Biology subjects

Krugliak, A.

Publications and source records attributed to Krugliak, A..

7 recordsLinked to original sources

bioRxiv2026

NTAD: A longitudinal neuroimaging dataset of Alzheimer's disease pathology

We introduce the New Therapeutics in Alzheimer's Disease (NTAD) dataset, a multi-modal and longitudinal imaging dataset from 70 biomarker-positive people with early dementia or Mild Cognitive Impairment (MCI) due to Alzheimer's Disease (AD), assessed over 2.5 years, and 35 healthy controls assessed at baseline. The data include simultaneous magneto- and electro-encephalography (M/EEG), 3-Tesla structural and functional magnetic resonance imaging (MRI), Amyloid-beta; positron emission tomography (PET), fluid proteomic biomarkers in cerebrospinal fluid and blood, and a battery of clinical and neuropsychological assessments. 11C UCB-J PET was undertaken for a subset of participants. For people with AD, assessments were repeated at approximately three weeks, 15 months, and 28 months after baseline. The data can be accessed through the Dementias Platform UK (DPUK), including pre-processed M/EEG and T1 MRI in pseudonymised BIDS format. With the pressing need to develop treatments for slowing, reversing, and preventing AD, these data provide an opportunity for identifying and validating novel biomarkers of Alzheimer's disease neurophysiology, as well as understanding its treatable pathology.

neuroscience↗

bioRxiv2026

Prior visual context accelerates the emergence of object representations

Our knowledge about how the world is structured allows for predictions about what objects we might see next. Visual context is known to impact the perception of subsequent objects, but we do not know what context does to the mental representation of those objects. Using MEG, we tested how a scene context changes the neural representation of visual objects, and whether the context simply enhances expected object representations, or if it acts to reorganise the temporal trajectory of object information in the brain. Using temporal generalisation decoding, we show that multiple dimensions of semantic information are shifted up to 200 ms earlier when the object and the prior context are congruent, and this temporally-shifted decoding was related to behavioural object recognition speed. This suggests that prior context can warp the temporal trajectory through which object representations are accessed and accelerate the emergence of semantic object representations in the mind.

neuroscience↗

bioRxiv2025

Neural oscillations and top-down connectivity are modulated by object-scene congruency

The knowledge we have about how the world is structured is known to influence object recognition. One way this is demonstrated is through a congruency effect, where object recognition is faster and more accurate if items are presented in expected scene contexts. However, our understanding of the dynamic neural mechanisms that underlie congruency effects are under-explored. Using MEG, we examine how the congruency between an object and a prior scene results in changes in the oscillatory activity in the brain, which regions underpin this effect, and whether congruency results arise from top-down or bottom-up modulations of connectivity. We observed that prior scene information impacts the processing of visual objects in behaviour, neural activity and connectivity. Processing objects that were incongruent with the prior scene resulted in slower reaction times, increased low frequency activity in the ventral visual pathway, and increased top-down connectivity from the anterior temporal lobe and frontal cortex to the posterior ventral temporal cortex. Our results reveal that the recurrent dynamics within the ventral visual pathway are modulated by the prior knowledge imbued by our surrounding environment, suggesting that the way we recognise objects is fundamentally linked to their context.

neuroscience↗

bioRxiv2024

Congruency effects on object recognition persist when objects are placed in the wild: An AR and mobile EEG study

Objects in expected locations are recognised faster and more accurately than objects in incongruent environments. This congruency effect has a neural component, with increased activity for objects in incongruent environments. Studies have increasingly shown differences between neural processes in realistic environments and tasks, and neural processes in the laboratory. Here, we aimed to push the boundaries of traditional cognitive neuroscience by tracking the congruency effect for objects in real world environments, outside of the lab. We investigated how neural activity is modulated when objects are placed in real environments using augmented reality while recording mobile EEG. Participants approached, viewed, and rated how congruent they found the objects with the environment. We found significant differences in ERPs and higher theta-band power for objects in incongruent contexts than objects in congruent contexts. This demonstrates that real-world contexts impacts how objects are processed, and that mobile brain imaging and augmented reality are effective tools to study cognition in the wild.

neuroscience↗

bioRxiv2022

Semantic object processing is modulated by prior scene context

Objects that are congruent with a scene are recognised more efficiently than objects that are incongruent. Further, semantic integration of incongruent objects elicits a stronger N300/N400 EEG component. Yet, the time course and mechanisms of how contextual information supports access to semantic object information is unclear. We used computational modelling and EEG to test how context influences semantic object processing. Using representational similarity analysis, we established that EEG patterns dissociated between objects in congruent or incongruent scenes from around 300 ms. By modelling semantic processing of objects using independently normed properties, we confirm that the onset of semantic processing of both congruent and incongruent objects is similar ([~]150 ms). Critically, after [~]275 ms, we discover a difference in the duration of semantic integration, lasting longer for incongruent compared to congruent objects. These results constrain our understanding of how contextual information supports access to semantic object information.

neuroscience↗

bioRxiv2021

Towards real-world neuroscience using mobile EEG and augmented reality

Our visual environment impacts multiple aspects of cognition including perception, attention and memory, yet most studies traditionally remove or control the external environment. As a result, we have a limited understanding of neurocognitive processes beyond the controlled lab environment. Here, we aim to study neural processes in real-world environments, while also maintaining a degree of control over perception. To achieve this, we combined mobile EEG (mEEG) and augmented reality (AR), which allows us to place virtual objects into the real world. We validated this AR and mEEG approach using a well-characterised cognitive response - the face inversion effect. Participants viewed upright and inverted faces in three EEG tasks (1) a lab-based computer task, (2) walking through an indoor environment while seeing face photographs, and (3) walking through an indoor environment while seeing virtual faces. We find greater low frequency EEG activity for inverted compared to upright faces in all experimental tasks, demonstrating that cognitively relevant signals can be extracted from mEEG and AR paradigms. This was established in both an epoch-based analysis aligned to face events, and a GLM-based approach that incorporates continuous EEG signals and face perception states. Together, this research helps pave the way to exploring neurocognitive processes in real-world environments while maintaining experimental control using AR.

neuroscience↗

bioRxiv2021

Dynamic Auditory Remapping Across the Sleep-Wake Cycle

In a single day we transition from vigilant wakefulness to unconscious sleep and dreaming, undergoing diverse behavioural, physiological and neural changes. While during the awake state, exogenous stimuli and endogenous changes lead to sensory reorganisation, this remapping has not been charted throughout the sleep-wake cycle. We recorded neural activity in response to a range of tones using electroencephalography during a full nights sleep, and examined whether auditory responses become more similar, dissimilar or remain unchanged between wakefulness, non-rapid (NREM) and rapid eye movement (REM) sleep. We found that neural similarities between pairs of auditory evoked potentials differed by conscious state in both early and late auditory processing stages. Furthermore, tone-pairs neural similarities were modulated by conscious state as a function of tone frequency, where some tone-pairs changed similarity between states and others continued unaffected. These findings demonstrate a state-, stimulus- and time-dependent functional reorganization of auditory processing across the sleep-wake cycle.

neuroscience↗