Sleep plays a crucial role in consolidating recently acquired memories and preparing the brain for learning new ones, but the relationship between these two processes is currently unclear. According to the prominent Active Systems Consolidation model, memory representations that are initially reliant on the hippocampus are redistributed to neocortex during sleep for long-term storage. An indirect assumption of this model is that sleep-associated memory processing paves the way for next-day learning by freeing up hippocampal encoding resources. In this review, we evaluate two central tenets of this 'resource reallocation hypothesis': (i) sleep-associated memory consolidation reduces hippocampal engagement during retrieval, and (ii) this reduction in hippocampal burden enhances the brain's capacity for new learning. We then describe recent work that has directly tested the relationship between sleep-associated memory processing and next-day learning. In the absence of clear evidence supporting the resource reallocation hypothesis, we consider alternative accounts in which efficient learning is not contingent on prior overnight memory processing, but rather that sleep-associated consolidation and post-sleep learning rely on overlapping or independent mechanisms. We conclude by outlining how future research can rigorously test the resource reallocation hypothesis.

When we retrieve memories of past navigational episodes, our brain reactivates cortical representations of the spatial information experienced along the way. Although navigation is temporally dynamic in nature, previous studies on cortical memory reactivation have mostly focused on single items or associated contexts. To investigate whether sequential reactivation of navigational events can be measured from cortical electrophysiological activity and depends on the availability of spatial cues such as environmental landmarks, we designed a task in which participants were passively navigated through virtual environments and then were asked to remember the routes or destinations that they traveled to. Navigational episodes comprised of an average of 5 turns and differed in the availability of landmarks. Given the decline in navigational abilities in aging, we separately tested both younger (ages 22-32) and middle-aged participants (ages 41-63) to identify age-related differences in this memory retrieval process. Comparing EEG spectral patterns between navigational encoding and retrieval, we found that sequential reactivation of turn events was associated with successful spatial memory in younger adults. This sequential reactivation was associated with the reinstatement of neural activity during distal landmark-viewing and was significantly driven by theta and alpha oscillations. While middle-aged adults showed diminished sequential reactivation overall, those with preserved landmark reinstatement and sequential reactivation patterns exhibited better spatial memory. These results may have implications for our understanding of episodic memory retrieval beyond navigation.

Cross-situational word learning describes the process by which learners acquire new words by tracking statistical regularities obtained from ambiguous word-referent encoding encounters over time. This study measured event-related potentials and behavioural responses to assess the acquisition of written word meanings through cross-situational word learning, in which novel orthographic forms served as written names for familiar objects. During the learning phase, participants disambiguated mappings between novel written words (e.g., 'ket') and familiar objects (e.g., sword). After learning, participants performed a semantic relatedness judgement task, pairing newly learned words with familiar written words from either a related (e.g., dagger) or unrelated (e.g., harp) semantic category. To provide a control measure, the semantic judgement task also included a condition comprising semantically related and unrelated familiar word pairs. Analyses revealed an N400 effect for semantic judgements of word meaning relatedness, both for the novel-familiar and familiar-familiar word pair conditions. These findings suggest that novel written word meanings can be rapidly acquired through cross-situational learning, with neurophysiological responses that resemble those for familiar words, albeit showing a more left-hemisphere distribution for novel words and a more right-hemisphere distribution for familiar words.

Accurate perception of visual motion is crucial for daily activities and develops rapidly from infancy to childhood. High-density electroencephalogram (EEG) was utilized longitudinally to study brain responses to structured optic flow and random visual motion in 10 full-term and 10 preterm children at 4 months, 12 months, and 6 years. Visual evoked potential (VEP) analysis showed improved sensitivity to structured optic flow in full-term infants by the end of the first year, indicating effective use of structured information, whereas preterm children showed delayed sensitivity and difficulty distinguishing between different forms of optic flow until early childhood. Temporal spectral evolution (TSE) analysis revealed desynchronizations predominantly in the theta band at 4 months, transitioning to the theta-alpha band at 12 months, and extending into the alpha-beta band at 6 years. Synchronizations were observed in older full-term infants and in 6-year-olds at higher frequencies, more so in full-term children. Coherence connectivity analysis demonstrated more widespread functional connectivity within occipital and parietal areas in full-term participants compared to their preterm peers when processing visual motion. Overall, full-term children showed vast progress from infancy, approaching an adult-like pattern for perceiving visual motion by early childhood. In contrast, preterm children experienced neurodevelopmental delays that persisted into school age, likely linked to dorsal visual stream vulnerabilities.

A hallmark of successful aging is increased life experiences and knowledge. Yet how this additional information is incorporated into semantic memory is unclear. Network science has proven to be a useful tool for modeling semantic memory networks in younger and older adults. Previous research suggests that although vocabulary and knowledge are largely stable across adulthood, older adults may have semantic memory networks that are less efficient, less interconnected, and more segregated. However, prior work, including our own, has largely focused on semantic memory networks derived from highly salient, physical concepts (e.g., animals). Though words essential for natural conversation vary greatly in terms of their psycholinguistic characteristics. In the present study, we examine age-related differences in semantic memory networks derived from a free association task, using both abstract and concrete cues that varied in semantic diversity - the number of unique contexts in which they could appear. Across several analytic approaches, we found that including abstract words in semantic memory networks minimized age-related differences: there were no age differences in network efficiency, but older adults had more interconnected and less segregated semantic memory networks compared to younger adults. Looking at word-level characteristics of the semantic memory networks suggested that for both younger and older adults, words that were high in semantic diversity and were more abstract had stronger connections to other words and were more interconnected. These results suggest that abstract and semantically diverse words are a cornerstone in maintaining older adults' semantic memory networks.

Attention shifts between global and local levels of visual objects, and these dynamics are altered in neuropsychiatric disorders. However, characterizing such dynamics is difficult because traditional Navon stimuli do not allow for the temporal separation of global and local information. We first investigated whether attentional selection mechanisms used with novel single-level stimuli are shared with those activated by traditional compound figures. In Experiment 1, two sequential target letters (referred to as T1 and T2) were shown at the same or different hierarchical levels with varying stimulus onset asynchronies (SOAs). When both targets were single-level stimuli, T2 recognition-conditional on correct T1 responses-was accurate following same-level transitions but impaired after different-level transitions, especially at short SOAs-an attentional blink (AB) that was stronger for global-to-local than local-to-global switches, replicating previous findings. Using a hybrid design with a traditional Navon T1 (cued to a single level) followed by a single-level T2, the same pattern emerged, indicating transfer of attentional effects across stimulus formats. The AB magnitudes correlated across paradigms, supporting shared mechanisms. To see if the attentional dynamics varied across participants, we applied this hybrid design in Experiment 2 to a larger sample, and used mixture modeling to explore individual differences, revealing four distinct clusters that varied in AB recovery speed depending on switch type, although a continuum of abilities cannot be excluded. These results demonstrate significant variability in attentional dynamics. Single-level stimuli thus offer a powerful tool to disentangle neural responses to hierarchical levels and provide new insights into both typical and disordered attentional processes.

Individuals usually have superior memory for bizarre stimuli compared to common ones. However, the extent to which bizarreness influences memory for actions remains unclear. Recent evidence has shown that performed actions represented by an action phrase (verb-object pair) in subject-performed task (SPT) result in better associative memory than simply reading it in verbal task (VT). Here, we directly investigated the effect of bizarreness on associative memory for action components following SPT relative to VT and its underlying memory processes using EEGs. During studying, the participants studied ordinary and bizarre verb-object phrases (pairs) in an SPT or VT condition. During testing, they discriminated between intact, recombined, and new pairs. Behaviorally, associative recognition of verb-object phrases was better following SPT than VT for ordinary and bizarre phrases. Bizarreness improved associative recognition under VT (but not SPT). In the event related potentials (ERP), an early frontal old-new effect (FN400) for intact vs. new pairs was observed under SPT for ordinary and bizarre phrases, whereas for VT, this effect was only observed for bizarre phrase. The FN400 for intact vs. recombined pairs was only present under SPT for ordinary phrases. In the late time window, a parietal old-new effect (LPC) for intact vs. new pairs was obtained under all conditions. The LPC for intact vs. recombined pairs only occurred under VT for bizarre phrases. These results demonstrate that enactment and bizarreness enhance associative recognition through distinct mechanisms by differentially modulating the contributions of familiarity and recollection during retrieval of action-object associations.

Despite hundreds of neuroimaging studies examining the neural correlates of 3D shape perception (as opposed to 2D), there is no consensus because of the diversity of stimuli and depth cues used. We addressed this problem through an activation likelihood estimation (ALE) coordinate-based meta-analysis, pooling together studies that examined the 3D vs 2D shape contrast across multiple depth cues used to render the 3D shapes. A systematic review was performed using Medline, PsychInfo and Embase databases and yielded 25 empirical studies after screening. Articles were split into cue types-disparity (11), motion (10), mental rotation (1), shading (2) and texture (2). We performed three sets of ALE-based coordinate analysis-full-sample ALE analysis, sub-analyses testing individual depth cues separately, and a contrast analysis between disparity-defined 3D shapes and monocularly-defined 3D shapes. Results for the full-sample analysis showed that 3D shape perception is widespread throughout the high-level visual cortex regardless of depth cue. Although cue-specific analyses were underpowered, some trends were observed. Disparity-defined 3D shapes seem to engage higher-level dorsal stream areas, including bilateral intraparietal sulcus (IPS). Motion-defined 3D shape recruited ventral stream regions associated with object recognition processes. Monocularly-defined 3D shapes recruited ventral stream areas, mainly the bilateral inferior lateral cortex and dorsal stream IPS for the right hemisphere. W et al.hen contrasted with disparity, monocularly-defined 3D shapes recruited the left lateral occipital cortex. The results suggest laterality in 3D versus 2D shape representations and that 3D shape representations occur in both ventral and dorsal pathways regardless of the depth cues that define them.

When performing goal-directed tasks, mistakes can motivate changes in our choices and behaviours. This process of behavioural adaptation is assumed to be at least partly driven by error processing mechanisms in the brain marked by the error-related negativity (ERN). A recently observed perceptual consequence of errors is a temporal binding effect, which is the perceived compression of time between actions and outcomes and is commonly claimed to be an implicit marker for the sense of agency. Given that both phenomena are triggered by errors, we sought to investigate the relationship between ERN amplitude and error-related temporal binding and assess the extent to which each of these predicted several measures of task performance. Utilising a modified Eriksen Flanker task to increase error rates, we measured error-related changes in ERP amplitude (ERN difference wave) and action-outcome interval estimates (error-related temporal binding). Both measures were significantly affected by erroneous responses, and this was correlated between measures - participants with larger ERN amplitude also exhibited stronger error-related binding. When controlling for each other as predictors of task performance, ERN amplitude was shown to independently predict overall error rates, while error-related binding was shown to independently predict the rate of improvement. To our knowledge, this is the first study to observe error-related changes in temporal binding in a flanker task, and the first to measure the relationship between ERN amplitude and temporal binding. We discuss the distinction (and overlap) between the ERN and error-related binding, along with the potential links to the sense of agency.

Falsely remembering never-before-seen information can have significant negative consequences during everyday life, and can occur when novel information is semantically or perceptually similar to previously encoded experiences. The aim of the current research was to investigate the extent to which semantic and perceptual false memory are associated with overlapping vs distinct neural processes. To investigate this question, 30 younger adults encoded lists of images and words. At retrieval, participants underwent fMRI scanning and made memory judgments for items seen at encoding (targets) and new items that were perceptually or semantically similar to targets (lures). Consistent with our previous work showing that domain-general cognitive processes predict individual differences in false memory production (West et al., 2025) and consistent with past behavioral and neuroimaging false memory research, false memory activity, irrespective of domain, was associated with overlapping activity within the medial prefrontal cortex and inferior parietal cortex. At the same time, unique domain-specific activation was observed in frontal (e.g., middle and inferior frontal gyri) and parietal (e.g., superior and inferior parietal lobes) regions for semantic false memory and in frontal (e.g., middle and inferior frontal gyri) and occipital (e.g., middle occipital gyrus) regions for perceptual false memory. Multivariate analyses examining the neural patterns associated with falsely remembered and novel, yet related information indicated that semantic and perceptual items were represented as distinct and discriminable within frontoparietal regions commonly active during both semantic and perceptual false memory. Taken together, these results suggest that false memory formation is associated with both domain-general and domain-specific neural processes at retrieval.

Functional laterality manifests across motor and sensory domains, yet analysis of their combined organization within individuals remains underexplored. Gerrits' 2024 (doi: 10.1007/s11065-022-09575-y) segregation bias model provides theoretical support that allows testing specific predictions for the lateralization of brain functions and their phenotype distributions in the population. We applied this approach to investigate sensory-motor laterality on the behavioral level (handedness, footedness, and eyedness) using a large sample (n = 900; 11-70 years).

Executive functions (EFs) are high-level cognitive processes essential for adaptive, goal-directed behavior. They are supported by oscillatory neural activity, particularly in the alpha and theta frequency bands, across local and distributed brain networks involving prefrontal regions. Previous studies have used transcranial alternating current stimulation (tACS) to modulate such activity and have reported significant performance improvement on EF tasks. However, most relied on single-task scores as outcome measures, which may reflect not only domain-general executive functioning but also task-specific or lower-level processes. This double-blind sham-controlled within-subject study examined the effects of online prefrontal tACS at alpha (10 Hz) and theta (6 Hz) frequencies on EF performance, measured via latent-variable scores that capture shared variance across multiple EF tasks, in healthy individuals (n = 24). Outcome measures were derived using the NIH EXAMINER battery, yielding latent scores for four EF components (common EF, cognitive control, working memory, and fluency) as well as task scores. Linear mixed models revealed significantly higher common EF and cognitive control scores during alpha-tACS, with large effect sizes, and smaller, more limited stimulation effects on task scores. Exploratory analyses suggested biological sex-specific response to stimulation, with alpha-tACS effects observed primarily in females. These findings support a causal role for prefrontal alpha-band oscillations in EFs and underscore the value of latent-variable measures of executive functioning in neuromodulation research.

The detection of threatening information conveyed by faces is crucial for human survival and development, especially for children. Previous research has shown that adults perceive male faces with a high facial width-to-height ratio (fWHR) as more aggressive and process this information automatically. However, it is unclear whether children possess similarly. In this study, two experiments were conducted with children (9.61 ± .67 years) to explore their ability to perceive aggression based on fWHR and whether they automatically process this information. In Experiment 1, children were asked to rate the perceived level of aggression in adult faces with high and low fWHR. It was found that high fWHR faces were perceived as more aggressive than low fWHR. In Experiment 2, visual mismatch negativity (vMMN) was used as an indicator to explore automatic processing further in an oddball paradigm. Children were asked to detect fixation size while being presented with adult faces with high or low fWHR in the background. It was observed that high fWHR faces induced vMMN in the 270-330 ms time range, while low fWHR faces did not, suggesting that children are able to automatically process high fWHR faces but not low fWHR. These results suggest that children can detect aggression cues through fWHR and automatically process high fWHR faces.

Successful speech perception in noise likely involves inhibition of the background noise in order to improve the signal-to-noise ratio, and thereby, the perception. However, the nature and extent of the contributions of the inhibitory mechanisms to speech perception in noise and the interactions among them are currently unclear. The current study investigated the contribution of auditory inhibitory measures mediated by olivocochlear and cortico-cortical processes and working memory (closely associated with cognitive inhibition) on speech perception in noise using structural equation models. For this purpose, a group of 72 neurotypical adults over a wide age range (20-65 years) who were homogenous in terms of their socioeconomic and educational status and quality of life were recruited. The results revealed a strong and significant association between speech perception in noise and the working memory capacity. The brainstem inhibitory measure - the medial olivocochlear reflex - also contributed to speech perception in noise. There was no evidence of a direct contribution by the cortico-cortical inhibitory measures (auditory sensory gating and context-dependent cortical encoding of speech) on speech perception in noise. However, the auditory brainstem and cortico-cortical processes demonstrated a trend of an inverse relationship. An additional finding was that age significantly influenced working memory but not speech perception in noise. Overall, the study demonstrated the relationships among the different inhibitory mechanisms and their contributions to speech perception in noise. It was found that individuals with higher working memory capacity and higher strength of the medial olivocochlear reflex had better speech perception in noise. The findings suggest potential considerations for refining rehabilitation protocols for speech perception in noise deficits and pave path for future studies, which may be conducted using ecologically more valid stimulus paradigms.

The early detection and continuous monitoring of psychosis is of utmost importance in ensuring timely and effective treatment. Current mental health care is unable to meet this demand, partially because methods to detect psychosis are relatively time-intensive and not scalable to large populations. Consequently, there has been an increasing focus on the potential of passive data collection from digital devices to overcome this issue. In the present article, we explore whether the analysis of social media (SM) posts through natural language processing (NLP) could improve the detection of psychosis. We first demonstrate how freely expressed speech can be processed automatically in the laboratory to predict and classify psychosis with high levels of accuracy. We further outline the current state of psychosis classification from SM-derived data and discuss methodological issues that are hampering progress in this field. Finally, we delve into potential pitfalls of such systems and provide insight into how these may be circumvented.

Investigating somatosensory representation and sensory processing changes provides valuable information about the neuroplastic adaptation in handless individuals with congenital limb deficiency (CLD). Four participants with CLD (19-31 years old), 14 controls (mean age, 19.57 ± 1.34 years) in the quantitative electroencephalography (QEEG) experiment, and 10 controls (mean age, 23.9 ± 2.21 years) in the functional magnetic resonance imaging (fMRI) experiment, participated in this study to determine changes in sensory representation of the hand and sensory processing. For the QEEG data, significance tests of Crawford & Howell were conducted to evaluate whether the mu suppression in the Cz, C3, and C4 electrodes in the participants with CLD differed from that in the controls when their 17 body regions were touched. fMRI data were obtained during the tactile stimulation of the face and hand or the residual limb. For the fMRI data, individual-level and group-level inferences were examined with one and two-sample t-tests, respectively. Moreover, masked regions of interest were systematically compared using the Crawford & Howell test. Our findings showed that the representation of the face showed activation predominantly towards the upper somatosensory cortex towards the hand representation area and mu suppression was lower in individuals with CLD compared to the controls during tactile stimulation, with the exception of one participant, suggesting reduced sensitivity. In addition, according to the electrophysiological data, it was observed that the cortical representation of the face in individuals with CLD differed from that of the controls. Handless individuals with CLD exhibit altered somatosensory organisation with shifts in cortical activation and reduced mu suppression, suggesting neuroplastic adaptation that may be relevant to the hypothesis that intrauterine hand and face contact is important.

Aphantasia is the inability to experience mental imagery during full wakefulness without any prominent perceptual deficits. Visual aphantasia is associated with differences in distributed brain networks, but its neurobiological underpinnings remain a mystery. In particular, aphantasia may arise due to impairments in the top-down control over visual imagination. We predicted that this in turn would prevent the brains of aphantasic participants from differentiating neural activity encoding the contents of imagination from the background noise of resting activity, particularly within the ventral temporal lobes. To test this hypothesis, we re-analysed functional magnetic resonance imaging (fMRI) data collected from aphantasics (n = 21), hyperphantasics (those with "photographic imagery"; n = 20), and controls (n = 17) during a simple perception and imagery task. We used two measures of informational complexity to quantify the complexity of the spatial pattern of thresholded BOLD signals in the participants' temporal lobes during visual perception and imagery. Both measures of spatial complexity showed significant correlations with imagery vividness. We then performed dynamic functional connectivity analyses on the same data revealing that the higher-order networks of aphantasics were abnormally coupled with the temporal lobes during imagery (p < 0.05). These results provide a novel perspective, reframing aphantasia as an inability of the visual system to selectively activate regions encoding object-specific visual categories above background levels of noise.

Single case studies have long been used to provide insights into the mechanisms underlying normal cognition, including in the domains of memory, language and visuoperceptual function, and standardized testing has been a steadfast companion in such investigations. Experimental approaches designed to address specific hypotheses have also been conducted and analytic methods have been developed for the comparison of single subject data to a control group. However, a seismic shift has occurred in the last decade or two in which neuroimaging, primarily magnetic resonance imaging, has been added to the experimental toolbox. The question addressed in this article is whether, with these newer methodologies offering novel and previously unattainable evidence, single case studies have become obsolete. Here, in a single patient with integrative visual agnosia, tested repeatedly over three decades, behavioral, neuroimaging and joint behavioral-neuroimaging studies are described and their yield evaluated. Behavioral investigations have served to characterize the perceptual deficit well, and structural and functional neuroimaging data have furthered our understanding of the distributed circuit engaged in object recognition. However, imaging studies executed in concert with a behavioral task have offered more direct causal evidence, providing a more complete understanding of brain-behavior correspondences that goes beyond the sum of the parts. The conclusion reached is that the contribution of causal evidence from single cases remains a powerful methodology in advancing our knowledge of the neural basis of cognition.

Whereas aphantasics report lacking voluntary conscious visual imagery, empirical findings indicate that they employ visual strategies to complete tasks. The discrepancy has led some researchers to propose that aphantasics rely on unconscious visual imagery. This paper instead motivates and defends a "conscious" view. Consciousness research uses both visibility and confidence measures. Participants in aphantasia studies are recruited based on their scores on the Vividness of Visual Imagery Questionnaire (VVIQ), which closely resembles a visibility measure. To assess whether aphantasics' task-relevant visual imagery is truly unconscious, we should also investigate their confidence in their first-order task performance. The few studies that have explored this suggest that they exhibit good metacognition. These findings therefore support the conscious interpretation.