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Disruptions in white matter microstructure associated with impaired visual associative memory in schizophrenia-spectrum illness. Eur Arch Psychiatry Clin Neurosci 2022; 272:971-983. [PMID: 34557990 DOI: 10.1007/s00406-021-01333-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 09/09/2021] [Indexed: 12/13/2022]
Abstract
Episodic memory ability relies on hippocampal-prefrontal connectivity. However, few studies have examined relationships between memory performance and white matter (WM) microstructure in hippocampal-prefrontal pathways in schizophrenia-spectrum disorder (SSDs). Here, we investigated these relationships in individuals with first-episode psychosis (FEP) and chronic schizophrenia-spectrum disorders (SSDs) using tractography analysis designed to interrogate the microstructure of WM tracts in the hippocampal-prefrontal pathway. Measures of WM microstructure (fractional anisotropy [FA], radial diffusivity [RD], and axial diffusivity [AD]) were obtained for 47 individuals with chronic SSDs, 28 FEP individuals, 52 older healthy controls, and 27 younger healthy controls. Tractography analysis was performed between the hippocampus and three targets involved in hippocampal-prefrontal connectivity (thalamus, amygdala, nucleus accumbens). Measures of WM microstructure were then examined in relation to episodic memory performance separately across each group. Both those with FEP and chronic SSDs demonstrated impaired episodic memory performance. However, abnormal WM microstructure was only observed in individuals with chronic SSDs. Abnormal WM microstructure in the hippocampal-thalamic pathway in the right hemisphere was associated with poorer memory performance in individuals with chronic SSDs. These findings suggest that disruptions in WM microstructure in the hippocampal-prefrontal pathway may contribute to memory impairments in individuals with chronic SSDs but not FEP.
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Francis MM, Hummer TA, Vohs JL, Yung MG, Liffick E, Mehdiyoun NF, Radnovich AJ, McDonald BC, Saykin AJ, Breier A. Functional neuroanatomical correlates of episodic memory impairment in early phase psychosis. Brain Imaging Behav 2016; 10:1-11. [PMID: 25749917 DOI: 10.1007/s11682-015-9357-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Studies have demonstrated that episodic memory (EM) is often preferentially disrupted in schizophrenia. The neural substrates that mediate EM impairment in this illness are not fully understood. Several functional magnetic resonance imaging (fMRI) studies have employed EM probe tasks to elucidate the neural underpinnings of impairment, though results have been inconsistent. The majority of EM imaging studies have been conducted in chronic forms of schizophrenia with relatively few studies in early phase patients. Early phase schizophrenia studies are important because they may provide information regarding when EM deficits occur and address potential confounds more frequently observed in chronic populations. In this study, we assessed brain activation during the performance of visual scene encoding and recognition fMRI tasks in patients with earlyphase psychosis (n = 35) and age, sex, and race matched healthy control subjects (n = 20). Patients demonstrated significantly lower activation than controls in the right hippocampus and left fusiform gyrus during scene encoding and lower activation in the posterior cingulate, precuneus, and left middle temporal cortex during recognition of target scenes. Symptom levels were not related to the imaging findings, though better cognitive performance in patients was associated with greater right hippocampal activation during encoding. These results provide evidence of altered function in neuroanatomical circuitry subserving EM early in the course of psychotic illness, which may have implications for pathophysiological models of this illness.
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Affiliation(s)
- Michael Matthew Francis
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Tom A Hummer
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jenifer L Vohs
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Matthew G Yung
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Emily Liffick
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Nicole F Mehdiyoun
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Alexander J Radnovich
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Brenna C McDonald
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew J Saykin
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Alan Breier
- Indiana University Psychotic Disorders Program, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
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Tamminga CA, Zukin RS. Schizophrenia: Evidence implicating hippocampal GluN2B protein and REST epigenetics in psychosis pathophysiology. Neuroscience 2015. [PMID: 26211447 DOI: 10.1016/j.neuroscience.2015.07.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The hippocampus is strongly implicated in the psychotic symptoms of schizophrenia. Functionally, basal hippocampal activity (perfusion) is elevated in schizophrenic psychosis, as measured with positron emission tomography (PET) and with magnetic resonance (MR) perfusion techniques, while hippocampal activation to memory tasks is reduced. Subfield-specific hippocampal molecular pathology exists in human psychosis tissue which could underlie this neuronal hyperactivity, including increased GluN2B-containing NMDA receptors in hippocampal CA3, along with increased postsynaptic density protein-95 (PSD-95) along with augmented dendritic spines on the pyramidal neuron apical dendrites. We interpret these observations to implicate a reduction in the influence of a ubiquitous gene repressor, repressor element-1 silencing transcription factor (REST) in psychosis; REST is involved in the age-related maturation of the NMDA receptor from GluN2B- to GluN2A-containing NMDA receptors through epigenetic remodeling. These CA3 changes in psychosis leave the hippocampus liable to pathological increases in neuronal activity, feedforward excitation and false memory formation, sometimes with psychotic content.
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Affiliation(s)
- C A Tamminga
- UT Southwestern Medical School, Dallas, TX, United States.
| | - R S Zukin
- Albert Einstein School of Medicine, New York, NY, United States
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Drummond SPA, Walker M, Almklov E, Campos M, Anderson DE, Straus LD. Neural correlates of working memory performance in primary insomnia. Sleep 2013; 36:1307-16. [PMID: 23997363 DOI: 10.5665/sleep.2952] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
STUDY OBJECTIVES To examine neural correlates of working memory performance in patients with primary insomnia (PIs) compared with well-matched good sleepers (GSs). DESIGN Twenty-five PIs and 25 GSs underwent functional MRI while performing an N-back working memory task. SETTING VA hospital sleep laboratory and University-based functional imaging center. PATIENTS OR PARTICIPANTS 25 PIs, 25 GSs. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Although PIs did not differ from GSs in cognitive performance, PIs showed the expected differences from GSs in both self-reported and objective sleep measures. PIs, relative to GSs, showed reduced activation of task-related working memory regions. This manifested both as an overall reduction in activation of task-related regions and specifically as reduced modulation of right dorsolateral prefrontal cortex with increasing task difficulty. Similarly, PIs showed reduced modulation (i.e., reduced deactivation) of default mode regions with increasing task difficulty, relative to GSs. However, PIs showed intact performance. CONCLUSIONS These data establish a profile of abnormal neural function in primary insomnia, reflected both in reduced engagement of task-appropriate brain regions and an inability to modulate task-irrelevant (i.e., default mode) brain areas during working memory performance. These data have implications for better understanding the neuropathophysiology of the well established, yet little understood, discrepancy between ubiquitous subjective cognitive complaints in primary insomnia and the rarely found objective deficits during testing.
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Affiliation(s)
- Sean P A Drummond
- Psychology Service, VA San Diego Healthcare System, San Diego, CA 92161, USA.
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Tamminga CA, Southcott S, Sacco C, Wagner AD, Ghose S. Glutamate dysfunction in hippocampus: relevance of dentate gyrus and CA3 signaling. Schizophr Bull 2012; 38:927-35. [PMID: 22532703 PMCID: PMC3446225 DOI: 10.1093/schbul/sbs062] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/15/2012] [Indexed: 01/02/2023]
Abstract
Synaptic glutamate signaling in brain is highly complex and includes multiple interacting receptors, modulating cotransmitters and distinct regional dynamics. Medial temporal lobe (MTL) memory structures receive excitatory inputs from neocortical sensory and associational projections: afferents from neocortex pass to parahippocampal cortex, then to layers II/III of entorhinal cortex, and then onto hippocampal subfields. Principles of Hebbian plasticity govern synaptic encoding of memory signals, and homeostatic plasticity processes influence the activity of the memory system as a whole. Hippocampal imaging studies in schizophrenia have identified 2 alterations in MTL--increases in baseline blood perfusion and decreases in task-related activation. These observations along with converging postsynaptic hippocampal protein changes suggest that homeostatic plasticity mechanisms might be altered in schizophrenia hippocampus. If hippocampal pattern separation is diminished due to partial dentate gyrus failure (resulting in 'spurious associations') and also if pattern completion is accelerated and increasingly inaccurate due to increased CA3 associational activity, then it is conceivable that associations could be false and, especially if driven by anxiety or stress, could generate psychotic content, with the mistaken associations being laid down in memory, despite their psychotic content, especially delusions and thought disorder.
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Affiliation(s)
- Carol A Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas, TX 75390, USA.
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6
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Tamminga CA, Thomas BP, Chin R, Mihalakos P, Youens K, Wagner AD, Preston AR. Hippocampal novelty activations in schizophrenia: disease and medication effects. Schizophr Res 2012; 138:157-63. [PMID: 22480957 DOI: 10.1016/j.schres.2012.03.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 03/03/2012] [Accepted: 03/07/2012] [Indexed: 11/29/2022]
Abstract
We examined hippocampal activation in schizophrenia (SZ) with fMRI BOLD in response to the presentation of novel and familiar scenes. Voxel-wise analysis showed no group differences. However, anatomical region-of-interest analyses contrasting normal (NL), SZ-on-medication (SZ-ON), SZ-off-medication (SZ-OFF) showed substantial differences in MTL-based novelty responding, accounted for by the reduction in novelty responses in the SZ-OFF predominantly in the anterior hippocampus and parahippocampal cortex. These differences in novelty-based activation in the SZ-OFF group represent disease characteristics of schizophrenia without confounding effects of antipsychotic medication and illustrate the tendency of antipsychotic drug treatment to improve memory functions in schizophrenia.
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Affiliation(s)
- Carol A Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas, TX, United States.
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Jonelis MB, Drummond SPA, Salamat JS, McKenna BS, Ancoli-Israel S, Bondi MW. Age-Related Influences of Prior Sleep on Brain Activation during Verbal Encoding. Front Neurol 2012; 3:49. [PMID: 22493590 PMCID: PMC3318226 DOI: 10.3389/fneur.2012.00049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 03/16/2012] [Indexed: 11/29/2022] Open
Abstract
Disrupted sleep is more common in older adults (OLD) than younger adults (YOUNG), often co-morbid with other conditions. How these sleep disturbances affect cognitive performance is an area of active study. We examined whether brain activation during verbal encoding correlates with sleep quantity and quality the night before testing in a group of healthy OLD and YOUNG. Twenty-seven OLD (ages 59–82) and 27 YOUNG (ages 19–36) underwent one night of standard polysomnography. Twelve hours post-awakening, subjects performed a verbal encoding task while undergoing functional magnetic resonance imaging. Analyses examined the group (OLD vs. YOUNG) by prior sleep quantity (total sleep time, TST) or quality (sleep efficiency, SE) interaction on cerebral activation, controlling for performance. Longer TST promoted higher levels of activation in the bilateral anterior parahippocampal in OLD and lower activation levels in the left anterior parahippocampus in YOUNG. Greater SE promoted higher activation levels in the left posterior parahippocampus and right inferior frontal gyrus in YOUNG, but not in OLD. The roles of these brain regions in verbal encoding suggest, in OLD, longer sleep duration may be linked to the ability to engage in functional compensation during cognitive challenges. By contrast, in YOUNG, shorter sleep duration may necessitate functional compensation to maintain cognitive performance, similar to what is seen following acute sleep deprivation. Additionally, in YOUNG, better sleep quality may improve semantic retrieval processes, thereby aiding encoding.
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Duan X, Dai Q, Gong Q, Chen H. Neural mechanism of unconscious perception of surprised facial expression. Neuroimage 2010; 52:401-7. [DOI: 10.1016/j.neuroimage.2010.04.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 04/05/2010] [Accepted: 04/07/2010] [Indexed: 10/19/2022] Open
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Shohamy D, Mihalakos P, Chin R, Thomas B, Wagner AD, Tamminga C. Learning and generalization in schizophrenia: effects of disease and antipsychotic drug treatment. Biol Psychiatry 2010; 67:926-32. [PMID: 20034612 PMCID: PMC4023678 DOI: 10.1016/j.biopsych.2009.10.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 09/24/2009] [Accepted: 10/13/2009] [Indexed: 11/30/2022]
Abstract
BACKGROUND Schizophrenia involves alterations in hippocampal function. The implications of these alterations for memory function in the illness remain poorly understood. Furthermore, it remains unknown how memory is impacted by drug treatments for schizophrenia. The goal of this study was to delineate specific memory processes that are disrupted in schizophrenia and explore how they are affected by medication. We specifically focus on memory generalization--the ability to flexibly generalize memories in novel situations. METHODS Individuals with schizophrenia (n = 56) and healthy control subjects (n = 20) were tested on a computerized memory generalization paradigm. Participants first engaged in trial-by-error associative learning. They were then asked to generalize what they learned by responding to novel stimulus combinations. Individuals with schizophrenia were tested on or off antipsychotic medication, using a between-subject design in order to eliminate concerns about learning-set effects. RESULTS Individuals with schizophrenia were selectively impaired in their ability to generalize knowledge, despite having intact learning and memory accuracy. This impairment was found only in individuals tested off medication. Individuals tested on medication generalized almost as well as healthy control subjects. This between-group difference was selective to memory generalization. CONCLUSIONS These findings suggest that individuals with schizophrenia have a selective alteration in the ability to flexibly generalize past experience toward novel learning environments. This alteration is unaccompanied by global memory impairments. Additionally, the results indicate a robust generalization difference on the basis of medication status. These results suggest that hippocampal abnormalities in schizophrenia might be alleviated with antipsychotic medication, with important implications for understanding adaptive memory-guided behavior.
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Affiliation(s)
- Daphna Shohamy
- Department of Psychology, Columbia University, New York, New York 10027, USA.
| | - Perry Mihalakos
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
| | - Ronald Chin
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
| | - Binu Thomas
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
| | | | - Carol Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
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10
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Rametti G, Junqué C, Vendrell P, Catalán R, Penadés R, Bargalló N, Bernardo M. Hippocampal underactivation in an fMRI study of word and face memory recognition in schizophrenia. Eur Arch Psychiatry Clin Neurosci 2009; 259:203-11. [PMID: 19224116 DOI: 10.1007/s00406-008-0852-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Accepted: 10/14/2008] [Indexed: 11/24/2022]
Abstract
Schizophrenia is a major mental disorder which is characterized by several cognitive deficits. Investigations of the neural basis of memory dysfunctions using neuroimaging techniques suggest that the hippocampus plays an important role in declarative memory impairment. The goal of this study was to investigate possible dysfunctions in cerebral activation in schizophrenic patients during both word and face recognition memory tasks. We tested 22 schizophrenics and 24 controls matched by gender, age, handedness and parental socioeconomic status. Compared to healthy volunteers, patients with schizophrenia showed decreased bilateral hippocampal activation during word and face recognition tasks. The whole brain analysis also showed a pattern of cortical and subcortical hypoactivation for both verbal and non-verbal recognition. This study provides further evidence of hippocampal involvement in declarative memory impairments of schizophrenia.
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Affiliation(s)
- Giuseppina Rametti
- Department of Psychiatry and Clinical Psychobiology, University of Barcelona, c/Casanova, 143, 08036, Barcelona, Spain
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11
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Ayalon L, Ancoli-Israel S, Aka AA, McKenna BS, Drummond SPA. Relationship between obstructive sleep apnea severity and brain activation during a sustained attention task. Sleep 2009; 32:373-81. [PMID: 19294957 DOI: 10.1093/sleep/32.3.373] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES The objectives of this study were to (1) characterize cognitive and cerebral correlates of attention and response speed in patients with obstructive sleep apnea (OSA) and (2) assess the association of performance and brain activation with measures of OSA severity. DESIGN Patients with OSA and controls were compared on performance and brain activation during a sustained attention task. The association of reaction time and brain activation with apnea-hypopnea index, nocturnal hypoxia, and arousals was assessed. SETTING Functional magnetic resonance imaging was conducted while participants performed a Go-No-Go task. The 'Go' trials of the Go-No-Go task were used to index attention processing. PARTICIPANTS Fourteen patients with OSA and 14 normal control subjects with equivalent age, body mass index, blood pressure, and education. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Patients with OSA showed decreased brain activation in cingulate, frontal, and parietal regions typically involved in attention tasks, compared with control subjects. Within the patients with OSA, increasing arousal index, but not desaturation index, was associated with slower mean reaction time and with decreased brain activation in areas involved in arousal and attention, response selection, motor response, and decision making. The apnea-hypopnea index, by itself, was not associated with changes in cerebral response. CONCLUSIONS Patients with OSA showed decreased brain activation compared with control subjects during an attention task. The association of arousal index (but not hypoxia) with slow reaction times and brain activation suggests that alertness and reaction times show greater correlations with measures of sleep disruption than with measures of hypoxia.
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Affiliation(s)
- Liat Ayalon
- Department of Psychiatry 151B, University of California, San Diego, 3350 La Jolla Village Dr, San Diego, CA 92161, USA.
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Ayalon L, Ancoli-Israel S, Drummond SP. Altered brain activation during response inhibition in obstructive sleep apnea. J Sleep Res 2009; 18:204-8. [PMID: 19302344 DOI: 10.1111/j.1365-2869.2008.00707.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study examined response inhibition during a Go-NoGo task in individuals with obstructive sleep apnea (OSA). Fourteen OSA patients and 14 controls were studied with functional magnetic resonance imaging. Compared to controls, the OSA group showed more false positives (error of commission) during the NoGo trials with decreased brain activation in the left postcentral gyrus, cingulate gyrus and inferior parietal lobe, as well as right insula and putamen. This is consistent with previous findings of impaired performance and decreased brain activation in OSA patients during a working memory task, suggesting that compromised brain function in response to cognitive challenges may underlie some of the cognitive deficits seen in patients with OSA.
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Affiliation(s)
- Liat Ayalon
- Department of Psychiatry, University of California, 3350 La Jolla Village Dr., San Diego, CA 92161, USA.
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Eyler LT, Kaup AR, Mirzakhanian HMS, Jeste DV. Schizophrenia patients lack normal positive correlation between age and brain response during verbal learning. Am J Geriatr Psychiatry 2009; 17:43-55. [PMID: 18849533 PMCID: PMC2654366 DOI: 10.1097/jgp.0b013e31817e8a7b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the differences in the relationship of age to brain function among individuals with schizophrenia and a healthy comparison group. The authors hypothesized that the correlation with age would be more strongly negative among schizophrenia patients, particularly in the frontal cortex. DESIGN Cross-sectional measures of functional MRI (fMRI) brain response were correlated with age in both groups. SETTING Participants came to university research facilities for testing. PARTICIPANTS The authors analyzed data from 30 patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition schizophrenia or schizoaffective disorder ranging in age from 25 to 68 years and 14 healthy comparison participants ranging in age from 21 to 70 years. MEASUREMENTS Brain response during word pair learning was measured with fMRI in each voxel of the brain. This measure was correlated with age within each group and the correlations were compared across groups in regions of interest determined a priori and based on a whole-brain analysis. In exploratory analyses, the authors examined the interaction of task performance with age and study group. RESULTS The correlations between age and brain response were more positive in the healthy group than in the schizophrenia group in several regions, including right lateral prefrontal cortex and clusters in midline precuneus and right superior temporal gyrus. Interactions with task performance suggest that age effects on brain function relate differently to cognitive output in patients and comparison participants. CONCLUSIONS There is no strong evidence that functional brain response during learning changes significantly with age among schizophrenia patients, in contrast to findings of positive associations with age among healthy individuals.
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Affiliation(s)
- Lisa T Eyler
- Mental Illness Research, Education and Clinical Center, Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA.
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14
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Abstract
OBJECTIVE Adult-onset schizophrenia has repeatedly been associated with disturbances in the temporal lobes and alterations in cortical folding, which are thought to reflect neurodevelopmental impairment. Early-onset schizophrenia (EOS; onset before 18 years) is considered to involve even more pronounced neurodevelopmental deviance across a wide range of brain structural measures. We hypothesized that overall alteration of cortical folding also applies to EOS, and EOS involves prominent structural aberrations in superior temporal and collateral sulci. METHOD Magnetic resonance T1 images of 51 patients with EOS and 59 healthy participants were investigated. A fully automated method was applied to the images to extract, label, and measure the sulcus area in the whole cortex. Cortical folding was assessed by computing global sulcal indices (the ratio between total sulcal area and total outer cortex area) for each hemisphere and local sulcal indices (the ratio between the area of labeled sulcus and total outer cortex area in the corresponding hemisphere) for superior temporal and collateral sulci. RESULTS Relative to healthy individuals, patients with EOS had significantly lower global sulcal indices in both hemispheres and a lower local sulcal index in the left collateral sulcus. CONCLUSIONS Reduced hemispheric sulcation appears to be a feature of schizophrenia, irrespective of age at onset. Structural aberration involving the left collateral sulcus may contribute to neurobiological substrate of EOS.
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Eyler LT, Jeste DV, Brown GG. Brain response abnormalities during verbal learning among patients with schizophrenia. Psychiatry Res 2008; 162:11-25. [PMID: 18055184 PMCID: PMC2552993 DOI: 10.1016/j.pscychresns.2007.03.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 03/03/2007] [Accepted: 03/21/2007] [Indexed: 10/22/2022]
Abstract
Patients with schizophrenia often show verbal learning deficits that have been linked to the pathophysiology of the disorder and result in functional impairment. This study examined the biological basis of these deficits by comparing the brain response of patients with schizophrenia (n=17) to that of healthy comparison participants (n=14) during a verbal paired-associates learning task using functional magnetic resonance imaging (fMRI). Brain response during new word learning was examined within and between groups in two a priori regions of interest, the inferior frontal gyrus and hippocampus, and across the whole brain. In regions of group difference, we also examined the relationship of brain response during learning to later recall of the word pairs. Despite successful matching of levels of word-pair recall, patients' brain response during new learning was abnormal in bilateral regions within the inferior frontal gyrus, a small region in left posterior hippocampus, and other areas within the frontal, parietal and temporal cortex compared with healthy individuals. In some regions, but not in the hippocampus, patients with the most normal brain response also remembered the most word pairs following scanning. Thus, verbal learning deficits found among patients with schizophrenia appear to be related to hypofunction of distributed brain networks.
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Affiliation(s)
- Lisa T Eyler
- Department of Psychiatry, University of California San Diego, San Diego, CA 92161, USA.
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Stricker JL, Brown GG, Wetherell LA, Drummond SPA. The impact of sleep deprivation and task difficulty on networks of fMRI brain response. J Int Neuropsychol Soc 2006; 12:591-7. [PMID: 16961940 DOI: 10.1017/s1355617706060851] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2006] [Revised: 06/05/2006] [Accepted: 06/06/2006] [Indexed: 11/07/2022]
Abstract
Previous fMRI research has found altered brain response after total sleep deprivation (TSD), with TSD effects moderated by task difficulty. Specific models of the impact of sleep deprivation and task difficulty on brain response have yet to be developed. Differences in networks of fMRI measured brain response during verbal encoding in sleep deprived and well-rested individuals were examined with structural equation modeling (SEM). During fMRI scanning, 23 healthy volunteers memorized words either easy or difficult to recall, 12 (well-rested) and 36 hours (sleep deprived) after awaking. A priori models that linked specified regions of interest were evaluated, with the focus on the extent to which two left parietal regions interacted with the left inferior frontal gyrus (Model 1) or with the right inferior frontal gyrus (Model 2). Task difficulty, not TSD, determined which model fit the brain response data; Model 2 fit best for hard words before and after TSD, whereas Model 1 fit best for easy words. TSD altered the patterns of interaction within each of the best fitting models: prefrontal interactions with the left inferior parietal lobe were diminished and intra-parietal interactions increased. Sleep deprivation and item difficulty produce different effects on brain networks involved in verbal learning.
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Affiliation(s)
- John L Stricker
- VISN 22 MIRECC Program, Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
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Ayalon L, Ancoli-Israel S, Klemfuss Z, Shalauta MD, Drummond SPA. Increased brain activation during verbal learning in obstructive sleep apnea. Neuroimage 2006; 31:1817-25. [PMID: 16626972 DOI: 10.1016/j.neuroimage.2006.02.042] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 02/17/2006] [Accepted: 02/21/2006] [Indexed: 11/16/2022] Open
Abstract
This study examined the cerebral response to a verbal learning (VL) task in obstructive sleep apnea (OSA) patients. Twelve OSA patients and 12 controls were studied with functional magnetic resonance imaging (FMRI). As hypothesized, VL performance was similar for both groups, but OSA patients showed increased brain activation in several brain regions. These regions included bilateral inferior frontal and middle frontal gyri, cingulate gyrus, areas at the junction of the inferior parietal and superior temporal lobes, thalamus, and cerebellum. Better free recall performance in the OSA group was related to increased cerebral responses within the left inferior frontal gyrus and left supramarginal area. Recall was negatively related to activation within the left inferior parietal lobe. The findings support the predictions that intact performance in OSA patients is associated with increased cerebral response. Recruitment of additional brain regions to participate in VL performance in OSA patients likely represents an adaptive compensatory recruitment response, similar to that observed in young adults following total sleep deprivation and in healthy older adults. These data, and those of the only other FMRI study in OSA, suggest that individuals with OSA show characteristic differences in the BOLD signal response to cognitive challenges. Including subjects with untreated OSA in neuroimaging studies may potentially influence the results by altering individual and group level activation patterns. Given this, future neuroimaging studies may want to be aware of this potential confound.
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Affiliation(s)
- Liat Ayalon
- Department of Psychiatry, University of California San Diego, CA 92161, USA.
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Brown GG, Eyler LT. Methodological and Conceptual Issues in Functional Magnetic Resonance Imaging: Applications to Schizophrenia Research. Annu Rev Clin Psychol 2006; 2:51-81. [PMID: 17716064 DOI: 10.1146/annurev.clinpsy.2.022305.095241] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Functional magnetic resonance imaging (MRI) is a noninvasive, highly repeatable, and increasingly available method to study disordered brain activity among patients with psychological or neurological disorders. In this chapter the biophysical principles underlying functional MRI are presented, and methodological limitations of the method are discussed. Artifacts related to the biophysical basis of the functional MRI signal or associated with image acquisition methods are presented, as are artifacts related to baseline effects-especially those associated with medication, caffeine, and nicotine use. The difficulties associated with the comparison of groups of subjects differing in performance receive special attention. The limitations of cognitive subtraction designs for functional MRI are also discussed. Functional MRI studies of schizophrenia patients are used to illustrate these points.
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Affiliation(s)
- Gregory G Brown
- Psychology Service, Veterans Administration San Diego Healthcare System, and Psychiatry Department, University of California, San Diego, California 92161, USA.
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19
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Birmaher B, Axelson D, Strober M, Gill MK, Valeri S, Chiappetta L, Ryan N, Leonard H, Hunt J, Iyengar S, Keller M. Clinical course of children and adolescents with bipolar spectrum disorders. ACTA ACUST UNITED AC 2006; 63:175-83. [PMID: 16461861 PMCID: PMC3079382 DOI: 10.1001/archpsyc.63.2.175] [Citation(s) in RCA: 467] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Despite the high morbidity associated with bipolar disorder (BP), few studies have prospectively studied the course of this illness in youth. OBJECTIVE To assess the longitudinal course of BP spectrum disorders (BP-I, BP-II, and not otherwise specified [BP-NOS]) in children and adolescents. DESIGN Subjects were interviewed, on average, every 9 months for an average of 2 years using the Longitudinal Interval Follow-up Evaluation. SETTING Outpatient and inpatient units at 3 university centers. PARTICIPANTS Two hundred sixty-three children and adolescents (mean age, 13 years) with BP-I (n = 152), BP-II (n = 19), and BP-NOS (n = 92). MAIN OUTCOME MEASURES Rates of recovery and recurrence, weeks with syndromal or subsyndromal mood symptoms, changes in symptoms and polarity, and predictors of outcome. RESULTS Approximately 70% of subjects with BP recovered from their index episode, and 50% had at least 1 syndromal recurrence, particularly depressive episodes. Analyses of weekly mood symptoms showed that 60% of the follow-up time, subjects had syndromal or subsyndromal symptoms with numerous changes in symptoms and shifts of polarity, and 3% of the time, psychosis. Twenty percent of BP-II subjects converted to BP-I, and 25% of BP-NOS subjects converted to BP-I or BP-II. Early-onset BP, BP-NOS, long duration of mood symptoms, low socioeconomic status, and psychosis were associated with poorer outcomes and rapid mood changes. Secondary analyses comparing BP-I youths with BP-I adults showed that youths significantly more time symptomatic and had more mixed/cycling episodes, mood symptom changes, and polarity switches. CONCLUSIONS Youths with BP spectrum disorders showed a continuum of BP symptom severity from subsyndromal to full syndromal with frequent mood fluctuations. Results of this study provide preliminary validation for BP-NOS.
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Affiliation(s)
- Boris Birmaher
- Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, PA 15213, USA.
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20
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Hanlon FM, Weisend MP, Yeo RA, Huang M, Lee RR, Thoma RJ, Moses SN, Paulson KM, Miller GA, Cañive JM. A specific test of hippocampal deficit in schizophrenia. Behav Neurosci 2006; 119:863-75. [PMID: 16187815 DOI: 10.1037/0735-7044.119.4.863] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Despite numerous studies in which hippocampal abnormalities were found, schizophrenia patients' hippocampal neural activity has not been systematically evaluated on a specific hippocampal-dependent task. The transverse-patterning task (TP) is sensitive to the relational mnemonic capabilities of the hippocampus. Ten schizophrenia patients and 10 controls performed TP and control tasks that are not hippocampal dependent. As predicted, patients displayed a behavioral impairment in TP and not in control tasks. Magnetoencephalography showed controls activating right hippocampus during TP performance. Patients showed more bilateral or left hippocampal activation during TP, and greater left lateralization was associated with better performance on TP. Patients' abnormal hippocampal lateralization may play a role in the hippocampal-dependent behavioral deficit.
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Affiliation(s)
- Faith M Hanlon
- Department of Psychiatry, New Mexico Veterans Affairs Health Care System, University of New Mexico, Albuquerque, NM 87131, USA.
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21
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Pickard BS, Pieper AA, Porteous DJ, Blackwood DH, Muir WJ. The NPAS3 gene--emerging evidence for a role in psychiatric illness. Ann Med 2006; 38:439-48. [PMID: 17008307 DOI: 10.1080/07853890600946500] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
NPAS3 is a member of the basic helix-loop-helix PAS domain class of transcription factors expressed in the brain. Evidence from a human chromosomal rearrangement and a mouse knock-out strain suggest that it may play a part in the aetiology of psychiatric illness. In this review, we describe evolutionary constraints on the NPAS3 gene, relevant functional studies from a related gene and the behavioural and hippocampal neurogenesis deficit observed in the mutant mouse. In addition, we speculate on the physiological regulation of NPAS3 and whether NPAS3 gene variation contributes to psychiatric illness at the population level.
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Affiliation(s)
- Benjamin S Pickard
- Medical Genetics Section, School of Clinical and Molecular Medicine, Molecular Medicine Centre, University of Edinburgh, Edinburgh, UK.
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22
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Drummond SPA, Meloy MJ, Yanagi MA, Orff HJ, Brown GG. Compensatory recruitment after sleep deprivation and the relationship with performance. Psychiatry Res 2005; 140:211-23. [PMID: 16263248 DOI: 10.1016/j.pscychresns.2005.06.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 03/28/2005] [Accepted: 06/26/2005] [Indexed: 11/15/2022]
Abstract
This study examined the effects of total sleep deprivation (TSD) on cerebral responses to a verbal learning task with two levels of word difficulty. A total of 32 subjects were studied with functional magnetic resonance imaging (FMRI) after normal sleep and following 36 h of TSD. Cerebral responses to EASY words were identical on both nights, but several brain regions showed increased activation to HARD words following TSD compared with following a normal night of sleep (NORM). These regions included bilateral inferior frontal gyrus, bilateral dorsolateral prefrontal cortex, and bilateral inferior parietal lobe. Better free recall performance on the HARD words after TSD was related to increased cerebral responses within the left inferior and superior parietal lobes and left inferior frontal gyrus. Recall was negatively related to activation within the right inferior frontal gyrus. Overall, the findings support the predictions of the compensatory recruitment hypothesis that task demands influence both the likelihood and location of increased cerebral activation during task performance following TSD, and refine that hypothesis by identifying a specific task demand that plays a role. The performance relationships suggest increased activation may be both beneficial (compensatory) and interfere with task performance, depending on the brain regions involved.
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Affiliation(s)
- Sean P A Drummond
- Department of Psychiatry, University of California San Diego, San Diego, CA 92161, USA.
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23
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Abstract
BACKGROUND Numerous studies have examined the neural correlates of episodic memory deficits in schizophrenia, yielding both consistencies and discrepancies in the reported patterns of results. AIMS To identify in schizophrenia the brain regions in which activity is consistently abnormal across imaging studies of memory. METHOD Data from 18 studies meeting the inclusion criteria were combined using a recently developed quantitative meta-analytic approach. RESULTS Regions of consistent differential activation between groups were observed in the left inferior prefrontal cortex, medial temporal cortex bilaterally, left cerebellum, and in other prefrontal and temporal lobe regions. Subsequent analyses explored memory encoding and retrieval separately and identified between-group differences in specific prefrontal and medial temporal lobe regions. CONCLUSIONS Beneath the apparent heterogeneity of published findings on schizophrenia and memory, a consistent and robust pattern of group differences is observed as a function of memory processes.
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Affiliation(s)
- Amélie M Achim
- Brain Imaging Group, Douglas Hospital Research Centre-FBCI, 6875 Boulevard LaSalle, Verdun, Québec H4H 1R3, Canada
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24
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Pieper AA, Wu X, Han TW, Estill SJ, Dang Q, Wu LC, Reece-Fincanon S, Dudley CA, Richardson JA, Brat DJ, McKnight SL. The neuronal PAS domain protein 3 transcription factor controls FGF-mediated adult hippocampal neurogenesis in mice. Proc Natl Acad Sci U S A 2005; 102:14052-7. [PMID: 16172381 PMCID: PMC1216832 DOI: 10.1073/pnas.0506713102] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The neuronal PAS domain protein 3 (NPAS3) gene encoding a brain-enriched transcription factor was recently found to be disrupted in a family suffering from schizophrenia. Mice harboring compound disruptions in the NPAS3 and related NPAS1 genes manifest behavioral and neuroanatomical abnormalities reminiscent of schizophrenia. Herein we demonstrate that Npas3-/- mice are deficient in expression of hippocampal FGF receptor subtype 1 mRNA, most notably in the dentate gyrus. In vivo BrdUrd-labeling shows that basal neural precursor cell proliferation in the dentate gyrus of Npas3-/- mice is reduced by 84% relative to wild-type littermates. We propose that a deficiency in adult neurogenesis may cause the behavioral and neuroanatomical abnormalities seen in Npas3-/- mice, and we speculate that impaired neurogenesis may be involved in the pathophysiology of schizophrenia.
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Affiliation(s)
- Andrew A Pieper
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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Preston AR, Shohamy D, Tamminga CA, Wagner AD. Hippocampal function, declarative memory, and schizophrenia: Anatomic and functional neuroimaging considerations. Curr Neurol Neurosci Rep 2005; 5:249-56. [PMID: 15987607 DOI: 10.1007/s11910-005-0067-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Alison R Preston
- Psychology Department, Stanford University, Jordan Hall, Building 420, Stanford, CA 94305-2130, USA
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26
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Honey GD, Honey RAE, O'Loughlin C, Sharar SR, Kumaran D, Suckling J, Menon DK, Sleator C, Bullmore ET, Fletcher PC. Ketamine disrupts frontal and hippocampal contribution to encoding and retrieval of episodic memory: an fMRI study. Cereb Cortex 2005; 15:749-59. [PMID: 15537676 PMCID: PMC3838947 DOI: 10.1093/cercor/bhh176] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The N-methyl-D-aspartate (NMDA) receptor antagonist ketamine produces episodic memory deficits. We used functional magnetic resonance imaging to characterize the effects of ketamine on frontal and hippocampal responses to memory encoding and retrieval in healthy volunteers using a double-blind, placebo-controlled, randomized, within-subjects comparison of two doses of intravenous ketamine. Dissociation of the effects of ketamine on encoding and retrieval processes was achieved using two study-test cycles: in the first, items were encoded prior to drug infusion and retrieval tested, during scanning, on drug; in the second, encoding was scanned on drug, and retrieval tested once ketamine plasma levels had declined. We additionally determined the interaction of ketamine with the depth of processing that occurred at encoding. A number of effects upon task-dependent activations were seen. Overall, our results suggest that left frontal activation is augmented by ketamine when elaborative semantic processing is required at encoding. In addition, successful encoding on ketamine is supplemented by additional non-verbal processing that is incidental to task demands. The effects of ketamine at retrieval are consistent with impaired access to accompanying contextual features of studied items. Our findings show that, even when overt behaviour is unimpaired, ketamine has an impact upon the recruitment of key regions in episodic memory task performance.
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Affiliation(s)
- G D Honey
- University of Cambridge, Department of Psychiatry, Cambridge, UK
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27
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Bondi MW, Houston WS, Eyler LT, Brown GG. fMRI evidence of compensatory mechanisms in older adults at genetic risk for Alzheimer disease. Neurology 2005; 64:501-8. [PMID: 15699382 PMCID: PMC1761695 DOI: 10.1212/01.wnl.0000150885.00929.7e] [Citation(s) in RCA: 285] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether APOE genotype influences brain response and whether nonverbal stimuli generate findings comparable with those of previous studies that used verbal stimuli. The relationship between APOE genotype and blood oxygenation level dependent (BOLD) brain response was examined during a picture-encoding task in nondemented older adults. METHODS Twenty nondemented participants with normal episodic memory function were divided into two groups based on the presence (n = 10) or absence (n = 10) of the APOE epsilon4 allele. Picture learning was completed during functional MRI in a blocked design alternating between experimental (novel pictures) and control (repeated picture) conditions. RESULTS Nondemented older adults with an APOE epsilon4 allele showed greater magnitude and extent of BOLD brain response during learning of new pictures relative to their matched epsilon3 counterparts. Different patterns and directions of association between hippocampal activity and learning and memory performance were also demonstrated. CONCLUSIONS The results suggest that brain response differences are not due to poorer general memory abilities, differential atrophy, or brain response during control conditions, but instead appear to be directly influenced by APOE genotype. Results are consistent with a compensatory hypothesis wherein older adults at genetic risk for Alzheimer disease by virtue of the APOE epsilon4 allele appear to require additional cognitive effort to achieve comparable performance levels on tests of episodic memory encoding.
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Affiliation(s)
- Mark W Bondi
- University of California San Diego and VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA.
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28
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Hill K, Mann L, Laws KR, Stephenson CME, Nimmo-Smith I, McKenna PJ. Hypofrontality in schizophrenia: a meta-analysis of functional imaging studies. Acta Psychiatr Scand 2004; 110:243-56. [PMID: 15352925 DOI: 10.1111/j.1600-0447.2004.00376.x] [Citation(s) in RCA: 234] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Hypofrontality is not a well-replicated finding in schizophrenia either at rest or under conditions of task activation. METHOD Studies comparing whole brain and frontal blood flow/metabolism in schizophrenic patients and normal controls were pooled. Voxel-based studies were also combined to examine the pattern of prefrontal activation in schizophrenia. RESULTS Whole brain flow/metabolism was reduced in schizophrenia to only a small extent. Resting and activation frontal flow/metabolism were both reduced with a medium effect size. Duration of illness significantly moderated resting hypofrontality, but the moderating effects of neuroleptic treatment were consistent with an influence on global flow/metabolism only. Pooling of voxel-based studies did not suggest an abnormal pattern of activation in schizophrenia. CONCLUSION Meta-analysis supports resting hypofrontality in schizophrenia. Task-activated hypofrontality is also supported, but there is little from voxel-based studies to suggest that this is associated with an altered pattern of regional functional architecture.
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Affiliation(s)
- K Hill
- Fulbourn Hospital, Cambridge, UK
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29
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Prasad KMR, Rohm BR, Keshavan MS. Parahippocampal gyrus in first episode psychotic disorders: a structural magnetic resonance imaging study. Prog Neuropsychopharmacol Biol Psychiatry 2004; 28:651-8. [PMID: 15276690 DOI: 10.1016/j.pnpbp.2004.01.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/30/2004] [Indexed: 11/16/2022]
Abstract
Neuropathological abnormalities in schizophrenia have been demonstrated in the parahippocampal gyrus (PHG). Only a few studies on first-episode neuroleptic-naive schizophrenia patients have been done using in vivo neuroimaging techniques. The authors examined the PHG morphology using structural MRI in neuroleptic-naive subjects with first episode psychoses. Volumetric measurements of PHG and intracranial volume (ICV) were obtained on subjects with schizophrenia and schizoaffective disorders (SCZ; n = 33), nonschizophrenia psychotic disorders (NSCZ; n = 11) and matched healthy subjects (HS; n = 43). The subjects were rated on the Brief Psychiatric Rating Scale (BPRS). Group differences and clinical correlations of ICV-adjusted PHG volumes were examined. Left PHG was significantly different across the groups consisting of SCZ, NSCZ and HS. PHG was larger in NSCZ compared to SCZ but not relative to HS. Bilaterally, PHG was no different between SCZ and HS. In pooled psychotic patients, the PHG volume negatively correlated with total positive symptom, delusion and conceptual disorganization scores on BPRS. Patients with delusions had relatively smaller PHG compared to nondelusional subjects. Observed differences in PHG volume in first-episode neuroleptic-naive patients suggest that these observations are not confounded by illness chronicity or medication effects. Significant association of PHG volume with psychotic symptoms suggests that PHG pathology plays an important role in the etiopathology of psychosis and its symptoms.
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Affiliation(s)
- Konasale M R Prasad
- Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, 3811 O'Hara Street, PA 15213, USA
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Eyler LT, Olsen RK, Jeste DV, Brown GG. Abnormal brain response of chronic schizophrenia patients despite normal performance during a visual vigilance task. Psychiatry Res 2004; 130:245-57. [PMID: 15135158 DOI: 10.1016/j.pscychresns.2004.01.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2003] [Revised: 12/16/2003] [Accepted: 01/30/2004] [Indexed: 01/03/2023]
Abstract
Deficits of attention are common among individuals with schizophrenia (SZ) and are related both to genetic liability to the disorder and to functional outcome among patients. To explore the brain systems underlying these attentional abnormalities, we compared the response of nine patients with chronic SZ or schizoaffective disorder to that of 10 matched healthy individuals performing a simple visual vigilance task during functional magnetic resonance imaging. The two groups performed equivalently on the task. When the blood oxygen level dependent (BOLD) signal during identification of a target letter among similar-looking letters was compared to the response during fixation trials, both groups showed multiple clusters of significant brain response in widespread cortical regions. Compared with healthy participants, SZ patients showed a diminished response in the inferior frontal cortex and an abnormally enhanced response in right postcentral gyrus, right medial temporal lobe and left cerebellum. The results suggest that abnormalities of functional brain response to attentional tasks can be observed among patients with SZ even when behavioral performance is unimpaired, and provide further evidence that brain systems related to attention are likely to be involved in the pathophysiology of the disorder.
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Affiliation(s)
- Lisa T Eyler
- Mental Illness Research, Education and Clinical Center, Veterans Affairs San Diego Healthcare System, and Department of Psychiatry, University of California at San Diego, La Jolla, USA
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31
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Weiss AP, Zalesak M, DeWitt I, Goff D, Kunkel L, Heckers S. Impaired hippocampal function during the detection of novel words in schizophrenia. Biol Psychiatry 2004; 55:668-75. [PMID: 15038994 DOI: 10.1016/j.biopsych.2004.01.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 01/07/2004] [Accepted: 01/08/2004] [Indexed: 11/19/2022]
Abstract
BACKGROUND Patients with schizophrenia have smaller hippocampal volumes and perform abnormally on most declarative memory tasks. Although these findings are likely related, the impact of hippocampal pathology on cognitive performance in schizophrenia remains unclear. This study examined this relationship by measuring the volume of the hippocampus and its activation during memory task performance. METHODS Participants included 15 patients with schizophrenia and 16 age-matched control subjects. Hippocampal volume was determined via three-dimensional volumetric analysis of high-resolution magnetic resonance images. Hippocampal activity was assessed by measuring changes in blood oxygen level-dependent signal during a recognition memory task. RESULTS Patients with schizophrenia had smaller hippocampal volumes bilaterally and demonstrated poorer performance on the recognition memory task, largely because of a heightened rate of false alarms to novel stimuli. Both groups showed robust hippocampal activity to old and new items when compared with a low-level baseline task; however, direct comparison of hippocampal activity during recognition task performance revealed that healthy control, but not the schizophrenia, subjects showed significant right anterior hippocampal activation during the evaluation of novel items. CONCLUSIONS The impaired ability to classify new items as previously not experienced is associated with decreased recruitment and smaller volume of the hippocampus in schizophrenia.
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Affiliation(s)
- Anthony P Weiss
- Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts, USA
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