Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 79
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Neuropsychol ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38899773

RESUMO

The neuropsychological disorder of anosognosia for hemiplegia (AHP) can offer unique insights into the neurocognitive processes of body consciousness and representation. Previous studies have found associations between selective social cognition deficits and anosognosia. In this study, we examined how such social cognition deficits may directly interact with representations of one's body as disabled in AHP. We used a modified set of previously validated Theory of Mind (ToM) stories to create disability-related content that was related to post-stroke paralysis and to investigate differences between right hemisphere damage patients with (n = 19) and without (n = 19) AHP. We expected AHP patients to perform worse than controls when trying to infer paralysis-related mental states in the paralysis-related ToM stories and explored whether such differences depended on the inference patients were asked to perform (e.g. self or other referent perspective-taking). Using an advanced structural neuroimaging technique, we expected selective social cognitive deficits to be associated with posterior parietal cortex lesions and deficits in self-referent perspective-taking in paralysis-related mentalising to be associated with frontoparietal disconnections. Group- and individual-level results revealed that AHP patients performed worse than HP controls when trying to infer paralysis-related mental states. Exploratory lesion analysis results revealed some of the hypothesised lesions, but also unexpected white matter disconnections in the posterior body and splenium of the corpus collosum associated with a self-referent perspective-taking in paralysis-related ToM stories. The study has implications for the multi-layered nature of body awareness, including abstract, social perspectives and beliefs about the body.

2.
Neurosci Conscious ; 2024(1): niae011, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38504827

RESUMO

Here we build on recent findings which show that greater alignment between our subjective experiences (how we feel) and physiological states (measurable changes in our body) plays a pivotal role in the overall psychological well-being. Specifically, we propose that the alignment or 'coherence' between affective arousal (e.g. how excited we 'feel') and autonomic arousal (e.g. heart rate or pupil dilation) may be key for maintaining up-to-date uncertainty representations in dynamic environments. Drawing on recent advances in interoceptive and affective inference, we also propose that arousal coherence reflects interoceptive integration, facilitates adaptive belief updating, and impacts our capacity to adapt to changes in uncertainty, with downstream consequences to well-being. We also highlight the role of meta-awareness of arousal, a third level of inference, which may permit conscious awareness, learning about, and intentional regulation of lower-order sources of arousal. Practices emphasizing meta-awareness of arousal (like meditation) may therefore elicit some of their known benefits via improved arousal coherence. We suggest that arousal coherence is also likely to be associated with markers of adaptive functioning (like emotional awareness and self-regulatory capacities) and discuss mind-body practices that may increase coherence.

3.
ArXiv ; 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37645053

RESUMO

Active Inference is a recently developed framework for modeling decision processes under uncertainty. Over the last several years, empirical and theoretical work has begun to evaluate the strengths and weaknesses of this approach and how it might be extended and improved. One recent extension is the "sophisticated inference" (SI) algorithm, which improves performance on multi-step planning problems through a recursive decision tree search. However, little work to date has been done to compare SI to other established planning algorithms in reinforcement learning (RL). In addition, SI was developed with a focus on inference as opposed to learning. The present paper therefore has two aims. First, we compare performance of SI to Bayesian RL schemes designed to solve similar problems. Second, we present and compare an extension of SI - sophisticated learning (SL) - that more fully incorporates active learning during planning. SL maintains beliefs about how model parameters would change under the future observations expected under each policy. This allows a form of counterfactual retrospective inference in which the agent considers what could be learned from current or past observations given different future observations. To accomplish these aims, we make use of a novel, biologically inspired environment that requires an optimal balance between goal-seeking and active learning, and which was designed to highlight the problem structure for which SL offers a unique solution. This setup requires an agent to continually search an open environment for available (but changing) resources in the presence of competing affordances for information gain. Our simulations demonstrate that SL outperforms all other algorithms in this context - most notably, Bayes-adaptive RL and upper confidence bound (UCB) algorithms, which aim to solve multi-step planning problems using similar principles (i.e., directed exploration and counterfactual reasoning about belief updates given different possible actions/observations). These results provide added support for the utility of Active Inference in solving this class of biologically-relevant problems and offer added tools for testing hypotheses about human cognition.

4.
Behav Brain Sci ; 46: e108, 2023 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-37154124

RESUMO

Convincing narratives are not confabulations. Presumably they "feel right" to decision-making agents because the probabilities they assign intuitively (i.e., implicitly) to potential outcomes are plausible. Can we render explicit the calculations that would be performed by a decision-making agent to evaluate the plausibility of competing narratives? And if we can, what, exactly, makes a narrative "feel right" to an agent?


Assuntos
Tomada de Decisões , Emoções , Humanos , Incerteza , Narração , Transtornos da Memória
6.
Clin Infect Dis ; 76(5): 842-849, 2023 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-36262054

RESUMO

BACKGROUND: Cognitive impairment is reported as a common complication in adult tuberculous meningitis (TBM), yet few studies have systematically assessed the frequency and nature of impairment. Moreover, the impact of impairment on functioning and medication adherence has not been described. METHODS: A cognitive test battery (10 measures assessing 7 cognitive domains) was administered to 34 participants with human immunodeficiency virus (HIV)-associated TBM 6 months after diagnosis. Cognitive performance was compared with that a comparator group of 66 people with HIV without a history of tuberculosis. A secondary comparison was made between participants with TBM and 26 participants with HIV 6 months after diagnosis of tuberculosis outside the central nervous system (CNS). Impact on functioning was evaluated, including through assessment of medication adherence. RESULTS: Of 34 participants with TBM, 16 (47%) had low performance on cognitive testing. Cognition was impaired across all domains. Global cognitive performance was significantly lower in participants with TBM than in people with HIV (mean T score, 41 vs 48, respectively; P < .001). These participants also had lower global cognition scores than those with non-CNS tuberculosis (mean global T score, 41 vs 46; P = .02). Functional outcomes were not significantly correlated with cognitive performance in the subgroup of participants in whom this was assessed (n = 19). CONCLUSIONS: Low cognitive performance following HIV-associated TBM is common. This effect is independent of, and additional to, effects of HIV and non-CNS tuberculosis disease. Further studies are needed to understand longer-term outcomes, clarify the association with treatment adherence, a key predictor of outcome in TBM, and develop context-specific tools to identify individuals with cognitive difficulties in order to improve outcomes in TBM.


Assuntos
Disfunção Cognitiva , Infecções por HIV , Tuberculose Meníngea , Adulto , Humanos , Tuberculose Meníngea/complicações , Tuberculose Meníngea/diagnóstico , Tuberculose Meníngea/tratamento farmacológico , Infecções por HIV/complicações , Disfunção Cognitiva/complicações
7.
Personal Neurosci ; 5: e10, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36258778

RESUMO

The Affective Neuroscience Personality Scales (ANPS) were designed to provide researchers in the mental sciences with an inventory to assess primary emotional systems according to Pankseppian Affective Neuroscience Theory (ANT). The original ANPS, providing researchers with such a tool, was published in 2003. In the present brief communication, about 20 years later, we reflect upon some pressing matters regarding the further development of the ANPS. We touch upon problems related to disentangling traits and states of the primary emotional systems with the currently available versions of the ANPS and upon its psychometric properties and its length. We reflect also on problems such as the large overlap between the SADNESS and FEAR dimensions, the disentangling of PANIC and GRIEF in the context of SADNESS, and the absence of a LUST scale. Lastly, we want to encourage scientists with the present brief communication to engage in further biological validation of the ANPS.

8.
Neuropsychologia ; 170: 108227, 2022 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-35364093

RESUMO

In recent decades, the research traditions of (first-person) embodied cognition and of (third-person) social cognition have approached the study of self-awareness with relative independence. However, neurological disorders of self-awareness offer a unifying perspective to empirically investigate the contribution of embodiment and social cognition to self-awareness. This study focused on a neuropsychological disorder of bodily self-awareness following right-hemisphere damage, namely anosognosia for hemiplegia (AHP). A previous neuropsychological study has shown AHP patients, relative to neurological controls, to have a specific deficit in third-person perspective taking and allocentric stance (the other unrelated to the self) in higher order mentalizing tasks. However, no study has tested if verbal awareness of motor deficits is influenced by perspective-taking and centrism and identified the related anatomical correlates. Accordingly, two novel experiments were conducted with right-hemisphere stroke patients with (n = 17) and without AHP (n = 17) that targeted either their own (egocentric, experiment 1) or another stooge patients (allocentric, experiment 2) motor abilities from a first-or-third person perspective. In both experiments, neurological controls showed no significant difference in perspective-taking, suggesting that social cognition is not a necessary consequence of right-hemisphere damage. More specifically, experiment 1 found AHP patients more aware of their own motor paralysis (egocentric stance) when asked from a third compared to a first-person perspective, using both group level and individual level analysis. In experiment 2, AHP patients were less accurate than controls in making allocentric judgements about the stooge patient, but with only a trend towards significance and with no difference between perspectives. As predicted, deficits in egocentric and allocentric third-person perspective taking were associated with lesions in the middle frontal gyrus, superior temporal and supramarginal gyri, and white matter disconnections were more prominent with deficits in allocentricity. Behavioural and neuroimaging results demonstrate the intersecting relationship between bodily self-awareness and self-and-other-directed metacognition or mentalisation.


Assuntos
Agnosia , Metacognição , Acidente Vascular Cerebral , Agnosia/etiologia , Agnosia/psicologia , Conscientização , Cognição , Hemiplegia/psicologia , Humanos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/psicologia
9.
J Am Psychoanal Assoc ; 70(6): 1169-1181, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36744664
10.
J Am Psychoanal Assoc ; 69(4): 767-774, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34727725
12.
Trends Neurosci ; 44(8): 619-628, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33994015

RESUMO

According to the predictive processing framework, perception is geared to represent the environment in terms of embodied action opportunities as opposed to objective truth. Here, we argue that such an optimisation is reflected by biases in expectations (i.e., prior predictive information) that facilitate 'useful' inferences of external sensory causes. To support this, we highlight a body of literature suggesting that perception is systematically biased away from accurate estimates under conditions where utility and accuracy conflict with one another. We interpret this to reflect the brain's attempt to adjudicate between conflicting sources of prediction error, as external accuracy is sacrificed to facilitate actions that proactively avoid physiologically surprising outcomes. This carries important theoretical implications and offers new insights into psychopathology.


Assuntos
Percepção , Humanos
13.
Exp Brain Res ; 239(5): 1639-1649, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33770219

RESUMO

Peripersonal space (PPS) is the space immediately surrounding the body, conceptualised as a sensory-motor interface between body and environment. PPS size differs between individuals and contexts, with intrapersonal traits and states, as well as social factors having a determining role on the size of PPS. Testosterone plays an important role in regulating social-motivational behaviour and is known to enhance dominance motivation in an implicit and unconscious manner. We investigated whether the dominance-enhancing effects of testosterone reflect as changes in the representation of PPS in a within-subjects testosterone administration study in women (N = 19). Participants performed a visuo-tactile integration task in a mixed-reality setup. Results indicated that the administration of testosterone caused a significant enlargement of participants' PPS, suggesting that testosterone caused participants to implicitly appropriate a larger space as their own. These findings suggest that the dominance-enhancing effects of testosterone reflect at the level of sensory-motor processing in PPS.


Assuntos
Espaço Pessoal , Percepção do Tato , Feminino , Humanos , Estimulação Física , Percepção Espacial , Testosterona , Tato
14.
iScience ; 24(1): 101923, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33409474

RESUMO

Functional dissociations in the brain observed during non-rapid eye movement (NREM) sleep have been associated with reduced information integration and impaired consciousness that accompany increasing sleep depth. Here, we explored the dynamical properties of large-scale functional brain networks derived from transient brain activity using functional magnetic resonance imaging. Spatial brain maps generally display significant modifications in terms of their tendency to occur across wakefulness and NREM sleep. Unexpectedly, almost all networks predominated in activity during NREM stage 2 before an abrupt loss of activity is observed in NREM stage 3. Yet, functional connectivity and mutual dependencies between these networks progressively broke down with increasing sleep depth. Thus, the efficiency of information transfer during NREM stage 2 is low despite the high attempt to communicate. Critically, our approach provides relevant data for evaluating functional brain network integrity and our findings robustly support a significant advance in our neural models of human sleep and consciousness.

15.
Psychoanal Q ; 90(4): 555-581, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35312422

RESUMO

This revision concerns primarily the biological origin of the Oedipus complex, classically understood as an inherited primal phantasy. However, a reconceptualization of the origin of what Freud called the nuclear complex of the neuroses also has consequences for understanding its nature. A review of current knowledge relevant to the biological mechanisms of inheritance and the type of memory system that Freud had in mind, and a review of modern instinct theory, suggests that the Oedipus complex is not an innate predisposition but rather the almost inevitable outcome of a combination of simpler biological processes.


Assuntos
Teoria Freudiana , Complexo de Édipo , Fantasia , Transtornos Neuróticos
16.
J Am Psychoanal Assoc ; 69(6): 1033-1091, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35170340

RESUMO

Several deep revisions of Freud's theory of the drives are proposed: (1) Drives are conscious and are in fact the source of all consciousness. (2) Drive energy is equated with variational free energy and is therefore quantifiable in principle. (3) There are not two drives but many, seven of which may be described as "emotional" as opposed to "bodily" drives. (4) All drives are self-preservative or preservative of the species; there is no death drive at work in the mind. This means, at the mechanistic level, that all drives are homeostatic and anti-entropic. (5) The great task of mental development is to supplement instinctual predictions about how our multiple drive demands may be met and reconciled with each other. This work is done by learning from experience, mainly through voluntary behavior, which is governed by conscious feelings.


Assuntos
Teoria Freudiana , Teoria Psicanalítica , Humanos
17.
PLoS One ; 15(7): e0228903, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701992

RESUMO

Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those collected after non-REM. However, a comparison of the word-to-word structural organization of dream reports is lacking, and traditional measures that distinguish REM and non-REM dreaming may be confounded by report length. This problem is amenable to the analysis of dream reports as non-semantic directed word graphs, which provide a structural assessment of oral reports, while controlling for individual differences in verbosity. Against this background, the present study had two main aims: Firstly, to investigate differences in graph structure between REM and non-REM dream reports, and secondly, to evaluate how non-semantic directed word graph analysis compares to the widely used measure of report length in dream analysis. To do this, we analyzed a set of 133 dream reports obtained from 20 participants in controlled laboratory awakenings from REM and N2 sleep. We found that: (1) graphs from REM sleep possess a larger connectedness compared to those from N2; (2) measures of graph structure can predict ratings of dream complexity, where increases in connectedness and decreases in randomness are observed in relation to increasing dream report complexity; and (3) measures of the Largest Connected Component of a graph can improve a model containing report length in predicting sleep stage and dream report complexity. These results indicate that dream reports sampled after REM awakening have on average a larger connectedness compared to those sampled after N2 (i.e. words recur with a longer range), a difference which appears to be related to underlying differences in dream complexity. Altogether, graph analysis represents a promising method for dream research, due to its automated nature and potential to complement report length in dream analysis.


Assuntos
Sonhos , Sono REM , Adolescente , Adulto , Feminino , Humanos , Modelos Lineares , Masculino , Rememoração Mental , Fases do Sono , Fatores de Tempo , Adulto Jovem
18.
Multisens Res ; 33(2): 161-187, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31648187

RESUMO

The Rubber Hand Illusion (RHI) is an experimental paradigm for assessing changes in body ownership. Recent findings in the field suggest that social emotions can influence such changes and that empathic motivation in particular appears to positively predict the malleability of body representations. Since the steroid hormone, testosterone, is well known to interrupt certain forms of empathic processing, in the current study we investigated whether 0.5 mg of testosterone affected ownership indices of the RHI. Forty-nine females participated in a double-blind, placebo-controlled experiment in which the RHI was induced. Compared to placebo, testosterone had no effects on the alteration of subjective ownership over the rubber limb or on subjective sense of proprioceptive drift. However, unlike the placebo group, testosterone-treated participants did not display an objective decline in the temperature of their own (hidden) hand following induction of the illusion. These findings suggest that testosterone strengthens implicit but not explicit bodily self-representations. We propose that effective maintenance of implicit body boundaries can be regarded, conceptually, as a primary defensive state facilitating integrity of the self.


Assuntos
Imagem Corporal , Emoções/fisiologia , Mãos/fisiologia , Ilusões/efeitos dos fármacos , Propriocepção/efeitos dos fármacos , Testosterona/farmacologia , Percepção do Tato/efeitos dos fármacos , Adolescente , Adulto , Androgênios/farmacologia , Temperatura Baixa , Feminino , Voluntários Saudáveis , Humanos , Adulto Jovem
19.
Front Hum Neurosci ; 13: 370, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31680920

RESUMO

BACKGROUND: Dreaming is a universal experience, yet there is considerable inter-individual variability in dream recall frequency (DRF). One dominant model, the "arousal-retrieval" model, posits that intra-sleep wakefulness is required for dream traces to be encoded into long-term storage, essentially proposing that a better memory for dreams underlie increased DRF. A recent study utilizing polysomnography combined with an event-related potentials paradigm, provides direct support for this model by demonstrating increased intra-sleep wakefulness in a healthy population by comparing high frequency recallers (HFRs) and low frequency recallers (LFRs). Another study by the same group demonstrated increased regional cerebral blood flow in regions associated with dream production, supporting the premise that HFRs also may produce more dreams. HYPOTHESES: This study investigated the profile of nocturnal awakenings and dream production in healthy HFRs and LFRs. Hypothesis (1a): HFRs will spend significantly more time awake after sleep onset; (1b): HFRs will experience significantly more awakenings across the night, and from rapid eye movement (REM) sleep in particular; (2) HFRs will have significantly higher rates of dream production across the night as measured by REM density. METHODS: We studied two groups of healthy adults: HFRs (n = 19) and LFRs (n = 17) who underwent polysomnographic recordings on two non-consecutive nights. RESULTS: Hypothesis (1a) was confirmed: HFRs spent significantly more time awake after sleep onset. Hypothesis (1b) was partially confirmed: HFRs experienced significantly more awakenings across the night; however, awakenings from REM sleep were comparable. Interestingly, HFRs had significantly more awakenings, as well as a higher number of longer awakenings, from non-rapid eye movement (NREM) stage 2 sleep. Hypothesis (2) was not confirmed: There was no significant difference in rates of REM density between groups. CONCLUSION: This is the first study to provide evidence that awakenings from NREM 2 sleep might underlie increased DRF in HFRs. This finding coupled with null findings in relation to REM sleep variables, support the premise that inter-individual variability in DRF cannot be ascribed to differences in REM sleep parameters in healthy individuals. Instead, the data indicates that awakenings from NREM sleep is of particular importance in relation to DRF in a healthy population.

20.
Sci Rep ; 9(1): 12959, 2019 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-31506497

RESUMO

There is extensive evidence of an association between early adversity and enduring neural changes that impact socioemotional processing throughout life. Yet little is known about the effects of on-going social discrimination on socioemotional functioning. Here we examined how cumulative experiences of social discrimination impact brain response during empathic responding-a crucial issue in South Africa, given its historical apartheid context and continuing legacies. White and Black South Africans completed measures of social adversity (early adversity and social discrimination), and underwent fMRI while viewing video clips depicting victims and perpetrators of apartheid crimes. Increased neural response was detected in brain regions associated with cognitive rather than affective empathy, and greater social adversity was associated with reduced reported compassion across participants. Notably, social discrimination (due to income level, weight, gender) in White participants was associated with increased amygdala reactivity, whereas social discrimination (due to race) in Black participants mediated the negative associations of temporoparietal junction and inferior frontal gyrus activation with compassion during emotionally provocative conditions. These findings suggest that (i) social discrimination has comparable associations at the neural level as other psychosocial stressors, and that (ii) the mechanisms underlying empathic responding vary as a function of the type of social discrimination experienced.


Assuntos
Encéfalo/fisiopatologia , Emoções/fisiologia , Empatia/fisiologia , Imageamento por Ressonância Magnética/métodos , Trauma Psicológico , Discriminação Social , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...