Journal of Cognitive Neuroscience最新文献

The animal brain is endowed with an innate sense of number allowing to intuitively perceive the approximate quantity of items in a scene, or "numerosity." This ability is not limited to items distributed in space, but also to events unfolding in time and to the average numerosity of dynamic scenes. How the brain computes and represents the average numerosity over time, however, remains unclear. Here, we investigate the mechanisms and EEG signature of the perception of average numerosity over time. To do so, we used stimuli composed of a variable number (3-12) of briefly presented dot arrays (50 msec each) and asked participants to judge the average numerosity of the sequence. We first show that the weight of different portions of the stimuli in determining the judgment depends on how many arrays are included in the sequence itself: the longer the sequence, the lower the weight of the latest arrays. Second, we show systematic adaptation effects across stimuli in consecutive trials. Importantly, the EEG results highlight two processing stages whereby the amplitude of occipital ERPs reflects the adaptation effect (∼300 msec after stimulus onset) and the accuracy and precision of average numerosity judgments (∼450-700 msec). These two stages are consistent with processes involved with the representation of perceived average numerosity and with perceptual decision-making, respectively. Overall, our findings provide new evidence showing how the visual system computes the average numerosity of dynamic visual stimuli, and support the existence of a dedicated, relatively low-level perceptual mechanism mediating this process.

Recent studies of visual working memory (VWM) underscore a structured hierarchy of storage states. Memories that are not immediately relevant to the task at hand but are essential for later use are transferred to a passive state, which operates independently of actively maintaining and manipulating current memories. Note that stimulating passive memory forcefully can reactivate it into an active state, resulting in a competition with active memory. Thus, to remain stable representations for both states within VWM, passive memory might involve sustained suppression during activity-silent maintenance to prevent reactivation from disrupting the current active storage. To investigate this, we analyzed lateralized electrophysiology signals while human participants (both women and men) were engaged in a sequential presentation memory task across two experiments. The results revealed positive contralateral delayed activity components and lateralized alpha enhancement for passive memory, neural indicative of suppression on passive storage. In addition, the suppression effect was independent of the memory load in both the active and the passive states. These findings support the notion of sustained suppression during activity-silent maintenance of passive memory, facilitating the stable maintenance of distinct storage states and advancing our understanding of the dynamic coding framework in VWM.

The question of whether cognitive control is specific to certain domains or domain-general remains an extensively debated question at both cognitive and neural levels. This study examined the neural substrates associated with resistance to interference (RI) in phonological, semantic, and visual domains by using strictly matched tasks and determining the domain-general or domain-specific manner in which aging affects the neural substrates associated with RI. In an fMRI experiment, young and older participants performed a similarity judgment task with phonological, semantic, or visual interference buildup. For both age groups, domain-specific RI effects were observed at the univariate level, with increased involvement in the phonological domain of the right angular gyrus and the right lingual gyrus, in the semantic domain of the bilateral inferior frontal gyrus, the bilateral superior parietal and angular gyri and the left middle temporal gyrus, and in the visual domain of the middle/superior frontal gyri and occipital gyri. At the multivariate level, although RI effects could be decoded from neural patterns in the bilateral inferior frontal gyrus for all domains and age groups, between-domain prediction of RI conditions was associated with Bayesian evidence for the null hypothesis. This study supports the domain specificity of neural substrates associated with RI while stressing its age independency.

Anticipating events and focusing attention accordingly are crucial for navigating our dynamic environment. Rhythmic patterns of sensory input offer valuable cues for temporal expectations and facilitate perceptual processing. Rhythm-based temporal expectations may rely on oscillatory entrainment, where neural activity and perceptual sensitivity synchronize with periodic stimuli. However, whether entrainment models can account for aperiodic predictable rhythms remains unclear. Our study aimed to delineate the distinct roles of predictability and periodicity in rhythm-based expectations. Participants performed a pitch-identification task preceded by periodic predictable, aperiodic predictable, or aperiodic unpredictable temporal sequences. By manipulating the temporal position of the target sound, we observed how auditory perceptual performance was modulated by the target position's relative phase relationship to the preceding sequences. Results revealed a significant performance advantage for predictable sequences, both periodic and aperiodic, compared with unpredictable ones. However, only the periodic sequence induced an entrained modulation pattern, with performance peaking in synchrony with the inherent sequence continuation. Event-related brain potentials corroborated these findings. The target-evoked P3b, possibly a neural marker of attention allocation, mirrored the behavioral performance patterns. This supports our hypothesis that temporal attention guided by rhythm-based expectations modulates perceptual performance. Furthermore, the predictive sequences were associated with enhanced target-preceding negativity (akin to the contingent negative variation), indicating enhanced target preparation. The periodic-specific modulation likely reflects more precise temporal expectations, potentially involving neural entrainment and/or more focused attention. Our findings suggest that predictability and periodicity influence perception through distinct mechanisms.

Prosody underpins various linguistic domains ranging from semantics and syntax to discourse. For instance, prosodic information in the form of lexical stress modifies meanings and, as such, syntactic contexts of words as in Turkish kaz-má "pickaxe" (noun) versus káz-ma "do not dig" (imperative). Likewise, prosody indicates the focused constituent of an utterance as the noun phrase filling the wh-spot in a dialogue like What did you eat? I ate----. In the present study, we investigated the relevance of such prosodic variations for discourse comprehension in Turkish. We aimed at answering how lexical stress and prosodic focus mismatches on critical noun phrases-resulting in grammatical anomalies involving both semantics and syntax and discourse-level anomalies, respectively-affect the perceived correctness of an answer to a question in a given context. To that end, 80 native speakers of Turkish, 40 participating in a psychometric experiment and 40 participating in an EEG experiment, were asked to judge the acceptability of prosodic mismatches that occur either separately or concurrently. Psychometric results indicated that lexical stress mismatch led to a lower correctness score than prosodic focus mismatch, and combined mismatch received the lowest score. Consistent with the psychometric data, EEG results revealed an N400 effect to combined mismatch, and this effect was followed by a P600 response to lexical stress mismatch. Conjointly, these results suggest that every source of prosodic information is immediately available and codetermines the interpretation of an utterance; however, semantically and syntactically relevant lexical stress information is assigned more significance by the language comprehension system compared with prosodic focus information.

Perceptual completion is ubiquitous when estimating properties such as the shape, size, or number of objects in partially occluded scenes. Behavioral experiments showed that the number of hidden objects is underestimated in partially occluded scenes compared with an estimation based on the density of visible objects and the amount of occlusion. It is still unknown at which processing level this (under)estimation of the number of hidden objects occurs. We studied this question using a passive viewing task in which observers viewed a game board that was initially partially occluded and later was uncovered to reveal its hidden parts. We simultaneously measured the electroencephalographic responses to the partially occluded board presentation and its uncovering. We hypothesized that if the underestimation is a result of early sensory processing, it would be observed in the activities of P1 and N1, whereas if it is because of higher level processes such as expectancy, it would be reflected in P3 activities. Our data showed that P1 amplitude increased with numerosity in both occluded and uncovered states, indicating a link between P1 and simple stimulus features. The N1 amplitude was highest when both the initially visible and uncovered areas of the board were completely filled with game pieces, suggesting that the N1 component is sensitive to the overall Gestalt. Finally, we observed that P3 activity was reduced when the density of game pieces in the uncovered parts matched the initially visible parts, implying a relationship between the P3 component and expectation mismatch. Overall, our results suggest that inferences about the number of hidden items are reflected in high-level processing.

Novelty exposure and the upregulation of the noradrenergic (NA) system have been suggested as crucial for developing cognitive reserve and resilience against neurodegeneration. Openness to experience (OE), a personality trait associated with interest in novel experiences, may play a key role in facilitating this process. High-OE individuals tend to be more curious and encounter a wider range of novel stimuli throughout their lifespan. To investigate the relationship between OE and the main core of the NA system, the locus coeruleus (LC), as well as its potential mediation of IQ-a measure of cognitive reserve-MRI structural analyses were conducted on 135 healthy young adults. Compared with other neuromodulators' seeds, such as dorsal and median raphe-5-HT, ventral tegmental area-DA-, and nucleus basalis of Meynert-Ach-, the results indicated that higher LC signal intensity correlated with greater OE and IQ. Furthermore, mediation analyses revealed that only the LC played a mediating role between OE and IQ. These findings shed light on the neurobiology of personality and emphasize the importance of LC-NA system integrity in a novelty-seeking behavior. They provide a psychobiological explanation for how OE expression can contribute to the maintenance of the NA system, enhancing cognitive reserve and resilience against neurodegeneration.

When a picture is repeatedly named in the context of semantically related pictures, (homogeneous context) responses are slower than when the picture is repeatedly named in the context of unrelated pictures (heterogeneous context). This semantic interference effect in blocked-cyclic naming plays an important role in devising theories of word production. Wöhner, Mädebach, and Jescheniak [2021; Wöhner, S., Mädebach, A., & Jescheniak, J. D. Naming pictures and sounds: Stimulus type affects semantic context effects. Journal of Experimental Psychology: Human Perception and Performance, 47, 716-730, 2021] have shown that the effect is substantially larger when participants name environmental sounds than when they name pictures. We investigated possible reasons for this difference, using EEG and pupillometry. The behavioral data replicated Wöhner and colleagues. ERPs were more positive in the homogeneous compared with the heterogeneous context over central electrode locations between 140-180 msec and 250-350 msec for picture naming and between 250 and 350 msec for sound naming, presumably reflecting semantic interference during semantic and lexical processing. The later component was of similar size for pictures and sounds. ERPs were more negative in the homogeneous compared with the heterogeneous context over frontal electrode locations between 400 and 600 msec only for sounds. The pupillometric data showed a stronger pupil dilation in the homogeneous compared with the heterogeneous context only for sounds. The amplitudes of the late ERP negativity and pupil dilation predicted naming latencies for sounds in the homogeneous context. The latency of the effects indicates that the difference in semantic interference between picture and sound naming arises at later, presumably postlexical processing stages closer to articulation. We suggest that the processing of the auditory stimuli interferes with phonological response preparation and self-monitoring, leading to enhanced semantic interference.

In everyday life, we frequently engage in 'hybrid' visual and memory search, where we look for multiple items stored in memory (e.g., a mental shopping list) in our visual environment. Across three experiments, we used event-related potentials to better understand the contributions of visual working memory (VWM) and long-term memory (LTM) during the memory search component of hybrid search. Experiments 1 and 2 demonstrated that the FN400 - an index of LTM recognition - and the CDA -an index of VWM load - increased with memory set size (target load), suggesting that both VWM and LTM are involved in memory search, even when target load exceeds capacity limitations of VWM. In Experiment 3, we used these electrophysiological indices to test how categorical similarity of targets and distractors affects memory search. The CDA and FN400 were modulated by memory set size only if items resembled targets. This suggests that dissimilar distractor items can be rejected before eliciting a memory search. Together, our findings demonstrate the interplay of VWM and LTM processes during memory search for multiple targets.