The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform

A. Vania Apkarian - One of the best experts on this subject based on the ideXlab platform.

  • Aging alters the multichemical networking profile of the human Brain: An in vivo 1H-MRS study of young versus middle-aged subjects
    Journal of neurochemistry, 2008
    Co-Authors: Igor D. Grachev, Amar Swarnkar, Nikolaus M. Szeverenyi, Tarakad S. Ramachandran, A. Vania Apkarian
    Abstract:

    In our most recent study of normal aging, we found decreased concentration of multiple chemicals in the Brain of middle-aged subjects, as compared with younger subjects using in vivo proton magnetic resonance spectroscopy (1H-MRS). We hypothesized that these age-dependent differences in Brain Chemistry changes might be a reflection of the multichemical-networking-profile (MCNP) changes during aging. Using 1H-MRS and correlation analysis, we examined the patterns of regional chemical levels and MCNP within and across multiple Brain regions for all nine chemicals of 1H-MR spectra. The Brain Chemistry changes and MCNP patterns were compared between 21 young (19–31-year-old) and 31 middle-aged (40–52-year-old) normal volunteers. Middle-aged subjects demonstrated a significant decrease of chemical levels in the prefrontal cortex and sensorimotor cortex (SMC), as compared with the young age group. Of these, neurotransmitters GABA and glutamate in the dorsolateral prefrontal cortex (DLPFC) were altered the most. We also found a significant increase of overall chemical correlation strength in MCNP within and across all studied Brain regions with increased age. These changes were caused by alterations in the pattern of negative chemical connectivity across Brain regions, which become weaker (less negative) in middle-aged subjects. The interregional chemical connectivity for the cingulate cortex, SMC and the thalamus was changed the most with increased age. Increased levels of chemical correlation strength across Brain regions in aging were found for most chemicals studied (including neurotransmitters GABA and glutamate), and not for N-acetyl aspartate. These age-related differences in the connectivity of neurotransmitters were not region dependent. The results suggest that aging is associated with changes of the regional Brain Chemistry and the Brain MCNP. The latter process may reflect an adaptive or compensatory response (possibly related to the elongation of dendrites with aging) to reduced levels of regional Brain chemicals. The 1H-MRS approach proposed here can be used as a valuable tool in the study of the Brain Chemistry, MCNP and their relationships in normal and abnormal aging.

  • Afwijkende hersenchemie: een protonisch spectroscopisch onderzoek met magnetische resonantie in vivo
    Stimulus, 2002
    Co-Authors: Igor G. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study [Pain 2000;89:7-18]

  • Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study.
    Pain, 2000
    Co-Authors: Igor D. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    The neurobiology of chronic pain, including chronic back pain, is unknown. Structural imaging studies of the spine cannot explain all cases of chronic back pain. Functional Brain imaging studies indicate that the Brain activation patterns are different between chronic pain patients and normal subjects, and the thalamus, and prefrontal and cingulate cortices are involved in some types of chronic pain. Animal models of chronic pain suggest abnormal spinal cord Chemistry. Does chronic pain cause Brain Chemistry changes? We examined Brain Chemistry changes in patients with chronic back pain using in vivo single- voxel proton magnetic resonance spectroscopy ((1)H-MRS). In vivo (1)H-MRS was used to measure relative concentrations of N-acetyl aspartate, creatine, choline, glutamate, glutamine, gamma-aminobutyric acid, inositol, glucose and lactate in relation to the concentration of creatine. These measurements were performed in six Brain regions of nine chronic low back pain patients and 11 normal volunteers. All chronic back pain subjects underwent clinical evaluation and perceptual measures of pain and anxiety. We show that chronic back pain alters the human Brain Chemistry. Reductions of N-acetyl aspartate and glucose were demonstrated in the dorsolateral prefrontal cortex. Cingulate, sensorimotor, and other Brain regions showed no chemical concentration differences. In chronic back pain, the interrelationship between chemicals within and across Brain regions was abnormal, and there was a specific relationship between regional chemicals and perceptual measures of pain and anxiety. These findings provide direct evidence of abnormal Brain Chemistry in chronic back pain, which may be useful in diagnosis and future development of more effective pharmacological treatments.

  • Research Papers Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study
    2000
    Co-Authors: Igor D. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    The neurobiology of chronic pain, including chronic back pain, is unknown. Structural imaging studies of the spine cannot explain all cases of chronic back pain. Functional Brain imaging studies indicate that the Brain activation patterns are different between chronic pain patients and normal subjects, and the thalamus, and prefrontal and cingulate cortices are involved in some types of chronic pain. Animal models of chronic pain suggest abnormal spinal cord Chemistry. Does chronic pain cause Brain Chemistry changes? We examined Brain Chemistry changes in patients with chronic back pain using in vivo single- voxel proton magnetic resonance spectroscopy ( 1 H-MRS). In vivo 1 H-MRS was used to measure relative concentrations of N-acetyl aspartate, creatine, choline, glutamate, glutamine, g-aminobutyric acid, inositol, glucose and lactate in relation to the concentration of creatine. These measurements were performed in six Brain regions of nine chronic low back pain patients and 11 normal volunteers. All chronic back pain subjects underwent clinical evaluation and perceptual measures of pain and anxiety. We show that chronic back pain alters the human Brain Chemistry. Reductions of N-acetyl aspartate and glucose were demonstrated in the dorsolateral prefrontal cortex. Cingulate, sensorimotor, and other Brain regions showed no chemical concentration differences. In chronic back pain, the interrelationship between chemicals within and across Brain regions was abnormal, and there was a specific relationship between regional chemicals and perceptual measures of pain and anxiety. These findings provide direct evidence of abnormal Brain Chemistry in chronic back pain, which may be useful in diagnosis and future development of more effective pharmacological treatments. q 2000 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.

Lanqun Mao - One of the best experts on this subject based on the ideXlab platform.

  • Self-powered electrochemical systems as neurochemical sensors: toward self-triggered in vivo analysis of Brain Chemistry
    Chemical Society reviews, 2017
    Co-Authors: Lanqun Mao
    Abstract:

    Real-time in vivo analysis of neurochemical dynamics has great physiological and pathological implications for a full understanding of the Brain. Self-powered electrochemical systems (SPESs) built on galvanic cell configurations bear the advantages of easy miniaturization for implantation and no interference to electric activities of neurons over traditional externally-powered electrochemical sensors for self-triggered in vivo analysis. However, this is still a new concept for in vivo neurochemical sensing with few implanted examples reported so far. This tutorial review summarizes the development of SPESs toward implantable applications from both principal and practical perspectives, ultimately aimed at providing a guide map to the future design of neurochemical sensors for in vivo analysis of Brain Chemistry.

  • Rational Design of Surface/Interface Chemistry for Quantitative in Vivo Monitoring of Brain Chemistry
    Accounts of chemical research, 2012
    Co-Authors: Meining Zhang, Lanqun Mao
    Abstract:

    To understand the molecular basis of Brain functions, researchers would like to be able to quantitatively monitor the levels of neurochemicals in the extracellular fluid in vivo. However, the chemical and physiological complexity of the central nervous system (CNS) presents challenges for the development of these analytical methods. This Account describes the rational design and careful construction of electrodes and nanoparticles with specific surface/interface Chemistry for quantitative in vivo monitoring of Brain Chemistry.We used the redox nature of neurochemicals at the electrode/electrolyte interface to establish a basis for monitoring specific neurochemicals. Carbon nanotubes provide an electrode/electrolyte interface for the selective oxidation of ascorbate, and we have developed both in vivo voltammetry and an online electrochemical detecting system for continuously monitoring this molecule in the CNS. Although Ca2+ and Mg2+ are involved in a number of neurochemical signaling processes, they are ...

  • rational design of surface interface Chemistry for quantitative in vivo monitoring of Brain Chemistry
    Accounts of Chemical Research, 2012
    Co-Authors: Meining Zhang, Lanqun Mao
    Abstract:

    To understand the molecular basis of Brain functions, researchers would like to be able to quantitatively monitor the levels of neurochemicals in the extracellular fluid in vivo. However, the chemical and physiological complexity of the central nervous system (CNS) presents challenges for the development of these analytical methods. This Account describes the rational design and careful construction of electrodes and nanoparticles with specific surface/interface Chemistry for quantitative in vivo monitoring of Brain Chemistry.We used the redox nature of neurochemicals at the electrode/electrolyte interface to establish a basis for monitoring specific neurochemicals. Carbon nanotubes provide an electrode/electrolyte interface for the selective oxidation of ascorbate, and we have developed both in vivo voltammetry and an online electrochemical detecting system for continuously monitoring this molecule in the CNS. Although Ca2+ and Mg2+ are involved in a number of neurochemical signaling processes, they are ...

Igor D. Grachev - One of the best experts on this subject based on the ideXlab platform.

  • Aging alters the multichemical networking profile of the human Brain: An in vivo 1H-MRS study of young versus middle-aged subjects
    Journal of neurochemistry, 2008
    Co-Authors: Igor D. Grachev, Amar Swarnkar, Nikolaus M. Szeverenyi, Tarakad S. Ramachandran, A. Vania Apkarian
    Abstract:

    In our most recent study of normal aging, we found decreased concentration of multiple chemicals in the Brain of middle-aged subjects, as compared with younger subjects using in vivo proton magnetic resonance spectroscopy (1H-MRS). We hypothesized that these age-dependent differences in Brain Chemistry changes might be a reflection of the multichemical-networking-profile (MCNP) changes during aging. Using 1H-MRS and correlation analysis, we examined the patterns of regional chemical levels and MCNP within and across multiple Brain regions for all nine chemicals of 1H-MR spectra. The Brain Chemistry changes and MCNP patterns were compared between 21 young (19–31-year-old) and 31 middle-aged (40–52-year-old) normal volunteers. Middle-aged subjects demonstrated a significant decrease of chemical levels in the prefrontal cortex and sensorimotor cortex (SMC), as compared with the young age group. Of these, neurotransmitters GABA and glutamate in the dorsolateral prefrontal cortex (DLPFC) were altered the most. We also found a significant increase of overall chemical correlation strength in MCNP within and across all studied Brain regions with increased age. These changes were caused by alterations in the pattern of negative chemical connectivity across Brain regions, which become weaker (less negative) in middle-aged subjects. The interregional chemical connectivity for the cingulate cortex, SMC and the thalamus was changed the most with increased age. Increased levels of chemical correlation strength across Brain regions in aging were found for most chemicals studied (including neurotransmitters GABA and glutamate), and not for N-acetyl aspartate. These age-related differences in the connectivity of neurotransmitters were not region dependent. The results suggest that aging is associated with changes of the regional Brain Chemistry and the Brain MCNP. The latter process may reflect an adaptive or compensatory response (possibly related to the elongation of dendrites with aging) to reduced levels of regional Brain chemicals. The 1H-MRS approach proposed here can be used as a valuable tool in the study of the Brain Chemistry, MCNP and their relationships in normal and abnormal aging.

  • Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study.
    Pain, 2000
    Co-Authors: Igor D. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    The neurobiology of chronic pain, including chronic back pain, is unknown. Structural imaging studies of the spine cannot explain all cases of chronic back pain. Functional Brain imaging studies indicate that the Brain activation patterns are different between chronic pain patients and normal subjects, and the thalamus, and prefrontal and cingulate cortices are involved in some types of chronic pain. Animal models of chronic pain suggest abnormal spinal cord Chemistry. Does chronic pain cause Brain Chemistry changes? We examined Brain Chemistry changes in patients with chronic back pain using in vivo single- voxel proton magnetic resonance spectroscopy ((1)H-MRS). In vivo (1)H-MRS was used to measure relative concentrations of N-acetyl aspartate, creatine, choline, glutamate, glutamine, gamma-aminobutyric acid, inositol, glucose and lactate in relation to the concentration of creatine. These measurements were performed in six Brain regions of nine chronic low back pain patients and 11 normal volunteers. All chronic back pain subjects underwent clinical evaluation and perceptual measures of pain and anxiety. We show that chronic back pain alters the human Brain Chemistry. Reductions of N-acetyl aspartate and glucose were demonstrated in the dorsolateral prefrontal cortex. Cingulate, sensorimotor, and other Brain regions showed no chemical concentration differences. In chronic back pain, the interrelationship between chemicals within and across Brain regions was abnormal, and there was a specific relationship between regional chemicals and perceptual measures of pain and anxiety. These findings provide direct evidence of abnormal Brain Chemistry in chronic back pain, which may be useful in diagnosis and future development of more effective pharmacological treatments.

  • Research Papers Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study
    2000
    Co-Authors: Igor D. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    The neurobiology of chronic pain, including chronic back pain, is unknown. Structural imaging studies of the spine cannot explain all cases of chronic back pain. Functional Brain imaging studies indicate that the Brain activation patterns are different between chronic pain patients and normal subjects, and the thalamus, and prefrontal and cingulate cortices are involved in some types of chronic pain. Animal models of chronic pain suggest abnormal spinal cord Chemistry. Does chronic pain cause Brain Chemistry changes? We examined Brain Chemistry changes in patients with chronic back pain using in vivo single- voxel proton magnetic resonance spectroscopy ( 1 H-MRS). In vivo 1 H-MRS was used to measure relative concentrations of N-acetyl aspartate, creatine, choline, glutamate, glutamine, g-aminobutyric acid, inositol, glucose and lactate in relation to the concentration of creatine. These measurements were performed in six Brain regions of nine chronic low back pain patients and 11 normal volunteers. All chronic back pain subjects underwent clinical evaluation and perceptual measures of pain and anxiety. We show that chronic back pain alters the human Brain Chemistry. Reductions of N-acetyl aspartate and glucose were demonstrated in the dorsolateral prefrontal cortex. Cingulate, sensorimotor, and other Brain regions showed no chemical concentration differences. In chronic back pain, the interrelationship between chemicals within and across Brain regions was abnormal, and there was a specific relationship between regional chemicals and perceptual measures of pain and anxiety. These findings provide direct evidence of abnormal Brain Chemistry in chronic back pain, which may be useful in diagnosis and future development of more effective pharmacological treatments. q 2000 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.

Bruce E. Fredrickson - One of the best experts on this subject based on the ideXlab platform.

  • Brain Chemistry reflects dual states of pain and anxiety in chronic low back pain.
    Journal of neural transmission (Vienna Austria : 1996), 2002
    Co-Authors: I. D. Grachev, Bruce E. Fredrickson, A. V. Apkarian
    Abstract:

    The neurobiology of the interaction between pain and anxiety is unknown. The present study examined interrelationships between: regional Brain Chemistry (as identified by in vivo proton magnetic resonance spectroscopy [1H-MRS] in dorsolateral prefrontal cortex [DLPFC], orbitofrontal cortex [OFC], cingulate and thalamus), pain (as measured by short form of the McGill Pain Questionnaire [SF-MPQ]), and anxiety (measured by the State-Trait Anxiety Inventory) in chronic low back pain (CLBP) patients, and contrasted to the relationship between Brain Chemistry and anxiety in sex and age-matched normal subjects. The results show that Brain Chemistry depends on a 3-way interaction of Brain regions examined, subject groups (normal vs. CLBP), and anxiety levels (high vs. low). The concentration of N-Acetyl aspartate (the largest peak in 1H-MRS) in OFC could distinguish between anxiety levels and between subject groups. Chemical-perceptual relationships were analyzed by calculating correlations between regional chemicals and perceptual measures of pain and anxiety. To isolate pain from anxiety, these maps were subdivided based on anxiety and, in the CLBP patients along anxiety-more-related vs. anxiety-less-related pain descriptors and along sensory vs. affective pain descriptors. There was a precise relationship between perception and Brain Chemistry. The chemical-perceptual network best related to pain in CLBP patients was comprised of the DLPFC and OFC; the chemical-anxiety network was best related to the OFC Chemistry in normals and to all four regions studied in CLBP patients; and the cingulate was best related to the affective component of pain. We conclude that the chemical-perceptual mapping differentiates between closely related perceptual states of pain and anxiety in chronic pain and provides a Brain regional-chemical-perceptual description of the long-term reorganization that occurs with chronic pain.

  • Afwijkende hersenchemie: een protonisch spectroscopisch onderzoek met magnetische resonantie in vivo
    Stimulus, 2002
    Co-Authors: Igor G. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study [Pain 2000;89:7-18]

  • Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study.
    Pain, 2000
    Co-Authors: Igor D. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    The neurobiology of chronic pain, including chronic back pain, is unknown. Structural imaging studies of the spine cannot explain all cases of chronic back pain. Functional Brain imaging studies indicate that the Brain activation patterns are different between chronic pain patients and normal subjects, and the thalamus, and prefrontal and cingulate cortices are involved in some types of chronic pain. Animal models of chronic pain suggest abnormal spinal cord Chemistry. Does chronic pain cause Brain Chemistry changes? We examined Brain Chemistry changes in patients with chronic back pain using in vivo single- voxel proton magnetic resonance spectroscopy ((1)H-MRS). In vivo (1)H-MRS was used to measure relative concentrations of N-acetyl aspartate, creatine, choline, glutamate, glutamine, gamma-aminobutyric acid, inositol, glucose and lactate in relation to the concentration of creatine. These measurements were performed in six Brain regions of nine chronic low back pain patients and 11 normal volunteers. All chronic back pain subjects underwent clinical evaluation and perceptual measures of pain and anxiety. We show that chronic back pain alters the human Brain Chemistry. Reductions of N-acetyl aspartate and glucose were demonstrated in the dorsolateral prefrontal cortex. Cingulate, sensorimotor, and other Brain regions showed no chemical concentration differences. In chronic back pain, the interrelationship between chemicals within and across Brain regions was abnormal, and there was a specific relationship between regional chemicals and perceptual measures of pain and anxiety. These findings provide direct evidence of abnormal Brain Chemistry in chronic back pain, which may be useful in diagnosis and future development of more effective pharmacological treatments.

  • Research Papers Abnormal Brain Chemistry in chronic back pain: an in vivo proton magnetic resonance spectroscopy study
    2000
    Co-Authors: Igor D. Grachev, Bruce E. Fredrickson, A. Vania Apkarian
    Abstract:

    The neurobiology of chronic pain, including chronic back pain, is unknown. Structural imaging studies of the spine cannot explain all cases of chronic back pain. Functional Brain imaging studies indicate that the Brain activation patterns are different between chronic pain patients and normal subjects, and the thalamus, and prefrontal and cingulate cortices are involved in some types of chronic pain. Animal models of chronic pain suggest abnormal spinal cord Chemistry. Does chronic pain cause Brain Chemistry changes? We examined Brain Chemistry changes in patients with chronic back pain using in vivo single- voxel proton magnetic resonance spectroscopy ( 1 H-MRS). In vivo 1 H-MRS was used to measure relative concentrations of N-acetyl aspartate, creatine, choline, glutamate, glutamine, g-aminobutyric acid, inositol, glucose and lactate in relation to the concentration of creatine. These measurements were performed in six Brain regions of nine chronic low back pain patients and 11 normal volunteers. All chronic back pain subjects underwent clinical evaluation and perceptual measures of pain and anxiety. We show that chronic back pain alters the human Brain Chemistry. Reductions of N-acetyl aspartate and glucose were demonstrated in the dorsolateral prefrontal cortex. Cingulate, sensorimotor, and other Brain regions showed no chemical concentration differences. In chronic back pain, the interrelationship between chemicals within and across Brain regions was abnormal, and there was a specific relationship between regional chemicals and perceptual measures of pain and anxiety. These findings provide direct evidence of abnormal Brain Chemistry in chronic back pain, which may be useful in diagnosis and future development of more effective pharmacological treatments. q 2000 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.

Meining Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Rational Design of Surface/Interface Chemistry for Quantitative in Vivo Monitoring of Brain Chemistry
    Accounts of chemical research, 2012
    Co-Authors: Meining Zhang, Lanqun Mao
    Abstract:

    To understand the molecular basis of Brain functions, researchers would like to be able to quantitatively monitor the levels of neurochemicals in the extracellular fluid in vivo. However, the chemical and physiological complexity of the central nervous system (CNS) presents challenges for the development of these analytical methods. This Account describes the rational design and careful construction of electrodes and nanoparticles with specific surface/interface Chemistry for quantitative in vivo monitoring of Brain Chemistry.We used the redox nature of neurochemicals at the electrode/electrolyte interface to establish a basis for monitoring specific neurochemicals. Carbon nanotubes provide an electrode/electrolyte interface for the selective oxidation of ascorbate, and we have developed both in vivo voltammetry and an online electrochemical detecting system for continuously monitoring this molecule in the CNS. Although Ca2+ and Mg2+ are involved in a number of neurochemical signaling processes, they are ...

  • rational design of surface interface Chemistry for quantitative in vivo monitoring of Brain Chemistry
    Accounts of Chemical Research, 2012
    Co-Authors: Meining Zhang, Lanqun Mao
    Abstract:

    To understand the molecular basis of Brain functions, researchers would like to be able to quantitatively monitor the levels of neurochemicals in the extracellular fluid in vivo. However, the chemical and physiological complexity of the central nervous system (CNS) presents challenges for the development of these analytical methods. This Account describes the rational design and careful construction of electrodes and nanoparticles with specific surface/interface Chemistry for quantitative in vivo monitoring of Brain Chemistry.We used the redox nature of neurochemicals at the electrode/electrolyte interface to establish a basis for monitoring specific neurochemicals. Carbon nanotubes provide an electrode/electrolyte interface for the selective oxidation of ascorbate, and we have developed both in vivo voltammetry and an online electrochemical detecting system for continuously monitoring this molecule in the CNS. Although Ca2+ and Mg2+ are involved in a number of neurochemical signaling processes, they are ...