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Brain Systems (brain + system)
Kinds of Brain Systems Selected AbstractsNeural correlates of consolidation in working memoryHUMAN BRAIN MAPPING, Issue 3 2007Nelly Mainy Abstract Many of our daily activities rely on a brain system called working memory, which implements our ability to encode information for short-term maintenance, possible manipulation, and retrieval. A recent intracranial study of patients performing a paradigmatic working memory task revealed that the maintenance of information involves a distributed network of oscillations in the gamma band (>40 Hz). Using a similar task, we focused on the encoding stage and targeted a process referred to as short-term consolidation, which corresponds to the encoding of novel items in working memory. The paradigm was designed to manipulate the subjects' intention to encode: series of 10 letters were presented, among which only five had to be remembered, as indicated by visual cues preceding or following each letter. During this task we recorded the intracerebral EEG of nine epileptic patients implanted in mesiotemporal structures, perisylvian regions, and prefrontal areas and used time,frequency analysis to search for neural activities simultaneous with the encoding of the letters into working memory. We found such activities in the form of increases of gamma band activity in a set of regions associated with the phonological loop, including the Broca area and the auditory cortex, and in the prefrontal cortex, the pre- and postcentral gyri, the hippocampus, and the fusiform gyrus. Hum Brain Mapp, 2007. © 2006 Wiley-Liss, Inc. [source] MRI white matter hyperintensities, 1H-MR spectroscopy and cognitive function in geriatric depression: a comparison of early- and late-onset casesINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 12 2001Tetsuhito Murata Abstract Background and Objectives Geriatric depression is often thought to differ from that at other times of adulthood. Recently, several studies have shown that the incidence of white matter hyperintense lessions identified by brain MRI is higher in patients with geriatric depression than in healthy elderly subjects, but a consensus has not yet been reached on the relationship between the severity of white matter lesions and either cognitive impairment or depressive symptoms. Method Forty-seven patients aged 50 to 75 years with major depression were divided into two groups based on age at onset of depression: early-onset (<,50 years) group (20 patients; mean age, 62.7,±,6.7) and late-onset (,50 years) group (27 patients; mean age, 65.6,±,5.4). The severity of hyperintense white matter lesions on MRI was classified by region, then a proton magnetic resonance spectroscopy (1H-MRS) focusing on the white matter of the frontal lobes, multidimensional neuropsychological tests and evaluation of depressive symptoms were conducted. Results The severity of the deep white matter lesions, the deterioration of cognitive function related to subcortical/frontal brain system and clinician-rated depressive symptoms were all more pronounced in the late-onset group compared with those in the early-onset group. It was further observed that the more severe the deep white matter lesions, the lower the levels of N-acetylaspartate/creatine. With the age of onset as the covariate, the patients with moderate deep white matter lesions had more pronounced cognitive impairment and clinician-rated depressive symptoms than those with none and/or mild lesions. Conclusion These results suggest that subcortical/frontal type cognitive impairment and the persistence of depressive symptoms in geriatric depression is related to moderate deep white matter lesions more often complicated in the late-onset group. The 1H-MRS findings were suggested to be a useful indicator of neuronal/axonal loss in the white matter of the frontal lobes which precedes cognitive impairment. Copyright © 2001 John Wiley & Sons, Ltd. [source] Neurodevelopmental expression and localization of the cellular prion protein in the central nervous system of the mouseTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 11 2010Stefano Benvegnù Abstract Transmissible spongiform encephalopathies (TSEs) are neurodegenerative disorders caused by PrPSc, or prion, an abnormally folded form of the cellular prion protein (PrPC). The abundant expression of PrPC in the central nervous system (CNS) is a requirement for prion replication, yet despite years of intensive research the physiological function of PrPC still remains unclear. Several routes of investigation point out a potential role for PrPC in axon growth and neuronal development. Thus, we undertook a detailed analysis of the spatial and temporal expression of PrPC during mouse CNS development. Our findings show regional differences of the expression of PrP, with some specific white matter structures showing the earliest and highest expression of PrPC. Indeed, all these regions are part of the thalamolimbic neurocircuitry, suggesting a potential role of PrPC in the development and functioning of this specific brain system. J. Comp. Neurol. 518:1879,1891, 2010. © 2010 Wiley-Liss, Inc. [source] Neurodevelopmental expression and localization of the cellular prion protein in the central nervous system of the mouseTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 11 2010Stefano Benvegnù Abstract Transmissible spongiform encephalopathies (TSEs) are neurodegenerative disorders caused by PrPSc, or prion, an abnormally folded form of the cellular prion protein (PrPC). The abundant expression of PrPC in the central nervous system (CNS) is a requirement for prion replication, yet despite years of intensive research the physiological function of PrPC still remains unclear. Several routes of investigation point out a potential role for PrPC in axon growth and neuronal development. Thus, we undertook a detailed analysis of the spatial and temporal expression of PrPC during mouse CNS development. Our findings show regional differences of the expression of PrP, with some specific white matter structures showing the earliest and highest expression of PrPC. Indeed, all these regions are part of the thalamolimbic neurocircuitry, suggesting a potential role of PrPC in the development and functioning of this specific brain system. J. Comp. Neurol. 518:1879,1891, 2010. © 2010 Wiley-Liss, Inc. [source] Circuits and systems in stress.DEPRESSION AND ANXIETY, Issue 1 2002Abstract This paper follows the preclinical work on the effects of stress on neurobiological and neuroendocrine systems and provides a comprehensive working model for understanding the pathophysiology of posttraumatic stress disorder (PTSD). Studies of the neurobiology of PTSD in clinical populations are reviewed. Specific brain areas that play an important role in a variety of types of memory are also preferentially affected by stress, including hippocampus, amygdala, medial prefrontal cortex, and cingulate. This review indicates the involvement of these brain systems in the stress response, and in learning and memory. Affected systems in the neural circuitry of PTSD are reviewed (hypothalamic-pituitary-adrenal axis (HPA-axis), catecholaminergic and serotonergic systems, endogenous benzodiazepines, neuropeptides, hypothalamic-pituitary-thyroid axis (HPT-axis), and neuro-immunological alterations) as well as changes found with structural and functional neuroimaging methods. Converging evidence has emphasized the role of early-life trauma in the development of PTSD and other trauma-related disorders. Current and new targets for systems that play a role in the neural circuitry of PTSD are discussed. This material provides a basis for understanding the psychopathology of stress-related disorders, in particular PTSD. Depression and Anxiety 16:14,38, 2002. © 2002 Wiley-Liss, Inc. [source] Imaging the developing brain with fMRIDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 3 2003M.C. Davidson Abstract Advancements in magnetic imaging techniques have revolutionized our ability to study the developing human brain in vivo. The ability to noninvasively image both anatomy and function in healthy volunteers, including young children, has already enhanced our understanding of brain and behavior relations. The application of these techniques to developmental research offers the opportunity to further explore these relationships and allows us to ask questions about where, when and how cognitive abilities develop in relation to changes in underlying brain systems. It is also possible to explore the contributions of maturation versus learning in the development of these abilities through cross-sectional and longitudinal research involving training and intervention procedures. Current imaging methodologies, in conjunction with new and rapidly evolving techniques, hold the promise of even greater insights into developmental issues in the near future. These methodologies and their application to development and learning are discussed in the current paper. MRDD Research Reviews 2003;9:161,167. © 2003 Wiley-Liss, Inc. [source] Neurocognitive correlates of socioeconomic status in kindergarten childrenDEVELOPMENTAL SCIENCE, Issue 1 2005Kimberly G. Noble Socioeconomic status (SES) is strongly associated with cognitive ability and achievement during childhood and beyond. Little is known about the developmental relationships between SES and specific brain systems or their associated cognitive functions. In this study we assessed neurocognitive functioning of kindergarteners from different socioeconomic backgrounds, using tasks drawn from the cognitive neuroscience literature in order to determine how childhood SES predicts the normal variance in performance across different neurocognitive systems. Five neurocognitive systems were examined: the occipitotemporal/visual cognition system, the parietal/spatial cognition system, the medial temporal/memory system, the left perisylvian/language system, and the prefrontal/executive system. SES was disproportionately associated with the last two, with low SES children performing worse than middle SES children on most measures of these systems. Relations among language, executive function, SES and specific aspects of early childhood experience were explored, revealing intercorrelations and a seemingly predominant role of individual differences in language ability involved in SES associations with executive function. [source] CNS response to a thermal stressor in human volunteers and rats may predict the clinical utility of analgesicsDRUG DEVELOPMENT RESEARCH, Issue 1 2007David Borsook Abstract fMRI was used to test the hypothesis that global brain activation following a stressor (a thermal stimulus) that activates multiple brain circuits in healthy subjects can predict which drugs have higher potential for clinical utility for neuropathic pain. The rationale is that a drug will modulate multiple neural circuits that are activated by the system-specific stressor (e.g., pain). In neuropathic pain, some brain circuits have altered function, but most brain systems are "normal." Thus, the manner in which a drug effect on neural circuits is modulated by the stressor may provide insight into the clinical utility based on the readout of brain activation in response to the stimulus. Six drugs with known clinical efficacy (or lack thereof) in treating neuropathic pain were selected and the CNS response to each drug in the presence or absence of a pain stimulus was examined. The present results suggest that it is possible to identify potentially effective drugs based on patterns of brain activation in healthy human subjects and indicate that CNS activity is a more sensitive measure of drug action than standard psychophysical measures of pain intensity. This approach was repeated in rats and showed that a similar fMRI paradigm segregates these drugs in a similar manner suggesting a potential "translational tool" in evaluating drug efficacy for neuropathic pain. The sensitivity of this paradigm using fMRI allows clinical screening in small groups of healthy subjects, suggesting it could become a useful tool for drug development as well as for elucidating the mechanisms of neuropathic disease and therapy. Drug Dev. Res. 68:23,41, 2007. © 2007 Wiley-Liss, Inc. [source] Differential involvement of the prelimbic cortex and striatum in conditioned heroin and sucrose seeking following long-term extinctionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2005E. Donné Schmidt Abstract Relapse to drug taking is triggered by stimuli previously associated with consumption of drugs of misuse (cues) and involves brain systems controlling motivated behaviour towards natural reinforcers. In this study, we aimed to identify and compare neuronal pathways in corticostriatal systems that control conditioned heroin or natural reward (sucrose) seeking. To that end, rats were trained to self-administer heroin or sucrose in association with an identical compound cue. After more than 3 weeks of abstinence during extinction training, cue exposure robustly reinstated heroin and sucrose seeking, but induced distinct and even opposing changes in the expression of the neuronal activation marker zif268 in the prelimbic cortex and striatal complex, respectively. Because in the prelimbic area zif268 expression was enhanced during cue-induced heroin seeking but unaffected during sucrose seeking, a pharmacological intervention was aimed at this prefrontal region. Injection of a GABA agonist mixture within the prelimbic area enhanced conditioned heroin seeking, but had no effect on conditioned sucrose seeking. Our findings suggest a differential role of the prelimbic area and the striatum in the persistence of heroin vs. sucrose seeking following long-term extinction. [source] Effects of hippocampal cholinergic deafferentation on learning strategy selection in a visible platform version of the water mazeHIPPOCAMPUS, Issue 6 2003J.L. Bizon Abstract Recent evidence has suggested that the relative levels of acetylcholine (ACh) between brain structures may be an important factor in the choice of behavioral strategy in settings in which either hippocampal or dorsal striatal brain systems can be employed both effectively and independently (McIntyre and Gold. 1999. Soc Neurosci Abs 25:1388). The current investigation used the neurotoxin 192 IgG-saporin to deplete the hippocampus of ACh selectively, while leaving ACh in other brain regions, including dorsal striatum, intact. Rats were then trained on a version of the Morris water maze, in which behavioral strategies attributed to the hippocampus and dorsal striatum are placed in direct competition. It was predicted that rats with hippocampal ACh depletion would display a cue bias. Contrary to this prediction, depleting hippocampal ACh did not bias against and, in fact, promoted use of a hippocampal place strategy in this task, as indicated by choice in competition tests and performance on hidden platform training trials. These data add to a growing literature demonstrating that the septohippocampal cholinergic system is not required for accurate spatial learning and suggest a complex role for basal forebrain projections in processing information about the spatial environment. © 2003 Wiley-Liss, Inc. [source] fMRI evidence for multisensory recruitment associated with rapid eye movements during sleepHUMAN BRAIN MAPPING, Issue 5 2009Charles Chong-Hwa Hong Abstract We studied the neural correlates of rapid eye movement during sleep (REM) by timing REMs from video recording and using rapid event-related functional MRI. Consistent with the hypothesis that REMs share the brain systems and mechanisms with waking eye movements and are visually-targeted saccades, we found REM-locked activation in the primary visual cortex, thalamic reticular nucleus (TRN), ,visual claustrum', retrosplenial cortex (RSC, only on the right hemisphere), fusiform gyrus, anterior cingulate cortex, and the oculomotor circuit that controls awake saccadic eye movements (and subserves awake visuospatial attention). Unexpectedly, robust activation also occurred in non-visual sensory cortices, motor cortex, language areas, and the ascending reticular activating system, including basal forebrain, the major source of cholinergic input to the entire cortex. REM-associated activation of these areas, especially non-visual primary sensory cortices, TRN and claustrum, parallels findings from waking studies on the interactions between multiple sensory data, and their ,binding' into a unified percept, suggesting that these mechanisms are also shared in waking and dreaming and that the sharing goes beyond the expected visual scanning mechanisms. Surprisingly, REMs were associated with a decrease in signal in specific periventricular subregions, matching the distribution of the serotonergic supraependymal plexus. REMs might serve as a useful task-free probe into major brain systems for functional brain imaging. Hum Brain Mapp 2009. © 2008 Wiley-Liss, Inc. [source] Functional connectivity of default mode network components: Correlation, anticorrelation, and causalityHUMAN BRAIN MAPPING, Issue 2 2009Lucina Q. Uddin Abstract The default mode network (DMN), based in ventromedial prefrontal cortex (vmPFC) and posterior cingulate cortex (PCC), exhibits higher metabolic activity at rest than during performance of externally oriented cognitive tasks. Recent studies have suggested that competitive relationships between the DMN and various task-positive networks involved in task performance are intrinsically represented in the brain in the form of strong negative correlations (anticorrelations) between spontaneous fluctuations in these networks. Most neuroimaging studies characterize the DMN as a homogenous network, thus few have examined the differential contributions of DMN components to such competitive relationships. Here, we examined functional differentiation within the DMN, with an emphasis on understanding competitive relationships between this and other networks. We used a seed correlation approach on resting-state data to assess differences in functional connectivity between these two regions and their anticorrelated networks. While the positively correlated networks for the vmPFC and PCC seeds largely overlapped, the anticorrelated networks for each showed striking differences. Activity in vmPFC negatively predicted activity in parietal visual spatial and temporal attention networks, whereas activity in PCC negatively predicted activity in prefrontal-based motor control circuits. Granger causality analyses suggest that vmPFC and PCC exert greater influence on their anticorrelated networks than the other way around, suggesting that these two default mode nodes may directly modulate activity in task-positive networks. Thus, the two major nodes comprising the DMN are differentiated with respect to the specific brain systems with which they interact, suggesting greater heterogeneity within this network than is commonly appreciated. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Interactive Effects of Cumulative Stress and Impulsivity on Alcohol ConsumptionALCOHOLISM, Issue 8 2010Fox Helen C. Background:, Alcohol addiction may reflect adaptations to stress, reward, and regulatory brain systems. While extensive research has identified both stress and impulsivity as independent risk factors for drinking, few studies have assessed the interactive relationship between stress and impulsivity in terms of hazardous drinking within a community sample of regular drinkers. Methods:, One hundred and thirty regular drinkers (56M/74F) from the local community were assessed for hazardous and harmful patterns of alcohol consumption using the Alcohol Use Disorders Identification Test (AUDIT). All participants were also administered the Barratt Impulsiveness Scale (BIS-11) as a measure of trait impulsivity and the Cumulative Stress/Adversity Checklist (CSC) as a comprehensive measure of cumulative adverse life events. Standard multiple regression models were used to ascertain the independent and interactive nature of both overall stress and impulsivity as well as specific types of stress and impulsivity on hazardous and harmful drinking. Results:, Recent life stress, cumulative traumatic stress, overall impulsivity, and nonplanning-related impulsivity as well as cognitive and motor-related impulsivity were all independently predictive of AUDIT scores. However, the interaction between cumulative stress and total impulsivity scores accounted for a significant amount of the variance, indicating that a high to moderate number of adverse events and a high trait impulsivity rating interacted to affect greater AUDIT scores. The subscale of cumulative life trauma accounted for the most variance in AUDIT scores among the stress and impulsivity subscales. Conclusions:, Findings highlight the interactive relationship between stress and impulsivity with regard to hazardous drinking. The specific importance of cumulative traumatic stress as a marker for problem drinking is also discussed. [source] Reading, complexity and the brainLITERACY, Issue 2 2008Usha Goswami Abstract Brain imaging offers a new technology for understanding the acquisition of reading by children. It can contribute novel evidence concerning the key mechanisms supporting reading, and the brain systems that are involved. The extensive neural architecture that develops to support efficient reading testifies to the complex developmental processes that underpin the acquisition of literacy. Here, I provide a brief overview of recent studies, analysed within a cognitive framework of reading development. [source] Pathological gambling in Parkinson's disease: Risk factors and differences from dopamine dysregulation.MOVEMENT DISORDERS, Issue 12 2007An analysis of published case series Abstract Pathological gambling (PG) has been reported as a complication of the treatment of Parkinson's disease (PD). We examined all published cases of PG for prevalence and risk factors of this complication, the relationship of PG and use of dopamine agonists (DA), and the relationship of PG to the dopamine dysregulation syndrome (DDS). The prevalence of PG in prospective studies of PD patients using DA has been reported between 2.3 and 8%, compared to approximately 1% in the general population. As in the general population, PD patients with this complication are often young, male and have psychiatric co-morbidity. The vast majority are on DA, often at maximum dose or above. Differences between oral DA failed to reach significance. PG associated with levodopa monotherapy is uncommon, but in the majority of cases levodopa is co-prescribed, suggesting possible cross-sensitization of brain systems mediating reward. PG can occur with DDS but often occurs in isolation. In contrast to DDS, escalation and self regulation of anti-parkinsonian medication are not usually seen. PG in patients with PD using DA is higher than PG reported in the general population, but shares similar characteristics and risk factors. PG is predominantly associated with oral DA. It often occurs in isolation and may not be associated with DDS, which typically occurs on treatment with levodopa or subcutaneous apomorphine. © 2007 Movement Disorder Society [source] Heritability of different measures of smooth pursuit eye tracking dysfunction: A study of normal twinsPSYCHOPHYSIOLOGY, Issue 6 2000Joanna Katsanis Research studies have found that smooth pursuit eye movement dysfunction may serve as an index of genetic liability to develop schizophrenia. The heritability of various measures of smooth pursuit eye tracking proficiency and the saccades that occur during smooth pursuit was examined in 64 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs. Two age cohorts were assessed (11,12 and 17,18 years of age). Intraclass correlations indicated significant similarity in the MZ twins for almost all measures in both age cohorts, whereas few of the DZ twin correlations attained significance. Biometrical modeling indicated that genetic mechanisms influence performance on both global and specific eye tracking measures, accounting for about 40% to 60% of the variance. These findings suggest that the underlying brain systems responsible for smooth pursuit and saccade generation during pursuit are under partial genetic control. [source] Interfacing mind and brain: A neurocognitive model of recognition memoryPSYCHOPHYSIOLOGY, Issue 5 2000Axel Mecklinger A variety of processes contribute to successful recognition memory, some of which can be associated with spatiotemporally distinct event-related potential old/new effects. An early frontal and a subsequent parietal old/new effect are correlated with the familiarity and recollection subcomponents of recognition memory, respectively, whereas a late, postretrieval old/new effect seems to reflect an ensemble of evaluation processes that are set by the task context in which retrieval occurs. Both the early frontal and the parietal old/new effects are differentially modulated by the informational content (e.g., object forms and spatial locations) of recognition and seem to rely on brain systems damaged in amnesia. The late frontal effect appears to reflect prefrontal cortex activation. A neurophysiologically based model of recognition memory retrieval is presented and it is shown that coupling recognition memory subprocesses with distinct old/new effects allow examination of the time course of the processes that contribute to correct and to illusory memories. In conjunction with event-related functional magnetic resonance imaging activation patterns the brain systems recruited by various aspects of episodic memory retrieval can be identified. [source] Brain oscillations forever , neurophysiology in future research of child psychiatric problemsTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 1-2 2009Aribert Rothenberger For decades neurophysiology has successfully contributed to research and clinical care in child psychiatry. Recently, methodological progress has led to a revival of interest in brain oscillations (i.e., a band of periodic neuronal frequencies with a wave-duration from milliseconds to several seconds which may code and decode information). These oscillations will nurture future information processing research during normal and pathological brain development, allowing us to investigate basic neuronal connectivity as well as interactions of brain systems and their modulation (e.g., by temporal neuronal synchronisation) as close correlates of behaviour and intermediate phenotypes from genes to behavioural variations. Especially, a systematic neurodynamic look at transitional processes from rest to stimulus-triggered goal-directed performance will aid behavioural understanding and guidance of children. Preliminary data suggest two separate oscillatory mechanisms in this respect. One is ongoing from pre- to post-stimulus processing and related to quantitative modification of behaviour, while another is merely related to qualitative effects of behaviour and reflects ,on-top' post-stimulus processing by temporal neuronal synchronisation of the oscillatory network in question. Suggested neurodynamic models may be tested in multilevel clinical experiments as well as in the framework of computational neuropsychiatry. [source] Quantification of acetylcholine, an essential neurotransmitter, in brain microdialysis samples by liquid chromatography mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 1 2010Ramakrishna Nirogi Abstract Chemical neurotransmission has been the subject of intensive investigations in recent years. Acetylcholine is an essential neurotransmitter in the central nervous system as it has an effect on alertness, memory and learning. Enzymatic hydrolysis of acetylcholine in the synaptic cleft is fast and quickly metabolizes to choline and acetate by acetylcholinesterase. Hence the concentration in the extracellular fluid of the brain is low (0.1,6,nm). Techniques such as microdialysis are routinely employed to measure acetylcholine levels in living brain systems and the microdialysis sample volumes are usually less than 50,µL. In order to develop medicine for the diseases associated with cognitive dysfunction like mild cognitive impairment, Alzheimer's disease, schizophrenia and Parkinson's disease, or to study the mechanism of the illness, it is important to measure the concentration of acetylcholine in the extracellular fluid of the brain. Recently considerable attention has been focused on the development of chromatographic,mass spectrometric techniques to provide more sensitive and accurate quantification of acetylcholine collected from in-vivo brain microdialysis experiments. This review will provide a brief overview of acetylcholine biosynthesis, microdialysis technique and liquid chromatography mass spectrometry, which is being used to quantitate extracellular levels of acetylcholine. Copyright © 2009 John Wiley & Sons, Ltd. [source] Concurrent determination of thalidomide in rat blood, brain and bile using multiple microdialysis coupled to liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 7 2005Yu-Jen Huang Abstract A rapid and sensitive system of liquid chromatography coupled with microdialysis was developed for the simultaneous determination of unbound thalidomide in rat blood, brain and bile for pharmacokinetic study. Microdialysis probes were concurrently inserted into the jugular vein toward the right atrium, the brain striatum and the bile duct of the anesthetized Sprague,Dawley rats for biological ,uid sampling after the administration of thalidomide (5 mg kg,1) through the femoral vein. Thalidomide and dialysates were separated using a Zorbax ODS C18 column and a mobile phase comprising acetonitrile,methanol,0.1 mm 1-octanesulufonic acid (32:3:65, v/v/v, pH 5.3) at ,ow rate of 1 mL min,1. The UV wavelength was set at 220 nm. The concentration,response relationship was linear (r2 > 0.995) over a concentration range of 0.025,25 µg mL,1. The intra-assay and inter-assay precision and accuracy of thalidomide fell within 7%. The average in vivo recoveries were 0.31 ± 0.02,0.046 ± 0.004 and 0.57 ± 0.02 (n = 6), respective to the dialysates of blood, brain and bile, with thalidomide at concentrations 2, 5 and 10 µg mL,1. The disposition of thalidomide in the blood, brain and bile ,uid suggests that there is a rapid thalidomide exchange and equilibration between the blood and brain systems. In addition, thalidomide undergoes hepatobiliary excretion. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||