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Trauma modulates amygdala and medial prefrontal responses to consciously attended fear

NEUROimage 2006年第2期29卷 347-357页

作者： Williams, LM Kemp, AH Felmingham, K Barton, M Olivieri, G Peduto, A Gordon, E Bryant, RA Westmead Hosp Brain Dynam Ctr Westmead NSW 2145 Australia Univ Sydney Sch Psychol Sydney NSW 2006 Australia Univ Sydney Western Clin Sch Div Psychol Med Sydney NSW 2006 Australia Westmead Hosp MRI Unit Westmead NSW 2145 Australia Univ New S Wales Sch Psychol Kensington NSW 2033 Australia Brain Resource Co Ultimo Brain Resource Int Database Sydney NSW 2007 Australia

Effective fear processing relies on the amygdala and medial prefrontal cortex (MPFC). Post-trauma reactions provide a compelling model for examining how the heightened experience of fear impacts these systems. Post-traumatic stress disorder (PTSD) has been associated with excessive amygdala and a lack of MPFC activity in response to nonconscious facial signals of fear, but responses to consciously processed facial fear stimuli have not been examined. We used functional MRI to elucidate the effect of trauma reactions on amygdala-MPFC function during an overt fear perception task. Subjects with PTSD (n = 13) and matched non-traumatized healthy subjects (it = 13) viewed 15 blocks of eight fearful face stimuli alternating pseudorandomly with 15 blocks of neutral faces (stimulus duration 500 ms;ISI 767 ms). We used random effects analyses in SPM2 to examine within- and between-group differences in the MPFC and amygdala search regions of interest. Time series data were used to examine amygdala-MPFC associations and changes across the first (Early) versus second (Late) phases of the experiment. Relative to non-traumatized subjects, PTSD subjects showed a marked bilateral reduction in MPFC activity (in particular, right anterior cingulate cortex, ACC), which showed a different Early-Late pattern to non-traumatized subjects and was more pronounced with greater trauma impact and symptomatology. PTSD subjects also showed a small but significant enhancement in left amygdala activity, most apparent during the Late phase, but reduction in Early right amygdala response. Over the time course, trauma was related to a distinct pattern of ACC and amygdala connections. The findings suggest that major life trauma may disrupt the normal pattern of medial prefrontal and amygdala regulation. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adult Amygdala/injuries Amygdala/physiopathology Brain Hemorrhage, Traumatic/physiopathology Brain Hemorrhage, Traumatic/physiopathology Brain Hemorrhage, Traumatic/psychology Brain Hemorrhage, Traumatic/psychology Echo-Planar Imaging Facial Expression Fear/physiology Female Humans image processing, computer-assisted Male Prefrontal Cortex/injuries Prefrontal Cortex/physiopathology Stress Disorders, Post-Traumatic/physiopathology Stress Disorders, Post-Traumatic/psychology War

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Skull-stripping magnetic resonance brain images using a model-based level set

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NEUROimage 2006年第1期32卷 79-92页

作者： Zhuang, Audrey H. Valentino, Daniel J. Toga, Arthur W. Univ Calif Los Angeles Dept Radiol Sci Div Intervent Neuroradiol Los Angeles CA 90095 USA Univ Calif Los Angeles Dept Neurol Lab Neuroimaging Los Angeles CA 90095 USA

The segmentation of brain tissue from nonbrain tissue in magnetic resonance (MR) images, commonly referred to as skull stripping, is an important image processing step in many neuroimage studies. A new mathematical algorithm, a model-based level set (MLS), was developed for controlling the evolution of the zero level curve that is implicitly embedded in the level set function. The evolution of the curve was controlled using two terms in the level set equation, whose values represented the forces that determined the speed of the evolving curve. The first force was derived from the mean curvature of the curve, and the second was designed to model the intensity characteristics of the cortex in MR images. The combination of these forces in a level set framework pushed or pulled the curve toward the brain surface. Quantitative evaluation of the MLS algorithm was performed by comparing the results of the MLS algorithm to those obtained using expert segmentation in 29 sets of pediatric brain MR images and 20 sets of young adult MR images. Another 48 sets of elderly adult MR images were used for qualitatively evaluating the algorithm. The MLS algorithm was also compared to two existing methods, the brain extraction tool (BET) and the brain surface extractor (BSE), using the data from the Internet brain segmentation repository (IBSR). The MLS algorithm provides robust skull-stripping results, making it a promising tool for use in large, multi-institutional, population-based neuroimaging studies. (c) 2006 Elsevier Inc. All rights reserved.

关键词： Aged Algorithms Automation Brain/anatomy & histology Humans image processing, computer-assisted Magnetic Resonance Imaging/methods Models, Neurological Skull/anatomy & histology

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Neural correlates of adjunctive rivastigmine treatment to antipsychotics in schizophrenia: A randomized, placebo-controlled, double-blind fMRI study

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NEUROimage 2006年第2期29卷 545-556页

作者： Kumari, V Aasen, I Ffytche, D Williams, SCR Sharma, T Kings Coll London Inst Psychiat Dept Psychol London SE5 8AF England Kings Coll London Inst Psychiat Div Psychol Med London SE5 8AF England Kings Coll London Inst Psychiat Ctr Neuroimaging London SE5 8AF England Clin Neurosci Res Ctr Dartford England

Facilitation of central cholinergic activity may form a potential treatment strategy for cognitive impairment in schizophrenia. In a randomized, placebo-controlled, double-blind, parallet-group design, we investigated the neural correlates of cognitive effects of rivastigmine, an acetylcholinesterase inhibitor, given as an add-on therapy to antipsychotic-treated schizophrenia patients. Thirty-six chronic schizophrenia patients with mild cognitive impairment took part. After I week on placebo (baseline), all patients entered a double-blind protocol;18 were allocated to receive rivastigmine and 18 placebo for the next 12 weeks (final sample with usable imaging data: It patients on rivastigmine, 10 on placebo). All patients underwent functional magnetic resonance imaging during a parametric 'n-back' task, involving monitoring of dots in particular locations on a screen at a given delay from the original occurrence, twice: at baseline and 12 weeks post-rivastigmine/placebo treatment. Compared to placebo, rivastigmine produced only a small and non-significant improvement in task accuracy across all conditions with no change in response latency, and increased activity in the extrastriate visual cortex in areas associated with visual and spatial attention but not in any region within the working memory network. Our observations suggest that cholinergic enhancement with rivastigmine at doses known to be effective in Alzheimer's disease does not produce strong and clinically meaningful cognitive and neural changes in schizophrenia patients treated with atypical antipsychotics although the neural effects in terms of enhanced neuronal activity in regions associated with visual and spatial attention are consistent with those reported previously with cholinergic enhancement in healthy subjects. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adult Antipsychotic Agents/therapeutic use Brain/pathology Cerebral Cortex/pathology Dose-Response Relationship, Drug Double-Blind Method Drug Therapy, Combination Female Humans image processing, computer-assisted Magnetic Resonance Imaging Male Middle Aged Models, Statistical Neuroprotective Agents/therapeutic use Phenylcarbamates/therapeutic use Psychiatric Status Rating Scales Reaction Time/physiology Schizophrenia/drug therapy Schizophrenia/pathology Smoking/pathology Smoking/pathology

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Levels of appraisal: A medial prefrontal role in high-level appraisal of emotional material

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NEUROimage 2006年第4期30卷 1458-1466页

作者： Kalisch, Raffael Wiech, Katja Critchley, Hugo D. Dolan, Raymond J. UCL Inst Neurol Funct Imaging Lab Wellcome Dept Imaging Neurosci London WC1N 3BG England

Appraisal refers to the evaluation of the meaning of emotional stimuli and is considered causal in the generation of an emotional response. Cognitive neuroscience has paid little attention to a theoretical distinction between low-level appraisal, considered to be automatic and preattentive, and high-level appraisal that requires attentional and working memory resources. To disentangle low-level from high-level appraisal, we varied cognitive load in a concurrent, unrelated working memory task, while anxiety was induced through anticipation of impending pain. Confirming theoretical predictions, we show that anxiety-related activity in dorsal medial prefrontal/rostral anterior cingulate cortex (dorsal MPFC/ACC) is attenuated under high, relative to low, cognitive load. Lateral prefrontal regions previously implicated in reappraisal and cognitive emotion regulation show a similar interaction between anxiety and cognitive load. Critically, there were no changes in physiological and subjective measures of low-level appraisal outcome and emotional response generation as a function of load, allowing us to conclude that MPFC/ACC and lateral PFC activity during anticipatory anxiety reflects high-level appraisal. Our data provide neurobiological evidence for a distinction between low-level and high-level appraisal mechanisms. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adolescent Adult Anxiety/physiopathology Arousal/physiology Attention/physiology Brain Mapping Brain Mapping Cerebral Cortex/physiopathology Emotions/physiology Female Functional Laterality/physiology Gyrus Cinguli/physiopathology Humans image processing, computer-assisted Imaging, Three-Dimensional Magnetic Resonance Imaging Male Memory, Short-Term/physiology Middle Aged Nerve Net/physiopathology Pain/physiopathology Prefrontal Cortex/physiology Prefrontal Cortex/physiopathology Psychomotor Performance/physiology Serial Learning/physiology

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An fMRI investigation of short-term source memory in young and older adults

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NEUROimage 2006年第2期30卷 627-633页

作者： Mitchell, KJ Raye, CL Johnson, MK Greene, EJ Yale Univ Dept Psychol New Haven CT 06520 USA

Using functional magnetic resonance imaging (fMRI) and a working memory procedure, we compared source memory judgments (format and location) with old-new judgments in young and older adults. Consistent with previous FMRI findings, for young adults, an area of left dorsolateral prefrontal cortex showed greater activity during format than old-new judgments made immediately, as well as those made after a brief, filled delay. In contrast, for older adults, activity I this area was not greater during format than old-new judgments at either retention interval. These data provide additional evidence that left lateral prefrontal cortex is important in monitoring specific source information and new, evidence that older adults' source memory deficits may be related, in part, to reduced function of this brain area. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adult Aged Aging/psychology Female Functional Laterality/physiology Humans image processing, computer-assisted Magnetic Resonance Imaging Male Memory, Short-Term/physiology Prefrontal Cortex/physiology Psychomotor Performance/physiology

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Self-initiated movements in chronic prefrontal traumatic brain injury:: An event-related functional MR1 study

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NEUROimage 2006年第4期30卷 1292-1301页

作者： Wiese, Holger Toennes, Christina de Greiff, Armin Nebel, Katharina Diener, Hans-Christoph Stude, Philipp Univ Duisburg Gesamthsch Dept Neurol Essen Germany Univ Duisburg Gesamthsch Inst Diagnost & Intervent Radiol & Neuroradiol Essen Germany

Electrophysiological studies found traumatic lesions of the prefrontal cortex (PFC) to affect the preparation of self-initiated movements. However, a precise localization of the observed effects has not been reported yet. Moreover, previous reports did not account for effects of lesion location. Therefore, the present study utilized functional MRI to investigate the influence of predominantly left or right hemispheric PFC lesions on movement preparation in chronic traumatic brain injury (TBI) patients. 18 TBI patients with MRI-defined contusions of the PFC as well as 18 healthy control subjects matched for age and gender were examined. Patients were divided into subgroups of predominantly left or right hemispheric lesions. During functional image acquisition, subjects performed self-initiated abductions of their right index finger. Neuropsychological tests of attention and working memory, which are supposed to modulate preparatory processes, were conducted. Patients with predominantly left contusions demonstrated enhanced activity of the dorsal lateral premotor cortex in comparison to healthy control subjects. In predominantly right lesioned patients, reduced activity within the right caudate head was observed. Compared to predominantly left lesioned patients, neuropsychological tests yielded reduced task performances in the right lesion subgroup. In line with previous electrophysiological research, imaging results of the present study are interpreted to represent altered preparatory networks in chronic prefrontal TBI patients. Since attentional and working memory functions are supposed to modulate preparatory processes, differences between the patient subgroups are suggested to result from the more pronounced cognitive impairments in the right-lesioned group. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adult Attention/physiology Brain/physiopathology Brain Injuries/physiopathology Brain Injuries/physiopathology Brain Injury, Chronic/physiopathology Brain Injury, Chronic/physiopathology Brain Mapping Brain Mapping Caudate Nucleus/physiopathology Dominance, Cerebral/physiology Female Fingers/innervation Humans image processing, computer-assisted Imaging, Three-Dimensional Magnetic Resonance Imaging Male Memory, Short-Term/physiology Middle Aged Motor Activity/physiology Motor Cortex/physiopathology Neural Pathways/physiopathology Neuropsychological Tests Prefrontal Cortex/injuries Prefrontal Cortex/physiopathology Reaction Time

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Human striatal activation reflects degree of stimulus saliency

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NEUROimage 2006年第3期29卷 977-983页

作者： Zink, CF Pagnoni, G Chappelow, J Martin-Skurski, M Berns, GS Emory Univ Sch Med Dept Psychiat & Behav Sci Atlanta GA 30322 USA

Salient stimuli are characterized by their capability to perturb and seize available cognitive resources. Although the striatum and its dopaminergic inputs respond to a variety of stimuli categorically defined as salient, including rewards, the relationship between striatal activity and saliency is not well understood. Specifically, it is unclear if the striatum responds in an all-or-none fashion to salient events or instead responds in a graded fashion to the degree of saliency associated with an event. Using functional magnetic resonance imaging, we measured activity in the brains of 20 participants performing a visual classification task in which they identified single digits as odd or even numbers. An auditory tone preceded each number, which was occasionally, and unexpectedly, substituted by a novel sound. The novel sounds varied in their ability to interrupt and reallocate cognitive resources (i.e., their saliency) as measured by a delay in reaction time to immediately subsequent numerical task-stimuli. The present findings demonstrate that striatal activity increases proportionally to the degree to which an unexpected novel sound interferes with the current cognitive focus, even in the absence of reward. These results suggest that activity in the human striatum reflects the level of saliency associated with a stimulus, perhaps providing a signal to reallocate limited resources to important events. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Acoustic Stimulation Adolescent Adult Female Galvanic Skin Response/physiology Humans image processing, computer-assisted Magnetic Resonance Imaging Male Neostriatum/physiology Psychomotor Performance/physiology Reaction Time/physiology Reward Visual Perception/physiology

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Developmental changes in the neural correlates of semantic processing

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NEUROimage 2006年第4期29卷 1141-1149页

作者： Chou, TL Booth, JR Burman, DD Bitan, T Bigio, JD Lu, D Cone, NE Northwestern Univ Dept Commun Sci & Disorders Evanston IL 60208 USA Evanston NW Healthcare Dept Radiol Evanston IL 60208 USA

Functional magnetic resonance imaging (fMRI) was used to explore the neural correlates of semantic judgments in the auditory modality in a group of 9- to 15-year-old children. Subjects were required to indicate if word pairs were related in meaning. Consistent with previous findings in adults, children showed activation in bilateral superior temporal gyri (BA 22) for recognizing spoken words as well as activations in bilateral inferior frontal gyri (BAs 47, 45) and left middle temporal gyrus (BA 21) for semantic processing. The neural substrates of semantic association and age differences were also investigated. Words with strong semantic association elicited significantly greater activation in the left inferior parietal lobule (BA 40), whereas words with weak semantic association elicited activation in left inferior frontal gyros (BAs 47/45). Correlations with age were observed in the left middle temporal gyrus (BA 21) and the right inferior frontal gyrus (BA 47). The pattern of results for semantic association implies that the left inferior parietal lobule effectively integrates highly related semantic features and the left inferior frontal gyros becomes more active for words that require a greater search for semantic associations. The developmental results suggest that older children recruit the right inferior frontal gyrus as they conduct a broader semantic search and the left middle temporal gyrus to provide more efficient access to semantic representations. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adolescent Age Factors Brain Mapping Brain Mapping Cerebral Cortex/physiology Child Dominance, Cerebral/physiology Female Humans image processing, computer-assisted Imaging, Three-Dimensional Language Development Magnetic Resonance Imaging Male Paired-Associate Learning/physiology Parietal Lobe/physiology Reference Values Semantics Speech Perception/physiology Temporal Lobe/physiology

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Systems level modeling of a neuronal network subserving intrinsic alertness

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NEUROimage 2006年第1期29卷 225-233页

作者： Mottaghy, FM Willmes, K Horwitz, B Müller, HW Krause, BJ Sturm, W Univ Hosp Ulm Dept Nucl Med D-89070 Ulm Germany HHU Dept Nucl Med Dusseldorf Germany KME Res Ctr Julich Germany RWTH Aachen Univ Univ Hosp Sect Neuropsychol Neurol Clin Aachen Germany NIDCD Voice Speech & Language Branch NIH Bethesda MD 20892 USA

Cognitive control of alertness in unwarned situations (intrinsic alertness) relies on a predominantly right hemisphere cortical and subcortical network. In a previous functional activation study, we have demonstrated that this network comprises the anterior cingulate gyrus, the dorsolateral and polar frontal as well as the inferior parietal cortex, the thalamus and ponto-mesencephalic parts of the brain stem. The aim of this study was to study effective connectivity of this network by employing structural equation modeling. Fifteen right-handed male subjects participated in the PET study. The functional network showed stronger connectivity in the right hemisphere. Furthermore, there were strong effective connections between thalamus and brainstem on the one hand and between thalamus and anterior cingulate on the other. Our results suggest that the anterior cingulate functions as the central coordinating structure for the right hemispheric neural network of intrinsic alertness and that the anterior cingulate gyrus is modulated mainly by prefrontal and parietal cortex. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adult Attention/physiology Cerebral Cortex/physiology Data Interpretation, Statistical Fixation, Ocular/physiology Functional Laterality/physiology Humans image processing, computer-assisted Male Models, Neurological Nerve Net/physiology Nerve Net/radionuclide imaging Photic Stimulation Positron-Emission Tomography Psychomotor Performance/physiology Visual Perception/physiology

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Neural substrates for dividing and focusing attention between simultaneous auditory and visual events

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NEUROimage 2006年第4期31卷 1673-1681页

作者： Johnson, Jennifer Adrienne Zatorre, Robert J. McGill Univ Montreal Neurol Inst Montreal PQ H3A 2B4 Canada

With information constantly bombarding the human sensory systems, how is it that we attend to behaviorally relevant information? The present study examined the behavioral and neural bases of attending to one sense while ignoring another sense (bimodal selective attention) contrasted with attending simultaneously to two senses (bimodal divided attention). In a functional magnetic resonance imaging (fMRI) study, subjects simultaneously heard novel melodies and viewed geometric shapes. They were instructed to actively attend to only one or to both senses (selective or divided attention) or as a baseline condition, passively observe both (bimodal passive). Memory tests for both attended and unattended stimuli validated that subjects were following the attention instructions. Selective attention led to increased activity in relevant sensory cortices while simultaneously leading to decreased activity in irrelevant sensory cortices. The divided attention instruction did not lead to a global increase in sensory cortex activity compared to the bimodal passive baseline condition. However, divided attention did recruit heteromodal areas in the left dorsolateral prefrontal cortex, while selective attention did not recruit any frontal areas. We propose that sustained selective and divided bimodal attention were achieved via distinct neural processes. Selective attention was achieved primarily via modulation of the sensory cortices. Divided attention was achieved for most individuals via recruitment of the middle-dorsolateral prefrontal cortex. However, there was also a trade-off between activity in posterior-dorsolateral prefrontal cortex and sensory regions, such that individuals who demonstrated the best performance during divided attention also showed the greatest recruitment of sensory cortices. (c) 2006 Elsevier Inc. All rights reserved.

关键词： Acoustic Stimulation Adult Algorithms Attention/physiology Auditory Perception/physiology Female Humans image processing, computer-assisted Magnetic Resonance Imaging Male Oxygen/blood Photic Stimulation Psychomotor Performance/physiology Recognition (Psychology)/physiology Visual Perception/physiology

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