Journal of Cognitive Neuroscience最新文献

Whenever a perceived event violates expectations compared with an expected event, the cortical response to this event tends to be augmented. The increase in cortical responses signals a mismatch between expectation and observation. Mismatch patterns of neural activity have been repeatedly observed in adults, but their emergence and evolution in infancy are not well understood, since most prediction-inducing paradigms require learning the association or rule underpinning the expectation, thus conflating the violation response with the ability to learn. To address this shortcoming, this article reports a neuroimaging study with 2- to 6-month-olds that measured neural responses to the colocation (expected or matched) or dislocation (deviant or mismatch) of sounds and visual events. The results indicated that even in early infancy, the brain is sensitive to violations of expectation: Stimuli that deviated from expectation elicited stronger neural responses in these infants' sensory cortices than expected stimuli.

This study investigates intelligence-related differences in the adjustment of brain activity and connectivity to varying cognitive demands, testing for a moderation of an association between intelligence and neural efficiency by task difficulty. In 72 young adults (34 female, 38 male), fMRI brain activity changes during a decision-making task with five levels of difficulty were related to intelligence scores from a nonverbal matrix reasoning test. In frontoparietal, subcortical, and cerebellar regions activated during task processing, we observed smaller increases in brain activity in more intelligent participants-independent of task difficulty. However, in two regions of the default mode network, dorsomedial prefrontal cortex and left angular gyrus, more intelligent participants showed greater decreases in activity with increasing task difficulty. Furthermore, with increasing difficulty, more intelligent participants showed greater increases in functional connectivity of dorsomedial prefrontal cortex and angular gyrus. These findings suggest a more dynamic adjustment of neural processing to varying cognitive demands in more intelligent individuals. Particularly when it comes to more difficult tasks, more intelligent people seem to be better able to down-regulate activity in the brain's default mode network. Due to the relatively small sample size, these findings must be considered preliminary. While their interpretation should therefore be treated with caution, they suggest conceptually new avenues for replication in larger samples. As far as the observed processes reflect the suppression of task-unrelated neural processing and a better focus on the task at hand, they can potentially explain the general performance advantage of more intelligent individuals across various cognitive tasks.

Statistical learning (SL) is a powerful mechanism that supports the ability to extract regularities from environmental input. Yet, its neural underpinnings are not well understood. Previous EEG studies of SL have found that the brain tracks regularities by synchronizing its activity with the presented stimuli-a phenomenon known as neural entrainment. However, EEG lacks the spatial resolution to unveil the specific brain regions where this process takes place. In our study, 18 patients with drug-resistant epilepsy who were implanted with intracranial electrodes for presurgical investigation listened to a continuous speech stream containing embedded trisyllabic words. Neural entrainment was measured at the syllable and word frequencies, with the latter providing an online index of learning. SL was further assessed through both explicit and implicit behavioral measures. Behaviorally, we found evidence of learning at the group level in both tasks. At the neural level, our analyses revealed three temporal tuning profiles: 25% of contacts showed entrainment at the syllable frequency, 11% of contacts showed entrainment at both the word and syllable frequencies, and 4% showed entrainment only to the word frequency. Word entrainment, indicating sensitivity to word structures, was most commonly found in auditory and language-related regions, including insula, middle temporal gyrus, superior temporal gyrus, and supramarginal gyrus. In contrast, evidence for neural entrainment in the hippocampus was weak. Overall, these results support the idea that speech-based SL is largely supported by modality-specific brain regions.

Our minds frequently drift from the task at hand to other mental content, a process commonly referred to as mind-wandering. Task focus typically leads to high-quality encoding of task events, whereas mind-wandering tends to result in low-quality encoding. This study conducted a meta-analysis of fMRI studies comparing high-quality and low-quality encoding to explore the neural correlates of mind-wandering. Key findings show that activation during mind-wandering is closely associated with four specific subnetworks: Default Mode Network-A, Frontoparietal Network-B and -C, and Ventral Attention Network-B. In contrast, deactivation primarily occurs within Dorsal Attention Network-A, Frontoparietal Network-A, and Default Mode Network-B and -C. These findings offer empirical support for several prominent theoretical accounts of mind-wandering, including those emphasizing internal cognition, perceptual decoupling, executive control (both failure and engagement), and reduced filtering. These results highlight the importance of a fine-grained, network-based approach to understanding the complex neural dynamics of mind-wandering.

We mentally represent all kinds of objects across a variety of tasks and source modalities (i.e., mental objects). Recent work has proposed that mental objects are represented by content-free, reassignable pointers (or indexicals, or tokens) in our moment-to-moment processing. Are all mental objects represented by the same set of pointers? If not, where should we draw the lines between different kinds of pointers? In this Perspective, we propose a novel research program aiming at unraveling the neural taxonomy of mental objects by testing how the neural markers for pointers generalize across different paradigms, task goals, source modalities, and more.

Humans complete different types of sequences as a part of everyday life. These sequences can be divided into two important categories: those that are abstract, in which the steps unfold according to a rule at super-second to minute time scale, and those that are motor, defined solely by individual movements and their order that unfold at the subsecond to second timescale. For example, the sequence of making spaghetti consists of abstract tasks (preparing the sauce and cooking the noodles) and nested motor actions (stir pasta water). Previous work shows neural activity increases (ramps) in the rostrolateral prefrontal cortex (RLPFC) during abstract sequence execution. During motor sequence production, activity occurs in regions of PFC. However, it remains unknown if ramping is a signature of motor sequence production as well or solely an attribute of abstract sequence monitoring and execution. We tested the hypothesis that significant ramping activity occurs during motor sequence production in the RLPFC. Contrary to our hypothesis, we did not observe significant ramping activity in the RLPFC during motor sequence production, but we found significant ramping activity in bilateral inferior parietal cortex, in regions distinct from those observed during an abstract sequence task. Our results suggest different prefrontal-parietal circuitry may underlie abstract versus motor sequence execution.

Chinese speakers have long suffered from character amnesia in handwriting, failing to handwrite a character despite being able to recognize it. However, it remains unclear whether character amnesia arises from the failure in accessing orthographic representations in the orthographic lexicon, reduced graphemic information in the graphemic buffer, or/and weakened phonology-orthography links. To address this issue, we employed functional near-infrared spectroscopy to identify brain regions that are associated with character amnesia. In particular, we tested whether character amnesia is associated with deactivation in the fusiform gyrus (FG), the superior parietal gyrus (SPG), or the supramarginal gyrus (SMG), which have been shown to be respectively associated with the orthographic lexicon, graphemic buffer, and phonology-orthography conversion. In a handwriting-to-dictation task, 23 Cantonese-speaking adults handwrote a character according to a dictation prompt and then reported whether they correctly handwrote the character or suffered from character amnesia. Functional near-infrared spectroscopy results showed that, compared with correct handwriting, character amnesia elicited reduced activation in the bilateral FG, the SPG, and the SMG. Parametric analyses showed that character frequency and number of strokes positively correlated with activation of the FG and the SPG, respectively. Functional connectivity analyses revealed that, compared with correct handwriting, character amnesia was associated with decreased connectivity between the left FG and the left SMG, the right FG and the right SMG, the right FG and the right SPG, the right FG and the left SMG, and the right FG and the left SPG. Together, these results suggest that character amnesia is associated with decayed orthographic representations (in the orthographic lexicon) and failure in phonology-orthography conversion, resulting in reduced orthographic information being retrieved (into the graphemic buffer) for handwriting execution.

A central debated question in the study of object-based attention (OBA) is whether attention to the object-mediated deployment of attention is obligatory and automatic [Chen, Z., & Cave, K. R. Reinstating object-based attention under positional certainty: The importance of subjective parsing. Perception & Psychophysics, 68, 992-1003, 2006] or whether the pattern of results is driven by other non-obligatory factors, such as prioritization of invalid target locations [Shomstein, S., & Yantis, S. Object-based attention: Sensory modulation or priority setting? Perception & Psychophysics, 64, 41-51, 2002]. However, virtually all behavioral measures attributed to OBA are based on examining performance on invalid-cue trials, the inclusion of which confounds the assessment of the automaticity hypothesis. Our approach to resolve this issue is to determine whether effects of OBA can be observed in a 100% valid cueing paradigm. In this article, we investigate the obligatory nature of OBA by leveraging the spatial specificity of fMRI and the retinotopic organization of early visual cortex. We aimed to identify potential neural correlates of OBA in the complete absence of invalid trials. Participants perform a version of the classic two-rectangle OBA paradigm while we simultaneously measure changes in BOLD signals arising from retinotopically organized cortical areas V1, V2, and V3. In the first half of the experiment, we used the classic two-rectangle OBA paradigm except that the cue was 100% valid. In the second half, we reduced cue validity to more closely match standard OBA paradigms (runs containing invalid trials). We analyzed BOLD signals arising from our ROIs in V1, V2, and V3 according to their topographic correspondences with the ends of the rectangles in the visual field and compared these. We then compared responses in each ROI according to where the cue had occurred (cued, uncued-same-object, uncued-other-object location). We replicated this procedure in Experiment 2, but changed the layout of the two rectangles from a vertical to a horizontal configuration. Critical result: We observed statistically significant effects of OBA in V3 (Experiment 1) and V1-2 (Experiment 2) in both the 100% valid runs and in runs containing invalid trials. Moreover, the effects of OBA were no smaller in the 100% runs compared with runs containing invalid trials. Conclusion: We see BOLD modulation at the uncued locations consistent with neural correlates of OBA.