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1.
Proc Natl Acad Sci U S A ; 120(48): e2307991120, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37983510

RESUMO

Working memory involves the short-term maintenance of information and is critical in many tasks. The neural circuit dynamics underlying working memory remain poorly understood, with different aspects of prefrontal cortical (PFC) responses explained by different putative mechanisms. By mathematical analysis, numerical simulations, and using recordings from monkey PFC, we investigate a critical but hitherto ignored aspect of working memory dynamics: information loading. We find that, contrary to common assumptions, optimal loading of information into working memory involves inputs that are largely orthogonal, rather than similar, to the late delay activities observed during memory maintenance, naturally leading to the widely observed phenomenon of dynamic coding in PFC. Using a theoretically principled metric, we show that PFC exhibits the hallmarks of optimal information loading. We also find that optimal information loading emerges as a general dynamical strategy in task-optimized recurrent neural networks. Our theory unifies previous, seemingly conflicting theories of memory maintenance based on attractor or purely sequential dynamics and reveals a normative principle underlying dynamic coding.


Assuntos
Memória de Curto Prazo , Neurônios , Memória de Curto Prazo/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Redes Neurais de Computação
2.
Proc Natl Acad Sci U S A ; 119(40): e2200400119, 2022 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161948

RESUMO

The ability of prefrontal cortex to quickly encode novel associations is crucial for adaptive behavior and central to working memory. Fast Hebbian changes in synaptic strength permit forming new associations, but neuronal signatures of this have been elusive. We devised a trialwise index of pattern similarity to look for rapid changes in population codes. Based on a computational model of working memory, we hypothesized that synaptic strength-and consequently, the tuning of neurons-could change if features of a subsequent stimulus need to be "reassociated," i.e., if bindings between features need to be broken to encode the new item. As a result, identical stimuli might elicit different neural responses. As predicted, neural response similarity dropped following rebinding, but only in prefrontal cortex. The history-dependent changes were expressed on top of traditional, fixed selectivity and were not explainable by carryover of previous firing into the current trial or by neural adaptation.


Assuntos
Memória de Curto Prazo , Modelos Neurológicos , Córtex Pré-Frontal , Sinapses , Memória de Curto Prazo/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Sinapses/fisiologia
3.
J Neurosci ; 43(15): 2730-2740, 2023 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-36868858

RESUMO

Behavioral reports of sensory information are biased by stimulus history. The nature and direction of such serial-dependence biases can differ between experimental settings; both attractive and repulsive biases toward previous stimuli have been observed. How and when these biases arise in the human brain remains largely unexplored. They could occur either via a change in sensory processing itself and/or during postperceptual processes such as maintenance or decision-making. To address this, we tested 20 participants (11 female) and analyzed behavioral and magnetoencephalographic (MEG) data from a working-memory task in which participants were sequentially presented with two randomly oriented gratings, one of which was cued for recall at the end of the trial. Behavioral responses showed evidence for two distinct biases: (1) a within-trial repulsive bias away from the previously encoded orientation on the same trial, and (2) a between-trial attractive bias toward the task-relevant orientation on the previous trial. Multivariate classification of stimulus orientation revealed that neural representations during stimulus encoding were biased away from the previous grating orientation, regardless of whether we considered the within-trial or between-trial prior orientation, despite opposite effects on behavior. These results suggest that repulsive biases occur at the level of sensory processing and can be overridden at postperceptual stages to result in attractive biases in behavior.SIGNIFICANCE STATEMENT Recent experience biases behavioral reports of sensory information, possibly capitalizing on the temporal regularity in our environment. It is still unclear at what stage of stimulus processing such serial biases arise. Here, we recorded behavior and neurophysiological [magnetoencephalographic (MEG)] data to test whether neural activity patterns during early sensory processing show the same biases seen in participants' reports. In a working-memory task that produced multiple biases in behavior, responses were biased toward previous targets, but away from more recent stimuli. Neural activity patterns were uniformly biased away from all previously relevant items. Our results contradict proposals that all serial biases arise at an early sensory processing stage. Instead, neural activity exhibited mostly adaptation-like responses to recent stimuli.


Assuntos
Memória de Curto Prazo , Percepção Visual , Humanos , Feminino , Percepção Visual/fisiologia , Memória de Curto Prazo/fisiologia , Cognição , Encéfalo , Sinais (Psicologia)
4.
PLoS Comput Biol ; 19(10): e1011555, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37851670

RESUMO

When multiple items are held in short-term memory, cues that retrospectively prioritise one item over another (retro-cues) can facilitate subsequent recall. However, the neural and computational underpinnings of this effect are poorly understood. One recent study recorded neural signals in the macaque lateral prefrontal cortex (LPFC) during a retro-cueing task, contrasting delay-period activity before (pre-cue) and after (post-cue) retrocue onset. They reported that in the pre-cue delay, the individual stimuli were maintained in independent subspaces of neural population activity, whereas in the post-cue delay, the prioritised items were rotated into a common subspace, potentially allowing a common readout mechanism. To understand how such representational transitions can be learnt through error minimisation, we trained recurrent neural networks (RNNs) with supervision to perform an equivalent cued-recall task. RNNs were presented with two inputs denoting conjunctive colour-location stimuli, followed by a pre-cue memory delay, a location retrocue, and a post-cue delay. We found that the orthogonal-to-parallel geometry transformation observed in the macaque LPFC emerged naturally in RNNs trained to perform the task. Interestingly, the parallel geometry only developed when the cued information was required to be maintained in short-term memory for several cycles before readout, suggesting that it might confer robustness during maintenance. We extend these findings by analysing the learning dynamics and connectivity patterns of the RNNs, as well as the behaviour of models trained with probabilistic cues, allowing us to make predictions for future studies. Overall, our findings are consistent with recent theoretical accounts which propose that retrocues transform the prioritised memory items into a prospective, action-oriented format.


Assuntos
Sinais (Psicologia) , Memória de Curto Prazo , Animais , Estudos Prospectivos , Estudos Retrospectivos , Córtex Pré-Frontal , Macaca
5.
J Neurosci ; 42(9): 1804-1819, 2022 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-35042770

RESUMO

Value-based decision-making is often studied in a static context, where participants decide which option to select from those currently available. However, everyday life often involves an additional dimension: deciding when to select to maximize reward. Recent evidence suggests that agents track the latent reward of an option, updating changes in their latent reward estimate, to achieve appropriate selection timing (latent reward tracking). However, this strategy can be difficult to distinguish from one in which the optimal selection time is estimated in advance, allowing an agent to wait a predetermined amount of time before selecting, without needing to monitor an option's latent reward (distance-to-goal tracking). Here, we show that these strategies can in principle be dissociated. Human brain activity was recorded using electroencephalography (EEG), while female and male participants performed a novel decision task. Participants were shown an option and decided when to select it, as its latent reward changed from trial-to-trial. While the latent reward was uncued, it could be estimated using cued information about the option's starting value and value growth rate. We then used representational similarity analysis (RSA) to assess whether EEG signals more closely resembled latent reward tracking or distance-to-goal tracking. This approach successfully dissociated the strategies in this task. Starting value and growth rate were translated into a distance-to-goal signal, far in advance of selecting the option. Latent reward could not be independently decoded. These results demonstrate the feasibility of using high temporal resolution neural recordings to identify internally computed decision variables in the human brain.SIGNIFICANCE STATEMENT Reward-seeking behavior involves acting at the right time. However, the external world does not always tell us when an action is most rewarding, necessitating internal representations that guide action timing. Specifying this internal neural representation is challenging because it might stem from a variety of strategies, many of which make similar predictions about brain activity. This study used a novel approach to test whether alternative strategies could be dissociated in principle. Using representational similarity analysis (RSA), we were able to distinguish between candidate internal representations for selection timing. This shows how pattern analysis methods can be used to measure latent decision information in noninvasive neural data.


Assuntos
Sinais (Psicologia) , Recompensa , Encéfalo , Comportamento de Escolha , Tomada de Decisões , Eletroencefalografia , Feminino , Humanos , Masculino , Estudos Prospectivos
6.
PLoS Biol ; 18(3): e3000625, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32119658

RESUMO

Working memory (WM) is important to maintain information over short time periods to provide some stability in a constantly changing environment. However, brain activity is inherently dynamic, raising a challenge for maintaining stable mental states. To investigate the relationship between WM stability and neural dynamics, we used electroencephalography to measure the neural response to impulse stimuli during a WM delay. Multivariate pattern analysis revealed representations were both stable and dynamic: there was a clear difference in neural states between time-specific impulse responses, reflecting dynamic changes, yet the coding scheme for memorised orientations was stable. This suggests that a stable subcomponent in WM enables stable maintenance within a dynamic system. A stable coding scheme simplifies readout for WM-guided behaviour, whereas the low-dimensional dynamic component could provide additional temporal information. Despite having a stable subspace, WM is clearly not perfect-memory performance still degrades over time. Indeed, we find that even within the stable coding scheme, memories drift during maintenance. When averaged across trials, such drift contributes to the width of the error distribution.


Assuntos
Memória de Curto Prazo/fisiologia , Processamento de Sinais Assistido por Computador , Adulto , Encéfalo/fisiologia , Eletroencefalografia , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Análise Multivariada , Experimentação Humana não Terapêutica , Estimulação Luminosa
7.
Psychol Health Med ; 28(9): 2672-2684, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36842996

RESUMO

Our aim was to explore the association between COVID-19 pandemic-related product shortages and symptoms of stress, anxiety, and depression in Australian families, concurrently and longitudinally, while controlling for demographic, health, and psychological characteristics. This prospective study used two waves of data (baseline, Time 0 = April 2020; Time 1 = May 2020) from a longitudinal cohort study of Australian parents of a child aged 0-18 years. Parents were surveyed at baseline about whether they had experienced product shortages related to COVID-19. DASS21 was used to measure symptoms of depression, anxiety, and stress at both waves. The sample included 2,110 participants (N = 1,701, 80.6% mothers). About 68.6% of the respondents reported being impacted by one or more shortages. Product shortages correlated significantly with higher combined and individual scores for anxiety, depression, and stress (r = 0.007 to 0.18, all p < 0.001) at baseline. At Time 1, parental emotion regulation explained 4.0% of the variance (p < .001). Our findings suggest a role for improving parental emotion regulation in coping with stressors, such as shortages and lockdowns.


Assuntos
COVID-19 , Saúde Mental , Criança , Humanos , Estudos Prospectivos , Estudos Longitudinais , Pandemias , COVID-19/epidemiologia , Austrália/epidemiologia , Controle de Doenças Transmissíveis , Ansiedade/epidemiologia , Depressão/epidemiologia
8.
J Neurosci ; 41(20): 4461-4475, 2021 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-33888611

RESUMO

Extensive research has examined how information is maintained in working memory (WM), but it remains unknown how WM is used to guide behavior. We addressed this question by combining human electrophysiology (50 subjects, male and female) with pattern analyses, cognitive modeling, and a task requiring the prolonged maintenance of two WM items and priority shifts between them. This enabled us to discern neural states coding for memories that were selected to guide the next decision from states coding for concurrently held memories that were maintained for later use, and to examine how these states contribute to WM-based decisions. Selected memories were encoded in a functionally active state. This state was reflected in spontaneous brain activity during the delay period, closely tracked moment-to-moment fluctuations in the quality of evidence integration, and also predicted when memories would interfere with each other. In contrast, concurrently held memories were encoded in a functionally latent state. This state was reflected only in stimulus-evoked brain activity, tracked memory precision at longer timescales, but did not engage with ongoing decision dynamics. Intriguingly, the two functional states were highly flexible, as priority could be dynamically shifted back and forth between memories without degrading their precision. These results delineate a hierarchy of functional states, whereby latent memories supporting general maintenance are transformed into active decision circuits to guide flexible behavior.SIGNIFICANCE STATEMENT Working memory enables maintenance of information that is no longer available in the environment. Abundant neuroscientific work has examined where in the brain working memories are stored, but it remains unknown how they are represented and used to guide behavior. Our study shows that working memories are represented in qualitatively different formats, depending on behavioral priorities. Memories that are selected for guiding behavior are encoded in an active state that transforms sensory input into decision variables, whereas other concurrently held memories are encoded in a latent state that supports precise maintenance without affecting ongoing cognition. These results dissociate mechanisms supporting memory storage and usage, and open the door to reveal not only where memories are stored but also how.


Assuntos
Encéfalo/fisiologia , Memória de Curto Prazo/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Modelos Neurológicos , Adulto Jovem
9.
J Cogn Neurosci ; 34(9): 1681-1701, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35704549

RESUMO

Attention can be allocated in working memory (WM) to select and privilege relevant content. It is unclear whether attention selects individual features or whole objects in WM. Here, we used behavioral measures, eye-tracking, and EEG to test the hypothesis that attention spreads between an object's features in WM. Twenty-six participants completed a WM task that asked them to recall the angle of one of two oriented, colored bars after a delay while EEG and eye-tracking data were collected. During the delay, an orthogonal "incidental task" cued the color of one item for a match/mismatch judgment. On congruent trials (50%), the cued item was probed for subsequent orientation recall; on incongruent trials (50%), the other memory item was probed. As predicted, selecting the color of an object in WM brought other features of the cued object into an attended state as revealed by EEG decoding, oscillatory α-power, gaze bias, and improved orientation recall performance. Together, the results show that attentional selection spreads between an object's features in WM, consistent with object-based attentional selection. Analyses of neural processing at recall revealed that the selected object was automatically compared with the probe, whether it was the target for recall or not. This provides a potential mechanism for the observed benefits of nonpredictive cueing in WM, where a selected item is prioritized for subsequent decision-making.


Assuntos
Atenção , Memória de Curto Prazo , Sinais (Psicologia) , Humanos , Rememoração Mental
10.
Aust N Z J Psychiatry ; 56(11): 1503-1514, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-34963330

RESUMO

BACKGROUND: Nascent evidence indicates that the mental health of parents and children has markedly declined during the COVID-19 pandemic. Considering disruptions to traditional face-to-face mental health services resultant from stay-at-home orders, the potential value of digital mental health interventions has become extremely apparent. Despite this, uptake of digital interventions remains poor, indicating that a better understanding is needed of factors that determine a willingness to use digital platforms. METHOD: The present multi-wave, longitudinal study of 2365 Australian parents explored between-person and within-person predictors of intentions to use digital interventions during the pandemic. RESULTS: More than one-third of parents reported likely use of a self-guided and therapist-guided digital intervention, with the most endorsed reason for use being to support their child's mental health. Between-person baseline predictors of higher intention ratings were parent's prior mental illness, not living with a partner and recent environmental stressors. Within-person predictors of higher intention ratings were endorsement of mindful parenting strategies, child access to the Internet, better perceived management of child's education, lower social support and financial hardship. CONCLUSION: Findings demonstrate that willingness to engage in digital interventions fluctuates in response to changing circumstances. Identifying novel ways to increase acceptance and uptake of digital interventions based on modifiable predictors established here is needed to realize the full potential of these modes of care in times of need.


Assuntos
COVID-19 , Saúde Mental , Criança , Humanos , Pandemias , Austrália , Estudos Longitudinais , Pais/psicologia , Poder Familiar/psicologia
11.
Aust N Z J Psychiatry ; 56(11): 1491-1502, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-34930045

RESUMO

OBJECTIVE: To control a second-wave COVID-19 outbreak, the state of Victoria in Australia experienced one of the world's first long and strict lockdowns over July-October 2020, while the rest of Australia experienced 'COVID-normal' with minimal restrictions. We (1) investigate trajectories of parent/child mental health outcomes in Victoria vs non-Victoria and (2) identify baseline demographic, individual and COVID-19-related factors associated with mental health trajectories. METHODS: Online community sample of 2004 Australian parents with rapid repeated assessment over 14 time-points over April 2020 to May 2021. Measures assessed parent mental health (Depression, Anxiety and Stress Scales-21), child depression symptoms (13-item Short Mood and Feelings Questionnaire) and child anxiety symptoms (four items from Brief Spence Children's Anxiety Scale). RESULTS: Mental health trajectories shadowed COVID-19 infection rates. Victorians reported a peak in mental health symptoms at the time of the second-wave lockdown compared to other states. Key baseline predictors, including parent and child loneliness (standardized regression coefficient [ß] = 0.09-0.46), parent/child diagnoses (ß = 0.07-0.21), couple conflict (ß = 0.07-0.18) and COVID-19 stressors, such as worry/concern about COVID-19, illness and loss of job (ß = 0.12-0.15), predicted elevated trajectories. Effects of predictors on parent and child mental health trajectories are illustrated in an online interactive app for readers (https://lingtax.shinyapps.io/CPAS_trend/). CONCLUSION: Our findings provide evidence of worse trajectories of parent and child mental health symptoms at a time coinciding with a second COVID-19 outbreak involving strict lockdown in Victoria, compared to non-locked states in Australia. We identified several baseline factors that may be useful in detecting high-risk families who are likely to require additional support early on in future lockdowns.


Assuntos
COVID-19 , Saúde Mental , Criança , Humanos , Controle de Doenças Transmissíveis , Pais/psicologia , Vitória/epidemiologia
12.
J Integr Neurosci ; 21(2): 57, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35364645

RESUMO

Frontal lobe volume has been extensively researched in individuals with Autism spectrum disorder (ASD), though findings are yet to be summarised to explain the developmental trends of frontal lobe volume. The aim of the present study is to consolidate all existing frontal lobe volume and age data of autistic individuals below 30 years of age, and compare this data to non-autistic (N-ASD) controls. Following a systematic review, frontal lobe volume data were obtained from seven papers. Raw data, or the means and standard deviations of frontal lobe volume, and age, were obtained from the studies giving 372 autistic and 190 N-ASD participants. Data were plotted and analysed. Findings revealed that regression lines of fit for ASD (R2L⁢i⁢n⁢e⁢a⁢r = 0.33; R2Q⁢u⁢a⁢d⁢r⁢a⁢t⁢i⁢c = 0.52) and N-ASD (R2L⁢i⁢n⁢e⁢a⁢r = 0.14; R2Q⁢u⁢a⁢d⁢r⁢a⁢t⁢i⁢c = 0.39) were significantly different by diagnosis (linear p = 0.002, quadratic p = 0.02) with quadratic models providing significantly better fit within ASD (p < 0.001) and N-ASD (p < 0.001). Additional analyses revealed that frontal lobe volume was greater in autistic individuals than N-ASD between two and four years (F(1,31) = 12.965, p < 0.005, η2 = 0.291). In the present study, there were distinct developmental trends for frontal lobe volume between ASD and N-ASD.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Transtorno do Espectro Autista/diagnóstico por imagem , Lobo Frontal/diagnóstico por imagem , Humanos
13.
Arch Gynecol Obstet ; 305(2): 299-311, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34085111

RESUMO

PURPOSE: The aim of this systematic review was to identify challenges faced by autistic women during pregnancy and birth due to sensory issues or other features of Autism Spectrum Disorder. METHODS: A systematic search of literature was conducted using Medline, PubMed, Embase, PsycINFO, CINAHL, MIDIRS, ProQuest Dissertations and Theses Global, and Open Access Theses and Dissertations. Eligible studies addressed autistic women's pregnancy or birth experiences, and were assessed for methodological quality. RESULTS: The search generated 2656 results, with six meeting inclusion criteria. Data from 427 autistic participants were extracted from four qualitative and two quantitative studies for synthesis. CONCLUSION: We found that the literature was exploratory and lacked focussed research questions addressing sensory issues in pregnancy. Sensory challenges were, however, identified as a key finding in all qualitative studies. Other challenges faced by autistic women during pregnancy and birth included communication issues in healthcare settings and lack of appropriate information and supports for pregnancy and birth. Implications for health professionals and challenges associated with research in this area are discussed.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Feminino , Pessoal de Saúde , Humanos , Parto , Gravidez , Pesquisa Qualitativa
14.
J Neurosci ; 40(26): 5033-5050, 2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32366722

RESUMO

Studies of selective attention typically consider the role of task goals or physical salience, but attention can also be captured by previously reward-associated stimuli, even if they are currently task irrelevant. One theory underlying this value-driven attentional capture (VDAC) is that reward-associated stimulus representations undergo plasticity in sensory cortex, thereby automatically capturing attention during early processing. To test this, we used magnetoencephalography to probe whether stimulus location and identity representations in sensory cortex are modulated by reward learning. We furthermore investigated the time course of these neural effects, and their relationship to behavioral VDAC. Male and female human participants first learned stimulus-reward associations. Next, we measured VDAC in a separate task by presenting these stimuli in the absence of reward contingency and probing their effects on the processing of separate target stimuli presented at different time lags. Using time-resolved multivariate pattern analysis, we found that learned value modulated the spatial selection of previously rewarded stimuli in posterior visual and parietal cortex from ∼260 ms after stimulus onset. This value modulation was related to the strength of participants' behavioral VDAC effect and persisted into subsequent target processing. Importantly, learned value did not influence cortical signatures of early processing (i.e., earlier than ∼200 ms); nor did it influence the decodability of stimulus identity. Our results suggest that VDAC is underpinned by learned value signals that modulate spatial selection throughout posterior visual and parietal cortex. We further suggest that VDAC can occur in the absence of changes in early visual processing in cortex.SIGNIFICANCE STATEMENT Attention is our ability to focus on relevant information at the expense of irrelevant information. It can be affected by previously learned but currently irrelevant stimulus-reward associations, a phenomenon termed "value-driven attentional capture" (VDAC). The neural mechanisms underlying VDAC remain unclear. It has been speculated that reward learning induces visual cortical plasticity, which modulates early visual processing to capture attention. Although we find that learned value modulates spatial signals in visual cortical areas, an effect that correlates with VDAC, we find no relevant signatures of changes in early visual processing in cortex.


Assuntos
Atenção/fisiologia , Aprendizagem/fisiologia , Plasticidade Neuronal/fisiologia , Recompensa , Córtex Somatossensorial/fisiologia , Adulto , Feminino , Humanos , Magnetoencefalografia , Masculino , Adulto Jovem
15.
J Neurosci ; 40(20): 4010-4020, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32284338

RESUMO

Probabilistic associations between stimuli afford memory templates that guide perception through proactive anticipatory mechanisms. A great deal of work has examined the behavioral consequences and human electrophysiological substrates of anticipation following probabilistic memory cues that carry spatial or temporal information to guide perception. However, less is understood about the electrophysiological substrates linked to anticipating the sensory content of events based on recurring associations between successive events. Here, we demonstrate behavioral and electrophysiological signatures of using associative-memory templates to guide perception, while equating spatial and temporal anticipation (experiments 1 and 2), as well as target probability and response demands (experiment 2). By recording the electroencephalogram in the two experiments (N = 55; 24 females), we show that two markers in human electrophysiology implicated in spatial and temporal anticipation also contribute to the anticipation of perceptual identity, as follows: attenuation of alpha-band oscillations and the contingent negative variation (CNV). Together, our results show that memory-guided identity templates proactively impact perception and are associated with anticipatory states of attenuated alpha oscillations and the CNV. Furthermore, by isolating object-identity anticipation from spatial and temporal anticipation, our results suggest a role for alpha attenuation and the CNV in specific visual content anticipation beyond general changes in neural excitability or readiness.SIGNIFICANCE STATEMENT Probabilistic associations between stimuli afford memory templates that guide perception through proactive anticipatory mechanisms. The current work isolates the behavioral benefits and electrophysiological signatures of memory-guided identity-based anticipation, while equating anticipation of space, time, motor responses, and task relevance. Our results show that anticipation of the specific identity of a forthcoming percept impacts performance and is associated with states of attenuated alpha oscillations and the contingent negative variation, extending previous work implicating these neural substrates in spatial and temporal preparatory attention. Together, this work bridges fields of attention, memory, and perception, providing new insights into the neural mechanisms that support complex attentional templates.


Assuntos
Antecipação Psicológica/fisiologia , Aprendizagem por Associação/fisiologia , Memória/fisiologia , Percepção Visual/fisiologia , Adulto , Ritmo alfa/fisiologia , Sinais (Psicologia) , Eletroencefalografia , Fenômenos Eletrofisiológicos/fisiologia , Feminino , Humanos , Masculino , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Adulto Jovem
16.
J Neurosci ; 40(3): 671-681, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31754009

RESUMO

It is unclear to what extent sensory processing areas are involved in the maintenance of sensory information in working memory (WM). Previous studies have thus far relied on finding neural activity in the corresponding sensory cortices, neglecting potential activity-silent mechanisms, such as connectivity-dependent encoding. It has recently been found that visual stimulation during visual WM maintenance reveals WM-dependent changes through a bottom-up neural response. Here, we test whether this impulse response is uniquely visual and sensory-specific. Human participants (both sexes) completed visual and auditory WM tasks while electroencephalography was recorded. During the maintenance period, the WM network was perturbed serially with fixed and task-neutral auditory and visual stimuli. We show that a neutral auditory impulse-stimulus presented during the maintenance of a pure tone resulted in a WM-dependent neural response, providing evidence for the auditory counterpart to the visual WM findings reported previously. Interestingly, visual stimulation also resulted in an auditory WM-dependent impulse response, implicating the visual cortex in the maintenance of auditory information, either directly or indirectly, as a pathway to the neural auditory WM representations elsewhere. In contrast, during visual WM maintenance, only the impulse response to visual stimulation was content-specific, suggesting that visual information is maintained in a sensory-specific neural network, separated from auditory processing areas.SIGNIFICANCE STATEMENT Working memory is a crucial component of intelligent, adaptive behavior. Our understanding of the neural mechanisms that support it has recently shifted: rather than being dependent on an unbroken chain of neural activity, working memory may rely on transient changes in neuronal connectivity, which can be maintained efficiently in activity-silent brain states. Previous work using a visual impulse stimulus to perturb the memory network has implicated such silent states in the retention of line orientations in visual working memory. Here, we show that auditory working memory similarly retains auditory information. We also observed a sensory-specific impulse response in visual working memory, while auditory memory responded bimodally to both visual and auditory impulses, possibly reflecting visual dominance of working memory.


Assuntos
Percepção Auditiva/fisiologia , Memória de Curto Prazo/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adolescente , Adulto , Sinais (Psicologia) , Eletroencefalografia , Potenciais Evocados , Feminino , Generalização Psicológica , Humanos , Masculino , Rede Nervosa/fisiologia , Orientação/fisiologia , Estimulação Luminosa , Percepção da Altura Sonora , Desempenho Psicomotor/fisiologia , Adulto Jovem
17.
Neuroimage ; 237: 118030, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-33836272

RESUMO

Recent advances have made it possible to decode various aspects of visually presented stimuli from patterns of scalp EEG measurements. As of recently, such multivariate methods have been commonly used to decode visual-spatial features such as location, orientation, or spatial frequency. In the current study, we show that it is also possible to track visual colour processing by using Linear Discriminant Analysis on patterns of EEG activity. Building on other recent demonstrations, we show that colour decoding: (1) reflects sensory qualities (as opposed to, for example, verbal labelling) with a prominent contribution from posterior electrodes contralateral to the stimulus, (2) conforms to a parametric coding space, (3) is possible in multi-item displays, and (4) is comparable in magnitude to the decoding of visual stimulus orientation. Through subsampling our data, we also provide an estimate of the approximate number of trials and participants required for robust decoding. Finally, we show that while colour decoding can be sensitive to subtle differences in luminance, our colour decoding results are primarily driven by measured colour differences between stimuli. Colour decoding opens a relevant new dimension in which to track visual processing using scalp EEG measurements, while bypassing potential confounds associated with decoding approaches that focus on spatial features.


Assuntos
Córtex Cerebral/fisiologia , Percepção de Cores/fisiologia , Eletroencefalografia/métodos , Neuroimagem Funcional/métodos , Reconhecimento Visual de Modelos/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Sensibilidades de Contraste/fisiologia , Eletroculografia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Processamento de Sinais Assistido por Computador , Aprendizado de Máquina Supervisionado , Adulto Jovem
18.
Reprod Biomed Online ; 43(1): 149-158, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34006483

RESUMO

RESEARCH QUESTION: How do the demographic characteristics, mental health experiences and disclosure experiences of donor-conceived adults shape motivations for seeking information about their sperm donors, contact with them, or both? DESIGN: Sixty-nine Australian adults who conceived through sperm donors completed an online survey. Uniquely, information and contact seeking were investigated as two distinct concepts. RESULTS: Participants reported a variety of demographic, mental health, disclosure and discovery experiences. Most had been motivated to seek information about their donor (88%), contact with them (71%), or both. The most commonly reported motivations for each act were for medical information, expanding their identity and curiosity. Logistic regression findings were significant for wanting medical information as a motivation for seeking donor information (P = 0.03). Endorsement of this motivation was associated with self-reported anxiety (P = 0.02) and less likely as participant age increased (P = 0.02). Motivation to contact donors for medical information was associated with self-reported anxiety (P = 0.02) and depression (P = 0.01), and more likely when the participant was raised in a household that included the recipient co-parent (P = 0.04). As years since disclosure or discovery increased, participants were less likely to report wanting medical information as a motivation (P = 0.02). CONCLUSION: Overall, participants were motivated to obtain information and seek contact with sperm donors. Motivations for each were similar despite participants varying in age and reporting a range of circumstances regarding disclosure, some of which were adverse.


Assuntos
Filhos Adultos/psicologia , Comportamento de Busca de Informação , Inseminação Artificial Heteróloga/psicologia , Adulto , Feminino , Humanos , Masculino , Motivação , Inquéritos e Questionários , Doadores de Tecidos
19.
J Neurosci ; 39(43): 8549-8561, 2019 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-31519820

RESUMO

Cognitive flexibility is critical for intelligent behavior. However, its execution is effortful and often suboptimal. Recent work indicates that flexible behavior can be improved by the prospect of reward, which suggests that rewards optimize flexible control processes. Here we investigated how different reward prospects influence neural encoding of task rule information to optimize cognitive flexibility. We applied representational similarity analysis to human electroencephalograms, recorded while female and male participants performed a rule-guided decision-making task. During the task, the prospect of reward varied from trial to trial. Participants made faster, more accurate judgements on high-reward trials. Critically, high reward boosted neural coding of the active task rule, and the extent of this increase was associated with improvements in task performance. Additionally, the effect of high reward on task rule coding was most pronounced on switch trials, where rules were updated relative to the previous trial. These results suggest that reward prospect can promote cognitive performance by strengthening neural coding of task rule information, helping to improve cognitive flexibility during complex behavior.SIGNIFICANCE STATEMENT The importance of motivation is evident in the ubiquity with which reward prospect guides adaptive behavior and the striking number of neurological conditions associated with motivational impairments. In this study, we investigated how dynamic changes in motivation, as manipulated through reward, shape neural coding for task rules during a flexible decision-making task. The results of this work suggest that motivation to obtain reward modulates the encoding of task rules needed for flexible behavior. The extent to which reward increased task rule coding also tracked improvements in behavioral performance under high-reward conditions. These findings help to inform how motivation shapes neural processing in the healthy human brain.


Assuntos
Encéfalo/fisiologia , Cognição/fisiologia , Função Executiva/fisiologia , Julgamento/fisiologia , Recompensa , Adolescente , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Adulto Jovem
20.
Cerebellum ; 19(5): 617-628, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32445170

RESUMO

Cerebellar volume, in particular vermal lobule areas VI-VII, have been extensively researched in individuals with autism spectrum disorder (ASD), although findings are often unclear. The aim of the present study is to consolidate all existing cerebellar and age data of individuals with ASD, and compare this data to typically developing (TD) controls. Raw data, or the means and standard deviations of cerebellar volume and age, were obtained from 17 studies (NCerebellum: 421 ASD and 370 TD participants; NVI-VII: 506 ASD and 290 TD participants). Total cerebellar volume, or VI-VII area, was plotted against age and lines of fit of ASD and TD data were compared. Mean differences in cerebellar volume and VI-VII area between participants with ASD and TD participants were then compared via ANCOVA analyses. Findings revealed multiple differences in VI-VII area between participants with ASD and TD participants below 18 years of age. Additionally, cerebellar volume was greater in males with ASD than TD males between 2 and 4 years. In the present study, cerebellar volume and VI-VII area show different rates of change across age for those with autism compared with those without. These morphological differences provide a neurobiological justification to investigate related behavioural correlates.


Assuntos
Transtorno do Espectro Autista/patologia , Transtorno Autístico/patologia , Córtex Cerebelar/patologia , Cerebelo/patologia , Adolescente , Adulto , Fatores Etários , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Adulto Jovem
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