Huawei, Cyber-Sovereignty and Liberal Norms: China's Challenge to the West/Democracies

As China's global footprint expands and Sino-American competition intensifies, it is apparent that one of the most important arenas for competition between Western Liberal norms and Chinese Communist Party's (CCP) authoritarian norms is going to come in competing technologies (Western/Korean/Taiwanese 5G/chips vs Huawei 5G/chips) and competing cyber-norms (Western cyber-libertarianism vs Chinese cyber-sovereignty). Inside China, China's technologies and its cyber-sovereign norms converge.Outside of China, while China champions the norm of cyber-sovereignty, Huawei itself may pose the greatest challenge to sovereign states' cyber-sovereignty where Huawei controls or otherwise participates significantly as a provider for telecommunications networks, given its relationship to the Chinese state. Is China sincere in advocating cyber-sovereignty as an international norm, or is this just something it is concerned about inside China?Are the laws of China and the technologies and practices of its own Huawei antithetical to China's own stated norms of cyber-sovereignty? Is cyber-sovereignty simply a stop-gap measure adopted by an insecure regime to justify draconian censorship and thought control at home while it seeks to use its growing presence in 5G telecommunications to expand its surveillance of foreign powers/actors worldwide? Finally, in keeping with the theme of this special issue, does digital orientalism explain the growing tension between China and some of the Western/Liberal powers as it regards competition in 5G? Is the US/West needlessly securitizing Huawei and its 5G, or is there something there worth securitizing? Clarity about these issues and the implications of the answers arrived at are important for nations around the world as China expands its technological reach via Huawei and other national champions.

Implementation of a patient-facing genomic test report in the electronic health record using a web-application interface

Background

Genomic medicine is emerging into clinical care. Communication of genetic laboratory results to patients and providers is hampered by the complex technical nature of the laboratory reports. This can lead to confusion and misinterpretation of the results resulting in inappropriate care. Patients usually do not receive a copy of the report leading to further opportunities for miscommunication. To address these problems, interpretive reports were created using input from the intended end users, patients and providers. This paper describes the technical development and deployment of the first patient-facing genomic test report (PGR) within an electronic health record (EHR) ecosystem using a locally developed standards-based web-application interface.

Methods

A patient-facing genomic test report with a companion provider report was configured for implementation within the EHR using a locally developed software platform, COMPASS™. COMPASS™ is designed to manage secure data exchange, as well as patient and provider access to patient reported data capture and clinical display tools. COMPASS™ is built using a Software as a Service (SaaS) approach which exposes an API that apps can interact with.

Results

An authoring tool was developed that allowed creation of patient-specific PGRs and the accompanying provider reports. These were converted to a format that allowed them to be presented in the patient portal and EHR respectively using the existing COMPASS™ interface thus allowing patients, caregivers and providers access to individual reports designed for the intended end user.

Conclusions

The PGR as developed was shown to enhance patient and provider communication around genomic results. It is built on current standards but is designed to support integration with other tools and be compatible with emerging opportunities such as SMART on FHIR. This approach could be used to support genomic return of results as the tool is scalable and generalizable.

Advanced machine learning in action: identification of intracranial hemorrhage on computed tomography scans of the head with clinical workflow integration

Intracranial hemorrhage (ICH) requires prompt diagnosis to optimize patient outcomes. We hypothesized that machine learning algorithms could automatically analyze computed tomography (CT) of the head, prioritize radiology worklists and reduce time to diagnosis of ICH. 46,583 head CTs (~2 million images) acquired from 2007–2017 were collected from several facilities across Geisinger. A deep convolutional neural network was trained on 37,074 studies and subsequently evaluated on 9499 unseen studies. The predictive model was implemented prospectively for 3 months to re-prioritize “routine” head CT studies as “stat” on realtime radiology worklists if an ICH was detected. Time to diagnosis was compared between the re-prioritized “stat” and “routine” studies. A neuroradiologist blinded to the study reviewed false positive studies to determine whether the dictating radiologist overlooked ICH. The model achieved an area under the ROC curve of 0.846 (0.837–0.856). During implementation, 94 of 347 “routine” studies were re-prioritized to “stat”, and 60/94 had ICH identified by the radiologist. Five new cases of ICH were identified, and median time to diagnosis was significantly reduced (p < 0.0001) from 512 to 19 min. In particular, one outpatient with vague symptoms on anti-coagulation was found to have an ICH which was treated promptly with reversal of anticoagulation, resulting in a good clinical outcome. Of the 34 false positives, the blinded over-reader identified four probable ICH cases overlooked in original interpretation. In conclusion, an artificial intelligence algorithm can prioritize radiology worklists to reduce time to diagnosis of new outpatient ICH by 96% and may also identify subtle ICH overlooked by radiologists. This demonstrates the positive impact of advanced machine learning in radiology workflow optimization.

A computer program that automatically analyzes brain images from patients undergoing CT scans of the head can reliably flag those with signs of hemorrhage. A team of researchers from Geisinger in Danville, Pennsylvania, USA, trained and tested a machine-learning algorithm using 46,583 computed tomography imaging studies of the head. Subsequently, they implemented the model into routine care for 3 months to help prioritize radiology worklists. Of 347 routine cases, the computer identified 94 as having an intracranial hemorrhage, two-thirds of which were confirmed by a radiologist, including five among patients who had a new diagnosis of a brain bleed. The algorithm reduced the average time in which a radiologist diagnosed these patients from around 8.5 h to just 19 min, demonstrating the positive impact of incorporating artificial intelligence into radiology workflow.

Influence of Group on Individual Subject Maps in SPM Voxel Based Morphometry

Voxel based morphometry (VBM) is a widely utilized neuroimaging technique for spatially normalizing brain structural MRI (sMRI) onto a common template. The DARTEL technique of VBM takes into account the spatial intensity distribution of sMRIs to construct a study specific group template. The group template is then used to create final individual normalized tissue maps (FINTM) for each subject in the group. In this study, we investigate the effect of group on FINTM, i.e., we evaluate the variability of a constant subject's FINTM when other subjects in the group are iteratively changed. We examine this variability under the following scenarios: (1) when the demographics of the iterative groups are similar, (2) when the average age of the iterative groups is increased, and (3) when the number of subjects with a brain disorder (here we use subjects with autism) is increased. Our results show that when subject demographics of the group remains similar the mean standard deviation (SD) of FINTM gray matter (GM) of the constant subject was around 0.01. As the average age of the group is increased, mean SD of GM increased to around 0.03 and at certain brain locations variability was as high as 0.23. A similar increase in variability was observed when the number of autism subjects in the group was increased where mean SD was around 0.02. Further, we find that autism vs. control GM differences are in the range of -0.05 to +0.05 for more than 97% of the voxels and note that the magnitude of the differences are comparable to GM variability. Finally, we report that opting not to modulate during normalization or increasing the size of the smoothing kernel can decrease FINTM variability but at the loss of subject-specific features. Based on the findings of this study, we outline precautions that should be considered by investigators to reduce the impact of group on FINTM and thereby derive more meaningful group differences when comparing two cohorts of subjects.

Inter-Method Discrepancies in Brain Volume Estimation May Drive Inconsistent Findings in Autism

Previous studies applying automatic preprocessing methods on Structural Magnetic Resonance Imaging (sMRI) report inconsistent neuroanatomical abnormalities in Autism Spectrum Disorder (ASD). In this study we investigate inter-method differences as a possible cause behind these inconsistent findings. In particular, we focus on the estimation of the following brain volumes: gray matter (GM), white matter (WM), cerebrospinal fluid (CSF), and total intra cranial volume (TIV). T1-weighted sMRIs of 417 ASD subjects and 459 typically developing controls (TDC) from the ABIDE dataset were estimated using three popular preprocessing methods: SPM, FSL, and FreeSurfer (FS). Brain volumes estimated by the three methods were correlated but had significant inter-method differences; except TIVSPM vs. TIVFS, all inter-method differences were significant. ASD vs. TDC group differences in all brain volume estimates were dependent on the method used. SPM showed that TIV, GM, and CSF volumes of ASD were larger than TDC with statistical significance, whereas FS and FSL did not show significant differences in any of the volumes; in some cases, the direction of the differences were opposite to SPM. When methods were compared with each other, they showed differential biases for autism, and several biases were larger than ASD vs. TDC differences of the respective methods. After manual inspection, we found inter-method segmentation mismatches in the cerebellum, sub-cortical structures, and inter-sulcal CSF. In addition, to validate automated TIV estimates we performed manual segmentation on a subset of subjects. Results indicate that SPM estimates are closest to manual segmentation, followed by FS while FSL estimates were significantly lower. In summary, we show that ASD vs. TDC brain volume differences are method dependent and that these inter-method discrepancies can contribute to inconsistent neuroimaging findings in general. We suggest cross-validation across methods and emphasize the need to develop better methods to increase the robustness of neuroimaging findings.

Conus Medullaris Level in Vertebral Columns With Lumbosacral Transitional Vertebra

BACKGROUND

The estimated prevalence of lumbar or sacral transitional vertebrae (LSTV) in the population is 4% to 30%. Few small patient series have studied the normal level of the conus medullaris (CM) in individuals with LSTV.

OBJECTIVE

To determine, by using a large cohort of patients, whether individuals of all ages with LSTV have different CM positions in the spinal canal in comparison with the rest of the population with normal vertebral columns.

METHODS

We performed an institutional retrospective analysis of spinal magnetic resonance images on individuals with LSTV of all ages, sexes, and pathologies during a 10-year period. Fifty-seven percent of patients (n = 467) had a lumbarized vertebra and 43% had sacralized vertebra (n = 355). Mean age at the time of the study was 55 ± 19 years (range 1-97 years). Fifty-two percent were male and 48% were female. Sixty percent of subjects with a sacralized vertebra were female, and 54.5% of those with a lumbarized vertebra were male (P = .001).

RESULTS

The CM in individuals with a lumbarized vertebra was seen to be lower at L1-2 to L2s, than un those with a sacralized vertebra where most conuses were at T12-L1 to L1s (P ≤ 0.001). The CM level was similarly distributed among sexes and ages.

CONCLUSION

In our series, the CM level, when lumbarization occurred, was lower, with a mean level at L1-L2, whereas a more superior mean level at T12-L1 was seen when sacralization occurred. CM level was not influenced by sex, age, or pathology other than tethered cords.

Biochemical correlates of neuropsychiatric illness in maple syrup urine disease

Maple syrup urine disease (MSUD) is an inherited disorder of branched chain amino acid metabolism presenting with neonatal encephalopathy, episodic metabolic decompensation, and chronic amino acid imbalances. Dietary management enables survival and reduces risk of acute crises. Liver transplantation has emerged as an effective way to eliminate acute decompensation risk. Psychiatric illness is a reported MSUD complication, but has not been well characterized and remains poorly understood. We report the prevalence and characteristics of neuropsychiatric problems among 37 classical MSUD patients (ages 5-35 years, 26 on dietary therapy, 11 after liver transplantation) and explore their underlying mechanisms. Compared with 26 age-matched controls, MSUD patients were at higher risk for disorders of cognition, attention, and mood. Using quantitative proton magnetic resonance spectroscopy, we found lower brain glutamate, N-acetylaspartate (NAA), and creatine concentrations in MSUD patients, which correlated with specific neuropsychiatric outcomes. Asymptomatic neonatal course and stringent longitudinal biochemical control proved fundamental to optimizing long-term mental health. Neuropsychiatric morbidity and neurochemistry were similar among transplanted and nontransplanted MSUD patients. In conclusion, amino acid dysregulation results in aberrant neural networks with neurochemical deficiencies that persist after transplant and correlate with neuropsychiatric morbidities. These findings may provide insight into general mechanisms of psychiatric illness.

Spinal subdural hemorrhage in abusive head trauma: a retrospective study

PURPOSE

To compare the relative incidence, distribution, and radiologic characteristics of spinal subdural hemorrhage after abusive head trauma versus that after accidental trauma in children.

MATERIALS AND METHODS

This study received prior approval from the Human Subjects Protection Office. Informed consent was waived. This study was HIPAA compliant. Two hundred fifty-two children aged 0-2 years treated for abusive head trauma at our institute between 1997 and 2009 were identified through retrospective chart review. A second group of 70 children aged 0-2 years treated at our institute for well-documented accidental trauma between 2003 and 2010 were also identified through retrospective chart review. All clinical data and cross-sectional imaging results, including computed tomographic and magnetic resonance imaging of the brain, spine, chest, abdomen, and pelvis, were reviewed for both of these groups. A Fisher exact test was performed to assess the statistical significance of the proportion of the spinal canal subdural hemorrhage in abusive head trauma versus that in accidental trauma.

RESULTS

In the abusive head trauma cohort, 67 (26.5%) of 252 children had evaluable spinal imaging results. Of these, 38 (56%) of 67 children had undergone thoracolumbar imaging, and 24 (63%) of 38 had thoracolumbar subdural hemorrhage. Spinal imaging was performed in this cohort 0.3-141 hours after injury (mean, 23 hours ± 27 [standard deviation]), with 65 (97%) of 67 cases having undergone imaging within 52 hours of injury. In the second cohort with accidental injury, only one (1%) of 70 children had spinal subdural hemorrhage at presentation; this patient had displaced occipital fracture. The comparison of incidences of spinal subdural hemorrhage in abusive head trauma versus those in accidental trauma was statistically significant (P < .001).

CONCLUSION

Spinal canal subdural hemorrhage was present in more than 60% of children with abusive head trauma who underwent thoracolumbar imaging in this series but was rare in those with accidental trauma.

Sulfone Containing Clay Electrolytes and Their Potential for Li-Rechargeable Batteries

Clays have been synthesized and several types of molecules have been intercalated into them to enhance their ionic conductivity. The clay has the molecular formula of Litaeniolite, Li(Mg2Li)Si4O10F2, and the inserted molecules include PEO and two varieties of sulfone, tetramethylene sulfone and ethylmethyl sulfone. These have been made in the interest of electrolytes in lithium secondary batteries in order to produce a truly solid state cell. The products have been thoroughly characterized by x-ray diffraction to verify the uptake of the molecules into the layers, thermal analysis to observe the stabilization of the intercalated molecules, along with impedance measurements to test their conductivity.

Region-specific alteration in brain glutamate: possible relationship to risk-taking behavior

Risk-taking behaviors involve increased motor activity and reduced anxiety in humans. Total sleep deprivation (SD) in animals produces a similar change in motor and fear behaviors. Investigators studied region-specific brain levels of glutamate in rats after TSD, an animal model of risk-taking behavior. We investigated the effects of sleep deprivation on these behaviors and associated levels of brain glutamate. Compared to the controls, the sleep-deprived rats spent a significantly greater percentage of time in the open arms of the elevated plus maze (EPM), demonstrating reduced fear-like and increased risk-taking behaviors. Additionally, sleep deprivation was associated with a significant increase in glutamate levels in the hippocampus and thalamus. An inverse relationship between glutamate in the medial prefrontal cortex and risk taking in the EPM and a positive association between the ratio of glutamate in the hippocampus to medial prefrontal cortex and risk taking was revealed. The role of sleep deprivation-induced changes in brain glutamate and its relationship to anxiety, fear, and posttraumatic stress disorder (PTSD) is discussed.

A longitudinal study of the effects of lithium treatment on prefrontal and subgenual prefrontal gray matter volume in treatment-responsive bipolar disorder patients

OBJECTIVE

Recent molecular, preclinical, and preliminary clinical studies suggest that the therapeutic effects of mood stabilizers may be mediated by modulating expression of potent neurotrophic and neuroprotective factors having the potential to reverse impairments of cellular resilience, reductions in brain volume, and cell death or atrophy. Our main goal was to investigate the potential clinical significance of these findings in relation to bipolar disorder.

METHOD

The longitudinal effect of lithium on brain gray matter volume was investigated in well-characterized (DSM-IV criteria) bipolar depressed subjects (N = 28) at baseline (medication-free) and after lithium administration (4 weeks). Total brain gray matter, prefrontal gray matter, and left subgenual prefrontal gray matter volumes were determined using validated semiautomated segmentation and region of interest methodology. The study was conducted from November 1997 until April 2004 at Wayne State University School of Medicine, Detroit, Mich.

RESULTS

Significant increases in total brain gray matter volume in bipolar subjects were observed after 4 weeks of lithium administration (p = .0043). Moreover, regional analyses in the bipolar subjects revealed significant differences between responders (>50% decrease in Hamilton Depression Rating Scale total score) and nonresponders; only responders showed a significant increase in gray matter volume in the prefrontal cortex (p = .003) and an increase at trend level in the left subgenual prefrontal cortex volume (p = .0786).

CONCLUSION

The increase in gray matter volume in these areas, which various neuroimaging and postmortem neuropathology studies have implicated in the neuropathophysiology of bipolar disorder, suggests that the observed effects may be linked to clinical response. The findings also support the notion that future treatments that more directly target molecules in critical central nervous system pathways that regulate cellular plasticity hold promise as novel, improved, long-term treatments for mood disorders as well as some neurodegenerative conditions, such as Alzheimer's disease.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00870311.

Medial temporal N-acetyl-aspartate in pediatric major depression

The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD case-control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in the left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability.

Amygdala and hippocampal volumes in familial early onset major depressive disorder

BACKGROUND

Abnormalities in the amygdala and hippocampus have been implicated in the pathogenesis of major depressive disorder (MDD). To our knowledge, no prior study has examined amygdala-hippocampus anatomy in pediatric patients with familial MDD (at least one first degree relative with MDD).

METHODS

Thirty-two psychotropic-naive patients with familial MDD, aged 8-21 years (12 males and 20 females), and 35 group-matched healthy participants (13 males and 22 females) underwent volumetric magnetic resonance imaging in order to evaluate hippocampal and amygdala volumes.

RESULTS

Patients with familial MDD had significantly smaller left hippocampal (p = .007, effect size [d] = .44) and right hippocampal volumes (p = .025, d = .33) than controls. No differences were noted in amygdala volumes between groups (right: p > .05, left: p > .05). No correlations between hippocampal or amygdala volumes and demographic or clinical variables were noted.

CONCLUSIONS

Reduced hippocampal volume may be suggestive of a risk factor for developing MDD.

Development and sexual dimorphism of the pituitary gland

The pituitary gland plays a central role in sexual development and brain function. Therefore, we examined the effect of age and gender on pituitary volume in a large sample of healthy children and adults. Volumetric magnetic resonance imaging (MRI) was conducted in one hundred and fifty four (77 males and 77 females) healthy participants. Males were between the ages of 7 to 35 years (16.91+/-5.89 years) and females were 7 to 35 years of age (16.75+/-5.75 years). Subjects were divided into subgroups of age (7 to 9, 10 to 13, 14 to 17, 18 to 21, 22 and older) and sex (male/female). Pituitary gland volume differed between sexes when comparing the age groups (F=3.55, df=2, 143, p=0.03). Females demonstrated larger pituitary glands than males in the age 14 to 17 year old groups (p=0.04). Young (19 years and under) and old (20 years and older) females demonstrated a correlation between pituitary volume and age. Males did not show this relationship. These findings provide additional evidence for gender differences in the normative anatomy of the pituitary and may have relevance for the study of various childhood onset neuropsychiatric disorders in which pituitary dysfunction has been implicated.

Pituitary volume in treatment-naïve pediatric major depressive disorder

BACKGROUND

Prior pilot investigation identified a larger pituitary gland volume (PGV) in pediatric patients with major depressive disorder (MDD) compared with healthy pediatric control subjects that was most prominent in boys with MDD. In this independent sample, we focus on gender differences in pituitary volume in a larger sample of pediatric patients with MDD.

METHODS

Volumetric magnetic resonance imaging studies were conducted in 35 psychotropic drug-naïve children (15 boys, 20 girls), ages 8-17 years, and 35 case-matched healthy control subjects.

RESULTS

The MDD boys had larger PGV (19%) compared with male control subjects. No significant diagnostic group differences in pituitary volume were observed in girls. Healthy boys had significantly smaller PGV (27%) than healthy girls, whereas MDD boys did not differ from girls with MDD. Nonfamilial (without a family history of mood disorder) boys with MDD had significantly larger PGV (35%) than male healthy control subjects and tended to have a larger PGV (27%) than familial (at least one first-degree relative with MDD) boys with MDD. Boys with familial MDD did not differ from control subjects.

CONCLUSIONS

These findings provide new evidence of increased pituitary volume in psychotropic-naïve pediatric patients with MDD that seems to be more prominent in male patients with nonfamilial MDD.

Magnetic resonance and spectroscopic imaging in prenatal alcohol-exposed children: preliminary findings in the caudate nucleus

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) offer unique, noninvasive methods of measuring, respectively, in vivo quantitative neuroanatomy and neurochemistry. The main purpose of the present study was to identify and compare the neuroanatomical and neurochemical abnormalities that are associated with prenatal exposure to alcohol in both fetal alcohol syndrome (FAS)-diagnosed children and those diagnosed with fetal alcohol effects (FAE). MR data of three age-, gender- and race-balanced groups of children, FAS-diagnosed, FAE-diagnosed and non-exposed controls, were compared. Effects of prenatal alcohol exposure, regardless of diagnosis, were found in the caudate nucleus. Specifically, a significantly smaller caudate nucleus was found for the FAS and FAE participants compared to the controls. In addition, the metabolite ratio of N-acetyl-aspartate to creatine (NAA/Cr), an indicator of neuronal function, in left caudate nucleus of both the FAS and FAE participants was elevated compared to the control group. Analysis of absolute concentrations revealed that the increase in the ratio of NAA/Cr was due to an increase in NAA alone. Although its exact function in the CNS is unknown, NAA is believed to be a neuronal marker due to its exclusive localization to neurons. Some also speculate a role for NAA in myelination. Elevated NAA in the prenatal alcohol-exposed participants could indicate a lack of normal program cell death, dendritic pruning and/or myelination during development. The present study demonstrates that prenatal alcohol-exposed children, with or without facial dysmorphology, have abnormal brain anatomy and chemistry.

Long-term treatment of rats with haloperidol: lack of an effect on brain N-acetyl aspartate levels

Proton magnetic resonance spectroscopy (1H-MRS) studies of schizophrenia suggest an effect of the disease or of antipsychotic medications on brain N-acetyl aspartate (NAA), a marker of neuronal viability. We studied in rat the effect of haloperidol on NAA, glutamate, and glutamine in several brain regions where metabolite reductions have been reported in chronically medicated patients with schizophrenia. Two groups of 16 rats each were treated with haloperidol depo (38 mg/kg/month) and vehicle for 6 months and were killed. Concentrations of metabolites were determined by high-resolution magic angle proton magnetic resonance spectroscopy (HR-MAS 1H-MRS) at 11.7 T in ex-vivo punch biopsies from the following brain regions: medial frontal and cingulate cortex, striatum, nucleus accumbens, dorsal and ventral hippocampus, amygdala, and temporal cortex. Factorial ANOVA of NAA concentrations revealed no significant effect of drug group (F(1,212) = 1.5; p = 0.22) or a group by brain region interaction (F(7,212) = 1.0; p = 0.43). There was a significant main effect of region (F(7,212) = 17.8; p < 0.001) with lower NAA in the striatum. A prolonged exposure to the dopamine D2 receptor blockade effects of haloperidol does not result in changes in NAA, glutamate, glutamine, and other metabolites in the proton spectrum. These results are consistent with the only other two studies of the effect of antipsychotic drugs on NAA in the rat brain. The documented lower NAA in chronically treated schizophrenia patients is most likely not a simple effect of antipsychotic medications.

Pituitary volume in pediatric obsessive-compulsive disorder

BACKGROUND

Abnormalities in the limbic-hypothalamic-pituitary-adrenal (LHPA) axis have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). To our knowledge, however, no prior study has measured pituitary gland volume in OCD.

METHODS

Volumetric magnetic resonance imaging studies were conducted in 31 psychotropic drug-naïve children (10 boys, 21 girls) aged 8-17 years and 31 case-matched healthy comparison subjects.

RESULTS

Pituitary volume was significantly smaller in patients with OCD as compared with healthy control subjects (11% smaller). Smaller pituitary volume in patients with OCD was associated with increased compulsive but not obsessive symptom severity. Boys with OCD had smaller pituitary gland volumes compared with control boys (20% smaller). No significant differences in pituitary volume were observed between girls with OCD and control girls. Boys with OCD had significantly smaller pituitary volumes than girls with OCD (31% smaller), whereas control boys also had smaller pituitary gland volumes compared with control girls (21% smaller).

CONCLUSIONS

These findings provide new evidence of reduced pituitary volume in pediatric OCD that seems to be more prominent in male patients. The observed alterations in pituitary volume are consistent with neuroendocrine studies that have reported abnormalities in the LHPA axis in OCD.

Reduced anterior cingulate glutamate in pediatric major depression: a magnetic resonance spectroscopy study

BACKGROUND

Anterior cingulate cortex has been implicated in the pathogenesis of major depressive disorder (MDD). With single voxel proton magnetic resonance spectroscopy, we reported reductions in anterior cingulate glutamatergic concentrations (grouped value of glutamate and glutamine) in 14 pediatric MDD patients versus 14 case-matched healthy control subjects. These changes might reflect a change in glutamate, glutamine, or their combination.

METHODS

Fitting to individually quantify anterior cingulate glutamate and glutamine was performed in these subjects with a new basis set created from data acquired on a 1.5 Tesla General Electric Signa (GE Healthcare, Waukesha, Wisconsin) magnetic resonance imaging scanner with LCModel (Version 6.1-0; Max-Planck-Institute, Gottingen, Germany).

RESULTS

Reduced anterior cingulate glutamate was observed in MDD patients versus control subjects (8.79 +/- 1.68 vs. 11.46 +/- 1.55, respectively, p = .0002; 23% decrease). Anterior cingulate glutamine did not differ significantly between patients with MDD and control subjects.

CONCLUSIONS

These findings provide confirmatory evidence of anterior cingulate glutamate alterations in pediatric MDD.

Anterior cingulate neurochemistry in social anxiety disorder: 1H-MRS at 4???Tesla

Recent studies suggest exaggerated responses in the limbic system of patients with generalized social anxiety disorder in response to threat/anxiety-related social situations and aversive conditioning, processes mediated by the glutamatergic system. This single-voxel, high-field 1H-magnetic resonance spectroscopy study examined concentrations of glutamate, and other metabolites, in the anterior cingulate cortex and occipital cortex (control region) of 10 medication-naive patients with generalized social anxiety and 10 matched healthy comparison subjects. Glutamate (relative to creatine) levels were significantly higher in patients than controls in the anterior cingulate, but not occipital, cortex. Anterior cingulate glutamate/creatine levels were also correlated with intensity of social anxiety symptoms. These findings provide new evidence of glutamate's involvement in the neural mechanism underlying social phobia.

Neural substrates for voluntary suppression of negative affect: a functional magnetic resonance imaging study

BACKGROUND

Successful control of affect partly depends on the capacity to modulate negative emotional responses through the use of cognitive strategies. Although the capacity to regulate emotions is critical to mental well-being, its neural substrates remain unclear.

METHODS

We used functional magnetic resonance imaging to ascertain brain regions involved in the voluntary regulation of emotion and whether dynamic changes in negative emotional experience can modulate their activation. Fourteen healthy subjects were scanned while they either maintained the negative affect evoked by highly arousing and aversive pictures (e.g., experience naturally) or suppressed their affect using cognitive reappraisal. In addition to a condition-based analysis, online subjective ratings of intensity of negative affect were used as covariates of brain activity.

RESULTS

Inhibition of negative affect was associated with activation of dorsal anterior cingulate, dorsal medial prefrontal, and lateral prefrontal cortices, and attenuation of brain activity within limbic regions (e.g., nucleus accumbens/extended amygdala). Furthermore, activity within dorsal anterior cingulate was inversely related to intensity of negative affect, whereas activation of the amygdala was positively covaried with increasing negative affect.

CONCLUSIONS

These findings highlight a functional dissociation of corticolimbic brain responses, involving enhanced activation of prefrontal cortex and attenuation of limbic areas, during volitional suppression of negative emotion.

Neural correlates of internally-generated disgust via autobiographical recall: a functional magnetic resonance imaging investigation

Converging lines of evidence suggest the involvement of the insula and basal ganglia in the processing of disgust, an important primary emotion that guides the avoidance of potential physical contamination and disease. Prior human lesion and functional brain imaging studies have employed exteroceptive sensory stimuli such as facial expressions of disgust, and disgust-eliciting pictures. Thus, the neural substrates underlying the internal experience of disgust remain unknown. The present fMRI study examined the neural correlates of self-induced disgust aided by the recall and re-experience of personally salient life events. Subjects were scanned while they recalled and re-experienced either a recent situation that evoked intense disgust or a time-matched, equally vivid neutral/non-emotional event. Relative to the emotionally neutral condition, self-induced disgust was associated with activation of the insula, hippocampus, anterior and posterior cingulate cortex, basal ganglia, thalamus, and primary visual cortex. These findings suggest that areas previously associated with the perception of disgust (e.g., insula, basal ganglia) are also involved interoceptive experience of disgust.

Reduced anterior cingulate glutamatergic concentrations in childhood OCD and major depression versus healthy controls

OBJECTIVE

To examine in vivo glutamatergic neurochemical alterations in the anterior cingulate cortex of pediatric patients with obsessive-compulsive disorder (OCD) without major depressive disorder (MDD) versus pediatric patients with MDD without OCD and healthy controls.

METHOD

Single-voxel proton magnetic resonance spectroscopic examinations of the anterior cingulate cortex were conducted in 14 psychotropic-naïve children and adolescents with MDD without OCD, 10 to 19 years of age, 14 case-matched healthy controls, and 20 nondepressed, psychotropic-naïve pediatric patients with OCD 7 to 19 years of age.

RESULTS

Anterior cingulate glutamatergic concentrations were significantly reduced in both patients with OCD (15.1% decrease) and patients with MDD (18.7% decrease) compared with controls. Anterior cingulate glutamatergic concentrations did not differ significantly between patients with OCD and those with MDD.

CONCLUSIONS

Altered anterior cingulate glutamatergic neurotransmission may be involved in the pathogenesis of OCD and MDD. These preliminary findings further suggest that reduced anterior cingulate glutamate does not differentiate pediatric patients with OCD from pediatric patients with MDD.

Brain structural abnormalities in psychotropic drug-naive pediatric patients with obsessive-compulsive disorder

OBJECTIVE

The authors investigated structural abnormalities in brain regions comprising cortical-striatal-thalamic-cortical loops in pediatric patients with obsessive-compulsive disorder (OCD).

METHOD

Volumes of the caudate nucleus, putamen, and globus pallidus and gray and white matter volumes of the anterior cingulate gyrus and superior frontal gyrus were computed from contiguous 1.5-mm magnetic resonance images from 23 psychotropic drug-naive pediatric patients with OCD (seven male patients and 16 female patients) and 27 healthy volunteers (12 male subjects and 15 female subjects).

RESULTS

Patients had smaller globus pallidus volumes than healthy volunteers, but the two groups did not differ in volumes of the caudate nucleus, putamen, or frontal white matter regions. Compared to healthy volunteers, patients had more total gray matter in the anterior cingulate gyrus but not the superior frontal gyrus. Total anterior cingulate gyrus volume correlated significantly and positively with globus pallidus volume in the healthy volunteers but not in patients.

CONCLUSIONS

These findings provide evidence of smaller globus pallidus volume in patients with OCD without the potentially confounding effects of prior psychotropic drug exposure. Volumetric abnormalities in the anterior cingulate gyrus appear specific to the gray matter in OCD, at least at the gross anatomic level, and are consistent with findings of functional neuroimaging studies that have reported anterior cingulate hypermetabolism in the disorder.

Real-time fMRI of cortico-limbic brain activity during emotional processing

The ability to detect dynamic changes in brain activity during affective processing within individual subjects in real-time can advance our understanding of the neural mechanisms of emotion, psychiatric illness, and therapeutic intervention. We investigated whether activity in limbic and paralimbic regions elicited by blocks of aversive (AV) and neutral (NEU) pictures can be detected by real-time fMRI. Real-time analysis of signal change during each block revealed that activations in insula and medial frontal cortex were more frequent during AV than NEU epochs. Single subject and group analysis off-line with conventional statistical parametric mapping methods matched the results obtained in real-time. Detecting cortico-limbic brain activation during perception and experience of emotionally salient visual stimuli with real-time fMRI technology is feasible.

Amygdala volume reductions in pediatric patients with obsessive-compulsive disorder treated with paroxetine: preliminary findings

The amygdala is believed to be highly relevant to the pathophysiology of obsessive-compulsive disorder (OCD) given its prominent role in fear conditioning and because it is an important target of the serotonin reuptake inhibitors (SRIs), the pharmacotherapy of choice for OCD. In the present study, we measured in vivo volumetric changes in the amygdala in pediatric patients with OCD following 16 weeks of monotherapy with the selective SRI, paroxetine hydrochloride. Amygdala volumes were computed from contiguous 1.5 mm magnetic resonance (MR) images in 11 psychotropic drug-naive patients with OCD prior to and then following treatment. Eleven healthy pediatric comparison subjects also had baseline and follow-up scans, but none of these subjects received medication. Patients demonstrated significant asymmetry of the amygdala (L>R) prior to pharmacologic intervention in contrast to healthy comparison subjects who showed no asymmetry at the time of their baseline scan. Mixed model analyses using age and total brain volume as time varying covariates indicated that left amygdala volume decreased significantly in patients following treatment. The reduction in left amygdala volume in patients correlated significantly with higher paroxetine dosage at the time of the follow-up scan and total cumulative paroxetine exposure between the scans. No significant changes in either right or left amygdala volume were evident among healthy comparison subjects from the baseline to the follow-up scan. These preliminary findings suggest that abnormal asymmetry of the amygdala may play a role in the pathogenesis of OCD and that paroxetine treatment may be associated with a reduction in amygdala volume.

Reduced anterior cingulate cortex glutamatergic concentrations in childhood major depression

OBJECTIVE

To examine in vivo glutamatergic neurochemical alterations in the anterior cingulate cortex of children with major depressive disorder (MDD).

METHOD

Single-voxel proton magnetic resonance spectroscopic (H-MRS) examinations of the anterior cingulate cortex were conducted in 13 psychotropic-naïve children and adolescents with MDD and 13 age- and sex-matched healthy children and adolescents. Ten of the 13 MDD patient-control pairs also had a H-MRS examination of occipital cortex.

RESULTS

Anterior cingulate glutamatergic (Glx) concentrations were significantly lower (19% decrease) in MDD patients versus controls (9.27 +/- 0.43 versus 11.47 +/- 0.26, respectively, p = 0.000). Reduced anterior cingulate Glx in MDD patients was associated with increased severity of functional impairment. These results remained comparably significant after controlling for age and anterior cingulate volume. Occipital cortex Glx did not differ between MDD patients and controls.

CONCLUSIONS

These preliminary findings provide new evidence of localized functional neurochemical marker alterations in Glx in anterior cingulate cortex in pediatric MDD. Altered anterior cingulate Glx neurotransmission may be involved in the pathogenesis of MDD.

Increased medial thalamic choline found in pediatric patients with obsessive-compulsive disorder versus major depression or healthy control subjects: a magnetic resonance spectroscopy study

BACKGROUND

Neurobiologic abnormalities in medial thalamus have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). We previously used multislice proton magnetic resonance spectroscopic imaging (1-H MRSI) to identify localized functional neurochemical marker alterations in choline (Cho) in medial but not lateral thalamus in treatment-naïve pediatric patients with OCD compared with matched control subjects. Altered brain Cho levels have also been implicated in the pathogenesis of mood disorders.

METHODS

We used 1-H MRSI to study absolute Cho concentrations in 18 psychotropic-naïve pediatric patients with major depressive disorder (MDD) not suffering from OCD, 9-17 years of age, 18 case-matched healthy control subjects, and 27 nondepressed, psychotropic-naïve pediatric patients with OCD, 7-16 years of age.

RESULTS

Significantly increased left and right medial thalamic Cho concentrations were observed in OCD patients compared with both healthy control subjects and patients with MDD. Medial thalamic Cho concentrations did not differ significantly between patients with MDD and control subjects.

CONCLUSIONS

These results suggest that localized functional neurochemical marker alterations in medial thalamic Cho differentiate patients with OCD from healthy control subjects and patients with MDD. Although these results must be considered preliminary, further study of the diagnostic specificity of Cho as a relevant biomarker in OCD is clearly warranted.

Localized functional neurochemical marker abnormalities in dorsolateral prefrontal cortex in pediatric obsessive-compulsive disorder

BACKGROUND

Neurobiological abnormalities in the prefrontal cortex have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). Although OCD commonly arises during childhood and adolescence, to our knowledge, no prior study has examined prefrontal cortex neurochemistry in pediatric patients with OCD.

METHODS

A multislice spectroscopic imaging sequence with validated phantom replacement methodology was used to measure N-acetyl-aspartate (NAA), a putative neuronal marker; choline compounds (Cho); and creatine/phosphocreatine (Cr) in right and left dorsolateral prefrontal cortex (DLPFC) of 15 treatment-naïve OCD patients, 8-15 years of age, and 15 case-matched healthy comparison subjects.

RESULTS

A significant increase (21% higher) in NAA was observed in left but not right DLPFC in OCD patients versus control subjects. No significant differences in Cho or Cr were observed between groups in left or right DLPFC.

CONCLUSIONS

These results provide new evidence of localized functional neurochemical marker alterations in left DLPFC in pediatric OCD. Increased left DLPFC NAA may represent neuronal hypertrophy or hyperplasia, glial hypoplasia, and/or abnormal pruning of neural brain elements in DLPFC.

Neurochemical analyses in pediatric obsessive-compulsive disorder in patients treated with cognitive-behavioral therapy

OBJECTIVE

To investigate neurochemical changes in the caudate nucleus of pediatric obsessive-compulsive disorder (OCD) patients before and after cognitive-behavioral therapy (CBT), and to examine corresponding changes in symptom severity.

METHOD

Single-voxel proton magnetic resonance spectroscopic (1H-MRS) examination of the left caudate was conducted in 21 treatment-naïve children, aged 6 to 16 years, before and after 12 weeks of CBT. Subjects were measured at baseline and posttreatment by the Yale-Brown Obsessive Compulsive Scale for Children, Hamilton Depression Rating Scale, and Hamilton Anxiety Rating Scale.

RESULTS

No significant changes in caudate neurochemistry were observed in OCD patients before and after CBT despite unambiguous improvement in OCD symptoms, depression, and anxiety.

CONCLUSIONS

Findings suggest that reduction in caudate Glx may be specific to SSRI treatment and not due to a more generalized treatment response or spontaneous improvement of symptoms. Differential sets of pathophysiologic and treatment response markers may moderate/mediate the effects of particular treatments on outcome.

Increased amygdala: hippocampal volume ratios associated with severity of anxiety in pediatric major depression

BACKGROUND

Neurobiologic abnormalities in the temporal lobe, particularly medial temporolimbic circuits, have been implicated in the pathogenesis of major depressive disorder (MDD). Although MDD commonly emerges during childhood and adolescence, to our knowledge, no prior study has examined temporal lobe anatomy in pediatric patients with MDD near the onset of illness before treatment.

METHODS

Volumetric magnetic resonance imaging scans were conducted in 23 psychotropic drug-naïve pediatric patients with MDD, aged 8-17 years, and 23 case-matched healthy comparison subjects.

RESULTS

Pediatric patients with MDD had significantly larger left (14%) and right (11%) amygdala:hippocampal volume ratios than controls. Increased left and right amygdala:hippocampal volume ratios were associated with increased severity of anxiety but not increased severity of depression or duration of illness.

CONCLUSION

These results suggest that alterations in amygdala:hippocampal volume ratios in pediatric MDD may more reflect severity of associated anxiety than depression. These results underscore the importance of assessment for comorbidity in the study of MDD.

The use of mood stabilizers as plasticity enhancers in the treatment of neuropsychiatric disorders

Mood disorders have traditionally been conceptualized as neurochemical disorders, but there is now evidence from a variety of sources demonstrating regional reductions in central nervous system (CNS) volume, as well as reductions in the numbers and/or sizes of glia and neurons in discrete brain areas. Although the precise cellular mechanisms underlying these morphometric changes remain to be fully elucidated, the data suggest that severe mood disorders are associated with impairments of structural plasticity and cellular resilience. It is thus noteworthy that lithium and valproate have recently been demonstrated to robustly increase the expression of the cytoprotective protein bcl-2 (an abbreviation for the B-cell lymphoma/leukemia-2 gene) in the CNS in vivo and in cells of human neuronal origin. Lithium and valproate also robustly activate a signaling cascade utilized by endogenous growth factors-the extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinase pathway. Complementary human studies have shown that chronic lithium administration significantly increases gray matter content in a regionally selective manner, suggesting a reversal of illness-related atrophy and an increase in the volume of the neuropil. These unique and unexpected properties of lithium and valproate suggest that they may have broader utility as adjunctive agents in the treatment of a variety of neuropsychiatric disorders associated with cell atrophy or loss. The adjunctive use of these agents-at low doses-may provide the trophic support necessary to restore, enhance, and maintain normal synaptic connectivity, thereby allowing the chemical signal to reinstate the optimal functioning of critical circuits necessary for normal functioning.

Proton echo-planar spectroscopic imaging with highly effective outer volume suppression using combined presaturation and spatially selective echo dephasing

A highly effective outer volume suppression (OVS) technique, termed spatially selective echo dephasing (SSED), which employs gradient dephasing of spatially selective spin echoes, is introduced. SSED, which is relatively insensitive to T(1) dispersion among lipid signals and B(1) inhomogeneity, was integrated with very high spatial resolution 2D proton echo-planar spectroscopic imaging (PEPSI) to assess residual lipid bleeding into cortical regions in the human brain. The method was optimized to minimize signal refocusing of secondary spin-echoes in areas of overlapping suppression slices. A comparison of spatial presaturation with single or double SSED, and with combined presaturation and SSED shows that the latter method has superior performance with spatially uniform lipid suppression factors in excess of 70. Metabolite mapping (choline, creatine, and NAA) with a 64 x 64 spatial matrix and 0.3 cm(3) voxels in close proximity to peripheral lipid regions was demonstrated at 1.5 T with a scan time of 32 min using the standard head coil.

Real-time fMRI of temporolimbic regions detects amygdala activation during single-trial self-induced sadness

Temporolimbic circuits play a crucial role in the regulation of human emotion. A highly sensitive single-shot multiecho functional magnetic resonance imaging (fMRI) technique with gradient compensation of local magnetic field inhomogeneities and real-time data analysis were used to measure increases in amygdala activation during single 60-s trials of self-induced sadness. Six healthy male and female subjects performed a validated mood induction paradigm with randomized presentation of sad or neutral faces in 10 trials per scan. Subjects reported the intensity of experienced sadness after each trial. Immediate feedback of amygdala activation was given to the subjects during the ongoing scan to reinforce mood induction. Correspondence between increased intensity of predominantly left sided amygdala activation and self-rating of sadness was found in 78% of 120 sad trials, in contrast to only 14% of neutral trials. Amygdala activation was reproducible during repeated scanning sessions and displayed the strongest correlation with self-rating among all regions. These results suggest that amygdala activation may be closely associated with self-induced sadness. This novel real-time fMRI technology is applicable to a wide range of neuroscience studies, particularly those of the limbic system, and to neuropsychiatric conditions, such as depression, in which pathology of the amygdala has been implicated.

Discovery and design of novel inhibitors of botulinus neurotoxin A: targeted 'hinge' peptide libraries

Intoxication by the zinc protease botulinus neurotoxin A (BoNT-A) results from cleavage of a single Q-R bond in the neuronal protein SNAP-25, which disables the docking mechanism required for neurotransmitter release. In the present study, potential inhibitors of BoNT-A were assessed from their effects on the BoNT-A cleavage of a synthetic 17-mer peptide (SNAP-25, residues 187-203) spanning the Q-R cleavage site. Compounds that inhibited BoNT-A included thiols (zinc chelators) such as dithiothreitol, dimercaptopropanesulfonic acid, mercaptosuccinic acid and captopril. In addition, compounds containing multiple acidic functions, such as the SNARE motif V2 (ELDDRADALQ), the tripeptide Glu-Glu-Glu and the steroid glycoside glycyrrhizic acid, were effective inhibitors. 'Hinge' peptide mini-libraries (PMLs) having the structure acetyl-X(1)-X(2)-linker-X(3)-X(4)-NH(2) or X(1)-X(2)-linker-X(3), where X(1)-X(4) were mixtures of selected amino acids and the flexible linker was 4-aminobutyric acid, also provided effective inhibition. Targeted PMLs containing the acidic amino acids Asp and Glu, the scissile-bond amino acids Gln and Arg and the zinc chelators His and Cys produced pronounced inhibition of BoNT-A. Deconvolution of these libraries will provide novel ligands with improved inhibitory potency as leads in the design of peptide mimetics to treat BoNT poisoning.

Magnetic resonance spectroscopy: neurochemistry and treatment effects in affective disorders

Recent developments in the clinical capabilities of magnetic resonance spectroscopy (MRS) have provided researchers with considerable insight into potential neurochemical alterations associated with the pathology and treatment of affective disorders. This review focuses on the clinical application of MRS to the study of affective disorders, discusses the major MRS visible neurochemicals, and addresses some essential principles of MRS methodology, such as pulse sequences and neurochemical quantitation. Additionally, some of the more recent key findings in the area of mood disorders and their treatment are highlighted, including pharmacological effects and mechanisms. For example, several independent groups have reported alterations in levels of choline, myoinositol, N-acetylaspartate, and gamma-aminobutyric acid in the central nervous systems of patients with major depression, bipolar disorder, panic disorder, or obsessive-compulsive disorder. Finally, the current direction of advances and areas of further investigation are discussed. This review will afford the reader a fundamental foundation in the applications of MRS in mood disorders and an update on some of the current findings in this rapidly developing discipline.

Mood disorders: treatment-induced changes in brain neurochemistry and structure

Continuing advances in neuroimaging technology as well as postmortem examinations have enabled researchers to begin to accumulate substantial evidence suggesting that chronic mood disorders may be associated with actual structural and neurochemical changes within the brain. There is emerging evidence to suggest that various treatment modalities may also induce measurable changes within the brain detectable with specialized neuroimaging techniques, which may be responsible for their clinical therapeutic effects. One such specialized neuroimaging technique, magnetic resonance spectroscopy (MRS), is briefly reviewed. Included is an overview of basic MRS technology and a review of its application in the study of chronic mood disorders to date. We review our recent studies investigating neurochemical changes induced by the mood stabilizer, lithium, in the treatment of bipolar disorder (BPD). Finally, in view of accumulating evidence suggesting a neuronal atrophy and cell death hypothesis for depression, we discuss the potential use of MRS to evaluate pharmacologic interventions for important potential neurotrophic and neuroprotective effects on the adult human brain.

Proton magnetic resonance spectroscopic imaging in pediatric major depression

BACKGROUND

Neurobiologic abnormalities in dorsolateral prefrontal cortex (DLPFC) are believed to be involved in the pathophysiology of major depressive disorder (MDD). Although MDD commonly emerges during childhood and adolescence, to our knowledge, no prior study has examined the DLPFC in pediatric patients with MDD.

METHODS

In this study, choline compounds (Cho), N-acetylaspartate (NAA), and creatine/phosphocreatine (Cr) were measured in left and right DLPFC using a multislice proton magnetic resonance spectroscopic imaging sequence with validated phantom replacement methodology in 11 treatment-naïve MDD patients, 10-16 years of age, and 11 case-matched healthy control subjects.

RESULTS

A significant increase in Cho was observed in left but not right DLPFC in MDD patients versus control subjects (32.5% higher). No significant differences in NAA or Cr were observed between case-control pairs.

CONCLUSIONS

These results provide new evidence of localized functional neurochemical marker alterations in left DLPFC in pediatric MDD. Our results must be considered preliminary, however, given the small sample size.

Patients lacking the major CNS myelin protein, proteolipid protein 1, develop length-dependent axonal degeneration in the absence of demyelination and inflammation

Axonal degeneration contributes to clinical disability in the acquired demyelinating disease multiple sclerosis. Axonal degeneration occurs during acute attacks, associated with inflammation, and during the chronic progressive phase of the disease in which inflammation is not prominent. To explore the importance of interactions between oligodendrocytes and axons in the CNS, we analysed the brains of rodents and humans with a null mutation in the gene encoding the major CNS myelin protein, proteolipid protein (PLP1, previously PLP). Histological analyses of the CNS of Plp1 null mice and of autopsy material from patients with null PLP1 mutations were performed to evaluate axonal and myelin integrity. In vivo proton magnetic resonance spectroscopy (MRS) of PLP1 null patients was conducted to measure levels of N-acetyl aspartate (NAA), a marker of axonal integrity. Length-dependent axonal degeneration without demyelination was identified in the CNS of Plp1 null mice. Proton MRS of PLP1-deficient patients showed reduced NAA levels, consistent with axonal loss. Analysis of patients' brain tissue also demonstrated a length-dependent pattern of axonal loss without significant demyelination. Therefore, axonal degeneration occurs in humans as well as mice lacking the major myelin protein PLP1. This degeneration is length-dependent, similar to that found in the PNS of patients with the inherited demyelinating neuropathy, CMT1A, but is not associated with significant demyelination. Disruption of PLP1-mediated axonal--glial interactions thus probably causes this axonal degeneration. A similar mechanism may be responsible for axonal degeneration and clinical disability that occur in patients with multiple sclerosis.

Prefrontal cortical volume in childhood-onset major depression: preliminary findings

BACKGROUND

Abnormalities in the prefrontal cortex have been implicated in the pathogenesis of major depressive disorder (MDD). To our knowledge, no prior study has examined prefrontal cortical anatomy in pediatric patients with MDD near the onset of illness before receiving treatment.

METHODS

Volumetric magnetic resonance imaging studies were conducted in 22 psychotropic-naive patients with MDD, aged 9 to 17 years (10 males and 12 females), and 22 case-matched healthy comparison control subjects. Twelve of the 22 patients with MDD had at least 1 first-degree relative with MDD (familial MDD), whereas 10 had no clear family history of MDD (nonfamilial MDD).

RESULTS

Patients with nonfamilial MDD had significantly larger left-sided but not right-sided prefrontal cortical volumes than patients with familial MDD (17% larger) and controls (11% larger). Left-sided and right-sided prefrontal cortical volumes did not differ significantly between patients with familial MDD and controls.

CONCLUSIONS

These results provide new evidence of prefrontal cortical alterations in pediatric MDD that may differ in familial and nonfamilial subtypes of MDD. Our findings must be considered preliminary, however, in view of the small sample size.

Increased medial thalamic choline in pediatric obsessive-compulsive disorder as detected by quantitative in vivo spectroscopic imaging

The thalamus has been implicated in the pathophysiology of obsessive-compulsive disorder. Using a multislice spectroscopic imaging sequence, we reported reductions in right and left medial thalamic N-acetylaspartate/cytosolic choline + creatine/phosphocreatine and N-acetylaspartate/cytosolic choline levels in 11 pediatric patients with obsessive-compulsive disorder, 8 to 15 years, versus 11 case-matched healthy controls. These changes may reflect a change in N-acetylaspartate, cytosolic choline, or creatine concentrations. Therefore, using a validated phantom replacement methodology, we obtained absolute measures (mmol/L) of N-acetylaspartate, a putative marker of neuronal viability, cytosolic choline, and creatine in these subjects. A significant increase in cytosolic choline was observed in right and left medial but not lateral thalami in patients with obsessive-compulsive disorder versus controls. N-acetylaspartate and creatine did not differ significantly between case-control pairs in the medial or lateral thalamus. These findings provide new evidence of cytosolic choline abnormalities in the thalamus in pediatric obsessive-compulsive disorder.

Case study: caudate glutamatergic changes with paroxetine persist after medication discontinuation in pediatric OCD

Proton magnetic resonance spectroscopy (1H-MRS) was used to examine glutamatergic (Glx) abnormalities in the caudate nucleus in pediatric obsessive-compulsive disorder (OCD), associated with severity of illness and response to acute (12 weeks) treatment with paroxetine. In this report, OCD symptoms improved markedly in an 8-year-old girl treated for 14 months with the selective serotonin reuptake inhibitor paroxetine (titrated from 10 to 40 mg/day). Paroxetine dose was then decreased in 10-mg decrements and discontinued without symptom recurrence. Serial 1H-MRS examinations were acquired before and after 12 weeks of paroxetine treatment (40 mg/day) and 3 months after medication discontinuation. A striking decrease in caudate Glx was observed after 12 weeks of treatment which persisted after medication discontinuation. These data provide further support for a reversible glutamatergically mediated dysfunction of the caudate nucleus in OCD that may serve as a pathophysiological and treatment response marker.

Prefrontal cortex as the site of estrogen's effect on cognition

The hippocampus has long been presumed the primary site of action of estrogens on cognition; and explicit memory is considered the cognitive function most vulnerable to menopausal loss of estrogen. We hypothesize instead that the prefrontal cortex and its neural circuitry are prime mediators of estrogen's role in cognition. We also propose that previously reported menopausal cognitive decline, presumed to be hippocampally mediated, may be secondary to executive dysfunction. We used a cross sectional design to compare the performance of nine menopausal women on hormone replacement therapy (HRT) and 10 menopausal women with no prior exposure to HRT on a battery of neuropsychological tests. The battery was comprised primarily of tests of memory and executive functioning. Executive functioning is mediated by the frontal lobes and encompasses working memory, directed attention, the inhibition of inappropriate responses, cognitive set switching, and behavioral monitoring. Unlike most previous studies, we used a memory measure that yields multiple scores reflecting various problem-solving strategies and error types, thus isolating spared and impaired cognitive processes. Results yielded both qualitative and quantitative evidence for disruption of cognitive processes subserved by the frontal lobes rather than the hippocampus: 1) despite intact free recall on a list-learning task (CVLT), untreated menopausal women were relatively impaired in correctly recognizing words previously learned and distinguishing them from items not on the list (discriminability), 2) untreated women also had difficulty inhibiting inappropriate responses in the form of perseverative errors, and 3) the non-HRT group consistently performed worse on the N-back test of working memory. The prefrontal cortex is critical for intact working memory and estrogen enhances performance on working memory tasks. In conclusion, this study provides preliminary evidence for executive dysfunction in untreated menopausal women as women with HRT outperformed women without HRT on tests requiring directed attention, inhibition of inappropriate responses, and cognitive set switching.

Bipolar disorder: leads from the molecular and cellular mechanisms of action of mood stabilizers

BACKGROUND

New research is dramatically altering our understanding of the molecular mechanisms underlying neuronal communication.

AIM

To elucidate the molecular mechanisms underlying the therapeutic effects of mood stabilizers.

METHOD

Results from integrated clinical and laboratory studies are reviewed.

RESULTS

Chronic administration of lithium and valproate produced a striking reduction in protein kinase C (PKC) isozymes in rat frontal cortex and hippocampus. In a small study, tamoxifen (also a PKC inhibitor) had marked antimanic efficacy. Both lithium and valproate regulate the DNA binding activity of the activator protein I family of transcription factors. Using mRNA differential display, it was also shown that chronic administration of lithium and valproate modulates expression of several genes. An exciting finding is that of a robust elevation in the levels of the cytoprotective protein, bcl-2.

CONCLUSIONS

The results suggest that regulation of signalling pathways may play a major part in the long-term actions of mood stabilizers. Additionally, mood stabilizers may exert underappreciated neuroprotective effects.

Bipolar disorder: leads from the molecular and cellular mechanisms of action of mood stabilisers

Background New research is dramatically altering our understanding of the molecular mechanisms underlying neuronal communication. Aim To elucidate the molecular mechanisms underlying the therapeutic effects of mood stabilisers. Method Results from integrated clinical and laboratory studies are reviewed. Results Chronic administration of lithium and valproate produced a striking reduction in protein kinase C (PKC) isozymes in rat frontal cortex and hippocampus. In a small study, tamoxifen (also a PKC inhibitor) had marked antimanic efficacy. Both lithium and valproate regulate the DNA binding activity of the activator protein 1 family of transcription factors. Using mRNA differential display, it was also shown that chronic administration of lithium and valproate modulates expression of several genes. An exciting finding is that of a robust elevation in the levels of the cytoprotective protein, bcl-2. Conclusions The results suggest that regulation of signalling pathways may play a major part in the long-term actions of mood stabilisers. Additionally, mood stabilisers may exert underappreciated neuroprotective effects.