Biology subjects

Andrews-Hanna, J.

Publications and source records attributed to Andrews-Hanna, J..

4 recordsLinked to original sources

bioRxiv2026

Beyond rumination: an ecological momentary assessment of daily thinking patterns in maladaptive daydreaming

Maladaptive daydreaming is a form of maladaptive repetitive thought characterized by excessive, dysfunctional fantasy engagement, with notable links to psychological distress and poor well-being. Although symptoms can be reliably measured along a continuum, it remains unclear how they manifest in the phenomenological characteristics of everyday thinking, as well as which thought characteristics are unique to maladaptive daydreaming versus shared with trait rumination, a transdiagnostic manifestation of maladaptive repetitive thinking that frequently co-occurs with maladaptive daydreaming. To advance these questions, we conducted a pre-registered study using ecological momentary assessment to track the everyday thoughts of 446 young adults (aged 18 to 34) spanning a range of maladaptive daydreaming symptom severity as assessed with the 16-item Maladaptive Daydreaming Scale. Higher maladaptive daydreaming scores were associated with several poor mental health indicators, including higher trait rumination. Positive associations between maladaptive daydreaming scores and both negatively-valenced and task-unrelated thinking emerged, yet these relationships were accounted for by variance shared with rumination. Beyond rumination, higher maladaptive daydreaming scores were uniquely associated with worse mood, as well as greater internally-oriented attention, more socially-oriented thought, and greater overall thought persistence. Maladaptive daydreaming also uniquely moderated the relationship between internal orientation and social orientation, such that the positive association between internal and social thought content became stronger at higher levels of maladaptive daydreaming. Overall, these findings provide novel evidence that maladaptive daydreaming levels are linked to unique socioemotional features and restricted dynamics, beyond its overlap with general ruminative distress in everyday life. These insights suggest that clinical interventions should target immersive fantasy engagement alongside transdiagnostic maladaptive repetitive thinking.

neuroscience↗

bioRxiv2023

Two distinct modes of hemodynamic responses in the human brain

Functional MRI measures brain activity by monitoring changes in blood oxygen levels, known as the blood-oxygen-level-dependent (BOLD) signal, rather than measuring neuronal activity directly. This approach crucially relies on neurovascular coupling, the mechanism that links neuronal activity to changes in cerebral blood flow (CBF). However, it remains unclear whether this relationship is consistent for both positive and negative BOLD responses across the human cortex. Here we found that about 40% of voxels with significant BOLD signal changes during various tasks showed reversed oxygen metabolism, particularly in the default mode network. These "discordant" voxels differed in baseline oxygen extraction fraction (OEF) and regulated oxygen demand via OEF changes, while "concordant" voxels depended mainly on CBF changes. Our findings challenge the canonical interpretation of the BOLD signal, indicating that quantitative fMRI provides a more reliable assessment of both absolute and relative changes in neuronal activity.

neuroscience↗

bioRxiv2017

Hippocampal atrophy and intrinsic brain network alterations relate to impaired capacity for mind wandering in neurodegeneration

Mind wandering represents the human capacity for internally focussed thought, and relies upon the brains default network and its interactions with attentional networks. Studies have characterised mind wandering in healthy people, yet there is limited understanding of how this capacity is affected in clinical populations. This study used a validated thought-sampling task to probe mind wandering capacity in two neurodegenerative disorders: behavioural variant frontotemporal dementia (bvFTD; n=35) and Alzheimers disease (AD; n=24), compared to older controls (n=37). These patient groups were selected due to canonical structural and functional changes across sites of the default and frontoparietal networks, and well-defined impairments in cognitive processes that support mind wandering. Relative to controls, bvFTD patients displayed significantly reduced mind wandering capacity, offset by a significant increase in stimulus-bound thought. In contrast, AD patients demonstrated comparable levels of mind wandering to controls, in the context of a relatively subtle shift towards stimulus-/task-related forms of thought. In the patient groups, mind wandering was associated with grey matter integrity in the hippocampus/parahippocampus, striatum, insula and orbitofrontal cortex. Resting state functional connectivity revealed associations between mind wandering capacity and connectivity within and between regions of the frontoparietal and default networks, with distinct patterns evident in patients vs. controls. These findings support a relationship between altered mind wandering capacity in neurodegenerative disorders, and structural and functional integrity of the default and frontoparietal networks. This study highlights a dimension of cognitive dysfunction not well documented in neurodegenerative disorders, and validates current models of mind wandering in a clinical population.\n\nSignificance statementHumans spend much of their waking life engaged in mind wandering. Underlying brain systems supporting this complex ability have been established in healthy individuals, yet it remains unclear how mind wandering is altered in neuropsychiatric populations. We reveal changes in the thought profiles elicited during periods of low cognitive demand in dementia, resulting in reduced mind wandering and an increased propensity towards stimulus-bound thought. These altered thought profiles were associated with structural and functional brain changes in the hippocampus, default and frontoparietal networks; key regions implicated in internal mentation in healthy individuals. Our findings provide a unique clinical validation of current theoretical models of mind wandering, and reveal a dimension of cognitive dysfunction that has received scant attention in dementia.

neuroscience↗

bioRxiv2017

Heterogeneity Within the Frontoparietal Control Network and its Relationship to the Default and Dorsal Attention Networks

The frontoparietal control network (FPCN) plays a central role in executive control. It has been predominantly viewed as a unitary domain general system. Here, we examined patterns of FPCN functional connectivity (FC) across multiple conditions of varying cognitive demands, in order to test for FPCN heterogeneity. We identified two distinct subsystems within the FPCN based on hierarchical clustering and machine learning classification analyses of within-FPCN FC patterns. These two FPCN subsystems exhibited distinct patterns of FC the default network (DN) and the dorsal attentional network (DAN). This 2-fold FPCN differentiation was observed across four independent data sets, across 9 different conditions (rest and 8 tasks), as well as in meta-analytic co-activation patterns. The extent of FPCN differentiation varied across conditions, suggesting flexible adaptation to task demands. These findings reveal a flexible and heterogeneous FPCN organization that may in part emerge from separable DN and DAN processing streams.

neuroscience↗