Biology subjects

Kvamme, T.

Publications and source records attributed to Kvamme, T..

4 recordsLinked to original sources

bioRxiv2026

How the Body Shapes the Mind's Eye: Cardiac vagal reactivity predicts visual imagery vividness

Mental imagery is known to be accompanied by autonomic responses, traditionally viewed as merely downstream consequences of imagery. Recent theoretical work has challenged this view, proposing that mental imagery requires the integration of cortical sensory representations with ascending interoceptive signals supplied by the autonomic nervous system. These two views make opposite predictions: if autonomic activity is only a consequence of imagery, then the responsiveness of the autonomic nervous system should not predict imagery vividness. If instead autonomic input shapes the generation of mental images, individuals with greater autonomic responsiveness should experience more vivid imagery. The present study tested these competing predictions by examining whether individual differences in cardiac vagal reactivity predict self-reported visual imagery vividness, with imagery assessed at a separate time point from the paced breathing protocol. Cardiac vagal reactivity significantly predicted VVIQ scores after controlling for factors such as resting HRV, respiratory amplitude, age and negative affect (b = 13.75, p = .022; model R2 = 0.12), whereas neither baseline HRV nor fast-breathing evoked HRV change were linked to imagery, suggesting the effect is specific to the capacity to enter a high parasympathetic state rather than reflecting general autonomic capacity. Self-reported interoceptive noticing (MAIA Noticing) was significantly associated with both delta HRV and VVIQ, suggesting that cardiac vagal reactivity and imagery vividness are linked through a broader individual difference in interoceptive function. These findings indicate that the vividness of mental imagery is not exclusively central in origin but also appears to be shaped by the capacity of the autonomic nervous system to enter a high parasympathetic state. Imagery thus likely involves bidirectional interaction between cortical and autonomic processes, with descending efferent pathways activating autonomic responses while ascending interoceptive signals contributing to the construction of mental images.

physiology↗

bioRxiv2026

Cardio-respiratory coordination during memory encoding predicts performance

Cardiorespiratory coupling (i.e., the phase synchronization between cardiac and respiratory rhythms) varies with physiological state, but whether coupling strength functionally predicts cognitive performance remains unknown. Here we demonstrate that cardiorespiratory coupling predicts trial-level accuracy during the initial formation of mental representations but not during their subsequent retention, revealing temporal specificity in the relationship between bodily rhythms and cognition. We experimentally manipulated coupling via paced breathing (slow: 6 bpm vs. fast: 20 bpm) while participants performed mental imagery and working memory tasks with continuous physiological monitoring. Slow breathing enhanced parasympathetic activity (respiratory sinus arrhythmia), which strengthened baseline cardiorespiratory coupling. This coordinated autonomic state persisted into subsequent cognitive trials, predicting trial-by-trial accuracy specifically during the initial encoding phase when internal representations were actively constructed, but not during subsequent maintenance when representations were sustained. This temporal dissociation indicates that cardiorespiratory coordination selectively predicts performance when the brain constructs internal representations under elevated processing demands. Experimental manipulation of breathing improved behavioral accuracy, validating couplings functional relevance. These findings establish cardiorespiratory coupling as a physiological state marker that reliably predicts encoding success, providing a measurable target for interventions targeting memory and mental representation.

physiology↗

bioRxiv2024

Vividness of Visual Imagery Supported by Intrinsic Structural-Functional Brain Network Dynamics

Vividness of visual imagery is subject to individual variability, a phenomenon with largely unexplored neurobiological underpinnings. By analyzing data from 273 participants we explored the link between the structural-functional organization of brain connectomes and the reported intensity of visual imagery (measured with VVIQ-2). Employing graph theory analyses we investigated both the structural (DTI) and functional (rs-fMRI) connectomes within a network of regions often implicated in visual imagery. Our results indicate a relationship between increased local efficiency and clustering coefficients in the structural connectome in individuals who experience more vivid visual imagery. Increased local efficiency and clustering coefficients were mirrored in the functional connectome with increases in left inferior temporal regions, a region frequently identified as a critical hub in the visual imagery literature. Furthermore, individuals with more vivid imagery were found to have lower levels of global efficiency in their functional connectome. We propose that the clarity and intensity of visual imagery are optimized by a network organization characterized by heightened localized information transfer and interconnectedness. Conversely, an excessively globally integrated network might dilute the specific neural activity crucial for generating vivid visual images, leading to less locally concentrated resource allocation in key regions involved in visual imagery vividness.

neuroscience↗

bioRxiv2021

Phylogeny of the Formicoxenus genus-group (Hymenoptera: Formicidae) reveals isolated lineages of Leptothorax acervorum in the Iberian Peninsula predating the Last Glacial Maximum

The Formicoxenus genus-group comprises six genera within the tribe Crematogastrini. The group is well known for repeated evolution of social parasitism among closely related taxa and cold-adapted species with large distribution ranges in the Nearctic and Palearctic regions. Previous analyses based on nuclear markers (ultraconserved elements, UCEs) and mitochondrial genes suggest close relationship between Formicoxenus Mayr, 1855, Leptothorax Mayr, 1855 and Harpagoxenus Forel, 1893. However, scant sampling has limited phylogenetic assessment of these genera. Also, previous phylogeographic analyses of L. acervorum (Fabricius, 1793) have been limited to its West-Palearctic range of distribution, which has provided a narrow view on recolonization, population structure and existing refugia of the species. Here, we inferred the phylogenenetic history of genera within the Formicoxenus genus-group and reconstructed the phylogeography of L. acervorum with more extensive sampling. We employed four datasets consisting of whole genomes and sequences of the COI. The topologies of previous nuclear and our inferences based on mitochondrial genomes were overall congruent. Further, Formicoxenus may not be monophyletic. We found several monophyletic lineages that do not correspond to the current species described within Leptothorax, especially in the Nearctic region. We identified a monophyletic L. acervorum lineage that comprises both Nearctic and Palearctic locations. The most recent expansion within L. acervorum probably occurred within the last 0.5 Ma with isolated populations predating the Last Glacial Maximum (LGM), which are localized in at least two refugial areas (Pyrenean and Northern plateau) in the Iberian Peninsula. The patterns recovered suggest a shared glacial refugium in the Iberian Peninsula with cold-adapted trees that currently share high-altitude environments in this region.

evolutionary biology↗