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1.
Neuroimage ; 193: 201-213, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30849527

RESUMO

Top-down cognitive control leads to changes in the sensory processing of the brain. In visual perception such changes can take place in the ventral visual cortex altering the functional asymmetry in forward and backward connections. Here we used fixation-related evoked responses of EEG measurement and dynamic causal modeling to examine hierarchical forward-backward asymmetry, while twenty-six healthy adults performed cognitive tasks that require different types of top-down cognitive control (memorizing or searching visual objects embedded in a natural scene image). The generative model revealed an enhanced asymmetry toward forward connections during memorizing, whereas enhanced backward connections were found during searching. This task-dependent modulation of forward and backward connections suggests two distinct modes of top-down cognitive processing in cortical networks. The alteration in forward-backward asymmetry might underlie the functional role in the cognitive control of visual information processing.


Assuntos
Cognição/fisiologia , Modelos Neurológicos , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Potenciais Evocados Visuais/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Adulto Jovem
2.
Hum Brain Mapp ; 40(15): 4470-4486, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31301203

RESUMO

The human capacity to integrate sensory signals has been investigated with respect to different sensory modalities. A common denominator of the neural network underlying the integration of sensory clues has yet to be identified. Additionally, brain imaging data from patients with autism spectrum disorder (ASD) do not cover disparities in neuronal sensory processing. In this fMRI study, we compared the underlying neural networks of both olfactory-visual and auditory-visual integration in patients with ASD and a group of matched healthy participants. The aim was to disentangle sensory-specific networks so as to derive a potential (amodal) common source of multisensory integration (MSI) and to investigate differences in brain networks with sensory processing in individuals with ASD. In both groups, similar neural networks were found to be involved in the olfactory-visual and auditory-visual integration processes, including the primary visual cortex, the inferior parietal sulcus (IPS), and the medial and inferior frontal cortices. Amygdala activation was observed specifically during olfactory-visual integration, with superior temporal activation having been seen during auditory-visual integration. A dynamic causal modeling analysis revealed a nonlinear top-down IPS modulation of the connection between the respective primary sensory regions in both experimental conditions and in both groups. Thus, we demonstrate that MSI has shared neural sources across olfactory-visual and audio-visual stimulation in patients and controls. The enhanced recruitment of the IPS to modulate changes between areas is relevant to sensory perception. Our results also indicate that, with respect to MSI processing, adults with ASD do not significantly differ from their healthy counterparts.


Assuntos
Percepção Auditiva/fisiologia , Transtorno do Espectro Autista/fisiopatologia , Mapeamento Encefálico , Olfato/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Teorema de Bayes , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos , Modelos Psicológicos , Prazer , Adulto Jovem
3.
Chem Senses ; 44(8): 593-606, 2019 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-31414135

RESUMO

Using a combined approach of functional magnetic resonance imaging (fMRI) and noninvasive brain stimulation (transcranial direct current stimulation [tDCS]), the present study investigated source memory and its link to mental imagery in the olfactory domain, as well as in the auditory domain. Source memory refers to the knowledge of the origin of mental experiences, differentiating events that have occurred and memories of imagined events. Because of a confusion between internally generated and externally perceived information, patients that are prone to hallucinations show decreased source memory accuracy; also, vivid mental imagery can lead to similar results in healthy controls. We tested source memory following cathodal tDCS stimulation using a mental imagery task, which required participants to perceive or imagine a set of the same olfactory and auditory stimuli during fMRI. The supplementary motor area (SMA) is involved in mental imagery across different modalities and potentially linked to source memory. Therefore, we attempted to modulate participants' SMA activation before entering the scanner using tDCS to influence source memory accuracy in healthy participants. Our results showed the same source memory accuracy between the olfactory and auditory modalities with no effects of stimulation. Finally, we found SMA's subregions differentially involved in olfactory and auditory imagery, with activation of dorsal SMA correlated with auditory source memory.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Imaginação/fisiologia , Córtex Olfatório/fisiologia , Percepção Olfatória/fisiologia , Estimulação Acústica/métodos , Adulto , Córtex Auditivo/diagnóstico por imagem , Feminino , Alucinações/psicologia , Voluntários Saudáveis , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória/fisiologia , Córtex Motor/diagnóstico por imagem , Córtex Motor/fisiologia , Odorantes/análise , Córtex Olfatório/diagnóstico por imagem , Estimulação Transcraniana por Corrente Contínua
4.
Eur J Neurosci ; 48(3): 1964-1975, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30044019

RESUMO

This is a case study involving a female patient (NN) with complete loss of autobiographical memory and identity despite normal neurological assessment. To test the hypothesis that patients with dissociative amnesia (DA) possess the ability to covertly process facial identities they are unaware of, we conducted functional magnetic resonance imaging (fMRI) and assessed skin conductance responses (SCR) to (a) strangers, (b) celebrities, and (c) familiar faces not seen since the onset of DA. We also performed associative face-name memory tasks to test the patient's ability to learn and recall newly learned face-name pairs. Although NN did not recognize any of the faces of her friends and relatives, their images triggered a stronger involvement of the left fusiform gyrus, the bilateral hippocampus/amygdala region, the orbitofrontal cortex, the middle temporal regions, and the precuneus, along with higher SCR. During recollection of previously learned face-name pairs, NN (compared to healthy controls) demonstrated a weaker involvement of the hippocampus. Our findings suggest that, in DA, specific arousal systems remain capable of being activated by familiar faces outside of conscious awareness. The decreased activation observed in the hippocampus demonstrates that the functioning of memory-sensitive regions may be impaired by trauma.


Assuntos
Amnésia/fisiopatologia , Amnésia/psicologia , Encéfalo/fisiopatologia , Reconhecimento Facial/fisiologia , Adulto , Idoso , Mapeamento Encefálico , Feminino , Resposta Galvânica da Pele , Humanos , Imageamento por Ressonância Magnética , Testes Neuropsicológicos , Reconhecimento Psicológico/fisiologia
5.
Horm Behav ; 105: 11-21, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29981752

RESUMO

The phenomenon of gender incongruence is hypothesized to arise from a discrepant sexual development of the brain and the genitals, contingent on genetic and hormonal mechanisms. We aimed at visualizing transgender identity on a neurobiological level, assuming a higher functional similarity to individuals of the aspired rather than assigned sex. Implementing a gender perception paradigm featuring male and female voice stimuli, behavioral and functional imaging data of transmen were compared to men and women, and to transwomen, respectively. Men had decreased activation in response to voices of the other sex in regions across the frontoparietal and insular cortex, while the activation patterns of women and transmen were characterized by little or no differentiation between male and female voices. Further, transmen had a comparatively high discrimination performance for ambiguous male voices, possibly reflecting a high sensitivity for voices of the aspired sex. Comparing transmen and transwomen yielded only few differences in the processing of male compared to female voices. In the insula, we observed a pattern similar to that of men and women, the neural responses of the transgender group being in accordance with their gender identity rather than assigned sex. Notwithstanding the similarities found dependent on biological sex, the findings support the hypothesis of gender incongruence being a condition in which neural processing modes are partly incongruent with one's assigned sex.


Assuntos
Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Pessoas Transgênero , Voz/fisiologia , Adulto , Comportamento/fisiologia , Mapeamento Encefálico , Discriminação Psicológica , Feminino , Disforia de Gênero/fisiopatologia , Disforia de Gênero/psicologia , Identidade de Gênero , Humanos , Masculino , Pessoa de Meia-Idade , Percepção/fisiologia , Caracteres Sexuais , Pessoas Transgênero/psicologia , Transexualidade/psicologia , Adulto Jovem
6.
Neuroimage ; 111: 602-10, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25687596

RESUMO

Human cognition relies on attentional capacities which, among others, are influenced by factors like tiredness or mood. Based on their inherent preferences in sleep and wakefulness, individuals can be classified as specific "chronotypes". The present study investigated how early, intermediate and late chronotypes (EC, IC, LC) differ neurally on an attention-to-motion task. Twelve EC, 18 IC and 17 LC were included into the study. While undergoing functional magnetic resonance imaging (fMRI) scans, subjects looked at vertical bars in an attention-to-motion task. In the STATIONARY condition, subjects focused on a central fixation cross. During Fix-MOVING and Attend-MOVING, bars were moving horizontally. Only during the Attend-MOVING, subjects were required to attend to changes in the velocity of bars and indicate those by button presses. A two-way repeated measures ANOVA probed group by attentional load effects. The dorsolateral prefrontal cortex (DLPFC), insula and anterior cingulate cortex showed group by attention specific activations. Specifically, EC and LC presented attenuated DLPFC activation under high attentional load (Attend-MOVING), while EC showed less anterior insula activation than IC. LC compared to IC exhibited attenuation of superior parietal cortex. Our study reveals that individual sleep preferences are associated with characteristic brain activation in areas crucial for attention and bodily awareness. These results imply that considering sleep preferences in neuroimaging studies is crucial when administering cognitive tasks. Our study also has socio-economic implications. Task performance in non-optimal times of the day (e.g. shift workers), may result in cognitive impairments leading to e.g. increased error rates and slower reaction times.


Assuntos
Atenção/fisiologia , Córtex Cerebral/fisiologia , Imageamento por Ressonância Magnética/métodos , Percepção de Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Sono/fisiologia , Adolescente , Adulto , Ritmo Circadiano/fisiologia , Humanos , Masculino , Fatores de Tempo , Adulto Jovem
7.
Hum Brain Mapp ; 36(5): 1662-76, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25545699

RESUMO

Food perception is characterized by a transition from initially separate sensations of the olfactory and gustatory properties of the object toward their combined sensory experience during consumption. The holistic flavor experience, which occurs as the smell and taste merge, extends beyond the mere addition of the two chemosensory modalities, being usually perceived as more object-like, intense and rewarding. To explore the cortical mechanisms which give rise to olfactory-gustatory binding during natural food consumption, brain activation during consumption of a pleasant familiar beverage was contrasted with presentation of its taste and orthonasal smell alone. Convergent activation to all presentation modes was observed in executive and chemosensory association areas. Flavor, but not orthonasal smell or taste alone, stimulated the frontal operculum, supporting previous accounts of its central role in the formation of the flavor percept. A functional dissociation was observed in the insula: the anterior portion was characterized by sensory convergence, while mid-dorsal sections activated exclusively to the combined flavor stimulus. psycho-physiological interaction analyses demonstrated increased neural coupling between the frontal operculum and the anterior insula during flavor presentation. Connectivity was also increased with the lateral entorhinal cortex, a relay to memory networks and central node for contextual modulation of olfactory processing. These findings suggest a central role of the insular cortex in the transition from mere detection of chemosensory convergence to a superadditive flavor representation. The increased connections between the frontal operculum and medial temporal memory structures during combined olfactory-gustatory stimulation point to a potential mechanism underlying the acquisition and modification of flavor preferences.


Assuntos
Sistema Límbico/fisiologia , Percepção Olfatória/fisiologia , Percepção Gustatória/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Citrus sinensis , Feminino , Sucos de Frutas e Vegetais , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Estimulação Física/métodos
8.
Br J Psychiatry ; 206(3): 198-205, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25573396

RESUMO

BACKGROUND: Individuals with schizophrenia and people with depression both show abnormal behavioural and neural responses when perceiving and responding to emotional stimuli, but pathology-specific differences and commonalities remain mostly unclear. AIMS: To directly compare empathic responses to dynamic multimodal emotional stimuli in a group with schizophrenia and a group with depression, and to investigate their neural correlates using functional magnetic resonance imaging (fMRI). METHOD: The schizophrenia group (n = 20), the depression group (n = 24) and a control group (n = 24) were presented with portrait-shot video clips expressing emotion through three possible communication channels: facial expression, prosody and content. Participants rated their own and the actor's emotional state as an index of empathy. RESULTS: Although no group differences were found in empathy ratings, characteristic differences emerged in the fMRI activation patterns. The schizophrenia group demonstrated aberrant activation patterns during the neutral speech content condition in regions implicated in multimodal integration and formation of semantic constructs. Those in the depression group were most affected during conditions with trimodal emotional and trimodal neutral stimuli, in key regions of the mentalising network. CONCLUSIONS: Our findings reveal characteristic differences in patients with schizophrenia compared with those with depression in their cortical responses to dynamic affective stimuli. These differences indicate that impairments in responding to emotional stimuli may be caused by pathology-specific problems in social cognition.


Assuntos
Córtex Cerebral/fisiopatologia , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/psicologia , Empatia/fisiologia , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Estimulação Acústica , Adulto , Estudos de Casos e Controles , Emoções/fisiologia , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Adulto Jovem
9.
Hum Brain Mapp ; 35(2): 471-82, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23033120

RESUMO

In depression, patients suffer from emotional and cognitive deficits, among others in semantic processing. If these semantic deficits are cognitive or interact with emotional dysfunctions, is still an open question. The aim of the current study was to investigate the influence of emotional valence on the neural correlates of semantic priming in major depression. In a lexical decision task, positive, negative, and neutral word pairs were presented during fMRI measurement. Nineteen inpatients and 19 demographically matched controls were recruited. Behaviorally, positive and neutral valence induced a priming effect whereas negative valence induced no effect (controls) or even inhibition (slower RT for related stimuli) in patients. At the neural level, the semantic relation effect revealed similar neural activation in right middle frontal regions for patients and controls. Group differences emerged in the right fusiform gyrus and the ACC. Activity associated with positive valence differed at the DLPFC and amygdala and for negative valence at putamen and cerebellum. The activation of amygdala and DLPFC correlated negatively with the severity of depression. To conclude, semantic processing deficits in depression are modulated by emotional valence of the stimulus on the behavioral as well as on neural level in right-lateralized prefrontal areas and the amygdala. The results highlighted an influence of depression severity on emotion information processing as the severity of symptoms correlated negatively with neural responses to positively and negatively valenced information. Hence, the dysfunctional emotion processing may further enhance the cognitive deficits in depression.


Assuntos
Encéfalo/irrigação sanguínea , Depressão/patologia , Depressão/fisiopatologia , Imageamento por Ressonância Magnética , Semântica , Adulto , Análise de Variância , Atenção/fisiologia , Encéfalo/patologia , Mapeamento Encefálico , Sinais (Psicologia) , Tomada de Decisões/fisiologia , Feminino , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Oxigênio/sangue , Estimulação Luminosa , Tempo de Reação/fisiologia , Estatística como Assunto , Adulto Jovem
10.
Front Psychiatry ; 15: 1288028, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38855645

RESUMO

Introduction: Deficits in emotion recognition and processing are characteristic for patients with schizophrenia [SCZ]. Methods: We targeted both emotion recognition and affective sharing, one in static and one in dynamic facial stimuli, during functional magnetic resonance imaging [fMRI] in 22 SCZ patients and 22 matched healthy controls [HC]. Current symptomatology and cognitive deficits were assessed as potential influencing factors. Results: Behaviorally, patients only showed a prolonged response time in age-discrimination trials. For emotion-processing trials, patients showed a difference in neural response, without an observable behavioral correlate. During emotion and age recognition in static stimuli, a reduced activation of the bilateral anterior cingulate cortex [ACC] and the right anterior insula [AI] emerged. In the affective sharing task, patients showed a reduced activation in the left and right caudate nucleus, right AI and inferior frontal gyrus [IFG], right cerebellum, and left thalamus, key areas of empathy. Discussion: We conclude that patients have deficits in complex visual information processing regardless of emotional content on a behavioral level and that these deficits coincide with aberrant neural activation patterns in emotion processing networks. The right AI as an integrator of these networks plays a key role in these aberrant neural activation patterns and, thus, is a promising candidate area for neurofeedback approaches.

11.
J Pain ; 25(6): 104457, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38211845

RESUMO

Small-fiber neuropathy (SFN) is defined by degeneration or dysfunction of peripheral sensory nerve endings. Central correlates have been identified on the level of gray matter volume (GMV) and cortical thickness (CT) changes. However, across SFN etiologies knowledge about a common structural brain signature is still lacking. Therefore, we recruited 26 SFN patients and 25 age- and sex-matched healthy controls to conduct voxel-based- and surface-based morphometry. Across all patients, we found reduced GMV in widespread frontal regions, left caudate, insula and superior parietal lobule. Surface-based morphometry analysis revealed reduced CT in the right precentral gyrus of SFN patients. In a region-based approach, patients had reduced GMV in the left caudate. Since pathogenic gain-of-function variants in voltage-gated sodium channels (Nav) have been associated with SFN pathophysiology, we explored brain morphological patterns in a homogenous subsample of patients carrying rare heterozygous missense variants. Whole brain- and region-based approaches revealed GMV reductions in the bilateral caudate for Nav variant carriers. Further research is needed to analyze the specific role of Nav variants for structural brain alterations. Together, we conclude that SFN patients have specific GMV and CT alterations, potentially forming potential new central biomarkers for this condition. Our results might help to better understand underlying or compensatory mechanisms of chronic pain perception in the future. PERSPECTIVE: This study reveals structural brain changes in small-fiber neuropathy (SFN) patients, particularly in frontal regions, caudate, insula, and parietal lobule. Notably, individuals with SFN and specific Nav variants exhibit bilateral caudate abnormalities. These findings may serve as potential central biomarkers for SFN and provide insights into chronic pain perception mechanisms.


Assuntos
Substância Cinzenta , Neuropatia de Pequenas Fibras , Humanos , Masculino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Feminino , Pessoa de Meia-Idade , Neuropatia de Pequenas Fibras/patologia , Neuropatia de Pequenas Fibras/diagnóstico por imagem , Neuropatia de Pequenas Fibras/fisiopatologia , Adulto , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/patologia , Idoso , Imageamento por Ressonância Magnética , Espessura Cortical do Cérebro
12.
J Neurosci ; 32(33): 11453-60, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22895727

RESUMO

Insights from both lesion and neuroimaging studies increasingly substantiate the view that the human cerebellum not only serves motor control but also supports various cognitive processes. Higher cognitive functions like working memory or executive control have been associated with the phylogenetically younger parts of the cerebellum, crus I and crus II. Functional connectivity studies corroborate this notion as activation of the cerebellum correlates with activity in numerous areas of the cerebral cortex. Moreover, these cerebrocerebellar loops were shown to be topographically organized. We used an attention-to-motion paradigm to elaborate on the effective connectivity of cerebellar crus I during visual attention. Psychophysiological interaction analyses demonstrated enhanced connectivity of the cerebellum--during attention--with dorsal visual stream regions including posterior parietal cortex (PPC) and left secondary visual cortex (V5). Dynamic causal modeling revealed a modulation of the connections from V5 to PPC and from crus I to V5 by attention. Remarkably, the influence which V5 exerted on PPC was reduced during attention, resulting in a suppression of the sensitivity of PPC to bottom-up information. Moreover, the sensitivity of V5 populations to inputs from crus I was increased under attention. This might underscore the presumed role of the cerebellum as a state estimator that provides hierarchically lower regions (V5) with top-down predictions, which in turn might be based on endogenous inputs from PPC to the cerebellum. These results are in line with formulations of attention in predictive coding, where attention increases the precision or sensitivity of hierarchically lower neuronal populations that may encode prediction error.


Assuntos
Atenção/fisiologia , Mapeamento Encefálico , Cerebelo/fisiologia , Vias Neurais/fisiologia , Percepção Visual/fisiologia , Adulto , Análise de Variância , Teorema de Bayes , Cerebelo/irrigação sanguínea , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Modelos Lineares , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/irrigação sanguínea , Dinâmica não Linear , Oxigênio/sangue , Estimulação Luminosa , Psicofísica , Tempo de Reação , Fatores de Tempo , Vias Visuais/irrigação sanguínea , Vias Visuais/fisiologia , Adulto Jovem
13.
Neuroimage ; 79: 264-74, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23660028

RESUMO

Deficits in response inhibition and heightened impulsivity have been linked to psychiatric disorders and aggression. They have been investigated in clinical groups as well as individuals with trait characteristics, yielding insights into the underlying neural and behavioral mechanisms of response inhibition and impulsivity. The motor inhibition tasks employed in most studies, however, have lacked an emotional component, which is crucial given that both response inhibition and impulsivity attain salience within a socio-emotional context. For this fMRI study, we selected a group with high trait aggression (HA, n=17) and one with low trait aggression (LA, n=16) from 550 males who had completed an Aggression Questionnaire. Neural activation was compared to an emotional version (including angry and neutral faces) of the stop signal task. Behavioral results revealed impaired response inhibition in HA, associated with higher motor impulsivity. This was accompanied by attenuated activation in brain regions involved in response inhibition, including the pre-supplementary motor area (SMA) and motor cortex. Together, these findings offer evidence that a reduced inhibition capacity is present in HA. Notably, response inhibition improved during anger trials in both groups, suggesting a facilitation effect through heightened activation in the related brain regions. In both groups, inclusion of the anger stimuli enhanced the activation of the motor and somatosensory areas, which modulate executive control, and of limbic regions including the amygdala. In summary, the investigation of response inhibition in individuals with high and low trait characteristics affords useful insights into the underlying distinct processing mechanisms. It can contribute to the investigation of trait markers in a clinical context without having to deal with the complex mechanisms of a clinical disorder itself. In contrast, the mechanisms of emotional response inhibition did not differ between groups. Hence, the specific emotional influence is not interacting with trait aggression.


Assuntos
Agressão/fisiologia , Mapeamento Encefálico , Encéfalo/fisiologia , Emoções/fisiologia , Inibição Psicológica , Rede Nervosa/fisiologia , Inibição Neural/fisiologia , Sinais (Psicologia) , Humanos , Masculino , Adulto Jovem
14.
Rev Neurosci ; 34(2): 223-245, 2023 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-36084305

RESUMO

Previous fMRI research identified superior temporal sulcus as central integration area for audiovisual stimuli. However, less is known about a general multisensory integration network across senses. Therefore, we conducted activation likelihood estimation meta-analysis with multiple sensory modalities to identify a common brain network. We included 49 studies covering all Aristotelian senses i.e., auditory, visual, tactile, gustatory, and olfactory stimuli. Analysis revealed significant activation in bilateral superior temporal gyrus, middle temporal gyrus, thalamus, right insula, and left inferior frontal gyrus. We assume these regions to be part of a general multisensory integration network comprising different functional roles. Here, thalamus operate as first subcortical relay projecting sensory information to higher cortical integration centers in superior temporal gyrus/sulcus while conflict-processing brain regions as insula and inferior frontal gyrus facilitate integration of incongruent information. We additionally performed meta-analytic connectivity modelling and found each brain region showed co-activations within the identified multisensory integration network. Therefore, by including multiple sensory modalities in our meta-analysis the results may provide evidence for a common brain network that supports different functional roles for multisensory integration.


Assuntos
Mapeamento Encefálico , Encéfalo , Humanos , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Sensação , Lobo Temporal , Imageamento por Ressonância Magnética
15.
Neuroimage ; 60(4): 2346-56, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22487549

RESUMO

Human communication is based on a dynamic information exchange of the communication channels facial expressions, prosody, and speech content. This fMRI study elucidated the impact of multimodal emotion processing and the specific contribution of each channel on behavioral empathy and its prerequisites. Ninety-six video clips displaying actors who told self-related stories were presented to 27 healthy participants. In two conditions, all channels uniformly transported only emotional or neutral information. Three conditions selectively presented two emotional channels and one neutral channel. Subjects indicated the actors' emotional valence and their own while fMRI was recorded. Activation patterns of tri-channel emotional communication reflected multimodal processing and facilitative effects for empathy. Accordingly, subjects' behavioral empathy rates significantly deteriorated once one source was neutral. However, emotionality expressed via two of three channels yielded activation in a network associated with theory-of-mind-processes. This suggested participants' effort to infer mental states of their counterparts and was accompanied by a decline of behavioral empathy, driven by the participants' emotional responses. Channel-specific emotional contributions were present in modality-specific areas. The identification of different network-nodes associated with human interactions constitutes a prerequisite for understanding dynamics that underlie multimodal integration and explain the observed decline in empathy rates. This task might also shed light on behavioral deficits and neural changes that accompany psychiatric diseases.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Emoções/fisiologia , Expressão Facial , Fala/fisiologia , Adulto , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Comportamento Social , Adulto Jovem
16.
Hum Brain Mapp ; 33(2): 398-418, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21438078

RESUMO

Sustained responsiveness to external stimulation is fundamental to many time-critical interactions with the outside world. We used functional magnetic resonance imaging during speeded stimulus detection to identify convergent and divergent neural correlates of maintaining the readiness to respond to auditory, tactile, and visual stimuli. In addition, using a multimodal condition, we investigated the effect of making stimulus modality unpredictable. Relative to sensorimotor control tasks, all three unimodal detection tasks elicited stronger activity in the right temporo-parietal junction, inferior frontal cortex, anterior insula, dorsal premotor cortex, and anterior cingulate cortex as well as bilateral mid-cingulum, midbrain, brainstem, and medial cerebellum. The multimodal detection condition additionally activated left dorsal premotor cortex and bilateral precuneus. Modality-specific modulations were confined to respective sensory areas: we found activity increases in relevant, and decreases in irrelevant sensory cortices. Our findings corroborate the modality independence of a predominantly right-lateralized core network for maintaining an alert (i.e., highly responsive) state and extend previous results to the somatosensory modality. Monitoring multiple sensory channels appears to induce additional processing, possibly related to stimulus-driven shifts of intermodal attention. The results further suggest that directing attention to a given sensory modality selectively enhances and suppresses sensory processing-even in simple detection tasks, which do not require inter- or intra-modal selection.


Assuntos
Estimulação Acústica , Atenção/fisiologia , Estimulação Luminosa , Percepção do Tato , Adulto , Mapeamento Encefálico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Tempo de Reação/fisiologia , Córtex Somatossensorial/fisiologia
17.
Eur Arch Psychiatry Clin Neurosci ; 262(4): 329-39, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22006639

RESUMO

The connection between cholinergic transmission and cognitive performance has been established in behavioural studies. The specific contribution of the muscarinic receptor system on cognitive performance and brain activation, however, has not been evaluated satisfyingly. To investigate the specific contribution of the muscarinic transmission on neural correlates of working memory, we examined the effects of scopolamine, an antagonist of the muscarinic receptors, using functional magnetic resonance imaging (fMRI). Fifteen healthy male, non-smoking subjects performed a fMRI scanning session following the application of scopolamine (0.4 mg, i.v.) or saline in a placebo-controlled, repeated measure, pseudo-randomized, single-blind design. Working memory was probed using an n-back task. Compared to placebo, challenging the cholinergic transmission with scopolamine resulted in hypoactivations in parietal, occipital and cerebellar areas and hyperactivations in frontal and prefrontal areas. These alterations are interpreted as compensatory strategies used to account for downregulation due to muscarinic acetylcholine blockade in parietal and cerebral storage systems by increased activation in frontal and prefrontal areas related to working memory rehearsal. Our results further underline the importance of cholinergic transmission to working memory performance and determine the specific contribution of muscarinic transmission on cerebral activation associated with executive functioning.


Assuntos
Imageamento por Ressonância Magnética/métodos , Memória de Curto Prazo , Receptores Muscarínicos/fisiologia , Escopolamina/farmacologia , Adulto , Regulação para Baixo/fisiologia , Função Executiva/efeitos dos fármacos , Função Executiva/fisiologia , Humanos , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Memória de Curto Prazo/fisiologia , Antagonistas Muscarínicos/farmacologia , Testes Neuropsicológicos , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiologia , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Método Simples-Cego , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia
18.
Cereb Cortex ; 21(12): 2850-62, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21527785

RESUMO

Valid expectations are known to improve target detection, but the preparatory attentional mechanisms underlying this perceptual facilitation remain an open issue. Using functional magnetic resonance imaging, we show here that expecting auditory, tactile, or visual targets, in the absence of stimulation, selectively increased baseline activity in corresponding sensory cortices and decreased activity in irrelevant ones. Regardless of sensory modality, expectancy activated bilateral premotor and posterior parietal areas, supplementary motor area as well as right anterior insula and right middle frontal gyrus. The bilateral putamen was sensitive to the modality specificity of expectations during the unexpected omission of targets. Thus, across modalities, detection improvement arising from selectively directing attention to a sensory modality appears mediated through transient changes in pretarget activity. This flexible advance modulation of baseline activity in sensory cortices resolves ambiguities among previous studies unable to discriminate modality-specific preparatory activity from attentional modulation of stimulus processing. Our results agree with predictive-coding models, which suggest that these expectancy-related changes reflect top-down biases--presumably originating from the observed supramodal frontoparietal network--that modulate signal-detection sensitivity by differentially modifying background activity (i.e., noise level) in different input channels. The putamen appears to code omission-related Bayesian "surprise" that depends on the specificity of predictions.


Assuntos
Antecipação Psicológica/fisiologia , Córtex Auditivo/fisiologia , Mapeamento Encefálico , Córtex Somatossensorial/fisiologia , Córtex Visual/fisiologia , Atenção/fisiologia , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Tempo de Reação/fisiologia , Adulto Jovem
19.
Cogn Emot ; 26(6): 995-1014, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22214265

RESUMO

BACKGROUND: Facial expressions, prosody, and speech content constitute channels by which information is exchanged. Little is known about the simultaneous and differential contribution of these channels to empathy when they provide emotionality or neutrality. Especially neutralised speech content has gained little attention with regards to influencing the perception of other emotional cues. METHODS: Participants were presented with video clips of actors telling short-stories. One condition conveyed emotionality in all channels while the other conditions either provided neutral speech content, facial expression, or prosody, respectively. Participants judged the emotion and intensity presented, as well as their own emotional state and intensity. Skin conductance served as a physiological measure of emotional reactivity. RESULTS: Neutralising channels significantly reduced empathic responses. Electrodermal recordings confirmed these findings. The differential effect of the communication channels on empathy prerequisites was that target emotion recognition of the other decreased mostly when the face was neutral, whereas decreased emotional responses attributed to the target emotion were especially present in neutral speech. CONCLUSION: Multichannel integration supports conscious and autonomous measures of empathy and emotional reactivity. Emotional facial expressions influence emotion recognition, whereas speech content is important for responding with an adequate own emotional state, possibly reflecting contextual emotion-appraisal.


Assuntos
Empatia/fisiologia , Expressão Facial , Acústica da Fala , Fala , Estimulação Acústica/métodos , Adulto , Emoções/fisiologia , Feminino , Resposta Galvânica da Pele/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodos , Reconhecimento Psicológico/fisiologia , Percepção da Fala , Percepção Visual
20.
Psychiatry Res ; 318: 114934, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36347125

RESUMO

Psychotic symptoms may be traced back to sensory sensitivity. Thereby, visual motion (VM) processing particularly has been suggested to be impaired in schizophrenia (SCZ). In healthy brains, VM underlies predictive processing within hierarchically structured systems. However, less is known about predictive VM processing in SCZ. Therefore, we performed fMRI during a VM paradigm with three conditions of varying predictability, i.e., Predictable-, Random-, and Arbitrary motion. The study sample comprised 17 SCZ patients and 23 healthy controls. We calculated general linear model (GLM) analysis to assess group differences in VM processing across motion conditions. Here, we identified significantly lower activity in right temporoparietal junction (TPJ) for SCZ patients. Therefore, right TPJ was set as seed for connectivity analyses. For patients, across conditions we identified increased connections to higher regions, namely medial prefrontal cortex, or paracingulate gyrus. Healthy subjects activated sensory regions as area V5, or superior parietal lobule. Reduced TPJ activity may reflect both a failure in the bottom-up flow of visual information and a decrease of signal processing as consequence of increased top-down input from frontal areas. In sum, these altered neural patterns provide a framework for future studies focusing on predictive VM processing to identify potential biomarkers of psychosis.


Assuntos
Esquizofrenia , Córtex Visual , Humanos , Esquizofrenia/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem , Percepção Visual , Mapeamento Encefálico , Imageamento por Ressonância Magnética
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