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Emily Stern

Publications and source records attributed to Emily Stern.

At least 19 recordsLinked to original sources
PubMed2006

Sex differences in mental rotation: top-down versus bottom-up processing.

Functional MRI during performance of a validated mental rotation task was used to assess a neurobiological basis for sex differences in visuospatial processing. Between-sex group analysis demonstrated greater activity in women than in men in dorsalmedial prefrontal and other high-order heteromodal association cortices, suggesting women performed mental rotation in an effortful, "top-down" fashion. In contrast, men activated primary sensory cortices as well as regions involved in implicit learning (basal ganglia) and mental imagery (precuneus), consistent with a more automatic, "bottom-up" strategy. Functional connectivity analysis in association with a measure of behavioral performance showed that, in men (but not women), accurate performance was associated with deactivation of parieto-insular vestibular cortex (PIVC) as part of a visual-vestibular network. Automatic evocation by men to a greater extent than women of this network during mental rotation may represent an effective, unconscious, bottom-up neural strategy which could reasonably account for men's traditional visuospatial performance advantage.

Brain↗
PubMed2006

Increased brainstem volume in panic disorder: a voxel-based morphometric study.

Neurocircuitry models of panic disorder have hypothesized that the panic attack itself stems from loci in the brainstem including the ascending reticular system and respiratory and cardiovascular control centers. Voxel-based morphometry with acobian modulation was used to examine gray matter volume changes in 10 panic disorder patients and 23 healthy controls. The panic disorder patients had a relatively increased gray matter volume in the midbrain and rostral pons of the brainstem. Increased ventral hippocampal and decreased regional prefrontal cortex volumes were also noted at a lower significance threshold. This finding has implications for pathophysiologic models of panic disorder, and provides structural evidence for the role of the brainstem in neurocircuitry models of panic disorder.

Adult↗
PubMed2006

The relation between computerized and paper-and-pencil mental rotation tasks: a validation study.

The present study aimed at validating a computerized mental rotation task developed for use in functional Magnetic Resonance Imaging (fMRI) studies. Eighty-three females and 74 males completed the computerized task, two pencil-and-paper tests of mental rotation, and reported their high school grades in mathematics, English, and history. The computerized task involved the presentation of pairs of three-dimensional stimuli that differed in orientation by 0, 40, 80, 120, or 160 degrees. Results showed significant gender differences in favor of males in the three main tasks, although gender interacted with angle of rotation in the computerized task. Evidence for concurrent validity was obtained in the form of significant correlations between performance on tasks relevant to mental rotation (paper and pencil tests and mathematics grades), whereas discriminant validity was demonstrated by a lack of correlation with tasks deemed irrelevant to mental rotation (English and history grades). These findings support the use of our computerized mental rotation task as a valid measure of mental rotation abilities in fMRI studies.

Adolescent↗
PubMed2006

Lack of ventral striatal response to positive stimuli in depressed versus normal subjects.

OBJECTIVE: Most of the functional neuroimaging studies of depression have focused primarily on the resting state or responses to negatively valenced stimuli. However, depression consists not only of an accentuation of negative affective processing but of an inability to experience pleasure or positive motivation. The authors tested the hypothesis that depressed subjects would show less activation than healthy comparison subjects, in response to positive stimuli, in ventral striatal regions associated with processing of reward and positive stimuli. METHOD: Positive, negative, and neutral words were presented to 10 unmedicated depressed patients and 12 healthy comparison subjects in the context of a 3T functional magnetic resonance imaging (MRI) paradigm. Image processing and analysis were performed using statistical parametric mapping with a mixed-effects model. Significant differences in neural responses were assessed, examining group, condition, and interaction effects of interest within the context of a general linear model. RESULTS: Relative to comparison subjects, depressed patients demonstrated significantly less bilateral ventral striatal activation to positive stimuli, correlating with decreased interest/pleasure in and performance of activities. They also displayed decreased activation to positive stimuli in a dorsomedial frontal region associated with processing of self-related stimuli. Responses of depressed subjects to negative stimuli were consistent with the growing literature on frontolimbic dysfunction in depression. CONCLUSIONS: This finding 1) supports a pathophysiological model of depression that includes reward/motivational pathway dysfunction, 2) suggests a contributing neural substrate of the inability to experience pleasure or engage in rewarding activities, 3) provides greater specification of abnormalities of basal ganglia function in depression, and 4) may help guide treatment approaches.

Adult↗
PubMed2005

Orbitofrontal cortex activity related to emotional processing changes across the menstrual cycle.

The orbitofrontal cortex (OFC) has been implicated in the representation of emotional stimuli, assignment of emotional valence/salience to stimuli, stimulus-reinforcement association learning, motivation, and socio-emotional control. Using functional magnetic resonance imaging in female subjects without premenstrual mood symptoms, we found that OFC activity to emotional linguistic stimuli varies depending on the menstrual cycle phase. Specifically, anterior-medial OFC activity for negative vs. neutral stimuli was increased premenstrually and decreased postmenstrually. The inverse pattern was seen in the lateral OFC. These findings suggest that specific subregional OFC activity to emotional stimuli is modulated across the menstrual cycle. The data also demonstrate that menstrual cycle phase is an important consideration in further studies attempting to elucidate the neural substrates of affective representation.

Adult↗
PubMed2005

Fear-related activity in subgenual anterior cingulate differs between men and women.

Functional magnetic resonance imaging in association with an instructed fear/anticipatory anxiety paradigm was used to explore sex differences in the human fear response. During anticipation of mild electrodermal stimulation, women, as compared with men, demonstrated increased activity in the subgenual anterior cingulate cortex and functionally related regions of the insula and brainstem. The subgenual anterior cingulate cortex is a region critical for emotional control implicated in the pathogenesis of psychiatric disease. Present findings suggest a contributory neural substrate for the greater susceptibility of women to anxiety and affective disorders, and emphasize the importance of considering participant sex when designing and interpreting functional neuroimaging studies.

Adult↗
PubMed2005

Top-down reorganization of activity in the visual pathway after learning a shape identification task.

Learning in shape identification led to global changes in activation across the entire visual pathway, as revealed with whole-brain fMRI. Following extensive training in a shape identification task, brain activity associated with trained shapes relative to the untrained shapes showed: (1) an increased level of activity in retinotopic cortex (RC), (2) a decrease in activation of the lateral occipital cortex (LO), and (3) a decrease in the dorsal attentional network. In addition, RC activations became more correlated (and LO activation, less correlated) with performance. When comparing target-present and target-absent trials within the trained condition, we observed a similar decrease in the dorsal attentional network but not in the visual cortices. These findings indicate a large-scale reorganization of activity in the visual pathway as a result of learning, with the RC becoming more involved (and the LO, less involved) and that these changes are triggered in a top-down manner depending on the perceptual task performed.

Adult↗
PubMed2005

Differential time courses and specificity of amygdala activity in posttraumatic stress disorder subjects and normal control subjects.

BACKGROUND: Previous neuroimaging studies have demonstrated exaggerated amygdala responses to negative stimuli in posttraumatic stress disorder (PTSD). The time course of this amygdala response is largely unstudied and is relevant to questions of habituation and sensitization in PTSD exposure therapy. METHODS: We applied blood oxygen level dependent functional magnetic resonance imaging and statistical parametric mapping to study amygdala responses to trauma-related and nontrauma-related emotional words in sexual/physical abuse PTSD and normal control subjects. We examined the time course of this response by separate analysis of early and late epochs. RESULTS: PTSD versus normal control subjects have a relatively increased initial amygdala response to trauma-related negative, but not nontrauma-related negative, versus neutral stimuli. Patients also fail to show the normal patterns of sensitization and habituation to different categories of negative stimuli. These findings correlate with measured PTSD symptom severity. CONCLUSIONS: Our results demonstrate differential time courses and specificity of amygdala response to emotional and control stimuli in PTSD and normal control subjects. This has implications for pathophysiologic models of PTSD and treatment response. The results also extend previous neuroimaging studies demonstrating relatively increased amygdala response in PTSD and expand these results to a largely female patient population probed with emotionally valenced words.

Adolescent↗
PubMed2005

Simultaneous perfusion and blood-oxygenation-level-dependent measurements using single-shot interleaved z-shim echo-planar imaging.

Single-shot interleaved z-shim EPI (SSIZS-EPI) was extended to a simultaneous perfusion and blood-oxygenation-level-dependent (BOLD) imaging technique that reduces susceptibility-induced signal loss while preserving rapid image acquisition. Experiments on human brains showed that images acquired with this technique had improved signal-to-noise ratio in the inferior prefrontal, meso-, and lateral-temporal lobes compared with a conventional EPI. Perfusion maps obtained from the SSIZS-EPI images at resting state illustrated substantial signal recovery in these brain areas. Perfusion and BOLD images collected with a sensorimotor paradigm demonstrated the feasibility of the technique to simultaneously measure cerebral blood flow and blood oxygenation signals associated with brain activation. Functional experiments with a neuropsychiatric paradigm showed increased brain activities in the periamygdalar regions in both perfusion and BOLD maps, consistent with a previous H(2) (15)O PET study. The proposed technique, with its advantages of reducing susceptibility artifacts and fast scanning speed, would be useful for obtaining more reliable measurements of functional signals, particularly in the brain regions with field inhomogeneities.

Artifacts↗
PubMed2005

Defining the neurocircuitry of borderline personality disorder: functional neuroimaging approaches.

Functional neuroimaging recently has been used to localize brain dysfunction in borderline personality disorder (BPD). Initial studies have examined baseline activity or emotional reactivity, and our group has investigated what we consider to be a crucial interaction between negative emotion and behavioral (dys)control. This research is beginning to identify abnormal frontolimbic circuitry likely underlying core clinical features of this condition. We review the evidence for dysfunction in specific frontolimbic regions, leading to a mechanistic model of symptom formation in BPD. In addition, we offer an integration of these neuroimaging findings with developmental perspectives on the emergence of borderline psychopathology, focusing on the ways in which early psychosocial experience may interact with developing brain systems. We also consider possible mechanisms of psychotherapeutic change at the neural systems level in BPD. Finally, we propose that future neuroimaging studies of BPD should integrate multiple levels of observation (structural, functional, neurochemical, genetic, and clinical) in a model-driven fashion to further understand the dynamic relationship between biological and psychological factors in the development and treatment of this difficult condition.

Adolescent↗
PubMed2003

Circular spectrum mapping for intravoxel fiber structures based on high angular resolution apparent diffusion coefficients.

A method is presented for mapping intravoxel fiber structures using spectral decomposition onto a circular distribution of measured apparent diffusion coefficients (ADCs). The zeroth-, second-, and fourth-order harmonic components of the ADC distribution on the circle spanned by the major and median eigenvectors of the diffusion tensor can be used to provide quantitative indices for isotropic, linear, and fiber-crossing diffusion, respectively. A diffusion-weighted MRI technique with 90 encoding orientations was implemented to estimate the circular ADC distribution and calculate the circular spectrum. A digital phantom was used to simulate various diffusion patterns. Comparisons were made between the circular spectrum and regular DTI-based index maps. The results indicated that the zeroth- and second-order circular spectrum maps exhibited a strong consistency with the DTI-based mean diffusivity and linear indices, respectively, and the fourth-order circular spectrum map was able to identify the fiber crossings. MRI experiments were performed on seven healthy human brains using a 3T scanner. The in vivo fourth-order maps showed significantly higher densities in several brain regions, including the corpus callosum, cingulum bundle, superior longitudinal fasciculus, corticospinal tract, and middle cerebellar peduncle, which indicated the existence of fiber crossings in these regions.

Adult↗
PubMed2003

An approach to the psychobiology of personality disorders.

Human variability in temperament allows a unique natural experiment where reactivity, self-regulation, and experience combine in complex ways to produce an individual personality. Personality disorders may result from changes in the way past memories filter new information in situations of emotional involvement with others. According to this view, disorders are specific to their initiating circumstances rather than a general difficulty that might extend to classes of information processing remote from triggers for the disorder. A different view suggests a more general deficit in attentional control mechanisms that might extend to a wide range of situations far from those related to the core abnormality. This paper outlines methods for examining these views and presents data from the study of borderline personality disorder, arguing in favor of high negative emotionality being combined with a deficit in an executive attentional control network. Because this attentional network has already been well described in terms of anatomy, the cognitive operations involved, development, chemical modulators, and effects of lesions and candidate genes, these findings may have implications for understanding the disorder and its treatment. We consider these implications in terms of a general approach to the study of personality development and its disorders.

Adult↗
PubMed2003

Single-shot MR imaging using trapezoidal-gradient-based Lissajous trajectories.

A novel single-shot trapezoidal-gradient-based Lissajous trajectory is described and implemented on a 3-tesla magnetic resonance (MR) scanner. A feature of this trajectory is that its sampling points are located on a nonequidistant rectangular grid, which permits the usage of one-dimensional optimal algorithms to increase the robustness and speed of image reconstruction. Another advantage of the trajectory is that two images with different effective echo times can be obtained within a single excitation, which might be used for fast T2* mapping, in functional MR imaging scanning of brain activity associated with mental processes. Potential artifacts in reconstructed images were investigated and methods for suppressing these artifacts were developed. Experiments on normal subjects at rest and during brain activation were performed to demonstrate the feasibility of the new sequence.

Algorithms↗
PubMed2003

The emerging dialogue between psychoanalysis and neuroscience: neuroimaging perspectives.

Current progress in the cognitive neurosciences is highly relevant to the development of psychoanalytic theory and practice. Neuroscience is today becoming mature enough to provide empirical biological approaches for the investigation of psychoanalytic models and observations. The current state of functional neuroimaging techniques is reviewed, selected paradigms and findings relevant to psychotherapy research are presented, and ways to pursue the dialogue between psychoanalysts and neuroscientists are discussed, as are some related obstacles and pitfalls. The emerging dialogue between psychoanalysts and neuroscientists may help not only to reestablish a solid position of psychodynamic theory and treatment in contemporary medicine, but also to bridge the division between "psychological" and "somatic" treatments, and gain important insights into the mind-brain relationship.

Brain↗
PubMed2002

Simultaneous perfusion and BOLD imaging using reverse spiral scanning at 3T: characterization of functional contrast and susceptibility artifacts.

Reverse spiral scanning with arterial spin-labeling was developed at 3T to simultaneously detect perfusion and BOLD signals in the brain by subtracting or adding the control and labeled images, respectively, in the same dataset. BOLD contrast was improved with the longer effective echo time achieved in the reverse spiral scan compared to conventional forward spiral scans. Susceptibility artifacts near air-tissue interfaces in the brain were substantially reduced in the reverse spiral images due to their early data acquisition time and, hence, less signal attenuation. Brain activation experiments with the reverse spiral scan were performed on normal subjects and were compared to forward spiral imaging in the same subjects. The experiments demonstrated that reverse spiral imaging was able to detect perfusion and BOLD signals simultaneously and reliably, even in the brain regions with severe susceptibility-induced local gradients, while forward spiral scans were either not optimal for detecting the two functional signals at the same time or were vulnerable to susceptibility artifacts.

Adult↗
PubMed2002

Physiological mapping of human auditory cortices with a silent event-related fMRI technique.

Cortical field boundaries of sensory areas can be physiologically defined. The delineation of the human auditory cortical architecture remains incomplete. Here we used systematic variation of pitch and duration of sinusoidal tones to define auditory cortical fields along Heschl's gyrus with a silent, event-related fMRI scanning technique that allowed us to determine spatially small shifts of neuronal responses. Thus, we were able to establish higher-resolution tonotopic maps. Acoustic intervals of two octaves correspond to an average 2-mm anatomical distance along Heschl's gyrus. We also demonstrate that one tonotopic map with a medio-lateral low- to high-frequency gradient is located on the lateral half of Heschl's gyrus, which might correspond to field R in primates. Furthermore, we studied cortical responses to brief (50-ms) transients with fMRI and demonstrate that silent, event-related fMRI is capable of measuring significant blood oxygen level-dependent effect to such brief events in the acoustic domain. Our results add to current knowledge on the number and precise localization of multiple tonotopic maps in human auditory cortex. More specifically, they support the hypothesis that there may be two primary auditory cortical fields with mirror tonotopic organization on Heschl's gyrus in man.

Acoustic Stimulation↗
PubMed2002

Single-shot interleaved z-shim EPI with optimized compensation for signal losses due to susceptibility-induced field inhomogeneity at 3 T.

A new single-shot echo-planar imaging (EPI) sequence with interleaved z-shim and optimized compensation for susceptibility-induced signal loss is proposed in this paper. Experiments on human brain demonstrated that the new method is able to regain signal dropout in brain areas with severe susceptibility-induced local gradients, while its image acquisition speed is comparable to that of conventional single-shot EPI techniques. Significant signal-to-noise ratio improvements were demonstrated in the ventral prefrontal and lateral temporal lobes with the new technique compared to a conventional EPI. Brain activation experiments with a bilateral finger-tapping task were performed with intentionally introduced local gradients near the left sensorimotor cortex, by a small gadolinium (Gd)-doped bottle placed on the left side of the head. The results of the functional experiments showed that the interleaved z-shim EPI sequence effectively recovered the signal loss caused by the Gd-doped bottle and reliably detected activation signals in bilateral sensorimotor regions, while the activation signals on the left side diminished considerably in a conventional EPI technique. The new technique, with the capability of reducing susceptibility artifacts and rapid scanning speed, may be particularly useful for event-related functional MRI experiments in the base of the brain, which are of great importance in neuropsychiatric studies.

Adult↗