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Monte S Buchsbaum - One of the best experts on this subject based on the ideXlab platform.

  • FDG-PET scans in patients with Kraepelinian and non-Kraepelinian schizophrenia
    European Archives of Psychiatry and Clinical Neuroscience, 2016
    Co-Authors: Marie-cécile Bralet, Monte S Buchsbaum, Alex Decastro, Lina Shihabuddin, Serge A. Mitelman
    Abstract:

    We recruited 14 unmedicated patients with Kraepelinian schizophrenia (12 men and 2 women; mean age = 47 years old), 27 non-Kraepelinian patients (21 men and 6 women; mean age = 36.4 years old) and a group of 56 age- and sex-matched healthy volunteers. FDG positron emission tomography and MRI scans were coregistered for both voxel-by-voxel statistical mapping and stereotaxic regions of interest analysis. While both Kraepelinian and non-Kraepelinian patients showed equally lower uptake than healthy volunteers in the frontal lobe, the temporal lobes (Brodmann areas 20 and 21) showed significantly greater decreases in Kraepelinian than in non-Kraepelinian patients. Kraepelinian patients had lower FDG uptake in parietal regions 39 and 40, especially in the right hemisphere, while non-Kraepelinian patients had similar reductions in the left. Only non-Kraepelinian patients had lower caudate FDG uptake than healthy volunteers. While both patient groups had lower uptake than healthy volunteers in the Medial Dorsal Nucleus of the thalamus, Kraepelinian patients alone had higher uptake in the ventral nuclei of the thalamus. Kraepelinian patients also showed higher metabolic rates in white matter. Our results are consistent with other studies indicating that Kraepelinian schizophrenia is a subgroup of schizophrenia, characterized by temporal and right parietal deficits and normal rather than reduced caudate uptake. It suggests that Kraepelinian schizophrenia may be more primarily characterized by FDG uptake decreased in both the frontal and temporal lobes, while non-Kraepelinian schizophrenia may have deficits more limited to the frontal lobe. This is consistent with some neuropsychological and prognosis reports of disordered sensory information processing in Kraepelinian schizophrenia in addition to deficits in frontal lobe executive functions shared with the non-Kraepelinian subtype.

  • Correlations between ventricular enlargement and gray and white matter volumes of cortex, thalamus, striatum, and internal capsule in schizophrenia
    European Archives of Psychiatry and Clinical Neuroscience, 2011
    Co-Authors: Guillermo Horga, William Byne, Eileen Kemether, Javier Bernacer, Nicola Dusi, Jonathan Entis, Erin A. Hazlett, M. Mehmet Haznedar, Monte S Buchsbaum
    Abstract:

    Ventricular enlargement is one of the most consistent abnormal structural brain findings in schizophrenia and has been used to infer brain shrinkage. However, whether ventricular enlargement is related to local overlying cortex and/or adjacent subcortical structures or whether it is related to brain volume change globally has not been assessed. We systematically assessed interrelations of ventricular volumes with gray and white matter volumes of 40 Brodmann areas (BAs), the thalamus and its Medial Dorsal Nucleus and pulvinar, the internal capsule, caudate and putamen. We acquired structural MRI ( patients with schizophrenia ( n  = 64) and healthy controls ( n  = 56)) and diffusion tensor fractional anisotropy (FA) (untreated schizophrenia n  = 19, controls n  = 32). Volumes were assessed by manual tracing of central structures and a semi-automated parcellation of BAs. Patients with schizophrenia had increased ventricular size associated with decreased cortical gray matter volumes widely across the brain; a similar but less pronounced pattern was seen in normal controls; local correlations (e.g. temporal horn with temporal lobe volume) were not appreciably higher than non-local correlations (e.g. temporal horn with prefrontal volume). White matter regions adjacent to the ventricles similarly did not reveal strong regional relationships. FA and center of mass of the anterior limb of the internal capsule also appeared differentially influenced by ventricular volume but findings were similarly not regional. Taken together, these findings indicate that ventricular enlargement is globally interrelated with gray matter volume diminution but not directly correlated with volume loss in the immediately adjacent caudate, putamen, or internal capsule.

  • Correlations between ventricular enlargement and gray and white matter volumes of cortex, thalamus, striatum, and internal capsule in schizophrenia
    European Archives of Psychiatry and Clinical Neuroscience, 2011
    Co-Authors: Guillermo Horga, William Byne, Eileen Kemether, Javier Bernacer, Nicola Dusi, Jonathan Entis, Erin A. Hazlett, M. Mehmet Haznedar, Monte S Buchsbaum
    Abstract:

    Ventricular enlargement is one of the most consistent abnormal structural brain findings in schizophrenia and has been used to infer brain shrinkage. However, whether ventricular enlargement is related to local overlying cortex and/or adjacent subcortical structures or whether it is related to brain volume change globally has not been assessed. We systematically assessed interrelations of ventricular volumes with gray and white matter volumes of 40 Brodmann areas (BAs), the thalamus and its Medial Dorsal Nucleus and pulvinar, the internal capsule, caudate and putamen. We acquired structural MRI ( patients with schizophrenia (n = 64) and healthy controls (n = 56)) and diffusion tensor fractional anisotropy (FA) (untreated schizophrenia n = 19, controls n = 32). Volumes were assessed by manual tracing of central structures and a semi-automated parcellation of BAs. Patients with schizophrenia had increased ventricular size associated with decreased cortical gray matter volumes widely across the brain; a similar but less pronounced pattern was seen in normal controls; local correlations (e.g. temporal horn with temporal lobe volume) were not appreciably higher than non-local correlations (e.g. temporal horn with prefrontal volume). White matter regions adjacent to the ventricles similarly did not reveal strong regional relationships. FA and center of mass of the anterior limb of the internal capsule also appeared differentially influenced by ventricular volume but findings were similarly not regional. Taken together, these findings indicate that ventricular enlargement is globally interrelated with gray matter volume diminution but not directly correlated with volume loss in the immediately adjacent caudate, putamen, or internal capsule. Electronic supplementary material The online version of this article (doi:10.1007/s00406-011-0202-x) contains supplementary material, which is available to authorized users.

  • thalamocortical circuits fmri assessment of the pulvinar and Medial Dorsal Nucleus in normal volunteers
    Neuroscience Letters, 2006
    Co-Authors: Monte S Buchsbaum, Bradley R Buchsbaum, Sylvie Chokron, Cheuk Y Tang, William Byne
    Abstract:

    Abstract This fMRI study investigates the activation of the thalamic nuclei in a spatial focusing-of-attention task previously shown to activate the pulvinar with FDG-PET and assesses the connectivity of the thalamic nuclei with cortical areas. Normal right-handed subjects (eight men, eight women, average age = 32 years) viewed four types of stimuli positioned to the right or left of the central fixation point (left hemifield-large letter, left hemifield-small letter display with flanking letters; right hemifield-large letter, right hemifield-small letter display with flankers). BOLD responses to small letters surrounded by flankers were compared with responses to large isolated letters. To examine maximum functional regional connectivity, we modeled “subject” as a random effect and attained fixed effect parameter estimates and t -statistics for functional connectivity between each of the thalamic nuclei (pulvinar, Medial Dorsal, and anterior) as the seed region and each non-seed voxel. Greater BOLD activation for letters surrounded by flankers than for large letters was observed in the pulvinar as anticipated and was also marked in the Medial Dorsal Nucleus (MDN), anterior and superior cingulate (BA24 and BA24′), dorsolateral prefrontal cortex, and frontal operculum and insula. For the MDN, maximal functional connectivity was with the dorsolateral prefrontal cortex; correlations with left superior temporal, parietal, posterior frontal, and occipital regions were also observed. For the pulvinar, maximal functional connectivity was with parietal BA39; for anterior thalamus, with anterior cingulate.

  • D2/D3 dopamine receptor binding with [F-18]fallypride in thalamus and cortex of patients with schizophrenia
    Schizophrenia Research, 2006
    Co-Authors: Monte S Buchsbaum, Bradley T Christian, Douglas S Lehrer, Tanjore K Narayanan, Joseph Mantil, Eileen Kemether, Terrence R Oakes, Jogeshwar Mukherjee
    Abstract:

    Abstract Background Abnormalities in the dopaminergic system are implicated in schizophrenia. [F-18]fallypride is a highly selective, high affinity PET ligand well suited for measuring D2/D3 receptor availability in the extrastriatal regions of the brain including thalamus, prefrontal, cingulate, and temporal cortex, brain regions implicated in schizophrenia with other imaging modalities. Methods Resting [F-18]fallypride PET studies were acquired together with anatomical MRI for accurate coregistration and image analysis on 15 drug naive schizophrenics (10 men, 5 women, mean age 28.5 years) and 15 matched controls (9 men, 6 women, mean age 27.4 years). Dopamine D2/D3 receptor levels were measured as binding potential (BP). The fallypride BP images of each subject were spatially normalized and subsequently smoothed for group comparison. Measures of significance between the schizophrenic and control groups were determined using statistical parametric mapping (SPM). The Medial Dorsal Nucleus and pulvinar were also traced on coregistered MRI for detailed assessment of BP in these regions. Results The thalamus of patients with schizophrenia had lower [F-18]fallypride BP than normal controls and this was the brain area with the greatest difference (range − 8.5% to − 27.2%). Left Medial Dorsal Nucleus and left pulvinar showed the greatest decreases (− 21.6% and − 27.2% respectively). The patients with schizophrenia also demonstrated D2/D3 BP reduction in the amygdala region, cingulate gyrus, and the temporal cortices. Conclusions These findings suggest that drug naive patients with schizophrenia have significant reductions in extrastratial D2/D3 receptor availability. The reductions were most prominent in regions of the thalamus, replicating other studies both with high affinity D2/D3 ligands and consistent with FDG-PET studies, further supporting the hypothesis of thalamic abnormalities in this patient population.

William Byne - One of the best experts on this subject based on the ideXlab platform.

  • Correlations between ventricular enlargement and gray and white matter volumes of cortex, thalamus, striatum, and internal capsule in schizophrenia
    European Archives of Psychiatry and Clinical Neuroscience, 2011
    Co-Authors: Guillermo Horga, William Byne, Eileen Kemether, Javier Bernacer, Nicola Dusi, Jonathan Entis, Erin A. Hazlett, M. Mehmet Haznedar, Monte S Buchsbaum
    Abstract:

    Ventricular enlargement is one of the most consistent abnormal structural brain findings in schizophrenia and has been used to infer brain shrinkage. However, whether ventricular enlargement is related to local overlying cortex and/or adjacent subcortical structures or whether it is related to brain volume change globally has not been assessed. We systematically assessed interrelations of ventricular volumes with gray and white matter volumes of 40 Brodmann areas (BAs), the thalamus and its Medial Dorsal Nucleus and pulvinar, the internal capsule, caudate and putamen. We acquired structural MRI ( patients with schizophrenia ( n  = 64) and healthy controls ( n  = 56)) and diffusion tensor fractional anisotropy (FA) (untreated schizophrenia n  = 19, controls n  = 32). Volumes were assessed by manual tracing of central structures and a semi-automated parcellation of BAs. Patients with schizophrenia had increased ventricular size associated with decreased cortical gray matter volumes widely across the brain; a similar but less pronounced pattern was seen in normal controls; local correlations (e.g. temporal horn with temporal lobe volume) were not appreciably higher than non-local correlations (e.g. temporal horn with prefrontal volume). White matter regions adjacent to the ventricles similarly did not reveal strong regional relationships. FA and center of mass of the anterior limb of the internal capsule also appeared differentially influenced by ventricular volume but findings were similarly not regional. Taken together, these findings indicate that ventricular enlargement is globally interrelated with gray matter volume diminution but not directly correlated with volume loss in the immediately adjacent caudate, putamen, or internal capsule.

  • Correlations between ventricular enlargement and gray and white matter volumes of cortex, thalamus, striatum, and internal capsule in schizophrenia
    European Archives of Psychiatry and Clinical Neuroscience, 2011
    Co-Authors: Guillermo Horga, William Byne, Eileen Kemether, Javier Bernacer, Nicola Dusi, Jonathan Entis, Erin A. Hazlett, M. Mehmet Haznedar, Monte S Buchsbaum
    Abstract:

    Ventricular enlargement is one of the most consistent abnormal structural brain findings in schizophrenia and has been used to infer brain shrinkage. However, whether ventricular enlargement is related to local overlying cortex and/or adjacent subcortical structures or whether it is related to brain volume change globally has not been assessed. We systematically assessed interrelations of ventricular volumes with gray and white matter volumes of 40 Brodmann areas (BAs), the thalamus and its Medial Dorsal Nucleus and pulvinar, the internal capsule, caudate and putamen. We acquired structural MRI ( patients with schizophrenia (n = 64) and healthy controls (n = 56)) and diffusion tensor fractional anisotropy (FA) (untreated schizophrenia n = 19, controls n = 32). Volumes were assessed by manual tracing of central structures and a semi-automated parcellation of BAs. Patients with schizophrenia had increased ventricular size associated with decreased cortical gray matter volumes widely across the brain; a similar but less pronounced pattern was seen in normal controls; local correlations (e.g. temporal horn with temporal lobe volume) were not appreciably higher than non-local correlations (e.g. temporal horn with prefrontal volume). White matter regions adjacent to the ventricles similarly did not reveal strong regional relationships. FA and center of mass of the anterior limb of the internal capsule also appeared differentially influenced by ventricular volume but findings were similarly not regional. Taken together, these findings indicate that ventricular enlargement is globally interrelated with gray matter volume diminution but not directly correlated with volume loss in the immediately adjacent caudate, putamen, or internal capsule. Electronic supplementary material The online version of this article (doi:10.1007/s00406-011-0202-x) contains supplementary material, which is available to authorized users.

  • thalamocortical circuits fmri assessment of the pulvinar and Medial Dorsal Nucleus in normal volunteers
    Neuroscience Letters, 2006
    Co-Authors: Monte S Buchsbaum, Bradley R Buchsbaum, Sylvie Chokron, Cheuk Y Tang, William Byne
    Abstract:

    Abstract This fMRI study investigates the activation of the thalamic nuclei in a spatial focusing-of-attention task previously shown to activate the pulvinar with FDG-PET and assesses the connectivity of the thalamic nuclei with cortical areas. Normal right-handed subjects (eight men, eight women, average age = 32 years) viewed four types of stimuli positioned to the right or left of the central fixation point (left hemifield-large letter, left hemifield-small letter display with flanking letters; right hemifield-large letter, right hemifield-small letter display with flankers). BOLD responses to small letters surrounded by flankers were compared with responses to large isolated letters. To examine maximum functional regional connectivity, we modeled “subject” as a random effect and attained fixed effect parameter estimates and t -statistics for functional connectivity between each of the thalamic nuclei (pulvinar, Medial Dorsal, and anterior) as the seed region and each non-seed voxel. Greater BOLD activation for letters surrounded by flankers than for large letters was observed in the pulvinar as anticipated and was also marked in the Medial Dorsal Nucleus (MDN), anterior and superior cingulate (BA24 and BA24′), dorsolateral prefrontal cortex, and frontal operculum and insula. For the MDN, maximal functional connectivity was with the dorsolateral prefrontal cortex; correlations with left superior temporal, parietal, posterior frontal, and occipital regions were also observed. For the pulvinar, maximal functional connectivity was with parietal BA39; for anterior thalamus, with anterior cingulate.

  • Thalamic and prefrontal FDG uptake in never medicated patients with schizophrenia.
    American Journal of Psychiatry, 2005
    Co-Authors: Douglas S Lehrer, Bradley R Buchsbaum, William Byne, Bradley T Christian, Joseph Mantil, Eileen Kemether, Terrence R Oakes, Aaron C. Murray, Monte S Buchsbaum
    Abstract:

    OBJECTIVE: Because neuroleptic treatment may cause long-lasting changes in brain structure and function, a group of patients with schizophrenia who had never been medicated was recruited to examine regional glucose metabolic rates in the frontal-striato-thalamic circuit. METHOD: Twelve never medicated patients with schizophrenia (seven men, five women; mean age=29 years) and 13 normal volunteers (eight men and five women; mean age=28.5 years) underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography, and coregistered anatomical magnetic resonance imaging scans were also obtained. During FDG uptake, subjects performed a spatial attention task previously shown to activate the pulvinar region of the thalamus. RESULTS: Diminished regional glucose metabolism was found in the Medial Dorsal Nucleus, posterior thalamus, and prefrontal cortex of patients with schizophrenia relative to normal volunteers, extending earlier results from studies of medicated and previously medicated patients. CONCLUSIONS: Th...

Edward H. Bertram - One of the best experts on this subject based on the ideXlab platform.

  • FULL-LENGTH ORIGINAL RESEARCH Multiple roles of midline Dorsal thalamic nuclei in induction and spread of limbic seizures
    2020
    Co-Authors: Edward H. Bertram, Dexing Zhang, John Williamson
    Abstract:

    SUMMARY Purpose: Studies have suggested that the Medial Dorsal Nucleus of the thalamus plays a role in the behavioral expression of limbic seizures, but it is unclear whether this region is a key component for the primary seizure circuitry or a path for seizure spread from one region to another. This study was undertaken to determine the potential role of this region in limbic seizure activity. Methods: Adult male rats received kindling stimulation either under urethane anesthesia or while awake. Glutamate or its agonists or the GABA antagonist bicuculline or agonist muscimol were infused into the Medial Dorsal Nucleus. In another series, kindling acquisition was compared among three thalamic sites as well as with the amygdala and hippocampus Results: Drugs that enhanced excitatory drive or blocked GABA resulted in significant prolongation of electrographic seizure activity compared to saline infused controls. Enhanced GABA activity resulted in a significant reduction of seizure duration. Infusion of the compounds lateral to the Medial Dorsal Nucleus did not affect seizure duration. In the kindling studies the Medial Dorsal region is the only thalamic Nucleus from which hippocampal seizures can be induced, but with an elevated afterdischarge threshold compared to the two limbic sites. However, the seizures generalized more rapidly from the Medial Dorsal region. Conclusions: This study demonstrates that the Medial Dorsal Nucleus and other Dorsal midline nuclei have a significant role in the primary seizure circuits of limbic seizures as well as in spread of seizure activity to other regions.

  • Genetic resistance to kindling associated with alterations in circuit function.
    Neurobiology of Disease, 2017
    Co-Authors: M. Tansel Kendirli, Edward H. Bertram
    Abstract:

    Abstract How a seizure spreads from a focal onset zone to other regions of the brain is not well understood, and animal studies suggest that there is a genetic influence. To understand how genetic factors may influence seizure spread, we examined whether the kindling resistance of WAG/Rij rats, which are slow to develop kindled motor seizures, is independent of the site of seizure induction and thus a global phenomenon, or whether it is circuit specific. We compared the kindling rates (number of stimulations to induce kindled motor seizures) of WAG/Rij rats to the rates of kindling in Sprague Dawley rats. Both groups underwent a standard hippocampal kindling protocol and a separate group was kindled from the Medial Dorsal Nucleus of the thalamus, a site that has been previously demonstrated to result in the very rapid development of motor seizures. To examine whether there were differences in the interaction in a circuit involved with the motor seizures, evoked responses were obtained from the prefrontal cortex following stimulation of the subiculum or Medial Dorsal thalamic Nucleus. The WAG/Rij rats once again demonstrated resistance to kindling in the hippocampus, but both strains kindled rapidly from the Medial Dorsal Nucleus. In the WAG/Rij rats there was also a reduction in the duration of the afterdischarge in the frontal cortex during hippocampal stimulation, but there was no reduction during thalamic kindling. The prefrontal cortex evoked responses were reduced following stimulation of the subiculum in the WAG/Rij rats, but the evoked responses to thalamic stimulation were the same in both strains. These findings suggest that there are genetic influences in the strength of the input from the subiculum to the prefrontal cortex in WAG/Rij rats that could explain the resistance to limbic kindling because of reduced excitatory drive onto a key target region.

  • suppressing limbic seizures by stimulating Medial Dorsal thalamic Nucleus factors for efficacy
    Epilepsia, 2015
    Co-Authors: Dexing Zhang, Edward H. Bertram
    Abstract:

    Summary Objective The optimal sites and stimulation protocols for brain stimulation in epilepsy have not been found. Clinical trials, which have shown modest benefit in seizure reduction, have involved patients with poorly localized intractable focal epilepsy and stimulation sites without clear relations to specific underlying seizure circuits. The Medial Dorsal thalamic Nucleus is a key node in limbic seizure circuits, and we wished to know what stimulation parameters might control seizures in a kindling model of limbic epilepsy. Methods In urethane-anesthetized rats, we induced limbic seizures by stimulation of the piriform cortex or CA3 of the hippocampus while recording in the entorhinal cortex or CA1 of the contralateral hippocampus to determine the effect of specific stimulation parameters on seizure duration. Results Stimulation consistently suppressed seizure duration from baseline by over 80% (p < 0.001), frequently completely preventing the seizures. Position of the thalamic electrode, stimulus intensity and frequency had a significant influence, with higher stimulus intensities (40 V vs. 20 V) and frequencies (20 Hz vs. 7 Hz) significantly suppressing seizures. The most effective position was the lateral Dorsal area of the Medial Dorsal Nucleus (MD), which corresponded to the region of axon entry. Stimulation in the MD center was not effective. An anterior-posterior relationship of the stimulating electrode pair was effective, whereas a Medial lateral orientation was not. Successful stimulation suppressed the evoked responses in the entorhinal cortex or CA1. Significance Position and orientation of the stimulating electrode has to be precise, which suggests that the placement of the electrodes must be tailored to the individual's own seizure circuit. The data also indicate that successful deep brain stimulation induces a fundamental change in system physiology, which could be a marker to guide the development of stimulation parameters for each patient.

  • Extratemporal lobe circuits in temporal lobe epilepsy.
    Epilepsy & Behavior, 2014
    Co-Authors: Edward H. Bertram
    Abstract:

    Abstract There is increasing interest in the functional anatomy of epilepsy with the goal to identify the critical nodes in the seizure circuits so that therapy can be directed at them. This goal is especially important because direct delivery of therapy, either through electrical stimulation, drug infusion, or molecular therapies such as optogenetics, has become increasingly possible. In this article, we will review the basic functional anatomy of mesial temporal lobe epilepsy and its primary subcortical connection, the Medial Dorsal Nucleus of the thalamus. Based on its anatomical connections and known physiological interactions, we propose a key role for this thalamic Nucleus that is essential for the development of seizures, and this role suggests that this region is a potential therapeutic target. This article is part of a Special Issue entitled “NEWroscience 2013”.

  • Multiple roles of midline Dorsal thalamic nuclei in induction and spread of limbic seizures
    Epilepsia, 2007
    Co-Authors: Edward H. Bertram, Dexing Zhang, John Williamson
    Abstract:

    PURPOSE: Studies have suggested that the Medial Dorsal Nucleus of the thalamus plays a role in the behavioral expression of limbic seizures, but it is unclear whether this region is a key component for the primary seizure circuitry or a path for seizure spread from one region to another. This study was undertaken to determine the potential role of this region in limbic seizure activity. METHODS: Adult male rats received kindling stimulation either under urethane anesthesia or while awake. Glutamate or its agonists or the GABA antagonist bicuculline or agonist muscimol were infused into the Medial Dorsal Nucleus. In another series, kindling acquisition was compared among three thalamic sites as well as with the amygdala and hippocampus RESULTS: Drugs that enhanced excitatory drive or blocked GABA resulted in significant prolongation of electrographic seizure activity compared to saline infused controls. Enhanced GABA activity resulted in a significant reduction of seizure duration. Infusion of the compounds lateral to the Medial Dorsal Nucleus did not affect seizure duration. In the kindling studies the Medial Dorsal region is the only thalamic Nucleus from which hippocampal seizures can be induced, but with an elevated afterdischarge threshold compared to the two limbic sites. However, the seizures generalized more rapidly from the Medial Dorsal region. CONCLUSIONS: This study demonstrates that the Medial Dorsal Nucleus and other Dorsal midline nuclei have a significant role in the primary seizure circuits of limbic seizures as well as in spread of seizure activity to other regions.

Jennifer L Robinson - One of the best experts on this subject based on the ideXlab platform.

Angela R Laird - One of the best experts on this subject based on the ideXlab platform.