and outside the medial portion of the temporal lobes would be associated with their neuropsychological performance. We performed a voxel based morphometry study of 36 consecutive patients with MTLE and unilateral hippocampal atrophy. We observed a significant simple regression between general and verbal memory performance based on Wechsler Memory Scale-Revised and the GMC of medial temporal and extratemporal structures in patients with left MTLE. We also performed a "regions of interest analysis" of the medial temporal lobe, and we observed that the GMC of the hippocampus, entorhinal, and perirhinal cortices were consistently associated with general and verbal memory performance in patients with MTLE. We also observed that the GMC of the cingulate and orbito-frontal cortex are independently associated with verbal and general memory performances. Our results suggest that general and verbal memory impairments in patients with left MTLE are associated with atrophy of the hippocampus, the entorhinal, and the perirhinal cortex. We also suggest that atrophy and dysfunction of limbic and frontal structures such as the cingulate and the orbito-frontal cortex contribute to memory impairment in MTLE.

Voxel-based morphometry study of brain volumetry and diffusivity in amyotrophic lateral sclerosis patients with mild disability

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive and simultaneous degeneration of upper and lower motor neurons. The pathological process associated to ALS, albeit more pronounced in the motor/premotor cortices and along the corticospinal tracts (CST), does not spare extra-motor brain gray (GM) and white (WM) matter structures. However, it remains unclear whether such extra-motor cerebral abnormalities occur with mildly disabling disease, and how irreversible tissue loss and intrinsic tissue damage are interrelated. To this end, we used an optimized version of voxel-based morphometry (VBM) analysis to investigate the patterns of regional GM density changes and to quantify GM and WM diffusivity alterations of the entire brain from mildly disabled patients with ALS. A high-resolution T1-weighted 3D magnetization-prepared rapid acquisition gradient echo and a pulsed gradient spin-echo single shot echo-planar sequence of the brain were acquired from 25 mildly disabled patients with ALS and 18 matched healthy controls. An analysis of covariance was used to compare volumetry and diffusivity measurements between patients and controls. Compared with controls, ALS patients had significant clusters of locally reduced GM density (P < 0.001) in the right premotor cortex, left inferior frontal gyrus (IFG), and superior temporal gyrus (STG), bilaterally. In ALS patients contrasted to controls, we also found significant clusters of locally increased MD (P < 0.001) in the splenium of the corpus callosum and in the WM adjacent to the IFG, STG, and middle temporal gyrus (MTG) of the right hemisphere, and in the WM adjacent to the MTG and lingual gyrus in the left hemisphere. Compared with controls, ALS patients also had significant clusters of locally decreased FA values (P < 0.001) in the CST in the midbrain and corpus callosum, bilaterally. This study supports the notion that ALS is a multisystem disorder and suggests that extra-motor involvement may be an early feature of the disease.

Relationship between body mass index and gray matter volume in 1,428 healthy individuals

OBJECTIVE

To investigate any correlation between BMI and brain gray matter volume, we analyzed 1,428 healthy Japanese subjects by applying volumetric analysis and voxel-based morphometry (VBM) using brain magnetic resonance (MR) imaging, which enables a global analysis of brain structure without a priori identification of a region of interest.

METHODS AND PROCEDURES

We collected brain MR images from 690 men and 738 women, and their height, weight, and other clinical information. The collected images were automatically normalized into a common standard space for an objective assessment of neuroanatomical correlations in volumetric analysis and VBM with BMI.

RESULTS

Volumetric analysis revealed a significant negative correlation in men (P < 0.001, adjusting for age, lifetime alcohol intake, history of hypertension, and diabetes mellitus), although not in women, between BMI and the gray matter ratio, which represents the percentage of gray matter volume in the intracranial volume. VBM revealed that, in men, the regional gray matter volume of the bilateral medial temporal lobes, anterior lobe of the cerebellum, occipital lobe, frontal lobe, precuneus, and midbrain showed significant negative correlations with BMI, while those of the bilateral inferior frontal gyri, posterior lobe of the cerebellum, frontal lobes, temporal lobes, thalami, and caudate heads showed significant positive correlations with BMI.

DISCUSSION

Global loss and regional alterations in gray matter volume occur in obese male subjects, suggesting that male subjects with a high BMI are at greater risk for future declines in cognition or other brain functions.

GFP imaging of live astrocytes: regional differences in the effects of ischaemia upon astrocytes

The basic division between white matter 'fibrous' astrocytes and grey matter 'protoplasmic' astrocytes is well established in terms of their morphological differences. The availability of transgenic animals with green fluorescent protein (GFP) expression restricted to specific glial cell types now provides an approach for looking at changes in cell number and morphology in the two astrocyte types in whole mount preparations. This is an important goal, as the ease of generating astrocyte cultures has led to a proliferation of studies that have examined ischaemic effects on astrocytes in vitro. This has in turn engendered a belief that astrocytes have an extraordinary resistance to ischaemic injury, a belief that runs counter to almost all the data available from in vivo and whole-mount preparations. One possible source of this confusion is the reactive changes that occur in astrocytes following injury, which include an increase in cell number that may obscure early astrocyte cell death and which has been reported to initiate within hours of an ischaemic event. However, we show here that neither white matter nor grey matter GFP(+) astrocytes exhibit any feature of reactive astrocytosis within a 180-min period of reperfusion following modelled ischaemia in neonatal whole-mount preparations. We also show that white matter astrocytes are much more sensitive to ischaemia-reperfusion injury than are grey matter astrocytes, a feature that may have high significance for developmental disorders of white matter tracts such as cerebral palsy.

In-vivo topography of structural alterations of the anterior cingulate in patients with schizophrenia: new findings and comparison with the literature

The anterior cingulate cortex (ACC) is part of the rostral limbic system and is involved in cognitive and affective processes that have been reported to be disturbed in schizophrenia. Despite the evidence for ACC abnormalities in schizophrenia indicated by functional imaging studies, structural magnetic resonance imaging (MRI) studies of this region of interest (ROI) have been relatively few and the results inconsistent. The aim of the present study was to examine the hypothesis that different subregions of the ACC are differentially affected by the disease process of schizophrenia, a circumstance that might contribute to contradictory results of earlier structural ACC studies. We investigated ACC volumes in 50 male and right-handed patients with schizophrenia according to ICD-10 and DSM-IV. The patients were individually matched for age, sex, handedness and education with 50 control subjects. ACC was subdivided into four parts: precallosal, subgenual, precommissural and postcommissural regions. Measurements were performed with a 1.5 T magnetom vision apparatus. Regions of interest were defined on consecutive coronal MRI-slices. The software program BRAINS was used for volumetry and segmentation into gray and white matter. We detected that ACC gray matter volume of the right precallosal region and right total ACC was significantly reduced in schizophrenic patients compared with control subjects. In addition, left ACC gray matter was selectively reduced in the subgenual region. These results confirmed our hypothesis that different ACC regions are differentially affected by structural alterations in schizophrenia, a circumstance that might explain in part the discrepant findings of former structural imaging studies of the ACC.

Two cases of lesions in brainstem in multiple sclerosis and refractory migraine

We report on 2 cases of multiple sclerosis in patients with refractory migraine as one of the initial manifestations of the disease. In both cases, the magnetic resonance image showed lesions in the brainstem that could be implicated in the genesis of such migraine attacks.

Association of Neocortical Volume Changes With Cognitive Deterioration in Relapsing-Remitting Multiple Sclerosis

BACKGROUND

We previously reported selective decreases of neocortical volumes in patients with early relapsing-remitting (RR) multiple sclerosis (MS) with mild cognitive impairment, with a good correlation between cortical volumes and cognitive measures.

OBJECTIVE

To assess the relevance of gray matter changes over time to changes in cognition in RRMS.

DESIGN

A longitudinal survey after 2.5 years. Each patient underwent a magnetic resonance imaging (MRI) protocol identical to that performed at baseline; cognitive performance was reassessed with the Rao Brief Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis.

SETTING

Two university MS clinics.

PATIENTS

Of 41 patients with RRMS who participated in the original cross-sectional study, 28 were available for the follow-up evaluation (18 women; mean +/- SD age, 37.1 +/- 8.9 years; mean +/- SD MS duration, 7.3 +/- 2.9 years; mean +/- SD Expanded Disability Status Scale score, 1.8 +/- 1.5).

MAIN OUTCOME MEASURES

We measured the percentage of brain volume changes, normalized cortical volume (NCV) changes, and normalized deep gray matter volume changes on conventional T1-weighted MRIs and changes in lesion load on T2-weighted MRIs. The number of tests failed on the Rao Brief Repeatable Battery were used to classify the patients as cognitively deteriorating or stable or improving.

RESULTS

We identified 12 of 28 cognitively deteriorating and 16 of 28 stable or improving patients. These subgroups did not differ in the mean +/- SD percentage of brain volume changes (-2.1% +/- 1.2% vs -1.3% +/- 1.3%; P = .11), normalized deep gray matter volume changes (-2.1 +/- 2.8 mL vs -0.6 +/- 3.1 mL; P = .60), and changes in lesion load on T2-weighted MRIs (1.9 +/- 2.6 mL vs 1.6 +/- 2.3 mL; P = .73). However, NCV changes were significantly higher in deteriorating than in stable or improving patients (-43.0 +/- 18.9 mL vs -17.8 +/- 26.6 mL; P = .007). In deteriorating patients, NCV changes were correlated with performance in a verbal fluency test (r = 0.73; P < .001). In a regression model, only NCV changes were significantly associated with deteriorating cognitive performance (odds ratio, 0.8; 95% confidence interval, 0.7-0.9).

CONCLUSION

Progressive neocortical gray matter loss is relevant to MS-associated cognitive impairment and may represent a sensitive marker of deteriorating cognitive performance in RRMS.

Dendritic cells are abundant in non-lesional gray matter in multiple sclerosis

We have analyzed the localization of dendritic cells (DCs) in non-lesional gray matter (NLGM) in comparison to non-lesional white matter (NLWM) and acute or chronic active multiple sclerosis (MS) lesions. Immunohistochemistry was performed on cryostat sections for DCs markers (CD209, CD205, CD83) and other markers for inflammatory cells (CD68, CD8, CD4, CD3, CCR7, CCR5). We found cells expressing CD209 and containing myelin basic protein in both perivascular and parenchymal areas of NLGM. Our findings showing the expression of CD209(+) cells in NLGM parenchymal areas are surprising relative to the previous literature which reported the presence of CD209(+) DCs only in MS plaque perivascular areas. Although less numerous than CD209(+) cells, NLGM cells expressing mature DCs marker CD205 were consistently detected in perivascular cuffs of most lesions. In double labeling experiments, some but not all of the CD209(+) cells also expressed CD68 and CCR5. We also found CD209(+) cells in close contact with CD3(+) lymphocytes suggesting that DCs might contribute to the local activation of pathogenic T cells in the NLGM. Since injury to the NLGM is one of the key factors associated with disability accumulation, targeting DCs may represent a possible new therapeutic approach in MS to prevent disease progression.

Interictal alterations of the trigeminal somatosensory pathway and periaqueductal gray matter in migraine

Migraine has been traditionally considered a nonprogressive, paroxysmal disorder with no brain abnormalities between attacks. We used diffusion tensor imaging to examine interictal diffusion properties of the brains of migraineurs with aura, migraineurs without aura and matched healthy controls. Areas of lower fractional anisotropy were present in migraineurs along the thalamocortical tract. In addition, migraineurs with aura had lower fractional anisotropy in the ventral trigeminothalamic tract, and migraineurs without aura had lower fractional anisotropy in the ventrolateral periaqueductal grey matter. Our results indicate the presence of permanent interictal changes in migraineurs, pointing to an effect of migraine on the trigeminal somatosensory and modulatory pain systems.

Subependymal periventricular heterotopias in a patient with ehlers-danlos syndrome: a new case

Ehlers-Danlos syndrome is a complex hereditary connective tissue disorder that is characterized by abnormalities of the skin and joints and visceral and neurological manifestations. At present, at least 11 forms are recognized on the basis of their clinical characteristics, methods of transmission, and biochemical defect. The neurologic manifestations include cerebrovascular disease, peripheral neuropathy, plexopathy, periventricular subependymal heterotopias, and epilepsy. Previously, 2 females were reported to be affected with subependimal periventricular heterotopias and Ehlers-Danlos syndrome type 1. The authors report a new case of a 12-year-old girl with similar clinical and neuroradiological features.

Magnetization transfer ratio measurement in multiple sclerosis normal-appearing brain tissue: limited differences with controls but relationships with clinical and MR measures of disease

We investigated the magnetization transfer ratio (MTR) of normal-appearing white (NAWM) and grey matter (NAGM) in a relatively large group of multiple sclerosis (MS) patients, and the relations of MTR changes with clinical disability. MTR was measured in 66 MS patients (12 PP, 35 RR, 19 SP) and 23 healthy controls, using a whole-brain 3D-FLASH technique corrected post-hoc for B1-induced variation. Histogram parameters of conservatively selected NAWM and cortical NAGM were analysed using Bonferroni-corrected ANOVA with age as covariate. Additionally, manually outlined regions of interest were analysed using a multilevel method. Lesions had low MTR (mean 22.7±6.9%), but NAWM exhibited limited changes: MTR histogram peak position was 32.8±1.0% in controls and 32.4±0.9% in MS patients, with a significant decrease compared to controls only in SPMS patients (31.9±1.1%, p=0.045). Cortical NAGM histograms did not differ significantly between patients and controls. In SPMS, regional mean MTR was significantly decreased in corpus callosum and hippocampus. MTR histogram parameters of NAGM and NAWM were correlated with EDSS and MSFC scores, with lesion volume and with normalized brain volume. We conclude that disease-induced MTR changes were small in MS NAWM and NAGM, but did correlate with clinical decline, lesion volume and overall cerebral atrophy. Multiple Sclerosis 2007; 13: 708-716. http://msj.sagepub.com

Voxel-based analysis of grey matter magnetization transfer ratio maps in early relapsing remitting multiple sclerosis

Previous studies using magnetization transfer ratio (MTR) histogram analysis have demonstrated the existence of global grey matter (GM) abnormalities in patients with early relapsing-remitting multiple sclerosis (RRMS). However, MTR histogram analysis does not provide any information on the localization of the morphological changes within the GM. The aim of this study was to investigate the localization of GM injury in early RRMS, performing voxel-based analysis of GM MTR maps. Statistical mapping analysis of GM MTR maps was performed in a group of 38 patients with early RRMS and 45 healthy controls. Between-group comparisons (P<0.05, corrected for multiple comparisons) demonstrated significant GM MTR decrease in patients located in the bilateral lenticular nuclei, the bilateral insula, the left posterior cingulate cortex, and the right orbitofrontal cortex. To limit the potential confounding effect of regional GM atrophy, the percentages of GM were assessed in the regions showing significant MTR decrease, and no GM atrophy was evidenced in these regions. This study demonstrates that several GM regions are commonly affected in patients with early RRMS. Predominant involvement of these structures may be partly related to their vulnerability to anterograde or retrograde degeneration from transected axons in the white matter and/or to the predominant localization of GM demyelinating lesions in such regions.

Double inversion recovery brain imaging at 3T: diagnostic value in the detection of multiple sclerosis lesions

BACKGROUND AND PURPOSE

To prospectively determine the sensitivity in the detection of multiple sclerosis (MS) lesions by using double inversion recovery (DIR), fluid-attenuated inversion recovery (FLAIR), and T2-weighted turbo spin-echo (T2 TSE) MR imaging at 3T.

METHODS

Seventeen patients presenting with a clinically isolated syndrome (CIS) suggestive of MS, 9 patients with definite MS, and 6 healthy control subjects were included. Imaging was performed on a 3T MR system using DIR, FLAIR, and T2 TSE sequences. Lesions were counted and classified according to 5 anatomic regions: infratentorial, periventricular, deep white matter, juxtacortical, and mixed white matter-gray matter. The sensitivity at DIR was compared with the corresponding sensitivity at FLAIR and T2 TSE sequence. The contrast between lesions and normal-appearing gray matter, normal-appearing white matter, and CSF was determined for all sequences.

RESULTS

Because of higher lesion-white matter contrast, the DIR showed a higher number of lesions compared with the FLAIR (7% gain, P = 0.04) and the T2 TSE (15% gain, P = 0.01). The higher sensitivity was also significant for the infratentorial region compared with the FLAIR (56% gain, P = 0.02) and the T2 TSE (44% gain, P = 0.02). Compared with the FLAIR, no significant changes of the lesion load measurements were observed in the supratentorial brain: slightly higher numbers of periventricular and mixed gray matter-white matter lesions on the DIR were counterbalanced by a slightly reduced sensitivity regarding juxtacortical lesions.

CONCLUSION

DIR brain imaging at 3T provides the highest sensitivity in the detection of MS lesions especially in the infratentorial region.

Involvement of the anterior lobe of the cerebellar vermis in perinatal profound hypoxia

BACKGROUND AND PURPOSE

We report abnormal high T2 signal intensity in the anterior lobe of the cerebellar vermis that we believe was the result of profound hypoxic ischemic encephalopathy in the perinatal period in term infants. We tested the hypothesis that this sign was associated with other signs of significant perinatal hypoxic damage.

METHODS

Thirty patients with clinically and radiologically confirmed perinatal profound hypoxia close to term were included in the study. The cranial MR images were reviewed by 2 pediatric neuroradiologists and were scored for the presence and severity of hypoxia/ischemia in the regions typically affected by profound hypoxia. The presence or absence of high T2 signal intensity in the vermis and other sites was correlated with the extent of damage in typically affected regions.

RESULTS

Eighteen of 30 patients had high T2 signal intensity in the vermis. The presence of vermian damage correlated positively with radiologic evidence of severe hypoxic damage and extremely poor (0 or 1) 1-minute Apgar scores.

CONCLUSIONS

High T2 signal intensity in the anterior lobe of the vermis probably represents gliosis secondary to hypoxia/ischemia and is related to the severity of damage in the term infant.

Fiber connections between the cerebral cortex and the corpus callosum in Alzheimer's disease: a diffusion tensor imaging and voxel-based morphometry study

Regional cortical atrophy in Alzheimer's disease (AD) most likely reflects the loss of cortical neurons. Several diffusion tensor imaging studies reported reduced fractional anisotropy (FA) in the corpus callosum in AD. The aim of this study was to investigate the association between reduced FA in the corpus callosum and gray matter atrophy in AD. Thirteen patients with AD with a mean (+/-standard deviation) age of 68.3 years (+/-11.5) and mean Mini Mental State Examination (MMSE) score of 21.8 (+/-4.8) were recruited. There were 13 control subjects with a mean age of 66.7 years (+/-6.4) and MMSE of 29.1 (+/-0.7). We used voxel-based morphometry of gray matter maps and region of interest-based analysis of FA in the corpus callosum. FA values of the anterior corpus callosum in AD patients were significantly correlated with gray matter volume in the prefrontal cortex and left parietal lobes. FA values of the posterior corpus callosum were significantly correlated with gray matter volume in the bilateral frontal, temporal, right parietal, and occipital lobes. In control subjects, no correlations were detected. Our findings suggest that decline of FA in the corpus callosum may be related to neuronal degeneration in corresponding cortical areas.

Excitatory amino acid receptor-mediated responses in periaqueductal gray neurons are increased during ethanol withdrawal

The ventrolateral periaqueductal gray (PAG) is critical for propagation in the neuronal network for ethanol withdrawal (ETX) seizures, and ethanol is known to alter glutamate effects. This study evaluated changes in glutamate antagonist effects on PAG neurophysiology in brain slices from rats treated with ethanol in vivo. Spontaneous action potentials were rare in control PAG neurons but common during ETX. Spontaneous excitatory postsynaptic potential (EPSP) frequency was increased during ETX, and an AMPA antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX) was more effective in suppressing this activity than an NMDA antagonist, 2-amino-7-phosphonoheptanoate (AP7). EPSPs evoked by stimulation of dorsolateral PAG were decreased by AP7 or DNQX in ETX and control neurons. EPSPs of ETX neurons were significantly less sensitive than controls to blockade by AP7 and DNQX. Paired-pulse facilitation of EPSPs was significantly increased during ETX, but paired-pulse inhibition occurred in controls. Thus, PAG hyperexcitability during ETX results from alterations of both NMDA and AMPA receptor-mediated neurotransmission, which may contribute importantly to ETX seizures. These results differ from previous findings in the seizure-initiating site for ETX seizures, inferior colliculus (IC), where NMDA receptor-mediated mechanisms dominate excitability increases during ETX. This dichotomy may be related to the different role played by IC and PAG in the ETX seizure network.

Distribution of the cellular prion protein (PrPC) in brains of livestock and domesticated species

In transmissible spongiform encephalopathies (TSEs) the prion protein (PrP) plays a central role in pathogenesis. The PrP gene (Prnp) has been described in a number of mammalian and avian species and its expression product, the cellular prion protein (PrP(C)), has been mapped in brains of different laboratory animals (rodent and non-human primates). However, mapping of PrP(C) expression in mammalian species suffering from natural (bovine and ovine) and experimental (swine) TSE or in species in which prion disease has never been reported (equine and canine) deserves further attention. Thus, localising the cellular prion protein (PrP(C)) distribution in brain may be noteworthy for the understanding of prion disease pathogenesis since lesions seem to be restricted to particular brain areas. In the present work, we analysed the distribution of PrP(C) expression among several brain structures of the above species. Our results suggest that the expression of PrP(C), within the same species, differs depending on the brain structure studied, but no essential differences between the PrP(C) distribution patterns among the studied species could be established. Positive immunoreaction was found mainly in the neuropil and to a lesser extent in neuronal bodies which occasionally appeared strongly stained in discrete regions. Overall, the expression of PrP(C) in the brain was significantly higher in grey matter areas than in white matter, where accumulation of PrP(Sc) is first observed in prion diseases. Therefore, other factors besides the level of expression of cellular PrP may account for the pathogenesis of TSEs.

Voxel-based morphometry demonstrates reduced grey matter density on brain MRI in patients with diabetic retinopathy

AIMS/HYPOTHESIS

In addition to nephropathy, retinopathy and peripheral neuropathy, a microvascular complication of type 1 diabetes that may be tentatively referred to as 'diabetic encephalopathy' has gained increasing attention. There is growing evidence that lowered cognitive performance in patients with type 1 diabetes is related to chronic hyperglycaemia rather than recurrent episodes of severe hypoglycaemia, as previously speculated. The aim of our study was to use magnetic resonance imaging (MRI) to establish whether long-term hyperglycaemia, resulting in advanced retinopathy, contributes to structural changes in the brain (reduced grey matter).

SUBJECTS, MATERIALS AND METHODS

We applied voxel-based morphometry on magnetic resonance images to compare grey matter density (GMD) between three groups of participants. GMD is used as a marker of cortical atrophy. We compared 13 type 1 diabetic patients with a microvascular complication (i.e. proliferative retinopathy) with 18 type 1 diabetic patients who did not have retinopathy in order to assess the effects of microvascular changes on GMD. Both patient groups were compared with 21 healthy control subjects to assess the effect of diabetes in itself.

RESULTS

Patients with diabetic retinopathy showed reduced GMD in the right inferior frontal gyrus and right occipital lobe compared both with patients without retinopathy and with healthy controls (p<0.05).

CONCLUSIONS/INTERPRETATION

Our data show that patients with type 1 diabetes, who, as a consequence of chronic hyperglycaemia, had developed advanced retinopathy, also showed increased focal cortical atrophy on brain MRI.

Antidepressant treatment reduces Fos-like immunoreactivity induced by swim stress in different columns of the periaqueductal gray matter

Antidepressant treatment attenuates behavioral changes induced by uncontrollable stress. The periaqueductal gray matter (PAG) is proposed to be a brain site involved in the behavioral responses to uncontrollable stress and antidepressant effects. The main goal of the present study was to investigate the effect of antidepressant treatment on the pattern of neural activation of the PAG along its mediolateral and rostrocaudal subregions after a forced swim stress episode. Male Wistar rats were sub-acutely treated with desipramine (a selective noradrenaline re-uptake blocker, three injections of 10 mg/kg in 24 h) or clomipramine (a non-selective serotonin and noradrenaline re-uptake blocker, three injections of 10 mg/kg in 24 h) and submitted to the forced swimming test (FST). Two hours after the test their brain were removed for Fos immunohistochemistry. Fos-like immunoreactivity (FLI) in rostral, intermediate and caudal portions of dorsomedial (dmPAG), dorsolateral (dlPAG), lateral (lPAG) and ventrolateral (vlPAG) PAG were quantified by a computerized system. The FST session increased FLI in most parts of the PAG. Previous treatment with desipramine or clomipramine reduced FLI in all columns of the PAG. FLI in the PAG correlated positively with to the immobility time and negatively with to climbing behavior scored during the test. These results indicate that neurons in the PAG are activated by uncontrollable stress. Moreover, inhibitory action of antidepressants on this activity may be associated with the anti-immobility effects of these drugs in the FST.

Arterioles of the Lenticular Nucleus in CADASIL

BACKGROUND AND PURPOSE

In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) the arteriopathy leads to recurrent infarcts in cerebral white matter (WM) and deep gray matter (GM), whereas cortex is spared. To assess the pathogenesis of deep GM infarcts, we analyzed structural changes in arterioles of the lenticular nucleus (LN) in 6 CADASIL patients.

METHODS

Five elderly and one 32-year-old deceased CADASIL patients were studied. Seven elderly and 4 young deceased persons without cerebrovascular diseases served as controls. In addition to immunohistochemical analysis the external and luminal diameters of arterioles in the LN, cerebral cortex and WM were measured. The thickness of arteriolar wall and sclerotic index were calculated.

RESULTS

In CADASIL patients, LN arterioles were immunoreactive for the extracellular domain of Notch3 and collagen I, whereas alpha-smooth muscle actin staining was irregular or negative. No major leakage of plasma fibrinogen or fibronectin was observed. Although in patients the walls of LN arterioles were significantly thicker than in controls, definite stenosis was not observed. Arteriolar lumina in the LN were not only significantly larger than in the WM, where most lacunar infarcts in CADASIL occur, but also larger than in cortical GM, where infarcts virtually never exist.

CONCLUSIONS

Fibrotic thickening of the arteriolar walls without consequent stenosis occurs in the LN of CADASIL patients. The pathogenesis of lacunar infarcts in the WM and LN seem to be different, stenosis in the former and probably hemodynamic disturbances in the latter.

[Alteration of the antinociceptive systems in chronic daily headaches]

INTRODUCTION

Chronic daily headache (CDH) is a chronic painful clinical condition that is frequently found in neurological practice. Diagnosis is clinical and the therapeutic approach is complex. Its mechanism of production is still not altogether clear, but a genetic component is acknowledged as a predisposing factor. Numerous areas are involved in the generation of primary headaches, including the periaqueductal grey matter (PAGM), which plays a role as a neuromodulator both in headaches and in other chronic painful conditions.

AIMS

In order to evaluate possible biochemical changes in patients with CDH, magnetic resonance imaging was used to study the spectra produced in the PAGM.

SUBJECTS AND METHODS

The spectra in the PAGM were studied in 17 patients with CDH. These were compared with the average spectra in 17 healthy subjects by means of differential spectroscopy.

RESULTS

Subjects with CDH show a reduction of over 70% in the level of the metabolite N-acetyl-aspartyl-glutamate (NAAG) in the PAGM. NAAG is a peptide involved in antinociceptive activity.

CONCLUSIONS

The reduction of NAAG in the PAGM suggests altered neuromodulation of the antinociceptive systems in subjects with CDH. Whether CDH is the cause or the consequence has still to be determined.

Abnormal deep grey matter development following preterm birth detected using deformation-based morphometry

Preterm birth is a leading risk factor for neurodevelopmental and cognitive impairment in childhood and adolescence. The most common known cerebral abnormality among preterm infants at term equivalent age is a diffuse white matter abnormality seen on magnetic resonance (MR) images. It occurs with a similar prevalence to subsequent impairment, but its effect on developing neural systems is unknown. MR images were obtained at term equivalent age from 62 infants born at 24-33 completed weeks gestation and 12 term born controls. Tissue damage was quantified using diffusion-weighted imaging, and deformation-based morphometry was used to make a non-subjective survey of the whole brain to identify significant cerebral morphological alterations associated with preterm birth and with diffuse white matter injury. Preterm infants at term equivalent age had reduced thalamic and lentiform volumes without evidence of acute injury in these regions (t = 5.81, P < 0.05), and these alterations were more marked with increasing prematurity (t = 7.13, P < 0.05 for infants born at less than 28 weeks) and in infants with diffuse white matter injury (t = 6.43, P < 0.05). The identification of deep grey matter growth failure in association with diffuse white matter injury suggests that white matter injury is not an isolated phenomenon, but rather, it is associated with the maldevelopment of remote structures. This could be mediated by a disturbance to corticothalamic connectivity during a critical period in cerebral development. Deformation-based morphometry is a powerful tool for modelling the developing brain in health and disease, and can be used to test putative aetiological factors for injury.

Brain gray matter changes in migraine patients with T2-visible lesions: a 3-T MRI study

BACKGROUND AND PURPOSE

In migraine patients, functional imaging studies have shown changes in several brain gray matter (GM) regions. However, 1.5-T MRI has failed to detect any structural abnormality of these regions. We used a 3-T MRI scanner and voxel-based morphometry (VBM) to assess whether GM density abnormalities can be seen in patients with migraine with T2-visible abnormalities and to grade their extent.

METHODS

In 16 migraine patients with T2-visible abnormalities and 15 matched controls, we acquired a T2-weighted and a high-resolution T1-weighted sequence. Lesion loads were measured on T2-weighted images. An optimized version of VBM analysis was used to assess regional differences in GM densities on T1-weighted scans of patients versus controls. Statistical parametric maps were thresholded at P<0.001, uncorrected for multiple comparisons.

RESULTS

Compared with controls, migraine patients had areas of reduced GM density, mainly located in the frontal and temporal lobes. Conversely, patients showed increased periacqueductal GM (PAG) density. Compared with patients without aura, migraine patients with aura had increased density of the PAG and of the dorsolateral pons. In migraine patients, reduced GM density was strongly related to age, disease duration, and T2-visible lesion load (r ranging from -0.84 to -0.73).

CONCLUSIONS

Structural GM abnormalities can be detected in migraine patients with brain T2-visible lesions using VBM and a high-field MRI scanner. Such GM changes comprise areas with reduced and increased density and are likely related to the pathological substrates associated with this disease.

Characterization of tau pathologies in gray and white matter of Guam parkinsonism-dementia complex

Guam parkinsonism-dementia complex (PDC) is a neurodegenerative tauopathy in ethnic Chamorro residents of the Mariana Islands that manifests clinically with parkinsonism as well as dementia and is characterized neuropathologically by prominent cortical neuron loss in association with extensive telencephalic neurofibrillary tau pathology. To further characterize cortical gray and white matter tau, alpha-synuclein and lipid peroxidation pathologies in Guam PDC, we examined the brains of 17 Chamorro PDC and control subjects using biochemical and immunohistological techniques. We observed insoluble tau pathology in both gray and white matter of PDC and Guam control cases, with frontal and temporal lobes being most severely affected. Using phosphorylation dependent anti-tau antibodies, abundant tau inclusions were detected by immunohistochemistry in both neuronal and glial cells of the neocortex, while less alpha-synuclein pathology was observed in more limited brain regions. Further, in sharp contrast to Alzheimer's disease (AD), levels of the lipid peroxidation product 8, 12-iso-iPF(2alpha)-VI isoprostane were not elevated in Guam PDC brains relative to controls. Thus, although the tau pathologies of Guam PDC share similarities with AD, the composite Guam PDC neuropathology profile of tau, alpha-synuclein and 8, 12-iso-iPF(2alpha)-VI isoprostane reported here more closely resembles that seen in other tauopathies including frontotemporal dementias (FTDs), which may imply that Guam PDC and FTD tauopathies share underlying mechanisms of neurodegeneration.

Assessment of MRI abnormalities of the brainstem from patients with migraine and multiple sclerosis

BACKGROUND

In patients with migraine, functional changes have been described in the red nucleus (RN), substantia nigra (SN) and periaqueductal gray matter (PAG).

PURPOSE

To evaluate whether and at which frequency these structures are involved by MRI-detectable structural abnormalities in migraineurs and to investigate the pathogenic role of these abnormalities by assessing their frequency and extent in patients with multiple sclerosis (MS) and migraine.

METHODS

On brain dual-echo scans obtained from 58 migraineurs (40 without and 18 with aura), 37 MS patients with migraine without aura and 42 MS patients without migraine, the presence of hyperintense lesions involving the brainstem structures was recorded. A test of heterogeneity between groups was used to compare the presence of lesions among patient groups.

RESULTS

Lesions of RN, SN and PAG were found in all patient groups, with frequency from 57.5% to 86.5%. Significant between-group differences for all these regions were found. No difference was found between migraine patients with and without aura. Compared with MS patients without migraine, MS patients with migraine had more significant involvement of the SN (p=0.02) and RN (p<0.0001). Compared with migraine patients, MS patients with migraine had more significant involvement of the SN and PAG (p ranging from 0.009 to 0.02).

CONCLUSIONS

T2-visible lesions in the brainstem are frequent in patients with migraine, but do not seem to be associated with the presence of aura. Demyelinating lesions in the RN, SN and PAG might be among the factors responsible for the presence of migraine in patients with MS.

A role for the periaqueductal gray in switching adaptive behavioral responses

Previous studies suggested a role for the rostral lateral periaqueductal gray (PAG) in the inhibition of maternal behavior induced by low doses of morphine in dams with previous morphine experience. In the present study, we first showed that unilateral NMDA lesions placed in this particular PAG region prevented the morphine-induced inhibition of maternal behavior in previously morphine-sensitized dams. As suggested by previous Fos data on the PAG, predatory hunting appears as a likely candidate to replace maternal behavior in the morphine-treated dams. By testing saline- and morphine-treated dams with live cockroaches only, we have presently shown that morphine challenge increased insect hunting. Moreover, morphine- and saline-treated dams were also observed in an environment containing pups and roaches. Although most of the saline-treated animals displayed active nursing and only occasionally presented insect hunting, all of the morphine-treated animals ignored the pups and avidly pursued and caught the roaches. We next questioned whether the rostral lateral PAG would be involved in this behavioral switch. Our results showed that unilateral lesions of the rostral lateral PAG, but not other parts of the PAG, partially impaired predatory hunting and restored part of the maternal response. Moreover, bilateral lesions of the rostral lateral PAG produced even more dramatic effects in inhibiting insect hunting and restoring maternal behavior. The present findings indisputably show that the rostral lateral PAG influences switching from maternal to hunting behavior in morphine-treated dams, thus supporting a previously unsuspected role for the PAG in selecting adaptive behavioral responses.

Distribution of Fos immunoreactivity in the rat brain after freezing or escape elicited by inhibition of glutamic acid decarboxylase or antagonism of GABA-A receptors in the inferior colliculus

It has been shown that electrical stimulation of the central nucleus of the inferior colliculus (IC) at freezing or escape thresholds activates different neural circuits in the brain. Since electrical stimulation activates cell bodies and fibers of passage it is necessary to use chemical stimulation that activates only post-synaptic receptors. To examine this issue in more detail, we took advantage of the fact that GABAergic neurons exert tonic control over the neural substrates of aversion in the IC. Reduction of GABA transmission in this structure was performed with the use of semicarbazide - an inhibitor of the GABA synthesizing enzyme glutamic acid decarboxylase (GAD) - and the GABA-A receptor antagonist bicuculline. Depending on the dose employed local infusions of semicarbazide (6.0 microg/0.2 microl) or bicuculline (40 ng/0.2 microl) into this region caused freezing and escape, respectively. The results obtained showed that freezing behavior induced by semicarbazide was associated with an increase in Fos expression in the dorsomedial column of the PAG (dmPAG) only, while bicuculline-induced escape was related to widespread increase in Fos labeling, notably in the periaqueductal gray, hypothalamus nuclei, amygdaloid nuclei, the laterodorsal nucleus of thalamus (LD), the cuneiform nucleus (CnF) and the locus coeruleus (LC). Thus, the present data support the notion that freezing and escape behaviors induced by GABA blockade in the IC are neurally segregated: acquisition of aversive information of acoustic nature from the IC probably uses the dmPAG column as a relay station to higher brain centers whereas bicuculline-induced escape activates structures involved in both sensory processing and motor output of defensive behavior. These results support the existence of distinct neural circuits mediating the sensory and motor responses of the defense reaction. The extent of the brain activation during freezing appears to be limited to the anatomical connections of the dmPAG, whereas an overall activation of the limbic system predominates during escape behavior induced by IC stimulation.

Association between microscopic brain damage as indicated by magnetization transfer imaging and anticardiolipin antibodies in neuropsychiatric lupus

The pathogenetic role of anticardiolipin antibodies (aCLs) in patients with neuropsychiatric systemic lupus erythematosus (NPSLE) without cerebral infarcts remains elusive. Magnetization transfer imaging (MTI) has proved to be a sensitive tool for detecting diffuse microscopic brain damage in NPSLE patients. In this study we examined the correlation between grey and white matter magnetization transfer ratio (MTR) parameters and the presence of IgM and IgG aCLs and lupus anticoagulant in 18 patients with systemic lupus erythematosus and a history of NPSLE but without cerebral infarcts on conventional magnetic resonance imaging. Lower grey matter mean MTR (P < 0.05), white matter mean MTR (P < 0.05), white matter peak location (P < 0.05) and grey matter peak location (trend toward statistical significance) were observed in IgM aCL-positive patients than in IgM aCL-negative patients. No significant differences were found in MTR histogram parameters with respect to IgG aCL and lupus anticoagulant status, nor with respect to anti-dsDNA or anti-ENA (extractable nuclear antigen) status. This is the first report of an association between the presence of aCLs and cerebral damage in grey and white matter in NPSLE. Our findings suggest that aCLs are associated with diffuse brain involvement in NPSLE patients.

Grey Matter Pathology in Multiple Sclerosis

The aim of our study is to evaluate the extent and distribution of grey matter demyelinating lesions in multiple sclerosis (MS), addressing also neuronal loss and synaptic loss. Whole coronal sections of 6 MS brains and 6 control brains were selected. Immunohistochemistry was performed for myelin basic protein, neurofilaments, synaptophysin, ubiquitin, and activated caspase-3. Neuronal density and optical density of synaptophysin staining were estimated in cortical lesions and compared with those observed in corresponding areas of normal (i.e. nondemyelinated) cortex in the same section. Demyelinating lesions were observed in the cerebral cortex, in the thalamus, basal ganglia, and in the hippocampus. The percentage of demyelinated cortex was remarkable in 2 cases of secondary progressive MS (48% and 25.5%, respectively). Neuronal density was significantly reduced in cortical lesions (18-23% reduction), if compared with adjacent normal cortex, in the 2 cases showing the higher extent of cortical demyelination; in the same cases, very rare apoptotic neurons expressing caspase-3 were observed in cortical lesions and not in adjacent normal cortex. No significant decrease in optical density of synaptophysin staining was observed in cortical lesions. Grey matter demyelination and neuronal loss could contribute to disability and cognitive dysfunctions in MS.

The association of brainstem lesions with migraine-like headache: an imaging study of multiple sclerosis

OBJECTIVE

To determine if the prevalence of migraine-like headache in patients with multiple sclerosis (MS) is associated with plaques in the brainstem or in other locations.

BACKGROUND

There is increasing evidence to suggest that periaqueductal gray matter (PAG) plays a role in the pathophysiology of migraine headache. There are a few clinical case studies and some experimental evidence in support of this observation.

METHODS

The study population of patients with demyelinating disease was identified by accessing the Department of Radiology magnetic resonance imaging (MRI) database accumulated between the years of December 1992 and June 2002. A total of 4369 MRI scan reports were available for review from that time period. Out of this, 1533 studies were reported to have possible demyelinating lesions. Medical records of these patients were reviewed to confirm the diagnosis of MS and also to document the headache complaints, if any. Two hundred and seventy-seven patients were identified with definite MS. A questionnaire was mailed to these patients to obtain additional details regarding MS and headache. The questionnaire response rate was 61% (169 of 277). This data were added to the information previously obtained from the medical records. The MRI films of each patient were examined, documenting location of the plaque, rather than the actual number. MRI and clinical data were kept separate until the final analysis. The International Headache Society criteria were used to classify headache types.

RESULTS

There were 207 female and 70 male patients available for analysis. Sixty-six percent (182 of 277) of patients were diagnosed with remitting-relapsing MS, 17% (47 of 277) with primary progressive MS, and 17% (48 of 277) with secondary progressive MS. Overall, 55.6% (154 of 277) of patients had a complaint of headache. Of these patients, 61.7% (95 of 154) met criteria for migraine-like headache, 25.3% (39 of 154) met criteria for tension-type headache, and 13% (20 of 154) had features of migraine and tension-type headache. MS patients with a plaque within the midbrain/periaqueductal gray matter areas had a four-fold increase in migraine-like headaches (odds ratio 3.91, 95% confidence interval 2.01 to 7.32; P < .0001), a 2.5-fold increase in tension-type headaches (odds ratio 2.58, 95% confidence interval 1.13 to 5.85; P= .02), and a 2.7-fold increase in combination of migraine and tension-type headaches (odds ratio 2.77, 95% confidence interval 0.98 to 7.82; P= .05) when compared to MS patients without a midbrain/periaqueductal gray matter lesion. Although not statistically significant, MS patients with three or more lesion locations were found to be approximately two times more likely to have migraine-like headaches compared to MS patients with 0 to 2 locations (3 to 5: odds ratio 2.47, 95% confidence interval 0.90 to 6.84; 6 to 8 locations: 1.82, 0.64 to 5.17; > or =9 locations: 2.41, 0.63 to 9.13). A linear trend was also observed between numbers of lesion locations and migraine-like headaches (P= .02).

CONCLUSION

The results of this study indicate that the presence of a midbrain plaque in patients with MS is associated with an increased likelihood of headache with migraine characteristics. (Headache 2005;45:670-677).

MR imaging and proton spectroscopy of neuronal injury in late-onset GM2 gangliosidosis

BACKGROUND AND PURPOSE

Despite the ubiquity of G(M2) gangliosides accumulation in patients with late-onset G(M2) gangliosidosis (G(M2)G), the only clinical MR imaging-apparent brain abnormality is profound cerebellar atrophy. The goal of this study was to detect the presence and assess the extent of neuroaxonal injury in the normal-appearing gray and white matter (NAGM and NAWM) of these patients.

METHODS

During a single imaging session, 9 patients with late-onset G(M2)G and 8 age-matched normal volunteers underwent the following protocol: (1) T1- and T2-weighted and fluid-attenuated inversion recovery MR images, as well as (2) multivoxel proton MR spectroscopy (1H-MR spectroscopy) to quantify the distribution of the n-acetylaspartate (NAA), creatine (Cr), and choline (Cho), were obtained.

RESULTS

The patients' NAA levels in the thalamus (6.5 +/- 1.9 mmol/L) and NAWM (5.8 +/- 2.1 mmol/L) were approximately 40% lower than the controls' (P = .003 and P = .005), whereas the Cr and Cho reductions ( approximately 30% and approximately 26%) did not reach significance (P values of .06-.1). All cerebellar metabolites, especially NAA and Cr, were much (30%-90%) lower in the patients, which reflects the atrophy.

CONCLUSION

In late-onset G(M2)G, NAA decreases are detectable in NAGM and NAWM even absent morphologic (MR imaging) abnormalities. Because the accumulation of G(M2) gangliosides can be reduced pharmacologically, 1H-MR spectroscopy might be a sensitive and specific for detecting and quantifying neuroaxonal injury and monitoring response to emerging treatments.

Acute Ophthalmoplegia and Nystagmus in Infants Fed a Thiamine-Deficient Formula: An Epidemic of Wernicke Encephalopathy

In 2003, an epidemic of Wernicke encephalopathy (WE) developed in Israeli infants fed a thiamine-deficient soy-based formula. Approximately 20 infants were affected out of an estimated 3500 fed the vitamin-deficient formula. The finding of gaze abnormalities in a single infant by neuro-ophthalmologists led to the unraveling of the epidemic. In this report, the findings in three infants are described. Early diagnosis and treatment with parenteral thiamine led to complete neurologic recovery in two infants; in the third infant, delayed diagnosis may have been responsible for severe lingering deficits. This is the first reported epidemic of WE secondary to thiamine-deficient infant formula. Early diagnosis and treatment are critical to avoid persistent neurologic impairment.

Distribution of extracellular signal-regulated kinase 1- and 2-activated neurons in the rat periaqueductal gray matter after noxious stimulation

The periaqueductal gray matter (PAG), the midbrain region made up of neuronal columns encircling the cerebral aqueduct, plays a key role in nociception. As the extracellular signal-regulated kinases (ERKs) 1 and 2 are activated after noxious stimulation, we analyzed the distribution of ERK-activated neurons in the PAG after visceral noxious stimulation. Ether- and urethane-anesthetized rats received an intraperitoneal injection of acetic acid or were left untreated and were perfused after 2 hr. Serial sections immunoreacted with an antibody selective for the activated ERKs. Significant ERK activation occurred only in the ether-anesthetized noxious stimulated rats. In these rats, we evaluated the number of ERK-activated neurons and their density as the ratio of the number of immunolabeled neurons to the extension of the region where they were located. ERK-activated neurons were more numerous in the lateral (LPAG) and ventrolateral (VLPAG) columns, but without significant differences. No ERK activation was seen in neurons of the most rostral PAG. The ERK-activated neurons were significantly denser at the intermediate level of the PAG. At the caudal level, they were denser in the LPAG and VLPAG columns, and in the DPAG column at the intermediate and rostral level. These findings suggest that noxious stimulation activates ERKs in neurons involved in the different functional activities related to nociception, overlapping in the PAG columns, and strengthens the role of PAG in integration.

Quantitative analysis of ubiquitin-immunoreactivity in the midbrain periaqueductal gray matter with regard to the causes of death in forensic autopsy

The aim of the present study was to examine Ub-immunoreactivity in the midbrain periaqueductal gray matter (PGM), which is involved in pain processing and modulation, in forensic autopsy cases (n=273) in relation to the causes of death: acute deaths from blunt injuries (n=75), sharp weapon injuries (n=36), fatal asphyxiation (n=22), drownings (n=16: freshwater, n=9; saltwater, n=7), fire fatalities (n=64), poisoning (n=12), hyperthermia (n=5), hypothermia (n=5), delayed deaths from blunt head injury (n=8), acute cardiac deaths (n=24), and acute cerebrovascular strokes (n=6). The Ub-immunoreactivity was clearly observed in the nuclei of the PGM neurons, showing no postmortem interference or age-dependency. A higher value was observed in blunt injuries, fire fatalities and also in saltwater drowning, hyperthermia and delayed head injury deaths. These findings suggest a complicated mechanism for the ubiquitination of PGM neurons, to which multiple factors including the intensity and duration of pains possibly under alert consciousness, traumatic and metabolic neurodegeneration may contribute.

Nystagmus de convergence et paralysie de la verticalité du regard d’origine vasculaire

A case of convergence-retraction nystagmus with upward vertical gaze paralysis and skew deviation (right hypotropia), without any other neurological signs, is reported. The probably vascular lesion was located at the mesodiencephalic junction, lying between the right border of the posterior commissure, the right interstitial nucleus of Cajal and the periaqueductal grey matter, accounting for the three ocular motor signs. The particular interest of this case is due to the relative smallness of the lesion.

Somatotopic organization of the human periventricular gray matter

The periventricular gray (PVG) matter is an established anatomical target for chronic deep brain stimulation (DBS) in the treatment of certain intractable pain syndromes. Data relating to the representation of pain and other somatosensory modalities within the PVG in humans are negligible. We examined the character and location of somatosensory responses elicited by electrical stimulation along the length of the PVG in a patient who underwent unilateral DBS for intractable nociceptive head pain. Consistent responses were obtained and indicated the presence of a somatotopic representation in this region. The contralateral lower limb was represented cranially, followed by the upper limb and trunk, with the face area located caudally, near the level of the superior colliculi. Bilateral representation was only observed in the forehead and scalp.

Cortical lesions in multiple sclerosis: combined postmortem MR imaging and histopathology

BACKGROUND AND PURPOSE

Cortical lesions constitute a substantial part of the total lesion load in multiple sclerosis (MS) brain. They have been related to neuropsychological deficits, epilepsy, and depression. However, the proportion of purely cortical lesions visible on MR images is unknown. The aim of this study was to determine the proportion of intracortical and mixed gray matter (GM)-white matter (WM) lesions that can be visualized with postmortem MR imaging.

METHODS

We studied 49 brain samples from nine cases of chronic MS. Tissue sections were matched to dual-echo T2-weighted spin-echo (T2SE) MR images. MS lesions were identified by means of myelin basic protein immunostaining, and lesions were classified as intracortical, mixed GM-WM, deep GM, or WM. Investigators blinded to the histopathologic results scored postmortem T2SE and 3D fluid-attenuated inversion recovery (FLAIR) images.

RESULTS

Immunohistochemistry confirmed 70 WM, eight deep GM, 27 mixed GM-WM, and 63 purely cortical lesions. T2SE images depicted only 3% of the intracortical lesions, and 3D FLAIR imaging showed 5%. Mixed GM-WM lesions were most frequently detectable on T2SE and 3D FLAIR images (22% and 41%, respectively). T2SE imaging showed 13% of deep GM lesions versus 38% on 3D FLAIR. T2SE images depicted 63% of the WM lesions, whereas 3D FLAIR images depicted 71%. Even after side-by-side review of the MR imaging and histopathologic results, many of the intracortical lesions could not be identified retrospectively.

CONCLUSION

In contrast to WM lesions and mixed GM-WM lesions, intracortical lesions remain largely undetected with current MR imaging resolution.

Brain volume in pediatric patients with sickle cell disease: evidence of volumetric growth delay?

BACKGROUND AND PURPOSE

Despite the large body of data available about somatic growth delay in patients with sickle cell disease (SCD), virtually nothing is known about the effect of the disease on volumetric growth of the brain. This study was designed to test a hypothesis that children with SCD have a disease-related delay in brain volumetric growth compared with healthy children.

METHODS

A cross-sectional study design was used to evaluate 83 children with SCD and 43 age-similar healthy children, including 27 patient siblings. Brain volume was measured by segmenting and classifying MR imaging data, by using at least three separate image sets (T1-, T2-, and proton density-weighted MR images). A linear model was used to compare the various brain volumes with the covariates of group (patient versus control) and age, with age treated as a continuous variable.

RESULTS

With age controlled for, no significant difference was noted in total brain volume between patients and control subjects at age 9.5 years. However, patients showed a deficit specifically in gray matter volume (P=.005), without significant differences in white matter or ventricular volume. The deficit in patient gray matter was greater in central gray matter (P <.005) than in cortical gray matter (P <.02). In healthy control subjects, gray matter volume decreased significantly with age (P <.005), probably due to myelination of white matter tracts. In patients with SCD, gray matter volume did not change with age.

CONCLUSION

Volumetric growth of brain gray matter may be delayed in children with SCD, suggesting that there may be neurodevelopmental consequences of this disease.