Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Brain Sci ; 10(12)2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33255604

RESUMO

Depression is a debilitating disorder with high prevalence and socioeconomic cost, but the brain-physiological processes that are altered during depressive states are not well understood. Here, we build on recent findings in macaques that indicate a direct causal relationship between pupil dilation and anterior cingulate cortex mediated arousal during anticipation of reward. We translated these findings to human subjects with concomitant pupillometry/fMRI in a sample of unmedicated participants diagnosed with major depression and healthy controls. We could show that the upregulation and maintenance of arousal in anticipation of reward was disrupted in patients in a symptom-load dependent manner. We could further show that the failure to maintain reward anticipatory arousal showed state-marker properties, as it tracked the load and impact of depressive symptoms independent of prior diagnosis status. Further, group differences of anticipatory arousal and continuous correlations with symptom load were not traceable only at the level of pupillometric responses, but were mirrored also at the neural level within salience network hubs. The upregulation and maintenance of arousal during reward anticipation is a novel translational and well-traceable process that could prove a promising gateway to a physiologically informed patient stratification and targeted interventions.

2.
Front Behav Neurosci ; 14: 569899, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33192365

RESUMO

Avoidance behavior is a key symptom of most anxiety disorders and a central readout in animal research. However, the quantification of real-life avoidance behavior in humans is typically restricted to clinical populations, who show actual avoidance of phobic objects. In experimental approaches for healthy participants, many avoidance tasks utilize button responses or a joystick navigation on the screen as indicators of avoidance behavior. To allow the ecologically valid assessment of avoidance behavior in healthy participants, we developed a new automated immersive Virtual Reality paradigm, where participants could freely navigate in virtual 3-dimensional, 360-degrees scenes by real naturalistic body movements. A differential fear conditioning procedure was followed by three newly developed behavioral tasks to assess participants' avoidance behavior of the conditioned stimuli: an approach, a forced-choice, and a search task. They varied in instructions, degrees of freedom, and high or low task-related relevance of the stimuli. We initially examined the tasks in a quasi-experiment (N = 55), with four consecutive runs and various experimental adaptations. Here, although we observed avoidance behavior in all three tasks after additional reinforcement, we only detected fear-conditioned avoidance behavior in the behavioral forced-choice and search tasks. These findings were largely replicated in a confirmatory experiment (N = 72) with randomized group allocation, except that fear-conditioned avoidance behavior was only manifest in the behavioral search task. This supports the notion that the behavioral search task is sensitive to detect avoidance behavior after fear conditioning only, whereas the behavioral approach and forced-choice tasks are still able to detect "strong" avoidance behavior after fear conditioning and additional reinforcement.

3.
BMC Psychiatry ; 20(1): 213, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393358

RESUMO

BACKGROUND: A major research finding in the field of Biological Psychiatry is that symptom-based categories of mental disorders map poorly onto dysfunctions in brain circuits or neurobiological pathways. Many of the identified (neuro) biological dysfunctions are "transdiagnostic", meaning that they do not reflect diagnostic boundaries but are shared by different ICD/DSM diagnoses. The compromised biological validity of the current classification system for mental disorders impedes rather than supports the development of treatments that not only target symptoms but also the underlying pathophysiological mechanisms. The Biological Classification of Mental Disorders (BeCOME) study aims to identify biology-based classes of mental disorders that improve the translation of novel biomedical findings into tailored clinical applications. METHODS: BeCOME intends to include at least 1000 individuals with a broad spectrum of affective, anxiety and stress-related mental disorders as well as 500 individuals unaffected by mental disorders. After a screening visit, all participants undergo in-depth phenotyping procedures and omics assessments on two consecutive days. Several validated paradigms (e.g., fear conditioning, reward anticipation, imaging stress test, social reward learning task) are applied to stimulate a response in a basic system of human functioning (e.g., acute threat response, reward processing, stress response or social reward learning) that plays a key role in the development of affective, anxiety and stress-related mental disorders. The response to this stimulation is then read out across multiple levels. Assessments comprise genetic, molecular, cellular, physiological, neuroimaging, neurocognitive, psychophysiological and psychometric measurements. The multilevel information collected in BeCOME will be used to identify data-driven biologically-informed categories of mental disorders using cluster analytical techniques. DISCUSSION: The novelty of BeCOME lies in the dynamic in-depth phenotyping and omics characterization of individuals with mental disorders from the depression and anxiety spectrum of varying severity. We believe that such biology-based subclasses of mental disorders will serve as better treatment targets than purely symptom-based disease entities, and help in tailoring the right treatment to the individual patient suffering from a mental disorder. BeCOME has the potential to contribute to a novel taxonomy of mental disorders that integrates the underlying pathomechanisms into diagnoses. TRIAL REGISTRATION: Retrospectively registered on June 12, 2019 on ClinicalTrials.gov (TRN: NCT03984084).

4.
Behav Res Ther ; 129: 103610, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32302820

RESUMO

Fear conditioning and extinction serve as a dominant model for the development and maintenance of pathological anxiety, particularly for phasic fear to specific stimuli or situations. The validity of this model would be supported by differences in the physiological or subjective fear response between patients with fear-related disorders and healthy controls, whereas the model's validity would be questioned by a lack of such differences. We derived pupillometry, skin conductance response and startle electromyography as well as unconditioned stimulus expectancy in a two-day fear acquisition, immediate extinction and recall task and compared an unmedicated group of patients (n = 73) with phobias or panic disorder and a group of patients with posttraumatic stress disorder (PTSD, n = 21) to a group of carefully screened healthy controls (n = 35). Bayesian statistics showed no convincing evidence for a difference in physiological and subjective responses between the groups during fear acquisition, extinction learning or recall. Only the PTSD subgroup had altered startle reactions during extinction learning. Our data do not provide evidence for general differences in associative fear or extinction learning in fear-related pathologies and thereby question the diagnostic validity of the associative fear learning model of these disorders.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32111578

RESUMO

BACKGROUND: Deficient extinction learning has been suggested as an important mechanism involved in the etiology of posttraumatic stress disorder. A key feature of posttraumatic stress disorder, reexperiencing the trauma in form of intrusions, may be linked to deficient extinction learning. This link is investigated in a novel, functional magnetic resonance imaging-compatible fear conditioning procedure that uses trauma films. Based on previous results, we expected deficient fear extinction indexed by exaggerated responding in the anterior insula and dorsal anterior cingulate cortex to predict subsequent intrusions. METHODS: A total of 58 healthy participants underwent acquisition and extinction learning with faces as conditioned stimuli (CS) and highly aversive 16-second films depicting interpersonal violence as unconditioned stimuli. During the subsequent 3 days, participants reported intrusive memories on their smartphone. RESULTS: Successful fear acquisition was evidenced by differential (CS+ > CS-) activity (threat cues associated with trauma films > cues paired only with neutral films) of a widespread network, including the anterior insula and dorsal anterior cingulate cortex, whereas extinction was characterized exclusively by differential anterior insula activity. Differential conditioned responding during late extinction in the anterior insula and dorsal anterior cingulate cortex was positively related to intrusive memory frequency independent of unconditioned stimuli responding. Exploratory analysis also revealed intrusion sensitivity of the hippocampus, rostral anterior cingulate cortex, and ventromedial prefrontal cortex, among others. CONCLUSIONS: Results support the role of extinction learning in intrusive memory formation; a failure to uncouple conditioned emotional responding from external threat cues was associated with subsequent intrusive memories, representing a potential risk marker for developing posttraumatic stress disorder symptomatology after trauma.

6.
Sleep ; 43(1)2020 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-31556954

RESUMO

STUDY OBJECTIVES: Frequent nightmares have a high prevalence and constitute a risk factor for psychiatric conditions, but their pathophysiology is poorly understood. Our aim was to examine sleep architecture and electroencephalographic markers-with a specific focus on state transitions-related to sleep regulation and hyperarousal in participants with frequent nightmares (NM participants) versus healthy controls. METHODS: Healthy controls and NM participants spent two consecutive nights in the sleep laboratory. Second night spectral power during NREM to REM sleep (pre-REM) and REM to NREM (post-REM) transitions as well as during NREM and REM periods were evaluated for 22 NM participants compared to 22 healthy controls with a similar distribution of age, gender, and dream recall frequency. RESULTS: We found significant differences between the groups in the pre-REM to post-REM changes in low- and high-frequency domains. NM participants experienced a lower amount of slow-wave sleep and showed increased beta and gamma power during NREM and pre-REM periods. No difference was present during REM and post-REM phases. Furthermore, while increased pre-REM high-frequency power seems to be mainly driven by post-traumatic stress disorder (PTSD) symptom intensity, decreased low-frequency activity occurred regardless of PTSD symptom severity. CONCLUSION: Our findings indicate that NM participants had increased high-frequency spectral power during NREM and pre-REM periods, as well as relatively reduced slow frequency and increased fast frequency spectral power across pre-and post-REM periods. This combination of reduced sleep-protective activity and increased hyperarousal suggests an imbalance between sleep regulatory and wake-promoting systems in NM participants.


Assuntos
Sonhos/fisiologia , Sonhos/psicologia , Sono REM/fisiologia , Sono de Ondas Lentas/fisiologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Eletroencefalografia , Feminino , Humanos , Masculino , Polissonografia , Fatores de Risco , Adulto Jovem
7.
J Sleep Res ; 29(5): e12965, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-31860778

RESUMO

The aim of this study was to investigate hyperarousal in individuals with frequent nightmares (NM participants) by calculating arousal events during nocturnal sleep. We hypothesized an increased number of arousals in NM participants compared with controls, especially during those periods where the probability of spontaneous arousal occurrence is already high, such as non-rapid eye movement to rapid eye movement transitions (pre-rapid eye movement periods). Twenty-two NM participants and 23 control participants spent two consecutive nights in our sleep laboratory, monitored by polysomnography. Arousal number and arousal length were calculated only for the second night, for 10 min before rapid eye movement (pre-rapid eye movement) and 10 min after rapid eye movement (post-rapid eye movement) periods, as well as non-rapid eye movement and rapid eye movement phases separately. Repeated-measures ANOVA model testing revealed significant Group (NM participants, controls) × Phase (pre-rapid eye movement, post-rapid eye movement) interaction in case of the number of arousals. Furthermore, post hoc analysis showed a significantly increased number of arousals during pre-rapid eye movement periods in NM participants, compared with controls, a difference that disappeared in post-rapid eye movement periods. We propose that focusing the analyses of arousals specifically on state transitory periods offers a unique perspective into the fragile balance between the sleep-promoting and arousal systems. This outlook revealed an increased number of arousals in NM participants, reflecting hyperarousal during pre-rapid eye movement periods.

8.
Front Hum Neurosci ; 13: 315, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31572150

RESUMO

Real-world memories involve the integration of multiple events across time, yet the mechanisms underlying this integration is unknown. Recent rodent studies show that distinct memories encoded within a few hours, but not several days, share a common neural ensemble, and a common fate whereby later fear conditioning can transfer from one memory to the other. Here, we tested if distinct memories could be linked by temporal proximity in humans. 74 young adults encoded two memories (A and B) close (3-h) or far apart (7-day) in time. One day after encoding the second memory (B), Memory A was updated by pairing it with electric shock (i.e., fear conditioning). We tested whether the memory and fear associated with Memory B would be stronger in the 3-h, compared with the 7-day condition. Results were generally consistent with rodent studies, where we found heightened Memory B fear expression when the two memories were encoded close, but not far apart, in time. Furthermore, there was less forgetting of Memory B in the 3-h compared to 7-day condition. Our results suggest that temporally proximal memories may be linked, such that updating one experience updates the other.

9.
Behav Brain Sci ; 42: e7, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30940272

RESUMO

Progress in psychiatric research has been hindered by the use of artificial disease categories to map distinct biological substrates. Efforts to overcome this obstacle have led to the misconception that relevant psychiatric dimensions are not biologically reducible. Consequently, the return to phenomenology is once again advocated. We propose a process-centered paradigm of biological reduction compatible with non-reductive materialism.


Assuntos
Encefalopatias , Psicopatologia , Humanos , Pesquisa
10.
Artigo em Inglês | MEDLINE | ID: mdl-30773472

RESUMO

BACKGROUND: Pathological peritraumatic encoding is proposed as a proximal risk factor for the development of posttraumatic stress disorder (PTSD), with trauma-analog studies linking increased neural processing of trauma films to intrusive trauma recollections, a core symptom of PTSD. Cumulative lifetime adversity is proposed as a more distal risk factor, with research indicating a tipping point at about five events with regard to PTSD development following re-exposure to trauma. Thus, within a diathesis × stress framework, increased peritraumatic neural processing may constitute a specific risk factor for PTSD, particularly in individuals with several lifetime adversities. METHODS: Fifty-three healthy women watched highly aversive films depicting severe interpersonal violence versus neutral films during functional magnetic resonance imaging, and they reported involuntary recollections during subsequent days. Moderation analyses tested the interactive relationship between peritraumatic neural processing and lifetime adversity in predicting intrusion load, i.e., the total number of intrusions weighted for their average distress. RESULTS: Increased processing of aversive versus neutral films in the amygdala, anterior insula, dorsal and rostral anterior cingulate cortices, and hippocampus predicted increased intrusion load only in participants reporting above five lifetime adversities; for participants reporting few to none, no such relationship was found. This interactive relationship explained ≤59% of variance. Conditioned stimuli preceding film viewing mirrored this pattern. CONCLUSIONS: Peritraumatic neural processing in multiple salience network regions and cumulative lifetime adversity interactively predicted PTSD-like symptomatology, representing a diathesis × stress framework that might guide identification of at-risk individuals and potential targets for symptom prevention after traumatic incidents.


Assuntos
Experiências Adversas da Infância , Tonsila do Cerebelo/fisiopatologia , Córtex Cerebral/fisiopatologia , Condicionamento Clássico/fisiologia , Rememoração Mental/fisiologia , Rede Nervosa/fisiopatologia , Trauma Psicológico/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Violência , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Feminino , Hipocampo/diagnóstico por imagem , Hipocampo/fisiopatologia , Humanos , Imagem por Ressonância Magnética , Rede Nervosa/diagnóstico por imagem , Trauma Psicológico/diagnóstico por imagem , Fatores de Risco , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Adulto Jovem
11.
J Sleep Res ; 28(4): e12820, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30697860

RESUMO

This consensus paper provides an overview of the state of the art in research on the aetiology and treatment of nightmare disorder and outlines further perspectives on these issues. It presents a definition of nightmares and nightmare disorder followed by epidemiological findings, and then explains existing models of nightmare aetiology in traumatized and non-traumatized individuals. Chronic nightmares develop through the interaction of elevated hyperarousal and impaired fear extinction. This interplay is assumed to be facilitated by trait affect distress elicited by traumatic experiences, early childhood adversity and trait susceptibility, as well as by elevated thought suppression and potentially sleep-disordered breathing. Accordingly, different treatment options for nightmares focus on their meaning, on the chronic repetition of the nightmare or on maladaptive beliefs. Clinically, knowledge of healthcare providers about nightmare disorder and the delivery of evidence-based interventions in the healthcare system is discussed. Based on these findings, we highlight some future perspectives and potential further developments of nightmare treatments and research into nightmare aetiology.


Assuntos
Sonhos/psicologia , Imagens, Psicoterapia/métodos , Criança , Feminino , Humanos , Masculino
12.
Psychophysiology ; 56(1): e13283, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30259985

RESUMO

In human fear conditioning studies, different physiological readouts can be used to track conditioned responding during fear learning. Commonly employed readouts such as skin conductance responses (SCR) or startle responses have in recent years been complemented by pupillary readouts, but to date it is unknown how pupillary readouts relate to other measures of the conditioned response. To examine differences and communalities among pupil responses, SCR, and startle responses, we simultaneously recorded pupil diameter, skin conductance, and startle electromyography in 47 healthy subjects during fear acquisition, extinction, and a recall test on 2 consecutive days. The different measures correlated only weakly, displaying most prominent differences in their response patterns during fear acquisition. Whereas SCR and startle responses habituated, pupillary measures did not. Instead, they increased in response to fear conditioned stimuli and most closely followed ratings of unconditioned stimulus (US) expectancy. Moreover, we observed that startle-induced pupil responses showed stimulus discrimination during fear acquisition, suggesting a fear potentiation of the auditory pupil reflex. We conclude that different physiological outcome measures of the conditioned response inform about different cognitive-affective processes during fear learning, with pupil responses being least affected by physiological habituation and most closely following US expectancy.


Assuntos
Piscadela/fisiologia , Condicionamento Clássico/fisiologia , Resposta Galvânica da Pele/fisiologia , Músculo Esquelético/fisiologia , Pupila/fisiologia , Reflexo de Sobressalto/fisiologia , Adulto , Eletromiografia , Extinção Psicológica/fisiologia , Medo/fisiologia , Feminino , Humanos , Masculino , Adulto Jovem
13.
Proc Natl Acad Sci U S A ; 115(43): E10206-E10215, 2018 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-30201713

RESUMO

Ample evidence links dysregulation of the stress response to the risk for psychiatric disorders. However, we lack an integrated understanding of mechanisms that are adaptive during the acute stress response but potentially pathogenic when dysregulated. One mechanistic link emerging from rodent studies is the interaction between stress effectors and neurovascular coupling, a process that adjusts cerebral blood flow according to local metabolic demands. Here, using task-related fMRI, we show that acute psychosocial stress rapidly impacts the peak latency of the hemodynamic response function (HRF-PL) in temporal, insular, and prefrontal regions in two independent cohorts of healthy humans. These latency effects occurred in the absence of amplitude effects and were moderated by regulatory genetic variants of KCNJ2, a known mediator of the effect of stress on vascular responsivity. Further, hippocampal HRF-PL correlated with both cortisol response and genetic variants that influence the transcriptional response to stress hormones and are associated with risk for major depression. We conclude that acute stress modulates hemodynamic response properties as part of the physiological stress response and suggest that HRF indices could serve as endophenotype of stress-related disorders.


Assuntos
Células Endócrinas/fisiologia , Hemodinâmica/fisiologia , Acoplamento Neurovascular/fisiologia , Estresse Psicológico/fisiopatologia , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Variação Genética/genética , Humanos , Imagem por Ressonância Magnética/métodos
14.
Neuroimage ; 178: 11-22, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29733957

RESUMO

The reward system may provide an interesting intermediate phenotype for anhedonia in affective disorders. Reward anticipation is characterized by an increase in arousal, and previous studies have linked the anterior cingulate cortex (ACC) to arousal responses such as dilation of the pupil. Here, we examined pupil dynamics during a reward anticipation task in forty-six healthy human subjects and evaluated its neural correlates using functional magnetic resonance imaging (fMRI). Pupil size showed a strong increase during monetary reward anticipation, a moderate increase during verbal reward anticipation and a decrease during control trials. For fMRI analyses, average pupil size and pupil change were computed in 1-s time bins during the anticipation phase. Activity in the ventral striatum was inversely related to the pupil size time course, indicating an early onset of activation and a role in reward prediction processing. Pupil dilations were linked to increased activity in the salience network (dorsal ACC and bilateral insula), which likely triggers an increase in arousal to enhance task performance. Finally, increased pupil size preceding the required motor response was associated with activity in the ventral attention network. In sum, pupillometry provides an effective tool for disentangling different phases of reward anticipation, with relevance for affective symptomatology.


Assuntos
Antecipação Psicológica/fisiologia , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Reflexo Pupilar/fisiologia , Recompensa , Adulto , Anedonia/fisiologia , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Adulto Jovem
15.
Neuroimage ; 156: 65-77, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28483719

RESUMO

Standard T2* weighted functional magnetic resonance imaging (fMRI) performed with echo-planar imaging (EPI) suffers from signal loss in the ventromedial prefrontal cortex (vmPFC) due to macroscopic field inhomogeneity. However, this region is of special interest to affective neuroscience and psychiatry. The Multi-echo EPI (MEPI) approach has several advantages over EPI but its performance against EPI in the vmPFC has not yet been examined in a study with sufficient statistical power using a task specifically eliciting activity in this region. We used a fear conditioning task with MEPI to compare the performance of MEPI and EPI in vmPFC and control regions in 32 healthy young subjects. We analyzed activity associated with short (12ms), standard (29ms) and long (46ms) echo times, and a voxel-wise combination of these three echo times. Behavioral data revealed successful differentiation of the conditioned versus safety stimulus; activity in the vmPFC was shown by the contrast "safety stimulus > conditioned stimulus" as in previous research and proved significantly stronger with the combined MEPI than standard single-echo EPI. Then, we aimed to demonstrate that the additional cluster extent (ventral extension) detected in the vmPFC with MEPI reflects activation in a relevant cluster (i.e., not just non-neuronal noise). To do this, we used resting state data from the same subjects to show that the time-course of this region was both connected to bilateral amygdala and the default mode network. Overall, we demonstrate that MEPI (by means of the weighted sum combination approach) outperforms standard EPI in vmPFC; MEPI performs always at least as good as the best echo time for a given brain region but provides all necessary echo times for an optimal BOLD sensitivity for the whole brain. This is relevant for affective neuroscience and psychiatry given the critical role of the vmPFC in emotion regulation.


Assuntos
Mapeamento Encefálico/métodos , Imagem Ecoplanar/métodos , Córtex Pré-Frontal/diagnóstico por imagem , Adulto , Condicionamento Clássico , Medo/fisiologia , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Adulto Jovem
16.
Neuroimage ; 147: 186-197, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-27915119

RESUMO

BACKGROUND: Fear conditioning and extinction are prevailing experimental and etiological models for normal and pathological anxiety. Pupil dilations in response to conditioned stimuli are increasingly used as a robust psychophysiological readout of fear learning, but their neural correlates remain unknown. We aimed at identifying the neural correlates of pupil responses to threat and safety cues during a fear learning task. METHODS: Thirty-four healthy subjects underwent a fear conditioning and extinction paradigm with simultaneous functional magnetic resonance imaging (fMRI) and pupillometry. After a stringent preprocessing and artifact rejection procedure, trial-wise pupil responses to threat and safety cues were entered as parametric modulations to the fMRI general linear models. RESULTS: Trial-wise magnitude of pupil responses to both conditioned and safety stimuli correlated positively with activity in dorsal anterior cingulate cortex (dACC), thalamus, supramarginal gyrus and insula for the entire fear learning task, and with activity in the dACC during the fear conditioning phase in particular. Phasic pupil responses did not show habituation, but were negatively correlated with tonic baseline pupil diameter, which decreased during the task. Correcting phasic pupil responses for the tonic baseline pupil diameter revealed thalamic activity, which was also observed in an analysis employing a linear (declining) time modulation. CONCLUSION: Pupil dilations during fear conditioning and extinction provide useful readouts to track fear learning on a trial-by-trial level, particularly with simultaneous fMRI. Whereas phasic pupil responses reflect activity in brain regions involved in fear learning and threat appraisal, most prominently in dACC, tonic changes in pupil diameter may reflect changes in general arousal.


Assuntos
Medo/psicologia , Aprendizagem/fisiologia , Pupila/fisiologia , Reflexo Pupilar/fisiologia , Adulto , Nível de Alerta/fisiologia , Mapeamento Encefálico , Condicionamento Psicológico , Sinais (Psicologia) , Extinção Psicológica , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética , Masculino , Adulto Jovem
17.
Neuroimage ; 139: 189-201, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27291493

RESUMO

Resting state functional magnetic resonance imaging (rs-fMRI) is increasingly applied for the development of functional biomarkers in brain disorders. Recent studies have revealed spontaneous vigilance drifts during the resting state, involving changes in brain activity and connectivity that challenge the validity of uncontrolled rs-fMRI findings. In a combined rs-fMRI/eye tracking study, the pupil size of 32 healthy subjects after 2h of sleep restriction was recorded as an indirect index for activity of the locus coeruleus, the brainstem's noradrenergic arousal center. The spontaneous occurrence of pupil dilations, but not pupil size per se, was associated with increased activity of the salience network, thalamus and frontoparietal regions. In turn, spontaneous constrictions of the pupil were associated with increased activity in visual and sensorimotor regions. These results were largely replicated in a sample of 36 healthy subjects who did not undergo sleep restriction, although in this sample the correlation between thalamus and pupil dilation fell below whole-brain significance. Our data show that spontaneous pupil fluctuations during rest are indeed associated with brain circuitry involved in tonic alertness and vigilance. Pupillometry is an effective method to control for changes in tonic alertness during rs-fMRI.


Assuntos
Nível de Alerta/fisiologia , Encéfalo/fisiologia , Imagem por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Pupila/fisiologia , Descanso/fisiologia , Privação do Sono/fisiopatologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
18.
J Clin Psychiatry ; 76(9): e1105-13, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26455674

RESUMO

OBJECTIVE: Nightmares are associated with psychopathology and daily distress. They are highly prevalent in a psychiatric population (30%). Currently, imagery rehearsal therapy (IRT) is the treatment of choice for nightmares. With IRT, the script of the nightmare is changed into a new dream, which is imagined during the day. However, the effects of IRT in a psychiatric population remain unknown. The aim of this study was to determine the effectiveness of IRT in a heterogeneous psychiatric population. METHOD: Between January 2006 and July 2010, 90 patients with psychiatric disorders (DSM-IV-TR) were randomized to IRT or treatment-as-usual conditions. IRT consisted of 6 individual sessions added to the treatment as usual. Nightmare frequency was assessed using daily nightmare logs and the Nightmare Frequency Questionnaire. Nightmare distress was assessed using the Nightmare Distress Questionnaire and the Nightmare Effects Survey. General psychiatric symptoms were assessed using the Symptom Checklist-90 and a PTSD symptom questionnaire. Assessments were administered at the start of the trial, after the IRT and at follow-up 3 months later. RESULTS: IRT showed a moderate effect (Cohen d = 0.5-0.7, P < .05) on nightmare frequency, nightmare distress, and psychopathology measures compared with treatment as usual. These effects were largely sustained at the 3-month follow-up (Cohen d = 0.4-0.6, P < .10). CONCLUSIONS: IRT is an effective treatment for nightmares among patients with comorbid psychiatric disorders and can be employed in addition to the on-going treatment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00291031.


Assuntos
Sonhos/psicologia , Imagens, Psicoterapia , Transtornos Mentais/psicologia , Transtornos Mentais/terapia , Adulto , Feminino , Humanos , Masculino , Resultado do Tratamento , Adulto Jovem
19.
Sleep Med Rev ; 20: 92-9, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25092021

RESUMO

The idea that dreaming can serve as a model for psychosis has a long and honourable tradition, however it is notoriously speculative. Here we demonstrate that recent research on the phenomenon of lucid dreaming sheds new light on the debate. Lucid dreaming is a rare state of sleep in which the dreamer gains insight into his state of mind during dreaming. Recent electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) data for the first time allow very specific hypotheses about the dream-psychosis relationship: if dreaming is a reasonable model for psychosis, then insight into the dreaming state and insight into the psychotic state should share similar neural correlates. This indeed seems to be the case: cortical areas activated during lucid dreaming show striking overlap with brain regions that are impaired in psychotic patients who lack insight into their pathological state. This parallel allows for new therapeutic approaches and ways to test antipsychotic medication.


Assuntos
Encéfalo/fisiologia , Sonhos/fisiologia , Transtornos Psicóticos/fisiopatologia , Encéfalo/fisiopatologia , Eletroencefalografia , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética
20.
J Neurophysiol ; 112(6): 1267-76, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-24920020

RESUMO

Sleep disturbances are prevalent in clinical anxiety, but it remains unclear whether they are cause and/or consequence of this condition. Fear conditioning constitutes a valid laboratory model for the acquisition of normal and pathological anxiety. To explore the relationship between disturbed sleep and anxiety in more detail, the present study evaluated the effect of partial sleep deprivation (SD) on fear conditioning in healthy individuals. The neural correlates of 1) nonassociative learning and physiological processing and 2) associative learning (differential fear conditioning) were addressed. Measurements entailed simultaneous functional MRI, EEG, skin conductance response (SCR), and pulse recordings. Regarding nonassociative learning, partial SD resulted in a generalized failure to habituate during fear conditioning, as evidenced by reduced habituation of SCR and hypothalamus responses to all stimuli. Furthermore, SCR and hypothalamus activity were correlated, supporting their functional relationship. Regarding associative learning, effects of partial SD on the acquisition of conditioned fear were weaker and did not reach statistical significance. The hypothalamus plays an integral role in the regulation of sleep and autonomic arousal. Thus sleep disturbances may play a causal role in the development of normal and possibly pathological fear by increasing the susceptibility of the sympathetic nervous system to stressful experiences.


Assuntos
Resposta Galvânica da Pele , Habituação Psicofisiológica , Hipotálamo/fisiopatologia , Privação do Sono/fisiopatologia , Adulto , Ansiedade/fisiopatologia , Aprendizagem por Associação , Condicionamento Clássico , Medo , Feminino , Humanos , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...