Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 112
Filtrar
1.
bioRxiv ; 2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39229056

RESUMO

Three-dimensional (3D) ex vivo imaging of cleared intact brains of animal models and large human and non-human primate postmortem brain specimens is important for understanding the physiological neural network connectivity patterns and the pathological alterations underlying neuropsychiatric and neurological disorders. Light-sheet microscopy has emerged as a highly effective imaging modality for rapid high-resolution imaging of large cleared samples. However, the orthogonal arrangements of illumination and detection optics in light sheet microscopy limits the size of specimen that can be imaged. Recently developed light sheet theta microscopy (LSTM) technology addressed this by utilizing a unique arrangement of two illumination light paths oblique to the detection light path, while allowing perpendicular arrangement of the detection light path relative to the specimen surface. Here, we report development of a next-generation, fully integrated, and user-friendly LSTM system for rapid sub-cellular resolution imaging uniformly throughout a large specimen without constraining the lateral (XY) size. In addition, we provide a seamlessly integrated workflow for image acquisition, data storage, pre- and post-processing, enhancement, and quantitative analysis. We demonstrate the system performance by high-resolution 3D imaging of intact mouse brains and human brain samples, and complete data analysis including digital neuron tracing, vessel reconstruction and design-based stereological analysis in 3D. This technically enhanced and user-friendly LSTM implementation will enable rapid quantitative mapping of molecular and cellular features of interests in diverse types of very large samples.

2.
Blood Adv ; 8(6): 1504-1508, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38330194

RESUMO

ABSTRACT: Metachromatic leukodystrophy (MLD) is a rare genetic disorder caused by pathogenic variants of the ARSA gene, leading to a deficiency of the arylsulfatase A enzyme (ARSA) and consecutive accumulation of galactosylceramide-3-0-sulfate in the nervous system. The condition leads to severe neurological deficits and subsequently results in profound intellectual and motoric disability. Especially, the adult form of MLD, which occurs in individuals aged >16 years, poses significant challenges for treating physicians because of the rarity of cases, limited therapeutic options, and different allogeneic hematopoietic cell transplantation (allo-HCT) protocols worldwide. Here, we report the results of allo-HCT treatment in 4 patients with a confirmed adult MLD diagnosis. Bone marrow or mobilized peripheral progenitor cells were infused after a reduced intensity conditioning regime consisting of fludarabine and treosulfan. In 3 patients, allo-HCT was followed by an infusion of mesenchymal cells to further consolidate ARSA production. We observed a good tolerability and an increase in ARSA levels up to normal range values in all patients. A full donor chimerism was detected in 3 patients within the first 12 months. In a 1-year follow-up, patients with complete donor chimerism showed a neurological stable condition. Only 1 patient with an increasing autologous chimerism showed neurological deterioration and a decline in ARSA levels in the first year. In summary, allo-HCT offers a therapeutic option for reconstituting ARSA enzyme levels in adult patients with MLD, with tolerable side effects.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucodistrofia Metacromática , Adulto , Humanos , Leucodistrofia Metacromática/terapia , Cerebrosídeo Sulfatase/genética
3.
Psychiatry Res Neuroimaging ; 335: 111708, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37717542

RESUMO

Thickness of the medial orbitofrontal cortex (mOFC) was assessed as it varied with reported symptoms of anxiety and depression in a large sample of anxiety patients. A principal component analysis identified a primary factor of transdiagnostic dimensional distress that predicted 24% of the mOFC variance. Severity of distress symptomology was associated with thinning of the mOFC in both hemispheres for both men and women, regardless of the primary DSM diagnosis. Taken together, the data indicate that mOFC thickness might be useful as an objective measure of disorder severity as well as to assess pharmacological or psychological treatment outcome.


Assuntos
Ansiedade , Córtex Pré-Frontal , Masculino , Humanos , Feminino , Córtex Pré-Frontal/diagnóstico por imagem , Ansiedade/diagnóstico por imagem , Transtornos de Ansiedade/diagnóstico por imagem , Córtex Cerebral , Lobo Frontal
4.
Biol Psychol ; 183: 108669, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37648076

RESUMO

The bioinformational theory of emotional imagery is a model of the hypothetical mental representations activated when people imagine emotionally engaging events, and was initially proposed to guide research and practice in the use of imaginal exposure as a treatment for fear and anxiety (Lang, 1979). In this 50 year overview, we discuss the development of bioinformational theory and its impact on the study of psychophysiology and psychopathology, most importantly assessing its viability and predictions in light of more recent brain-based studies of neural functional activation. Bioinformational theory proposes that narrative imagery, typically cued by language scripts, activates an associative memory network in the brain that includes stimulus (e.g., agents, contexts), semantic (e.g., facts and beliefs) and, most critically for emotion, response information (e.g., autonomic and somatic) that represents relevant real-world coping actions and reactions. Psychophysiological studies in healthy and clinical samples reliably find measurable response output during aversive and appetitive narrative imagery. Neuroimaging studies confirm that emotional imagery is associated with significant activation in motor regions of the brain, as well as in regions implicated in episodic and semantic memory retrieval, supporting the bioinformational view that narrative imagery prompts mental simulation of events that critically includes the actions and reactions engaged in emotional contexts.

5.
Biol Psychol ; 177: 108501, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36646300

RESUMO

Reduced hippocampal and/or amygdala volumes have been reported in patients with a variety of different anxiety diagnoses, suggesting that structural alterations may vary transdiagnostically across the internalizing disorders. The current study measured hippocampal and amygdala volumes in anxiety and mood disorder patients assessing differences that vary dimensionally with transdiagnostic factors of distress, anxious arousal, and trauma, based on a principal components analysis of questionnaires relating to symptomology. High-resolution structural images were collected in a sample of 165 patients, and volumes extracted from the hippocampal formation (including CA1, CA2/3, CA4/DG, subiculum, and molecular layer) and the amygdala. Transdiagnostically, increasing distress was associated with reduced hippocampal CA1 volume, increasing anxious arousal was associated with reduced hippocampal CA4/DG volume, and increasing trauma severity was associated with reduced amygdala volume in women. Taken together, the data indicate that subcortical brain volumes decrease as the severity of transdiagnostic psychopathological symptomology increases.


Assuntos
Hipocampo , Imageamento por Ressonância Magnética , Humanos , Feminino , Imageamento por Ressonância Magnética/métodos , Tonsila do Cerebelo , Ansiedade , Transtornos de Ansiedade , Tamanho do Órgão
6.
Neuropsychologia ; 169: 108203, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35248583

RESUMO

Understanding the neural correlates of repetitive retrieval of emotional events is critical in addressing pathological emotional processing, as repeated processing is central for a number of different therapeutic interventions. In the current study, single-trial functional brain activity was assessed in key regions implicated in episodic retrieval, including the medial prefrontal cortex (mPFC), anterior hippocampus, posterior hippocampus, and the posteromedial parietal cortex (i.e., posterior cingulate cortex and the precuneus) following repeated retrieval of pleasant and unpleasant autobiographical events. Replicating previous studies, repetition prompted reduced blood-oxygen-level-dependent (BOLD) amplitude in the anterior hippocampus and the mPFC, but not in the posterior hippocampus, due to no functional activity during mental imagery, or in the posteromedial parietal cortex, due to enhanced activation that was sustained across repetitions. Neural activation during pleasant and unpleasant autobiographical retrieval did not differ as a function of repetition, indicating similar processing effects regardless of motivational relevance. Taken together, the hedonic valence of retrieved memories does not affect functional activity associated with repeated retrieval of episodic events, in which the pattern of BOLD amplitude change suggests a dissociation between the hippocampal-prefrontal circuit, which shows repetition suppression, and the posteromedial parietal cortex, which shows sustained activation.


Assuntos
Encéfalo , Memória Episódica , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Mapeamento Encefálico , Emoções/fisiologia , Hipocampo/diagnóstico por imagem , Hipocampo/fisiologia , Humanos , Imageamento por Ressonância Magnética , Rememoração Mental/fisiologia , Lobo Parietal
7.
Neuropsychologia ; 164: 108087, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34785150

RESUMO

The default mode network (DMN) is activated when constructing and imagining narrative events, with functional brain activity in the medial-prefrontal cortex hypothesized to be modulated during emotional processing by adding value (or pleasure) to the episodic representation. However, since enhanced reactivity during emotional, compared to neutral, content is a more frequent finding in both the brain and body in physiological, neural, and behavioral measures, the current study directly assesses the effects of pleasure and emotion during narrative imagery in the DMN by using a within-subject design to first identify the DMN during resting state and then assess activation during pleasant, neutral, or unpleasant imagery. Replicating previous findings, enhanced functional activity in the medial prefrontal cortex was found when imagining pleasant, compared to unpleasant, events. On the other hand, emotion-related activation was found when imagining either pleasant or unpleasant, compared to neutral, events in other nodes of the DMN including the posterior cingulate cortex (PCC), angular gyrus, anterior hippocampus, lateral temporal cortex, temporal pole, dorsomedial prefrontal cortex (dmPFC), and ventrolateral prefrontal cortex (vlPFC). Pervasive emotional modulation in the DMN is consistent with the view that a primary function of event retrieval and construction is to remember, recreate, and imagine motivationally relevant events important for planning adaptive behavior.


Assuntos
Rede de Modo Padrão , Imageamento por Ressonância Magnética , Encéfalo/fisiologia , Mapeamento Encefálico , Emoções/fisiologia , Humanos
8.
J Affect Disord ; 287: 359-366, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33827011

RESUMO

INTRODUCTION: Reduced reactivity to pleasurable stimulation is a defining symptom of post-traumatic stress disorder (PTSD), but trauma exposure also increases the severity of many anxiety and mood disorders, including depression, social anxiety, and panic disorder, suggesting that reward system dysfunction might be pervasive in the internalizing disorders. The ventromedial prefrontal cortex (vmPFC) and ventral striatum are core components of the reward circuit and the current study assesses functional activity and connectivity in this circuit during emotional picture viewing in anxiety and mood disorder patients. METHOD: Functional brain activity (fMRI) and functional connectivity in the fronto-striatal circuit were measured in a large sample of patients diagnosed with anxiety and mood disorders (n=155) during affective scene viewing as it varied with trauma exposure and temperament. RESULTS: In women, but not men, blunted fronto-striatal connectivity was associated with increased posttraumatic anhedonic symptoms, whereas the amplitude of functional activity was not related to trauma exposure. In both men and women, reduced fronto-striatal connectivity was associated with decreases in temperamental positive affect. When predicting fronto-striatal connectivity, temperament and posttraumatic symptomology accounted for independent proportions of variance. LIMITATIONS: In this civilian sample of anxiety disorder patients, men reported very little trauma-related symptomology. CONCLUSIONS: Because dysfunctional reward processing due to trauma and temperament is pervasive across the internalizing disorder spectrum, assessing the integrity of the fronto-striatal reward circuit could provide important information in diagnostic and treatment protocols.


Assuntos
Transtornos de Estresse Pós-Traumáticos , Estriado Ventral , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Recompensa , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Estriado Ventral/diagnóstico por imagem
9.
J Affect Disord ; 276: 1142-1148, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791350

RESUMO

INTRODUCTION: The DSM-5 explicitly states that the neural system model of specific phobia is centered on the amygdala. However, this hypothesis is predominantly supported by human studies on animal phobia, whereas visual cuing of other specific phobias, such as dental fear, do not consistently show amygdala activation. Considering that fear of anticipated pain is one of the best predictors of dental phobia, the current study investigated neural and autonomic activity of pain anticipation in individuals varying in the degree of fear of dental pain. METHOD: Functional brain activity (fMRI) was measured in women (n = 31) selected to vary in the degree of self-reported fear of dental pain when under the threat of shock, in which one color signaled the possibility of receiving a painful electric shock and another color signaled safety. RESULTS: Enhanced functional activity during threat, compared to safety, was found in regions including anterior insula and anterior/mid cingulate cortex. Importantly, threat reactivity in the anterior insula increased as reported fear of pain increased and further predicted skin conductance changes during pain anticipation. LIMITATIONS: The sample was comprised of women. CONCLUSIONS: Individual differences in fear of pain vary with activation in the anterior insula, rather than with the amygdala, indicating that fear is not uniquely associated with amygdala activation. Whereas coping techniques such as emotion regulation have been found to vary with activation in a frontal-amygdala circuit when confronted with visual cues, precision psychiatry may need to target specific brain circuits to diagnose and treat different types of specific phobia.


Assuntos
Tonsila do Cerebelo , Transtornos Fóbicos , Animais , Encéfalo , Mapeamento Encefálico , Feminino , Giro do Cíngulo , Humanos , Imageamento por Ressonância Magnética , Dor
10.
Biol Psychol ; 154: 107926, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32621851

RESUMO

Unpleasant, compared to neutral, scenes reliably prompt enhanced functional brain activity in the amygdala and inferotemporal cortex. Considering data from psychophysiological studies in which defensive reactivity is further enhanced when viewing unpleasant scenes under threat of shock (compared to safety), the current study investigates functional activation in the amygdala-inferotemporal circuit when unpleasant (or neutral) scenes are viewed under threat of shock or safety. In this paradigm, a cue signaling threat or safety was presented in conjunction with either an unpleasant or neutral picture. Replicating previous studies, unpleasant, compared to neutral, scenes reliably enhanced activation in the amygdala and inferotemporal cortex. Functional activity in these regions, however, did not differ whether scenes were presented in a context threatening shock exposure, compared to safety, which instead activated regions of the anterior insula and cingulate cortex. Taken together, the data support a view in which neural regions activated in different defensive situations act independently.


Assuntos
Aprendizagem da Esquiva/fisiologia , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Neurônios/fisiologia , Adolescente , Tonsila do Cerebelo/citologia , Tonsila do Cerebelo/fisiologia , Estimulação Elétrica , Feminino , Giro do Cíngulo/citologia , Giro do Cíngulo/fisiologia , Humanos , Lobo Temporal/citologia , Lobo Temporal/fisiologia , Córtex Visual/citologia , Córtex Visual/fisiologia
11.
Biol Psychol ; 153: 107885, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32278595

RESUMO

Pupil diameter is dynamically modulated by a number of factors, including emotion, motor activity, and attention. Here, pupil modulation was examined as it varies with locus of control during aversive processing. Participants could control aversive exposure either by escape (terminating the event) or avoidance (blocking the event entirely), or they had no control. Highly anxious (n = 19), moderately anxious (n = 23), and less anxious (n = 23) participants saw cues that signaled whether a fast button press would terminate, prevent, or not affect subsequent presentation of an aversive picture. Pupil diameter was measured throughout the cuing interval. Pupil diameter was larger when preparing to escape or avoid compared to anticipating uncontrollable exposure. All participants, regardless of reported anxiety, showed increased pupil diameter in coping, relative to uncontrollable, contexts. Results support hypotheses that pupil diameter reflects action preparation and that differences in trait anxiety do not modulate this aspect of coping behavior in healthy subjects.


Assuntos
Adaptação Psicológica/fisiologia , Motivação , Pupila/fisiologia , Ansiedade/fisiopatologia , Ansiedade/psicologia , Atenção/fisiologia , Sinais (Psicologia) , Emoções/fisiologia , Feminino , Humanos , Masculino , Adulto Jovem
12.
Psychophysiology ; 57(4): e13522, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32011742

RESUMO

Meta-analytic and experimental studies investigating the neural basis of emotion often compare functional activation in different emotional induction contexts, assessing evidence for a "core affect" or "salience" network. Meta-analyses necessarily aggregate effects across diverse paradigms and different samples, which ignore potential neural differences specific to the method of affect induction. Data from repeated measures designs are few, reporting contradictory results with a small N. In the current study, functional brain activity is assessed in a large (N = 61) group of healthy participants during two common emotion inductions-scene perception and narrative imagery-to evaluate cross-paradigm consistency. Results indicate that limbic and paralimbic regions, together with visual and parietal cortex, are reliably engaged during emotional scene perception. For emotional imagery, in contrast, enhanced functional activity is found in several cerebellar regions, hippocampus, caudate, and dorsomedial prefrontal cortex, consistent with the conception that imagery is an action disposition. Taken together, the data suggest that a common emotion network is not engaged across paradigms, but that the specific neural regions activated during emotional processing can vary significantly with the context of the emotional induction.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Emoções/fisiologia , Imaginação/fisiologia , Rede Nervosa/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Feminino , Humanos , Sistema Límbico/diagnóstico por imagem , Sistema Límbico/fisiologia , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Adulto Jovem
13.
Psychophysiology ; 57(1): e13349, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-30861143

RESUMO

Exposure to traumatic events is not unique to post-traumatic stress disorder (PTSD) and is a significant factor in the development of physical and mental disease across the diagnostic spectrum. Using fMRI, this study assesses functional activation in the amygdala and visual cortex during emotional scene processing in a sample of anxiety and mood disorder patients (N = 162). Replicating previous studies with healthy young participants, a strong covariation was found between functional activity in the amygdala and ventral visual cortex, with blood-oxygen-level dependent (BOLD) activity overall significantly enhanced in both regions when viewing emotionally arousing, compared to neutral, scenes. BOLD changes during emotional processing predicted questionnaire reports of experienced trauma and PTSD-like symptoms (e.g., intrusive thoughts, bad dreams, re-experiencing) and associated functional impairment. Patients showing the smallest BOLD changes when viewing emotional (compared to neutral) scenes in the amygdala and ventral visual cortex reported the highest trauma scores, whereas those patients with the largest amygdala emotional reactivity differences reported the lowest trauma scores. Experiencing a life-threatening event (to self or other) that prompts high fear, distress, and functional impairment was associated with reduced functional limbic-visual activity, independent of a PTSD diagnosis. The findings suggest that experienced trauma may be a transdiagnostic vulnerability factor contributing significantly to psychopathology in many patients with anxiety and mood disorders.


Assuntos
Tonsila do Cerebelo/fisiopatologia , Transtornos de Ansiedade/fisiopatologia , Mapeamento Encefálico , Emoções/fisiologia , Transtornos do Humor/fisiopatologia , Trauma Psicológico/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Córtex Visual/fisiopatologia , Percepção Visual/fisiologia , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Transtornos de Ansiedade/diagnóstico por imagem , Transtornos de Ansiedade/epidemiologia , Comorbidade , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos do Humor/diagnóstico por imagem , Transtornos do Humor/epidemiologia , Trauma Psicológico/diagnóstico por imagem , Trauma Psicológico/epidemiologia , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Córtex Visual/diagnóstico por imagem , Adulto Jovem
14.
Leukemia ; 34(2): 613-624, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31578451

RESUMO

AML SCT-BFM 2007 was the first hematopoietic stem cell transplantation (HCT) trial in Germany to comply with the European Clinical Trials Directive, and aimed to standardize pediatric HCT for acute myeloid leukemia (AML) across centers in Germany, Austria, and the Czech Republic. Children with high-risk features and a good early response achieving a complete first remission (CR-1) and those in CR-2 after a first relapse were stratified to receive HCT from a matched donor after myeloablative conditioning consisting of busulfan, cyclophosphamide, and melphalan. Four-year EFS and OS were 61 and 70%. Cumulative incidence of relapse (CIR) was 22%. TRM was 15% and correlated with age reaching 9% (SE 3%) in children younger than 12 years and 31% (SE 9%) in older children and adolescents. Children with poorly responding primary disease or relapse were allocated to receive early HCT after a cytoreductive regimen with fludarabine, amsacrine, and cytarabine, followed by reduced intensity conditioning and prophylactic donor lymphocyte infusions. Four-year EFS and OS were 49 and 53%. CIR was 38% and TRM 11%. For patients with primary poor response disease, early use of RIC HCT followed by prophylactic DLI can induce long-term remissions in more than 50% (EFS 46% (SE 9%)).

16.
Artigo em Inglês | MEDLINE | ID: mdl-30047478

RESUMO

BACKGROUND: The National Institute of Mental Health Research Domain Criteria initiative encourages a search for dimensional biological measures of psychopathology unconstrained by current diagnostic categories. Consistent with this aim, the presented research studies a large sample of anxiety and mood disorder patients, assessing differences in principal diagnoses and comorbidity patterns, clinicians' ratings, and questionnaire measures of negative affect and life dysfunction as they relate to a potential brain marker of pathology: the amplitude of the event-related potential (ERP) elicited by a startle-evoking stimulus. METHODS: Patients seeking evaluation or treatment for anxiety and mood disorders (N = 208) participated in two tasks at the University of Florida (Gainesville, FL): 1) imagining emotional and neutral events and 2) viewing emotional and neutral pictures while acoustic startle probes were presented and the ERP was recorded. For a comparison patient group (N = 120), startle probes were administered and ERPs recorded at the University of Greifswald (Greifswald, Germany) while performing the same imagery task. RESULTS: Reduced positive amplitude of a centroparietal startle-evoked ERP (156-352 ms after onset) significantly predicted higher questionnaire scores of anxiety/depression, reports of increased life dysfunction, greater comorbidity, and clinician ratings of heightened severity and poorer prognosis. The effect was general across principal diagnoses, found for both the Florida and German samples, and consistent in pattern despite differences in the tasks administered. CONCLUSIONS: The startle-evoked ERP reliably predicts severity and breadth of psychopathology, independent of task context. It is a potential significant contributor to a needed array of biological measures that might improve classification of anxiety and mood disorders.


Assuntos
Transtornos de Ansiedade/fisiopatologia , Córtex Cerebral/fisiopatologia , Potenciais Evocados/fisiologia , Transtornos do Humor/fisiopatologia , Reflexo de Sobressalto/fisiologia , Índice de Gravidade de Doença , Adulto , Percepção Auditiva/fisiologia , Eletroencefalografia , Feminino , Humanos , Masculino , Reconhecimento Visual de Modelos/fisiologia
17.
Psychophysiology ; 55(10): e13197, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29732578

RESUMO

Stimulus repetition elicits either enhancement or suppression in neural activity, and a recent fMRI meta-analysis of repetition effects for visual stimuli (Kim, 2017) reported cross-stimulus repetition enhancement in medial and lateral parietal cortex, as well as regions of prefrontal, temporal, and posterior cingulate cortex. Repetition enhancement was assessed here for repeated and novel scenes presented in the context of either an explicit episodic recognition task or an implicit judgment task, in order to study the role of spontaneous retrieval of episodic memories. Regardless of whether episodic memory was explicitly probed or not, repetition enhancement was found in medial posterior parietal (precuneus/cuneus), lateral parietal cortex (angular gyrus), as well as in medial prefrontal cortex (frontopolar), which did not differ by task. Enhancement effects in the posterior cingulate cortex were significantly larger during explicit compared to implicit task, primarily due to a lack of functional activity for new scenes. Taken together, the data are consistent with an interpretation that medial and (ventral) lateral parietal cortex are associated with spontaneous episodic retrieval, whereas posterior cingulate cortical regions may reflect task or decision processes.


Assuntos
Encéfalo/fisiologia , Julgamento , Memória Episódica , Rememoração Mental/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Visual , Adolescente , Mapeamento Encefálico , Tomada de Decisões/fisiologia , Feminino , Giro do Cíngulo/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Lobo Parietal/fisiologia , Estimulação Luminosa , Córtex Pré-Frontal
18.
Behav Res Ther ; 104: 62-68, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29549752

RESUMO

Although avoidance and escape behaviors each contribute to maintaining anxiety disorders, only avoidance completely eliminates exposure to the aversive context. Current research compared anticipatory defensive engagement when aversion could either be completely avoided or escaped after initial exposure; in addition, this research examined the impact of trait anxiety on coping-related defensive engagement. Cues signaled that upcoming rapid action would avoid (block), escape (terminate), or not affect subsequent aversive exposure; the acoustic startle reflex was measured during each anticipatory interval to index defensive engagement, and blink magnitudes were compared across low-, moderate-, and high-anxious individuals. For all participants, startle was potentiated when aversive exposure was uncontrollable and attenuated when aversion was avoidable. On escape trials, on the other hand, startle potentiation increased with rising participant anxiety. Results suggest 1) defensive engagement is generally reduced in avoidance contexts relative to contexts in which exposure is certain, and; 2) trait anxiety increases defensive engagement specifically when aversive exposure can be controlled but remains certain.


Assuntos
Ansiedade/fisiopatologia , Sistema Nervoso Autônomo/fisiopatologia , Medo/fisiologia , Adolescente , Feminino , Resposta Galvânica da Pele/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Tempo de Reação/fisiologia , Reflexo de Sobressalto/fisiologia , Adulto Jovem
19.
Psychophysiology ; 55(2)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28881032

RESUMO

During threat of shock, the startle reflex is potentiated, suggesting modulation by defensive mobilization. To determine whether startle potentiation is specific to aversive anticipation, startle reflexes were measured in the context of either aversive or appetitive anticipation in a between-subject study. Participants wore a device on the wrist that could deliver electrical shock (n = 49), or vibrotactile stimulation indicating monetary reward (n = 48). Cues signaling "threat" or "safe" periods were presented alone, or accompanied by presentation of affective and neutral pictures on half of the trials. Results indicated that the startle reflex was significantly potentiated when anticipating either shock or reward, compared to safe periods, both when no picture was presented, as well as during picture viewing. The difference between threat and safety in both reflex magnitude and skin conductance changes was larger for those anticipating shock, suggesting that the aversive context was more motivationally engaging. The pattern of reflex modulation as a function of picture valence varied under threat and safety, but was identical in the shock and reward groups, consistent with a hypothesis that anticipation of either aversive or appetitive events prompts heightened perceptual vigilance, potentiating the acoustic startle reflex.


Assuntos
Antecipação Psicológica/fisiologia , Ansiedade/fisiopatologia , Emoções/fisiologia , Resposta Galvânica da Pele/fisiologia , Reflexo de Sobressalto/fisiologia , Recompensa , Estimulação Elétrica , Eletromiografia , Feminino , Humanos , Masculino , Estimulação Luminosa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA