Neuropsychologia最新文献

The current study examined whether adults with Developmental Dyslexia are impaired in learning linguistic regularities in a novel language, and whether this may be explained by a domain general deficit in the effect of sleep on consolidation. We compared online learning and offline consolidation of morphological regularities in individuals with Developmental Dyslexia (N = 40) and typical readers (N = 38). Participants learned to apply plural inflections to novel words based on morpho-phonological rules embedded in the input and learned to execute a finger motor sequence task. To test the effects of time and sleep on consolidation, participants were assigned into one of two sleep-schedule groups, trained in the evening or in the morning and tested 12 and 24 h later. Unlike typical readers, Dyslexic readers did not extract the morpho-phonological regularities during training and as a group they did not show offline gains in inflecting trained items 24 h after training, suggesting that the deficit in extraction of regularities during training may be related to the deficit in consolidation. The offline gains in dyslexic readers, were correlated with their prior phonological abilities, and were less affected by sleep than those of typical readers. Although no deficit was found in the consolidation of the motor task, dyslexic readers were again less successful in generating an abstract representation of the motor sequence, reflected in a difficulty to generalize the motor sequence knowledge acquired using one hand to the untrained hand. The results suggest that individuals with Developmental Dyslexia have a domain general deficit in extracting statistical regularities from an input. Within the language domain this deficit is reflected in reduced benefits of consolidation, particularly during sleep, perhaps due to reduced prior phonological abilities, which may impede the individual's ability to extract the linguistic regularities during and after training and thus constrain the consolidation process.

Developmental dyslexia is a reading disorder that is associated with atypical brain function. One neuropsychological theory posits that dyslexia reflects a deficit in the procedural memory system, which supports implicit learning, or the acquisition of knowledge without conscious awareness or intention. This study investigated various forms of procedural learning in adults with dyslexia and typically-reading adults. Adults with dyslexia exhibited typical skill learning on mirror tracing and rotary pursuit tasks that have been well-established as reflecting purely procedural memory and dependent on basal ganglia and cerebellar structures. They also exhibited typical statistical learning for visual material, but impaired statistical learning for auditory material. Auditory statistical learning proficiency correlated positively with single-word reading performance across all participants and within the group with dyslexia, linking a major difficulty in dyslexia with impaired auditory statistical learning. These findings dissociate multiple forms of procedural memory that are intact in dyslexia from a specific impairment in auditory statistical learning that is associated with reading difficulty.

Poor phonological awareness is associated with greater risk for reading disability. The underlying neural mechanism of such association may lie in the brain processing of phonological information. Lower amplitude of auditory mismatch negativity (MMN) has been associated with poor phonological awareness and with the presence of reading disability. The current study recorded auditory MMN to phoneme and lexical tone contrast with odd-ball paradigm and examined whether auditory MMN mediated the associations between phonological awareness and character reading ability through a three-year longitudinal study in 78 native Mandarin-speaking kindergarten children. Hierarchical linear regression and mediation analyses showed that the effect of phoneme awareness on the character reading ability was mediated by the phonemic MMN in young Chinese children. Findings underscore the key role of phonemic MMN as the underlying neurodevelopmental mechanism linking phoneme awareness and reading ability.

Free will has been at the heart of philosophical and scientific discussions for many years. However, recent advances in neuroscience have been perceived as a threat to the commonsense notion of free will as they challenge two core requirements for actions to be free. The first is the notion of determinism and free will, i.e., decisions and actions must not be entirely determined by antecedent causes. The second is the notion of mental causation, i.e., our mental state must have causal effects in the physical world, in other words, actions are caused by conscious intention.

We present the classical philosophical positions related to determinism and mental causation, and discuss how neuroscience could shed a new light on the philosophical debate based on recent experimental findings. Overall, we conclude that the current evidence is insufficient to undermine free will.

We studied the role of the ventromedial prefrontal cortex (vmPFC) in supporting the self-schema, by asking vmPFC patients, along with healthy and brain-damaged controls, to judge the degree to which they (or another person) were likely to engage in a series of activities, and how confident they were in their responses. Critically, participants provided their judgments on two separate occasions, a week apart. Our underlying assumption was that a strong self-schema would lead to confident and stable self-related judgments. We observed that control groups exhibited higher across-session consistency for self-related compared to other-related judgments, while this self-advantage was absent in vmPFC patients. In addition, regression analyses showed that in control groups the level of confidence associated with a specific (self- or other-related) judgment predicted the stability of that judgment across sessions. In contrast, vmPFC patients’ confidence and rating consistency were aligned only for other-related judgments. By contrast, self-related judgments changed across sessions regardless of the confidence level with which they were initially endorsed. These findings indicate that the vmPFC is crucial to maintaining the self-schema and supporting the reliable retrieval of self-related information.

Mel Goodale has had a multi-faceted career in cognitive neuroscience, principally in the areas of perception, visually-guided action, and visual consciousness. This short article presents a personal reflection on his career from the point of view of a long-time colleague and friend.

Language is a key part of human cognition, essential for our well-being at all stages of our lives. Whereas many neurocognitive abilities decline with age, for language the picture is much less clear, and how exactly speech comprehension changes with ageing is still unknown. To investigate this, we employed magnetoencephalography (MEG) and recorded neuromagnetic brain responses to auditory linguistic stimuli in healthy participants of younger and older age using a passive task-free paradigm and a range of different linguistic stimulus contrasts, which enabled us to assess neural processing of spoken language at multiple levels (lexical, semantic, morphosyntactic). Using machine learning-based classification algorithms to scrutinise intertrial phase coherence of MEG responses in cortical source space, we found that patterns of oscillatory neural activity diverged between younger and older participants across several frequency bands (alpha, beta, gamma) for all tested linguistic information types. The results suggest multiple age-related changes in the brain's neurolinguistic circuits, which may be due to both healthy ageing in general and compensatory processes in particular.

The recognition of objects is strongly facilitated when they are presented in the context of other objects (Biederman, 1972). Such contexts facilitate perception and induce expectations of context-congruent objects (Trapp and Bar, 2015). The neural mechanisms underlying these facilitatory effects of context on object processing, however, are not yet fully understood. In the present study, we investigate how context-induced expectations affect subsequent object processing. We used functional magnetic resonance imaging and measured repetition suppression as a proxy for prediction error processing. Participants viewed pairs of alternating or repeated object images which were preceded by context-congruent, context-incongruent or neutral cues. We found a stronger repetition suppression in congruent as compared to incongruent or neutral cues in the object sensitive lateral occipital cortex. Interestingly, this stronger effect was driven by enhanced responses to alternating stimulus pairs in the congruent contexts, rather than by suppressed responses to repeated stimulus pairs, which emphasizes the contribution of surprise-related response enhancement for the context modulation on RS when expectations are violated. In addition, in the congruent condition, we discovered significant functional connectivity between object-responsive and frontal cortical regions, as well as between object-responsive regions and the fusiform gyrus. Our findings indicate that prediction errors, reflected in enhanced brain responses to violated contextual expectations, underlie the facilitating effect of context during object perception.

The aspiration for insight into human cognitive processing has traditionally driven research in cognitive science. With methods such as the Hidden semi-Markov Model-Electroencephalography (HsMM-EEG) method, new approaches have been developed that help to understand the temporal structure of cognition by identifying temporally discrete processing stages. However, it remains challenging to assign concrete functional contributions by specific processing stages to the overall cognitive process. In this paper, we address this challenge by linking HsMM-EEG³ with cognitive modelling, with the aim of further validating the HsMM-EEG³ method and demonstrating the potential of cognitive models to facilitate functional interpretation of processing stages. For this purpose, we applied HsMM-EEG³ to data from a mental rotation task and developed an ACT-R cognitive model that is able to closely replicate human performance in this task. Applying HsMM-EEG³ to the mental rotation experiment data revealed a strong likelihood for 6 distinct stages of cognitive processing during trials, with an additional stage for non-rotated conditions. The cognitive model predicted intra-trial mental activity patterns that project well onto the processing stages, while explaining the additional stage as a marker of non-spatial shortcut use. Thereby, this combined methodology provided substantially more information than either method by itself and suggests conclusions for cognitive processing in general.

Non-arbitrary mapping between the sound of a word and its meaning, termed sound symbolism, is commonly studied through crossmodal correspondences between sounds and visual shapes, e.g., auditory pseudowords, like ‘mohloh’ and ‘kehteh’, are matched to rounded and pointed visual shapes, respectively. Here, we used functional magnetic resonance imaging (fMRI) during a crossmodal matching task to investigate the hypotheses that sound symbolism (1) involves language processing; (2) depends on multisensory integration; (3) reflects embodiment of speech in hand movements. These hypotheses lead to corresponding neuroanatomical predictions of crossmodal congruency effects in (1) the language network; (2) areas mediating multisensory processing, including visual and auditory cortex; (3) regions responsible for sensorimotor control of the hand and mouth. Right-handed participants (n = 22) encountered audiovisual stimuli comprising a simultaneously presented visual shape (rounded or pointed) and an auditory pseudoword (‘mohloh’ or ‘kehteh’) and indicated via a right-hand keypress whether the stimuli matched or not. Reaction times were faster for congruent than incongruent stimuli. Univariate analysis showed that activity was greater for the congruent compared to the incongruent condition in the left primary and association auditory cortex, and left anterior fusiform/parahippocampal gyri. Multivoxel pattern analysis revealed higher classification accuracy for the audiovisual stimuli when congruent than when incongruent, in the pars opercularis of the left inferior frontal (Broca's area), the left supramarginal, and the right mid-occipital gyri. These findings, considered in relation to the neuroanatomical predictions, support the first two hypotheses and suggest that sound symbolism involves both language processing and multisensory integration.