Deborah Yurgelun-Todd - Academia.edu (original) (raw)

Papers by Deborah Yurgelun-Todd

Psychiatry Research: Neuroimaging, 2004

Non-invasive measures of brain gamma-aminobutyric acid (GABA) concentrations may be especially us... more Non-invasive measures of brain gamma-aminobutyric acid (GABA) concentrations may be especially useful in the identification of cocaine-related changes in brain chemistry that can be used to guide the development of future treatments for cocaine-dependent persons. This study assessed whether brain GABA levels in cocaine-dependent subjects with and without an alcohol disorder differ from GABA levels in healthy comparison subjects. Two-dimensional, proton magnetic resonance spectroscopy was used to determine GABA levels in the left prefrontal lobe of cocaine-dependent subjects (N=35) recruited from a National Institute on Drug Abuse (NIDA)-sponsored treatment trial of cocaine dependence and a comparison group (N=20). At treatment baseline, mean GABA concentrations were 0.93+/-0.27 mM/kg in cocaine-dependent subjects and 1.32+/-0.44 mM/kg in the comparison sample (t [d.f.=53]=3.65, P<0.001). Cocaine-dependent subjects with a history of a co-morbid alcohol disorder (N=23) had significantly lower baseline GABA levels (0.87 mM/kg) (t [d.f.=41]=4.31, P<0.001) than the comparison group. However, cocaine-dependent subjects without an alcohol disorder (N=12) also had lower GABA levels (1.04 mM/kg) than the comparison subjects (t [d.f.=30]=2.09, P=0.045), suggesting that cocaine dependence alone can decrease GABA levels.

This study was conducted to explore differences in gray and white matter volume between cocaine-d... more This study was conducted to explore differences in gray and white matter volume between cocaine-dependent and healthy comparison subjects using optimized voxel-based morphometry (VBM). Brain magnetic resonance imaging (MRI) and neuropsychological function tests were performed for 40 cocaine-dependent subjects (41.476.9 years, 27 men) and 41 healthy age-and sex-matched comparison subjects (38.778.8 years, 26 men). Optimally normalized whole brain MR images were segmented, modulated, smoothed, and compared between groups with statistical parametric mapping. The cocaine-dependent group had lower gray matter volumes in bilateral premotor cortex (Brodmann area (BA) 6, 8; 16.6%), right orbitofrontal cortex (BA 10, 15.1%), bilateral temporal cortex (BA 20, 38; 15.9%), left thalamus (12.6%), and bilateral cerebellum (13.4%) as well as lower right cerebellar white matter volume (10.0%) relative to the comparison group at a corrected po0.05 for multiple comparisons. Duration of cocaine use negatively correlated with right and left cerebellar gray matter volumes (r ¼ À0.37, r ¼ À0.39, respectively). In cocaine-dependent subjects, lower cerebellar hemispheric gray and white matter volumes were correlated with deficits in executive function and decreased motor performance. This study reports that cocaine-dependent subjects have lower gray matter volumes in cerebellar hemispheres as well as in frontal, temporal cortex, and thalamus. These findings are the first to suggest that the cerebellum may be vulnerable to cocaine-associated brain volume changes, and that cerebellar deficits may contribute to neuropsychological deficits and motor dysfunction frequently observed in cocaine-dependent subjects.

Drug and Alcohol Dependence, 2004

The major psychoactive component of MRJ is ∆9-tetrahydrocannabinol (∆9-THC), which acts as an ago... more The major psychoactive component of MRJ is ∆9-tetrahydrocannabinol (∆9-THC), which acts as an agonist at the CB1 cannabinoid receptor . The densely-expressed CB1 receptor is the only known cannabinoid receptor in the central nervous system and is involved in the regulation of cognition, memory, and motor activity . Dense concentrations of cannabinoid receptor binding sites are located in frontal cortex, temporal cortex, hippocampal formation, occipito-temporal gyrus, as well as the parietal and occipital cortices . Cannabinoid binding sites also are localized within the thalamus, including the mediodorsal, medioventral, and anterior thalamic nuclei that are connected to forebrain regions involved in cognitive functions . To date, the relationship between protracted THC exposure and neurochemical sequelae in regions like the thalamus and temporal cortex, which are critically involved in mediating executive cognitive function, has not been well characterized.

NeuroImage, 2004

poorly articulated, agrammatic speech associated with nonfluent aphasia. Published by Elsevier Inc.

Cognitive Neuroscience, 2010

During nonconscious perception of facial affect, healthy adults commonly activate a right-lateral... more During nonconscious perception of facial affect, healthy adults commonly activate a right-lateralized pathway comprising the superior colliculus, pulvinar, and amygdala. Whether this system is fully developed prior to adulthood is unknown. Twenty-three healthy adolescents underwent functional magnetic resonance imaging (fMRI) while viewing fearful, angry, and happy faces, backward masked by neutral faces. Left amygdala activation differed among the three affects, showing reductions to masked anger and increases to masked fear and happy faces. During masked fear, left amygdala activation correlated positively with extrastriate cortex and temporal poles and negatively with precuneus and middle cingulate gyrus. Responses of the left amygdala to masked anger correlated positively with right parahippocampal gyrus and negatively with dorsal anterior cingulate. Amygdala responses to masked happy faces were uncorrelated with other brain regions. Contrary to the right-lateralized pathway seen in adults, adolescents show evidence of a predominantly left-lateralized extrastriate pathway during masked presentations of facial affect.

Frontiers in Psychiatry, 2013

Post-mortem studies have suggested a link between the thalamus, psychiatric disorders, and suicid... more Post-mortem studies have suggested a link between the thalamus, psychiatric disorders, and suicide. We evaluated the thalamus and anterior thalamic radiations (ATR) in a group of Veterans with and without a history of suicidal behavior (SB) to determine if thalamic abnormalities were associated with an increased risk of SB. Forty Veterans with mild traumatic brain injury (TBI) and no SB (TBI-SB), 19 Veterans with mild TBI and a history of SB (TB + SB), and 15 healthy controls (HC) underwent magnetic resonance imaging scanning including a structural and diffusion tensor imaging scan. SBs were evaluated utilizing the Columbia Suicide Rating Scale and impulsivity was measured using the Barratt Impulsiveness Scale (BIS). Differences in thalamic volumes and ATR fractional anisotropy (FA) were examined between (1) TBI + SB versus HC and (2) TBI + SB versus combined HC and TBI-SB and (3) betweenTBI + SB andTBI-SB. Left and right thalamic volumes were significantly increased in those with TBI + SB compared to the HC, TBI-SB, and the combined group. Veterans with TBI + SB had increased FA bilaterally compared to the HC, HC and TBI-SB group, and the TBI-SB only group. Significant positive associations were found for bilateral ATR and BIS in the TBI + SB group. Our findings of thalamic enlargement and increased FA in individuals with TBI + SB suggest that this region may be a biomarker for suicide risk. Our findings are consistent with previous evidence indicating that suicide may be associated with behavioral disinhibition and frontal-thalamic-limbic dysfunction and suggest a neurobiologic mechanism that may increase vulnerability to suicide.

Schizophrenia Research, 1997

Journal of Nervous and Mental Disease, 1993

APA PsycNET Our Apologies! - The following features are not available with your current Browser c... more APA PsycNET Our Apologies! - The following features are not available with your current Browser configuration. - alerts user that their session is about to expire - display, print, save, export, and email selected records - get My ...

Journal of Abnormal Psychology, 1999

The prevalence of eye-tracking dysfunction (ETD) is significantly elevated in individuals with a ... more The prevalence of eye-tracking dysfunction (ETD) is significantly elevated in individuals with a diagnosis of schizophrenia and in their nonschizophrenic relatives, suggesting that ETD marks a familial (most likely genetic) risk factor for schizophrenia. Birth in a season with intemperate weather is also a widely reported risk factor for schizophrenia and is particularly marked for the subgroup with no family history of the disorder. This study examined how these two risk factors covaried in 78 patients with a Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) diagnosis of schizophrenia. Eye tracking and birth-month weather were independently assessed. As hypothesized, patients without ETD were significantly more likely to be born in months with intemperate weather (both hot and cold) than either patients with ETD or people in the general population. Etiologic factors associated with severe weather near birth may be important sources of nonfamilial schizophrenia.

Current Opinion in Neurobiology, 2007

Adolescence is a critical period for maturation of neurobiological processes that underlie higher... more Adolescence is a critical period for maturation of neurobiological processes that underlie higher cognitive functions and social and emotional behavior. Recent studies have applied new advances in magnetic resonance imaging to increase understanding of the neurobiological changes that occur during the transition from childhood to early adulthood. Structural imaging data indicate progressive and regressive changes in the relative volumes of specific brain regions, although total brain volume is not significantly altered. The prefrontal cortex matures later than other regions and its development is paralleled by increased abilities in abstract reasoning, attentional shifting, response inhibition and processing speed. Changes in emotional capacity, including improvements in affective modulation and discrimination of emotional cues, are also seen during adolescence. Functional imaging studies using cognitive and affective challenges have shown that frontal cortical networks undergo developmental changes in processing. In summary, brain regions that underlie attention, reward evaluation, affective discrimination, response inhibition and goal-directed behavior undergo structural and functional re-organization throughout late childhood and early adulthood. Evidence from recent imaging studies supports a model by which the frontal cortex adopts an increasingly regulatory role. These neurobiological changes are believed to contribute, in part, to the range in cognitive and affective behavior seen during adolescence.

Neuroimage, 2004

Previous functional neuroimaging studies have demonstrated that the amygdala activates in respons... more Previous functional neuroimaging studies have demonstrated that the amygdala activates in response to fearful faces presented below the threshold of conscious visual perception. Using a backward masking procedure similar to that of previous studies, we used functional magnetic resonance imaging (fMRI) to study the amygdala and anterior cingulate gyrus during preattentive presentations of sad and happy facial affect. Twelve healthy adult females underwent blood oxygen level dependent (BOLD) fMRI while viewing sad and happy faces, each presented for 20 ms and “masked” immediately by a neutral face for 100 ms. Masked happy faces were associated with significant bilateral activation within the anterior cingulate gyrus and amygdala, whereas masked sadness yielded only limited activation within the left anterior cingulate gyrus. In a direct comparison, masked happy faces yielded significantly greater activation in the anterior cingulate and amygdala relative to identically masked sad faces. Conjunction analysis showed that masked affect perception, regardless of emotional valence, was associated with greater activation within the left amygdala and left anterior cingulate. Findings suggest that the amygdala and anterior cingulate are important components of a network involved in detecting and discriminating affective information presented below the normal threshold of conscious visual perception.

Journal of Neural Transmission, 2006

Until today, morphometric neuroimaging studies on affective disorders concentrate on the limbic s... more Until today, morphometric neuroimaging studies on affective disorders concentrate on the limbic system, especially the hippocampus, amygdala, and anterior cingulate. In most of the studies and reviews available today, the basal ganglia are of secondary interest. It seems that the basal ganglia are interest of neurologist, whereas the limbic system is reserved for psychiatric neuroimaging studies. We follow a different approach in this review, studying all available papers on MRI research of the basal ganglia in unipolar depression and bipolar disorder. We found a possibly larger neostriatum in bipolar and possibly smaller one in unipolar patients. None of the unipolar studies found any larger basal ganglion, and only one out of 12 bipolar studies found smaller basal ganglia. Both findings seemed to depend on age (tendency toward smaller volumes in unipolar and bipolar with older age), sex (men tending to pathology in both disorders) and bipolar patients show a possible influence of medication, which is not assessed so far in unipolar depression. We conclude that several methodological shortcomings in volumetric MRI research on the basal ganglia in affective disorders make it necessary to imply more research in this area. We suggest (a) better MRI methods (we do not have a single volumetric 3 Tesla study in this patient group); (b) studies of medication-naïve patients (thus ruling out the medication effect); (c) Studies that directly compare unipolar depressed and bipolar patients are needed to determine whether these apparent differences in morphometric abnormalities, as observed through the mediating comparison with healthy subjects, are real.

Annals of The New York Academy of Sciences, 2004

Abstract: Frontal lobe functions include a range of cognitive, emotional, and social abilities th... more Abstract: Frontal lobe functions include a range of cognitive, emotional, and social abilities that enable goal-directed behavior. Although a number of studies have plotted the development of frontal lobe functions in childhood, few have extended into the adolescent years. There is also little information on which cognitive and emotional components of frontal functioning may be correlated. The aims of this study were to identify and compare age effects on different components of frontal functioning in childhood and adolescence and to examine whether abstract reasoning skills were associated with levels of emotional intelligence and social sensitivity. Twenty children (ages 9-18) were recruited from the local community for a study of normal adolescent brain development. All subjects were free of psychiatric or developmental disorders, as determined by a structured interview. Subjects completed a comprehensive neuropsychological test battery, as well as self-report measures of social sensitivity (anxiety) and emotional intelligence. Significant age effects were found for measures of abstract reasoning, response inhibition, and attentional set shifting. Levels of social anxiety increased moderately with age, although not significantly at this sample size. Abstract reasoning skills correlated positively with levels of social anxiety but not emotional intelligence. The pattern of results suggests differential developmental trajectories across various cognitive and emotional domains of frontal lobe functioning in childhood and adolescence. Increased abstract reasoning ability may be associated with increased vulnerability to social anxiety during this period.

Current Psychiatry Reports, 2001

Acute intoxication with cannabis clearly produces cognitive impairment, but it is less clear how ... more Acute intoxication with cannabis clearly produces cognitive impairment, but it is less clear how long cognitive deficits persist after an individual stops regular cannabis use. Numerous methodologic difficulties confront investigators in the field attempting to assess the residual neuropsychologic effects of cannabis among heavy users, and these must be understood to properly evaluate available studies. At present, it appears safe to conclude that deficits in attention and memory persist for at least several days after discontinuing regular heavy cannabis use. Some of these deficits may be caused or exacerbated by withdrawal effects from the abrupt discontinuation of cannabis; these effects typically peak after 3 to 7 days of abstinence. It is less clear, however, whether heavy cannabis use can cause neurotoxicity that persists long after discontinuation of use. It seems likely that such long-term effects, if they exist, are subtle and not clinically disabling—at least in the majority of cases.

Schizophrenia Research - SCHIZOPHR RES, 1991

Drug-free schizophrenic patients were compared with neuroleptic-treated patients and normal contr... more Drug-free schizophrenic patients were compared with neuroleptic-treated patients and normal control subjects on a selective attention task. The particular attention task required subjects to press a button only when the letter "0" appeared on a monitor. One type of display (with flankers) presented the "0" target with eight "Gs" and "Qs" surrounding it; the other display (no flankers) presented the "0" alone. The target appeared randomly at the center or in two locations to each side of the center. The comparison of main interest was the time to respond to targets presented in the left vs. right visual field. When the flanker display was presented, drug-free schizophrenic subjects showed a significant elevation in response times to targets in the right visual field (vs. the left), while the neuroleptic-treated schizophrenic and control subjects did not. When the non-flanker display was presented, the response times in the two fields were virtually equal for all three groups. The flanker task required filtering of the surrounding "Gs" or "Qs" in order to identify the target. A recent PET scan study (LaBerge & Buchsbaum, J. Neurosci., 1989) in normal controls implicated the contralateral pulvinar of the thalamus in this filtering task. These results are consistent with abnormal thalamic filtering of attention in schizophrenia especially in the left hemisphere. These data provide further evidence for abnormal straitothalamocortical functioning in schizophrenic patients.

Social Neuroscience, 2007

Psychiatry Research: Neuroimaging, 2004

Non-invasive measures of brain gamma-aminobutyric acid (GABA) concentrations may be especially us... more Non-invasive measures of brain gamma-aminobutyric acid (GABA) concentrations may be especially useful in the identification of cocaine-related changes in brain chemistry that can be used to guide the development of future treatments for cocaine-dependent persons. This study assessed whether brain GABA levels in cocaine-dependent subjects with and without an alcohol disorder differ from GABA levels in healthy comparison subjects. Two-dimensional, proton magnetic resonance spectroscopy was used to determine GABA levels in the left prefrontal lobe of cocaine-dependent subjects (N=35) recruited from a National Institute on Drug Abuse (NIDA)-sponsored treatment trial of cocaine dependence and a comparison group (N=20). At treatment baseline, mean GABA concentrations were 0.93+/-0.27 mM/kg in cocaine-dependent subjects and 1.32+/-0.44 mM/kg in the comparison sample (t [d.f.=53]=3.65, P<0.001). Cocaine-dependent subjects with a history of a co-morbid alcohol disorder (N=23) had significantly lower baseline GABA levels (0.87 mM/kg) (t [d.f.=41]=4.31, P<0.001) than the comparison group. However, cocaine-dependent subjects without an alcohol disorder (N=12) also had lower GABA levels (1.04 mM/kg) than the comparison subjects (t [d.f.=30]=2.09, P=0.045), suggesting that cocaine dependence alone can decrease GABA levels.

This study was conducted to explore differences in gray and white matter volume between cocaine-d... more This study was conducted to explore differences in gray and white matter volume between cocaine-dependent and healthy comparison subjects using optimized voxel-based morphometry (VBM). Brain magnetic resonance imaging (MRI) and neuropsychological function tests were performed for 40 cocaine-dependent subjects (41.476.9 years, 27 men) and 41 healthy age-and sex-matched comparison subjects (38.778.8 years, 26 men). Optimally normalized whole brain MR images were segmented, modulated, smoothed, and compared between groups with statistical parametric mapping. The cocaine-dependent group had lower gray matter volumes in bilateral premotor cortex (Brodmann area (BA) 6, 8; 16.6%), right orbitofrontal cortex (BA 10, 15.1%), bilateral temporal cortex (BA 20, 38; 15.9%), left thalamus (12.6%), and bilateral cerebellum (13.4%) as well as lower right cerebellar white matter volume (10.0%) relative to the comparison group at a corrected po0.05 for multiple comparisons. Duration of cocaine use negatively correlated with right and left cerebellar gray matter volumes (r ¼ À0.37, r ¼ À0.39, respectively). In cocaine-dependent subjects, lower cerebellar hemispheric gray and white matter volumes were correlated with deficits in executive function and decreased motor performance. This study reports that cocaine-dependent subjects have lower gray matter volumes in cerebellar hemispheres as well as in frontal, temporal cortex, and thalamus. These findings are the first to suggest that the cerebellum may be vulnerable to cocaine-associated brain volume changes, and that cerebellar deficits may contribute to neuropsychological deficits and motor dysfunction frequently observed in cocaine-dependent subjects.

Drug and Alcohol Dependence, 2004

The major psychoactive component of MRJ is ∆9-tetrahydrocannabinol (∆9-THC), which acts as an ago... more The major psychoactive component of MRJ is ∆9-tetrahydrocannabinol (∆9-THC), which acts as an agonist at the CB1 cannabinoid receptor . The densely-expressed CB1 receptor is the only known cannabinoid receptor in the central nervous system and is involved in the regulation of cognition, memory, and motor activity . Dense concentrations of cannabinoid receptor binding sites are located in frontal cortex, temporal cortex, hippocampal formation, occipito-temporal gyrus, as well as the parietal and occipital cortices . Cannabinoid binding sites also are localized within the thalamus, including the mediodorsal, medioventral, and anterior thalamic nuclei that are connected to forebrain regions involved in cognitive functions . To date, the relationship between protracted THC exposure and neurochemical sequelae in regions like the thalamus and temporal cortex, which are critically involved in mediating executive cognitive function, has not been well characterized.

NeuroImage, 2004

poorly articulated, agrammatic speech associated with nonfluent aphasia. Published by Elsevier Inc.

Cognitive Neuroscience, 2010

During nonconscious perception of facial affect, healthy adults commonly activate a right-lateral... more During nonconscious perception of facial affect, healthy adults commonly activate a right-lateralized pathway comprising the superior colliculus, pulvinar, and amygdala. Whether this system is fully developed prior to adulthood is unknown. Twenty-three healthy adolescents underwent functional magnetic resonance imaging (fMRI) while viewing fearful, angry, and happy faces, backward masked by neutral faces. Left amygdala activation differed among the three affects, showing reductions to masked anger and increases to masked fear and happy faces. During masked fear, left amygdala activation correlated positively with extrastriate cortex and temporal poles and negatively with precuneus and middle cingulate gyrus. Responses of the left amygdala to masked anger correlated positively with right parahippocampal gyrus and negatively with dorsal anterior cingulate. Amygdala responses to masked happy faces were uncorrelated with other brain regions. Contrary to the right-lateralized pathway seen in adults, adolescents show evidence of a predominantly left-lateralized extrastriate pathway during masked presentations of facial affect.

Frontiers in Psychiatry, 2013

Post-mortem studies have suggested a link between the thalamus, psychiatric disorders, and suicid... more Post-mortem studies have suggested a link between the thalamus, psychiatric disorders, and suicide. We evaluated the thalamus and anterior thalamic radiations (ATR) in a group of Veterans with and without a history of suicidal behavior (SB) to determine if thalamic abnormalities were associated with an increased risk of SB. Forty Veterans with mild traumatic brain injury (TBI) and no SB (TBI-SB), 19 Veterans with mild TBI and a history of SB (TB + SB), and 15 healthy controls (HC) underwent magnetic resonance imaging scanning including a structural and diffusion tensor imaging scan. SBs were evaluated utilizing the Columbia Suicide Rating Scale and impulsivity was measured using the Barratt Impulsiveness Scale (BIS). Differences in thalamic volumes and ATR fractional anisotropy (FA) were examined between (1) TBI + SB versus HC and (2) TBI + SB versus combined HC and TBI-SB and (3) betweenTBI + SB andTBI-SB. Left and right thalamic volumes were significantly increased in those with TBI + SB compared to the HC, TBI-SB, and the combined group. Veterans with TBI + SB had increased FA bilaterally compared to the HC, HC and TBI-SB group, and the TBI-SB only group. Significant positive associations were found for bilateral ATR and BIS in the TBI + SB group. Our findings of thalamic enlargement and increased FA in individuals with TBI + SB suggest that this region may be a biomarker for suicide risk. Our findings are consistent with previous evidence indicating that suicide may be associated with behavioral disinhibition and frontal-thalamic-limbic dysfunction and suggest a neurobiologic mechanism that may increase vulnerability to suicide.

Schizophrenia Research, 1997

Journal of Nervous and Mental Disease, 1993

APA PsycNET Our Apologies! - The following features are not available with your current Browser c... more APA PsycNET Our Apologies! - The following features are not available with your current Browser configuration. - alerts user that their session is about to expire - display, print, save, export, and email selected records - get My ...

Journal of Abnormal Psychology, 1999

The prevalence of eye-tracking dysfunction (ETD) is significantly elevated in individuals with a ... more The prevalence of eye-tracking dysfunction (ETD) is significantly elevated in individuals with a diagnosis of schizophrenia and in their nonschizophrenic relatives, suggesting that ETD marks a familial (most likely genetic) risk factor for schizophrenia. Birth in a season with intemperate weather is also a widely reported risk factor for schizophrenia and is particularly marked for the subgroup with no family history of the disorder. This study examined how these two risk factors covaried in 78 patients with a Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) diagnosis of schizophrenia. Eye tracking and birth-month weather were independently assessed. As hypothesized, patients without ETD were significantly more likely to be born in months with intemperate weather (both hot and cold) than either patients with ETD or people in the general population. Etiologic factors associated with severe weather near birth may be important sources of nonfamilial schizophrenia.

Current Opinion in Neurobiology, 2007

Adolescence is a critical period for maturation of neurobiological processes that underlie higher... more Adolescence is a critical period for maturation of neurobiological processes that underlie higher cognitive functions and social and emotional behavior. Recent studies have applied new advances in magnetic resonance imaging to increase understanding of the neurobiological changes that occur during the transition from childhood to early adulthood. Structural imaging data indicate progressive and regressive changes in the relative volumes of specific brain regions, although total brain volume is not significantly altered. The prefrontal cortex matures later than other regions and its development is paralleled by increased abilities in abstract reasoning, attentional shifting, response inhibition and processing speed. Changes in emotional capacity, including improvements in affective modulation and discrimination of emotional cues, are also seen during adolescence. Functional imaging studies using cognitive and affective challenges have shown that frontal cortical networks undergo developmental changes in processing. In summary, brain regions that underlie attention, reward evaluation, affective discrimination, response inhibition and goal-directed behavior undergo structural and functional re-organization throughout late childhood and early adulthood. Evidence from recent imaging studies supports a model by which the frontal cortex adopts an increasingly regulatory role. These neurobiological changes are believed to contribute, in part, to the range in cognitive and affective behavior seen during adolescence.

Neuroimage, 2004

Previous functional neuroimaging studies have demonstrated that the amygdala activates in respons... more Previous functional neuroimaging studies have demonstrated that the amygdala activates in response to fearful faces presented below the threshold of conscious visual perception. Using a backward masking procedure similar to that of previous studies, we used functional magnetic resonance imaging (fMRI) to study the amygdala and anterior cingulate gyrus during preattentive presentations of sad and happy facial affect. Twelve healthy adult females underwent blood oxygen level dependent (BOLD) fMRI while viewing sad and happy faces, each presented for 20 ms and “masked” immediately by a neutral face for 100 ms. Masked happy faces were associated with significant bilateral activation within the anterior cingulate gyrus and amygdala, whereas masked sadness yielded only limited activation within the left anterior cingulate gyrus. In a direct comparison, masked happy faces yielded significantly greater activation in the anterior cingulate and amygdala relative to identically masked sad faces. Conjunction analysis showed that masked affect perception, regardless of emotional valence, was associated with greater activation within the left amygdala and left anterior cingulate. Findings suggest that the amygdala and anterior cingulate are important components of a network involved in detecting and discriminating affective information presented below the normal threshold of conscious visual perception.

Journal of Neural Transmission, 2006

Until today, morphometric neuroimaging studies on affective disorders concentrate on the limbic s... more Until today, morphometric neuroimaging studies on affective disorders concentrate on the limbic system, especially the hippocampus, amygdala, and anterior cingulate. In most of the studies and reviews available today, the basal ganglia are of secondary interest. It seems that the basal ganglia are interest of neurologist, whereas the limbic system is reserved for psychiatric neuroimaging studies. We follow a different approach in this review, studying all available papers on MRI research of the basal ganglia in unipolar depression and bipolar disorder. We found a possibly larger neostriatum in bipolar and possibly smaller one in unipolar patients. None of the unipolar studies found any larger basal ganglion, and only one out of 12 bipolar studies found smaller basal ganglia. Both findings seemed to depend on age (tendency toward smaller volumes in unipolar and bipolar with older age), sex (men tending to pathology in both disorders) and bipolar patients show a possible influence of medication, which is not assessed so far in unipolar depression. We conclude that several methodological shortcomings in volumetric MRI research on the basal ganglia in affective disorders make it necessary to imply more research in this area. We suggest (a) better MRI methods (we do not have a single volumetric 3 Tesla study in this patient group); (b) studies of medication-naïve patients (thus ruling out the medication effect); (c) Studies that directly compare unipolar depressed and bipolar patients are needed to determine whether these apparent differences in morphometric abnormalities, as observed through the mediating comparison with healthy subjects, are real.

Annals of The New York Academy of Sciences, 2004

Abstract: Frontal lobe functions include a range of cognitive, emotional, and social abilities th... more Abstract: Frontal lobe functions include a range of cognitive, emotional, and social abilities that enable goal-directed behavior. Although a number of studies have plotted the development of frontal lobe functions in childhood, few have extended into the adolescent years. There is also little information on which cognitive and emotional components of frontal functioning may be correlated. The aims of this study were to identify and compare age effects on different components of frontal functioning in childhood and adolescence and to examine whether abstract reasoning skills were associated with levels of emotional intelligence and social sensitivity. Twenty children (ages 9-18) were recruited from the local community for a study of normal adolescent brain development. All subjects were free of psychiatric or developmental disorders, as determined by a structured interview. Subjects completed a comprehensive neuropsychological test battery, as well as self-report measures of social sensitivity (anxiety) and emotional intelligence. Significant age effects were found for measures of abstract reasoning, response inhibition, and attentional set shifting. Levels of social anxiety increased moderately with age, although not significantly at this sample size. Abstract reasoning skills correlated positively with levels of social anxiety but not emotional intelligence. The pattern of results suggests differential developmental trajectories across various cognitive and emotional domains of frontal lobe functioning in childhood and adolescence. Increased abstract reasoning ability may be associated with increased vulnerability to social anxiety during this period.

Current Psychiatry Reports, 2001

Acute intoxication with cannabis clearly produces cognitive impairment, but it is less clear how ... more Acute intoxication with cannabis clearly produces cognitive impairment, but it is less clear how long cognitive deficits persist after an individual stops regular cannabis use. Numerous methodologic difficulties confront investigators in the field attempting to assess the residual neuropsychologic effects of cannabis among heavy users, and these must be understood to properly evaluate available studies. At present, it appears safe to conclude that deficits in attention and memory persist for at least several days after discontinuing regular heavy cannabis use. Some of these deficits may be caused or exacerbated by withdrawal effects from the abrupt discontinuation of cannabis; these effects typically peak after 3 to 7 days of abstinence. It is less clear, however, whether heavy cannabis use can cause neurotoxicity that persists long after discontinuation of use. It seems likely that such long-term effects, if they exist, are subtle and not clinically disabling—at least in the majority of cases.

Schizophrenia Research - SCHIZOPHR RES, 1991

Drug-free schizophrenic patients were compared with neuroleptic-treated patients and normal contr... more Drug-free schizophrenic patients were compared with neuroleptic-treated patients and normal control subjects on a selective attention task. The particular attention task required subjects to press a button only when the letter "0" appeared on a monitor. One type of display (with flankers) presented the "0" target with eight "Gs" and "Qs" surrounding it; the other display (no flankers) presented the "0" alone. The target appeared randomly at the center or in two locations to each side of the center. The comparison of main interest was the time to respond to targets presented in the left vs. right visual field. When the flanker display was presented, drug-free schizophrenic subjects showed a significant elevation in response times to targets in the right visual field (vs. the left), while the neuroleptic-treated schizophrenic and control subjects did not. When the non-flanker display was presented, the response times in the two fields were virtually equal for all three groups. The flanker task required filtering of the surrounding "Gs" or "Qs" in order to identify the target. A recent PET scan study (LaBerge & Buchsbaum, J. Neurosci., 1989) in normal controls implicated the contralateral pulvinar of the thalamus in this filtering task. These results are consistent with abnormal thalamic filtering of attention in schizophrenia especially in the left hemisphere. These data provide further evidence for abnormal straitothalamocortical functioning in schizophrenic patients.

Social Neuroscience, 2007

Frontiers of Architectural Research, May 15, 2017

Built environments can induce contemplative states, but direct evidence for their impact on the b... more Built environments can induce contemplative states, but direct evidence for their impact on the brain is lacking. This exploratory work investigated brain correlates of internal states elicited by architecture designed for contemplative experience. Functional MRI and self-reports of 12 architects were assessed to study their responses to photographs of ordinary and contemplative architectures. Images of contemplative buildings: (1) induced attentive, receptive, and absorbing experiences and diminished internal dialogue; (2) involved decreased engagement of prefrontal cortex; and (3) activated the occipital lobe, precentral gyrus, and inferior parietal lobule. They suggest that viewing buildings designed for contemplation may evoke experiential and brain signatures that consistently differ from those induced by buildings that serve everyday functions. The depth of such externally induced states was inversely correlated with the engagement of the Default Mode Network. Our study points toward a novel avenue for investigating how contemplation can be cultivated in the human brain/mind.