Biology subjects

Wikman, P.

Publications and source records attributed to Wikman, P..

8 recordsLinked to original sources

bioRxiv2026

The Influence of Early Life Stress on the Development of Neural Representations during Mentalizing

Early life stress (ELS) is associated with altered social cognition, but the neurodevelopmental mechanisms of this association remain understudied. In the present longitudinal study spanning 20-years, eighty-nine young adults performed the Reading the Mind in the Eyes Test (RMET) with a matched control condition during fMRI. Two ELS indices were inspected separately: a prospective cumulative risk score based on caregiver wellbeing during pregnancy and first year of life, and a retrospective self-report of adverse experiences by the participants in late adolescence. Neural outcomes were characterized by univariate activation, representational similarity analysis (RSA), and inter-subject RSA. Inter-subject RSA tested two pairwise approaches to intersubject similarity in ELS: absolute pairwise difference, and pairwise average. Prospective ELS was associated with better RMET performance, and one region survived correction across 360 cortical regions tested in RSA and IS-RSA: left anterior inferior frontal sulcus. The IS-RSA effect was pairwise average: low-exposure participants shared a more typical neural representational geometry, while high-exposure participants demonstrated increasing neural representational idiosyncrasy. Additionally, higher prospective ELS was associated with weaker RMET-versus-control separation within the same region. Retrospective ELS yielded no behavioral nor neural associations. The present study offers novel findings relating to neural representations of mentalizing using the RMET, alongside their neurodevelopmental susceptibility to ELS. The present study additionally highlights implications relating to the differentiation of mentalizing from lexical-semantic and semantic-control demands for future research.

neuroscience↗

bioRxiv2026

Attention modulates neural representations of acoustic, categorical, and identity features in a task-dependent manner

The human auditory system represents sounds at multiple levels, from low-level acoustic features to abstract category- and object-level information. Although selective attention enables listening in complex natural soundscapes, it remains unclear which representational levels are modulated by attention and how this depends on scene structure. Using fMRI, representational similarity analysis, and cross-experiment decoding, we examined attentional modulation of auditory representations under three conditions 1) listening to isolated sounds, 2) attending to one of three overlapping sounds from different categories or 3) one of three overlapping sounds from the same category. We show that attentional modulation is task-dependent: when competing sounds could not be distinguished by category, attention enhanced low-level acoustic feature processing, whereas in cross-category scenes it targeted abstract category-level representations. Object-identity representations were modulated by attention across both scene types, with category-specific differences, demonstrating flexible, task-dependent targeting of auditory features.

neuroscience↗

bioRxiv2025

Emotional Semantic Meaning Enhances Neural Tracking of Conversations Through Context-Sensitive Modulation of Auditory - Language Areas

Engagement in interaction arises through the continuous monitoring of conversation content, allowing individuals to detect and act upon information that is personally relevant or socially significant. Emotional salience of speech content is a key factor in guiding this attentional engagement. By combining an audiovisual "Cocktail-party" paradigm with source-localized magnetoencephalography and encoding-decoding models, we examined whether emotionally salient content continuously enhances attentional tracking of conversations. Decoding analyses showed that emotional salience strengthened neural speech tracking across the conversational arc, but only when dialogue was attended to. The emotional enhancement was also sensitive to the dialogues semantic structure, peaking earlier in semantically coherent than incoherent conversations. Encoding analyses revealed latency-specific effects across temporal, parietal and frontal regions. Emotional salience and semantic structure co-modulated mid-latency sensory encoding, whereas later semantic integration was driven by emotionality alone. The observed results support the notion of adaptive tuning of auditory-language networks to socially and motivationally significant semantic cues. Rather than acting as a simple amplifier of semantic processing, emotional salience of dialogue topics shapes neural speech processing at multiple stages. The exact modulations depend on the semantic structure of the dialogue, balancing the needs between efficiency and adaptability that together support the ability to engage optimally in real-world interactions. Significance statementThe emotionality of a conversation is a key factor in how people allocate attention during interaction. Using a multi-speaker "cocktail-party" paradigm with magnetoencephalography, we show that emotionally salient content and semantic coherence influence the brains tracking of continuous dialogues in the presence of competing speech. Emotionally salient content enhances neural tracking only for attended speech, and this enhancement appears earlier when the conversation consists of semantically interrelated turns and is easier to follow. This is supported by modulations in neural activity at distinct processing stages across a distributed cortical network. These findings indicate that emotionality functions as a relevance signal, sustaining attentional engagement in conversation by affecting predictive processing and modulating activations in a large-scale cortical system linked to speech comprehension.

neuroscience↗

bioRxiv2025

Attention modulates the geometry of auditory representations

Selective attention enables the brain to prioritize behaviourally relevant information in complex environments, yet its neural mechanisms remain unclear. Here, we combined fMRI with representational geometry analyses to examine how attention reshapes neural population codes during naturalistic sound scenes. Participants attended to individual sound objects presented either with distractors from different categories (three objects across, 3OA) or the same category (three objects within, 3OW). Attention attracted neural population responses in low-dimensional manifolds toward the representation of each object presented in isolation, consistent with a reorganization of high-dimensional representational geometry. This effect depended on acoustic context: in 3OA, attended representations were significantly closer to object-alone representations than to distractors, whereas in 3OW attentional modulation was minimal. Category-specific effects were observed, with speech engaging left-lateralized language regions beyond the auditory cortex. Finally, stronger behavioural performance predicted greater representational attraction. These findings show that selective attention reshapes neural geometry in a context- and category-dependent manner closely linked to behaviour.

neuroscience↗

bioRxiv2025

Selective attention network in naturalistic auditory scenes is object and scene specific

Everyday auditory scenes often contain overlapping sound objects, requiring selective attention to isolate relevant objects from irrelevant background objects. This study examined how selective attention shapes neural representations of naturalistic sound scenes in the auditory cortex (AC). Using functional magnetic resonance imaging, we recorded brain activity from participants (n = 20) as they attended to a designated object in scenes comprising three overlapping sounds. Scenes were constructed in two manners: one where each object belonged to a different category (speech, animal, instrument) and another where all objects were from the same category. Attending to speech consistently enhanced activations in lateral AC subfields, while attention to animal and instrument sounds preferentially modulated medial subfields, supporting models where attention modulates feature-selective neural gain in AC. Remarkably, however, spatial pattern analysis revealed that the attended object dominated the AC activation patterns of the entire scene in a manner depending on both object type and scene composition: When the objects of the scene belonged to different categories, attended objects dominated fields processing higher-level category-specific features. In contrast, when all scene objects shared the same category, dominance shifted to fields processing low-level acoustic features. Thus, attention seems to dynamically prioritize the features offering maximal contrast within a given context, emphasizing object-specific patterns in feature-similar scenes and category-level patterns in feature-diverse scenes. Our results support models where top-down signals not only modulate gain but also affect several steps of auditory scene decomposition and analysis - influencing stream segregation and gating of higher-level processing in a contextual manner, adapting to specific auditory environments.

neuroscience↗

bioRxiv2024

Similarity in Early Life Stress Exposure is Associated with Similarity in Neural Representations in Early Adulthood

Early life stress (ELS) has profound implications for developmental trajectories, yet the neural mechanisms underlying its long-term effects remain incompletely understood. In the present study, we examined whether interindividual similarity in ELS exposure aligns with similarity in neural representations and behavioral task performance in early adulthood. Leveraging a 20-year longitudinal dataset of Finnish families, we evaluated 87 young adults who underwent functional magnetic resonance imaging (fMRI) during an emotional go/no-go task. Intersubject representational similarity analysis (IS-RSA) was used to assess the associations between pairwise similarities in prospectively or retrospectively measured ELS, neural representations in 360 cortical regions, and task performance. We incorporated multidimensional scaling and Procrustes alignment to visualize interindividual differences in representational spaces. Prospective ELS, but not Retrospective ELS, was significantly associated with neural representational similarity across 40 cortical regions, including the anterior insula, frontal operculum, and anterior cingulate cortex. Higher Prospective ELS was also linked to reduced detection sensitivity, mediated by neural responses to angry facial expressions. These findings highlight the systematic and chronic effects of more moderate ELS on brain development and emphasize the value of prospective measurements and advanced similarity analyses in capturing the nuanced influences of ELS. By integrating spatial and shape analytical techniques, the present study provides new insights into the long-term neurobiological correlates of ELS and introduces novel methodological tools for neurodevelopmental research.

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bioRxiv2023

Selective attention to audiovisual speech is associated with recurrent feedback-feedforward loops in the ventral processing stream

Selective attention related top-down modulation plays a significant role in separating relevant speech from irrelevant background speech when vocal attributes separating concurrent speakers are small and continuously evolving. Electrophysiological studies have shown that such top-down modulation enhances neural tracking of attended speech. Yet, the specific cortical regions involved remain unclear due to the limited spatial resolution of most electrophysiological techniques. To overcome such limitations, we collected both EEG (high temporal resolution) and fMRI (high spatial resolution), while human participants selectively attended to speakers in audiovisual scenes containing overlapping cocktail party speech. To utilize the advantages of the respective techniques, we analysed neural tracking of speech using the EEG data and performed representational dissimilarity-based EEG-fMRI fusion. We observed that attention enhanced neural tracking and modulated EEG correlates throughout the latencies studied. Further, attention related enhancement of neural tracking fluctuated in predictable temporal profiles. We discuss how such temporal dynamics could arise from a combination of interactions between attention and prediction as well as plastic properties of the auditory cortex. EEG-fMRI fusion revealed attention related iterative feedforward-feedback loops between hierarchically organised nodes of the ventral auditory object related processing stream. Our findings support models where attention facilitates dynamic neural changes in the auditory cortex, ultimately aiding discrimination of relevant sounds from irrelevant ones while conserving neural resources.

neuroscience↗

bioRxiv2019

Modulation of brain activity by selective attention to audiovisual dialogues

In real-life noisy situations, we can selectively attend to conversations in the presence of irrelevant voices, but neurocognitive mechanisms in such natural listening situations remaiin largely unexplored. Previous research has shown distributed activity in the mid superior temporal gyrus (STG) and sulcus (STS) while listening to speech and human voices, in the posterior STS and fusiform gyrus when combining auditory, visual and linguistic information, as well as in lefthemisphere temporal and frontal cortical areas during comprehension. In the present functional magnetic resonance imaging (fMRI) study, we investigated how selective attention modulates neural responses to naturalistic audiovisual dialogues. Our healthy adult participants (N = 15) selectively attended to video-taped dialogues between a man and woman in the presence of irrelevant continuous speech in the background. We modulated the auditory quality of dialogues with noise vocoding and their visual quality by masking speech-related facial movements. Both increased auditory quality and increased visual quality were associated with bilateral activity enhancements in the STG/STS. In addition, decreased audiovisual stimulus quality elicited enhanced fronto-parietal activity, presumably reflecting increased attentional demands. Finally, attention to the dialogues, in relation to a control task where a fixation cross was attended and the dialogue ignored, yielded enhanced activity in the left planum polare, angular gyrus, the right temporal pole, as well as in the orbitofrontal/ventromedial prefrontal cortex and posterior cingulate gyrus. Our findings suggest that naturalistic conversations effectively engage participants and reveal brain networks related to social perception in addition to speech and semantic processing networks.

neuroscience↗