Biology subjects

Turnbull, A.

Publications and source records attributed to Turnbull, A..

11 recordsLinked to original sources

bioRxiv2026

Amygdala Persistence in Aging: Replication and Extension of Puccetti et al. (2021)

Age-related differences in affect are well established, but their neural mechanisms remain unclear. In a preregistered replication of Puccetti et al. (2021) and extension, we examined age, affect, left-amygdala negative persistence, and amygdala-ventromedial prefrontal cortex (vmPFC) task-based connectivity using MIDUS 3 daily diary and fMRI data. Older age predicted higher positive and lower negative affect in the daily diary sample (N = 1,168; ps < .001). In the primary diary + fMRI sample (N = 81; ages 48-95, 61.7% female, 82.7% White), greater persistence predicted higher raw negative affect ({beta} = 0.278, 95% CI [0.012, 0.544], p = .020); associations with positive and log-transformed negative affect were nonsignificant (ps [≥] .063). Older age predicted lower persistence in the final fMRI sample (N = 127; {beta} = -0.00260, 95% CI [-0.00504, -0.00016], p = .018), but this association was weaker in the primary diary + fMRI sample (p = .200), with no evidence of mediation. Greater anterior vmPFC connectivity predicted lower raw negative affect ({beta} = -0.106, 95% CI [-0.223, 0.012], p = .039) and log-transformed negative affect (p = .014). In MIDUS Refresher 1, affect estimates were directionally similar but nonsignificant (N = 48; ps [≥] .081), whereas the age-persistence estimate reversed direction. These findings provide partial support for amygdala persistence and task-based connectivity as neural correlates of daily affect, while highlighting variability in the magnitude and replicability of fMRI-behavior associations.

neuroscience↗

bioRxiv2026

Brain-thought states during movie-watching reflect shared sensory anchors and film- and person- specific processes in association cortex

Naturalistic paradigms such as movie-watching have transformed functional neuroimaging by capturing cognitive dynamics during rich, real-world experiences. A fundamental challenge, however, is determining whether the neural signatures identified during these experiences reflect general principles of cognition or the specific contexts in which they are measured. To address this question, we combined fMRI data from participants watching eight diverse films with continuous reports of ongoing thought. We found that the generalizability of brain-thought relationships depends on the cognitive process being recruited. Neural signatures linked to sensory processing remained robust across films, whereas those involving memory-related association networks depended on how we modelled between-film variability, indicating that cognition becomes increasingly context-dependent along the cortical hierarchy from sensory to association cortex. Within default and limbic networks, we identified two contrasting memory-related states with opposite consequences for comprehension. One, reflecting the integration of prior knowledge with ongoing experience, predicted better narrative comprehension and was revealed only after accounting for between-film variability. The other, associated with stimulus-independent thought, predicted poorer comprehension and emerged only when between-film variability was not modelled. Together, these findings establish when brain-experience relationships measured during naturalistic paradigms can generalize across contexts and when they instead reflect interactions between cognition and the specific environments in which cognition unfolds. More broadly, the consistency of a given brain-experiential association may depend less on where it occurs in the brain and more on the viewer's contextual experience: perceiving the film, drawing on memory to understand it, or drifting away.

neuroscience↗

bioRxiv2025

AI-assisted modeling of attentional control for intervention engagement

Digital cognitive interventions can improve cognition in older adults, but individual differences in transfer to executive function (EF) remain substantial and are difficult to anticipate before treatment completion. We developed a compact Facial Signature Score (FSS) from passive webcam recordings collected during therapeutic cognitive challenges in BREATHE (NCT04522791; development, N=87) and evaluated it in PSOPT (NCT06005038; external validation, N=39), an independent trial using a different intervention format. The FSS discriminated EF responders under nested cross-validation in BREATHE (AUROC=0.77) and generalized to PSOPT without feature reselection or reweighting (AUROC=0.78). The FSS was associated with continuous EF change in BREATHE (Spearman {rho}=0.49, p<0.001) and after outcome-independent recalibration in PSOPT ({rho}=0.32, p=0.045). Predictive performance was retained when the signature was computed from the first 25% and 50% of intervention sessions, and the FSS added value beyond baseline characteristics and conventional behavioral measures. Passive facial dynamics during therapeutic cognitive challenge may serve as a scalable intervention-process marker for early assessment of cognitive response among older adults.

neuroscience↗

bioRxiv2024

Personality traits vary in their association with brain activity across situations.

Human cognition supports complex behaviour across a range of situations, and traits (such as personality) influence how we react in these different contexts. Although viewing traits as situationally grounded is common in social sciences it is often overlooked in neuroscience. Often studies focus on linking brain activity to trait descriptions of humans examine brain-trait associations in a single task, or, under passive conditions like wakeful rest. These studies, often referred to as brain wide association studies (BWAS) have recently become the subject of controversy because results are often unreliable even with large sample sizes. Although there are important statistical reasons why BWAS yield inconsistent results, we hypothesised that results are inconsistent because the situation in which brain activity is measured will impact the power in detecting a reliable link to a specific trait. To examine this possibility, we performed a state-space analysis in which tasks from the Human Connectome Project (HCP) were organized into a low-dimensional space based on how they activated different large-scale neural systems. We examined how individuals observed brain activity across these different contexts related to their personality. Our analysis found that for multiple personality traits (including Agreeableness, Openness to Experience and Conscientiousness) stronger associations with brain activity emerge in some tasks than others. These data establish that for specific personality traits there are situations in which reliable associations with brain activity can be identified with greater accuracy, highlighting the importance of context-bound views of understanding how brain activity links to trait variation in human behaviour. Significance statementAs a species humans act efficiently in many contexts, however, as individuals our personality makes us more specialised in some situations than others. This "if-then" view of personality is widely accepted in the social sciences but is often overlooked in neuroscience. Here we show adopting a situationally bound view of human traits provides more meaningful descriptions of a brain-trait associations than are possible in traditional brain wide association studies (BWAS) that measure brain activity in a single situation. Our results demonstrate multiple personality traits (including Agreeableness, Openness to Experience and Conscientiousness) show stronger associations with brain activity in some tasks than others, explaining why studies focusing on changes in brain activity at rest can lead to weak or contradictory results.

neuroscience↗

bioRxiv2023

Experience sampling reveals the role that covert goal states play in task-relevant behavior.

Cognitive neuroscience has gained insight into covert states using experience sampling. Traditionally, this approach has focused on off-task states, however, task-relevant states are also maintained via covert processes. Our study examined whether experience sampling can also provide insights into covert goal-relevant states that support task performance. To address this question, we developed a neural state-space, using dimensions of brain function variation, that allows neural correlates of overt and covert states to be examined in a common analytic space. We use this to describe brain activity during task performance, its relation to covert states identified via experience sampling, and links between individual variation in overt and covert states and task performance. Our study established activity patterns within association cortex emphasizing the fronto-parietal network both during target detection and a covert state of deliberate task focus which was associated with better task performance. In contrast, periods of vigilance and a covert off-task state were both linked to activity patterns emphasizing the default mode network. Our study shows experience sampling can not only describe covert states that are unrelated to the task at hand, but can also be used to highlight the role fronto-parietal regions play in the maintenance of covert task-relevant states.

neuroscience↗

bioRxiv2022

Macro-scale patterns in functional connectivity associated with ongoing thought patterns and dispositional traits

Complex macro-scale patterns of brain activity that emerge during periods of wakeful rest provide insight into the organisation of neural function, how these differentiate individuals based on their traits, and the neural basis of different types of self-generated thoughts. Although brain activity during wakeful rest is valuable for understanding important features of human cognition, its unconstrained nature makes it difficult to disentangle neural features related to personality traits from those related to the thoughts occurring at rest. Our study builds on recent perspectives from work on ongoing conscious thought that highlight the interactions between three brain networks - ventral and dorsal attention networks, as well as the default mode network. We combined measures of personality with state-of-the-art indices of ongoing thoughts at rest and brain imaging analysis and explored whether this tri-partite view can provide a framework within which to understand the contribution of states and traits to observed patterns of neural activity at rest. To capture macro-scale relationships between different brain systems, we calculated cortical gradients to describe brain organisation in a low dimensional space. Our analysis established that for more introverted individuals, regions of the ventral attention network were functionally more aligned to regions of the somatomotor system and the default mode network. At the same time, a pattern of detailed self-generated thought was associated with a decoupling of regions of dorsal attention from regions in the default mode network. Our study, therefore, establishes that interactions between attention systems and the default mode network are important influences on ongoing thought at rest and highlights the value of integrating contemporary perspectives on conscious experience when understanding patterns of brain activity at rest.

neuroscience↗

bioRxiv2022

Patterns of Ongoing Thought in the Real-World

Previous research has indicated that health and well-being are impacted on by both the way we think, and the things we do. In the laboratory, studies suggest that specific task contexts affect this process because the people we are with, the places we are in, and the activities we perform may influence our thought patterns. In our study participants completed multi-dimensional experience-sampling surveys eight times per day for 5 days to generate thought data across a variety of dimensions in daily life. Principal component analysis was used to decompose the experience sampling data, and linear mixed modelling related these patterns to the activity in daily life in which they emerged. Our study replicated the influence of socializing on patterns of ongoing thought observed in our prior study and established that this is part of a broader set of relationship that links our current activities to how our thoughts are organised in daily life. We also found that factors such as time of day and the physical location are associated with reported patterns of thought, factors that are important for future studies to explore. Our study suggests that sampling thinking in the real world may be able to provide a set of comprehensive thinking-activity mappings that will be useful to researchers and health care professionals interested in health and well-being.

neuroscience↗

bioRxiv2021

Transient definitive host presence is sufficient to sustain avian schistosome populations

To control swimmers itch in northern Michigan inland lakes, one species of bird, the common merganser (Mergus merganser), has been relocated from several lakes since 2015. Relocation efforts are driven by a desire to reduce the prevalence of the swimmers itch-causing parasite Trichobilharzia stagnicolae. The intention of this state-sponsored control effort was to interrupt the life cycle of T. stagnicolae and reduce parasite egg contribution into the environment from summer resident mergansers such that infections of the intermediate snail host Stagnicola emarginata declined. Reduced snail infection prevalence was expected to greatly reduce abundance of the swimmers itch-causing cercarial stage of the parasite in water. With no official program in place to assess the success of this relocation effort, we sought to study the effectiveness and impact of the removal of a single definitive host from a location with high definitive host and parasite diversity. This was assessed through a comprehensive, lake-wide monitoring study measuring longitudinal changes in the abundance of three species of avian schistosome cercariae in four inland Michigan lakes. Environmental measurements were also taken at these lakes to understand how they can affect swimmers itch incidence. Results from this study demonstrate that the diversity of avian schistosomes at the study lakes would likely make targeting of a single species of swimmers itch-causing parasite meaningless from a swimmers itch control perspective. Our data also suggest that removal of the common merganser is not an effective control strategy for the T. stagnicolae parasite, likely due to parasite contributions of migratory birds in the fall and spring. This suggests that only minimal contact time between the definitive host and the lake ecosystem is required to contribute sufficient parasite numbers to maintain a thriving population of parasite species with a high host-specificity.

ecology↗

bioRxiv2020

Exploring patterns of ongoing thought under naturalistic and task-based conditions

Previous research suggests that patterns of ongoing thought are heterogeneous, varying across situations and individuals. The current study investigated the influence of a wide range of tasks and individual affective style on ongoing patterns of thought. In total, we used 9 different tasks and measured ongoing thought using multidimensional experience sampling. A Principle Component Analysis of the experience sampling data revealed four patterns of ongoing thought. Linear Mixed Modelling was used to examine the contextual distribution of the thought patterns. Different thought patterns were found to relate to different types of conditions. Intrusive and negative thought pattern expression was found to be influenced by individual affective style (depression level). Overall, these data show that patterns of thought are subject to both contextual and intrinsic variation, suggesting that understanding these important features of experience across a broad range of situations will be useful in understanding their role in human experience. HighlightsO_LIPatterns of thought vary across different task contexts C_LIO_LIThought pattern expression is influenced by individual affective style C_LIO_LIThere is a need to broaden the tasks used to study ongoing thought C_LI

neuroscience↗

bioRxiv2019

Emergence of neural dynamics within a co-ordinate space of large-scale neural hierarchies

When unoccupied by an explicit external task, humans engage in a wide range of different types of self-generated thinking. These are often unrelated to the immediate environment and have unique psychological features. Although contemporary perspectives on ongoing thought recognise the heterogeneity of these self-generated states, we lack both a clear understanding of how to classify the specific states, and how they can be mapped empirically. In the current study, we capitalise on advances in machine learning that allow continuous neural data to be divided into a set of distinct temporally re-occurring patterns, or states. We applied this technique to a large set of resting state data in which we also acquired retrospective descriptions of the participants experiences during the scan. We found that two of the identified states were predictive of patterns of thinking at rest. One state highlighted a pattern of neural activity commonly seen during demanding tasks, and the time individuals spent in this state was associated with descriptions of experience focused on problem solving in the future. A second state was associated with patterns of activity that are commonly seen under less demanding conditions, and the time spent in it was linked to reports of negative rumination. Finally, we found that these two neural states tended to fall at either end of a neural hierarchy that is thought to reflect the brains response to cognitive demands. Together, these results demonstrate that approaches which take advantage of time-varying changes in neural function can play an important role in understanding the repertoire of self-generated states. Moreover, they establish that important features of self-generated ongoing experience are related to variation along a similar vein to those seen when the brain responds to cognitive task demands.

neuroscience↗

bioRxiv2019

Targeted cancer cell killing by highly selective miRNA-triggered activation of a prokaryotic toxin-antitoxin system

Although not evolved to function in eukaryotes, prokaryotic toxin Kid induces apoptosis in human cells, and this is avoided by co-expression of its neutralizing antitoxin, Kis. Inspired by the way Kid becomes active in bacterial cells we had previously engineered a synthetic toxin-antitoxin system bearing a Kis protein variant that is selectively degraded in cells expressing viral oncoprotein E6, thus achieving highly selective killing of cancer cells transformed by human papillomavirus. Here we aimed to broaden the type of oncogenic insults, and therefore of cancer cells, that can be targeted using this approach. We show that appropriate linkage of the kis gene to a single, fully complementary, target site for an oncogenic human microRNA enables the construction of a synthetic toxin-antitoxin pair that selectively kills cancer cells overexpressing that particular microRNA. Importantly, the resulting system spares non-targeted cells from collateral damage, even when they overexpress highly homologous, though non-targeted, microRNAs.

synthetic biology↗