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LATEST RESEARCH

Factors associated with healthy aging in Latin American populations
Nature Medicine

This research from the Ibanez Lab explores the unique dynamics of healthy aging in Latin American and Caribbean (LAC) populations, highlighting the significant influence of various factors beyond traditional markers like age and sex.

 

Latin American populations may present patterns of sociodemographic, ethnic and cultural diversity that can defy current universal models of healthy aging. The potential combination of risk factors that influence aging across populations in Latin American and Caribbean (LAC) countries is unknown. Compared to other regions where classical factors such as age and sex drive healthy aging, higher disparity-related factors and between-country variability could influence healthy aging in LAC countries. We investigated the combined impact of social determinants of health (SDH), lifestyle factors, cardiometabolic factors, mental health symptoms and demographics (age, sex) on healthy aging (cognition and functional ability) across LAC countries with different levels of socioeconomic development using cross-sectional and longitudinal machine learning models (n = 44,394 participants). Risk factors associated with social and health disparities, including SDH (β > 0.3), mental health (β > 0.6) and cardiometabolic risks (β > 0.22), significantly influenced healthy aging more than age and sex (with null or smaller effects: β < 0.2). These heterogeneous patterns were more pronounced in low-income to middle-income LAC countries compared to high-income LAC countries (cross-sectional comparisons), and in an upper-income to middle-income LAC country, Costa Rica, compared to China, a non-upper-income to middle-income LAC country (longitudinal comparisons). These inequity-associated and region-specific patterns inform national risk assessments of healthy aging in LAC countries and regionally tailored public health interventions.

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You can find the full publication in Nature Medicine.

Santamaria-Garcia, H., Sainz-Ballesteros, A., Hernandez, H., Moguilner, S., Maito, M., Ochoa-Rosales, C., ... & Ibanez, A. (2023). Factors associated with healthy aging in Latin American populations. Nature Medicine, 1-11.

Responsiveness variability during anaesthesia relates to inherent differences in brain structure and function of the frontoparietal networks
Human Brain Mapping

This research was led by Dr Feng Deng from Dr Lorina Naci's lab, 1/4 patients presumed to be unconscious during anaesthesia have subjective experiences, e.g. dreaming, and in rare cases individuals become accidentally aware during a medical procedure. The research used an experimental design to show that participants that are resistant to anaesthesia have fundamental differences in the function and structures of the fronto-parietal regions of the brain compared to those who remained fully unconscious. Specifically, individuals with larger grey matter volume in frontal regions and stronger functional connectivity in fronto-parietal networks require higher doses of propofol to become nonresponsive, compared to those with weaker features in these regions. Crucially, these brain differences could be predicted prior to sedation, which has important implications for patient safety and wellbeing.

Congrats to Dr Deng who was has been awarded the School of Psychology Doctoral Research Paper Prize for this exceptional work!

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Responsiveness variability during anaesthesia relates to inherent differences in brain structure and function of the frontoparietal networks

You can find the full publication in Human Brain Mapping.

Deng, F., Taylor, N., Owen, A. M., Cusack, R., & Naci, L. (2023). Responsiveness variability during anaesthesia relates to inherent differences in brain structure and function of the frontoparietal networks. Human Brain Mapping, 44(6), 2142-2157.

The development of intrinsic timescales: A comparison between the neonate and adult brain
NeuroImage

This research was led by Dr Anna Truzzi from Prof Rhodri Cusack's lab and compares the intrinsic timescales of neonatal and adult brains. In the adult brain a hierarchy of intrinsic timescales exists, from short in sensory-motor areas to long in associative areas, which can account for the ability of flexibly integrating information on different timescales. This study examined intrinsic timescales for the first time in the neonate brain, finding that the infant brain integrates information over a longer period of time compared to the adult brain. Anatomically, this feature could be a result of the ongoing myelination process. Functionally, this characteristic could be an advantage for human infants because it could favour the initial learning of long range, more holistic information over fast changing, fleeting, less relevant details. Results from this project provide a fist steppingstone to understand the neurological mechanisms underlying how the infant brain learns from a continuously changing stream of information.

Dr. Truzzi has been honored with the School of Psychology Postdoctoral Research Paper Prize for this outstanding work!

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You can find the full publication in NeuroImage.

Truzzi, A., & Cusack, R. (2023). The development of intrinsic timescales: A comparison between the neonate and adult brain. NeuroImage, 275, 120155.

Gillan Lab Researchers published in Nature Communications!
Using language in social media posts to study the network dynamics of depression longitudinally

This study led by Sean Kelley from the Gillan Lab constructed personalised, within-subject, networks based on depression-relevant linguistic features from Twitter data. It was found that people with greater depression severity had higher overall network connectivity between depression-relevant linguistic features than those with less severe depression. Network theory of mental illness posits that causal interactions between symptoms give rise to mental health disorders. Increasing evidence suggests that depression network connectivity may be a risk factor for transitioning and sustaining a depressive state.

 

The study analysed social media (Twitter) data from 946 participants who retrospectively self-reported the dates of any depressive episodes in the past 12 months and current depressive symptom severity. Personalised, within-subject, networks were constructed based on depression-related linguistic features. An association existed between current depression severity and 8 out of 9 text features examined. Individuals with greater depression severity had higher overall network connectivity between depression-relevant linguistic features than those with lesser severity. The study observed within-subject changes in overall network connectivity associated with the dates of a self-reported depressive episode. The connectivity within personalized networks of depression-associated linguistic features may change dynamically with changes in current depression symptoms.

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You can find the full publication in Nature Communications.

Kelley, S. W., & Gillan, C. M. (2022). Using language in social media posts to study the network dynamics of depression longitudinally. Nature communications, 13(1), 1-11.

Multimodal mechanisms of human socially reinforced learning across neurodegenerative diseases
Brain

Social reinforcement is a powerful facilitator of learning. However, most evidence

comes from healthy individuals, offering limited (correlational) information to identify critical

neural signatures. The neurodegenerative lesion model approach partially overcomes these limitations by revealing direct links between affected brain mechanisms and behavioral performance. This study lead by Ibanez Lab in collaboration with the Gillan Lab assessed socially reinforced and non-socially reinforced learning in healthy participants as well as persons with behavioral variant frontotemporal dementia (bvFTD), Parkinson’s disease (PD), and Alzheimer’s disease (AD). In healthy participants, learning was facilitated by social feedback relative to non-social feedback. In comparison with controls, this effect was specifically impaired in vcFTD and PD, while unspecific learning deficits (across social and non-social conditions) were observed in Alzheimer’s disease. EEG results showed increased medial frontal negativity in healthy controls during social feedback and learning. Such a modulation was selectively disrupted in behavioral variant frontotemporal dementia. Neuroanatomical results revealed extended temporo-parietal and fronto-limbic correlates of socially reinforced learning, with specific temporo-parietal associations in behavioral variant frontotemporal dementia, and predominantly fronto-limbic regions in Alzheimer’s disease. In contrast, non-socially reinforced learning was consistently linked to medial temporal/hippocampal regions. No associations with cortical volume were found in Parkinson’s disease. Results are consistent with core social deficits in behavioral variant frontotemporal dementia, subtle disruptions in ongoing feedback-mechanisms and social processes in Parkinson’s disease, and generalized learning alterations in Alzheimer’s disease. This multimodal approach highlights the impact of different neurodegenerative profiles on learning and social feedback. Our findings inform a promising theoretical and clinical agenda in the fields of social learning, socially-reinforced learning and neurodegeneration.

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You can find the full publication here.

 

Legaz A, Abrevaya S, Dottori M, Campo CG, Birba A, Caro MM, Aguirre J, Slachevsky A, Aranguiz R, Serrano C, Gillan CM, Leroi I, García AM, Fittipaldi S, Ibañez A. Multimodal mechanisms of human socially reinforced learning across neurodegenerative diseases. Brain. 2021 Sep 16:awab345. doi: 10.1093/brain/awab345. PMID: 34529034.

Predicting and characterizing neurodegenerative subtypes with multimodal neurocognitive signatures of social and cognitive processes
Journal of Alzheimer’s Disease

Although social cognition is critically compromised across neurodegenerative disorders (including behavioral variant frontotemporal dementia, bvFTD; Alzheimer’s disease, AD; and Parkinson disease, PD) their power to predict diagnosis subtype and their neuroanatomical signatures (brain atrophy and connectivity) are unclear. This study led by Ibanez Lab tackled these gaps by developing multiple group discriminant function analyses (MDAs) to perform a diagnostic classification analysis using social cognition, cognitive screening (CS), and executive function (EF) measures, and explored which anatomical and functional networks were associated with main predictors. Although all patient groups revealed deficits in social cognition, CS, and EF, the classification approach provided robust discriminatory characterizations. Regarding controls, probabilistic social cognition outcomes provided the best characterization for bvFTD (together with CS) and PD, but not AD (for which CS alone was the best predictor). Within patient groups, the best MDA probabilities scores yielded high classification rates for bvFTD versus PD (98.3% , social cognition), AD versus PD (98.6% , social cognition + CS), and bvFTD versus AD (71.7% , social cognition + CS). Top MDA scores were associated with specific patterns of atrophy and functional networks across neurodegenerative conditions. Thus, standardized validated measures of social cognition, in combination with cognitive screening, can provide a dimensional classification with specific pathophysiological markers of neurodegeneration diagnoses

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You can find the full publication here.


Ibañez A, Fittipaldi S, Trujillo C, Jaramillo T, Torres A, Cardona JF, Rivera R, Slachevsky A, García A, Bertoux M, Baez S. Predicting and Characterizing Neurodegenerative Subtypes with Multimodal Neurocognitive Signatures of Social and Cognitive Processes. J Alzheimers Dis. 2021 Jul 15. doi: 10.3233/JAD-210163. 

Interoception primes emotional Processing at behavioral multimodal neuroimaging levels: Evidence from Neurodegeneration
Journal of Neuroscience

Are external social signals differently appraised by the brain depending on our inner body states?

This study lead by Ibanez Lab evidenced that focusing on internal body states (cardiac interoception) regulates the appraisal of others’ emotions at behavioral, electrophysiological, neuroanatomical, and functional connectivity levels. Moreover, frontotemporal dementia, a condition characterized by socio-emotional impairments, presented convergent and multimodal neurocognitive markers of interoceptive disruption (selective behavioral deficits, abnormal heart evoked potential modulations, insular-cingulate atrophy, and salience network alterations) during emotional processing, in comparisons with Alzheimer’s, Parkinson’s disease and controls. These results support a predictive coding account of interoceptive emotions and a disbalanced allostasis in frontotemporal dementia.

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You can find the full publication here.

 

Salamone PC, Legaz A, Sedeño L, Moguilner S, Fraile-Vazquez M, Campo CG, Fittipaldi S, Yoris A, Miranda M, Birba A, Galiani A, Abrevaya S, Neely A, Caro MM, Alifano F, Villagra R, Anunziata F, Okada de Oliveira M, Pautassi RM, Slachevsky A, Serrano C, García AM, Ibañez A. Interoception Primes Emotional Processing: Multimodal Evidence from Neurodegeneration. J Neurosci. 2021 May 12;41(19):4276-4292. doi: 10.1523/JNEUROSCI.2578-20.2021.

Model-Based Planning Deficits in Compulsivity Are Linked to Faulty Neural Representations of Task Structure
Journal of Neuroscience

Compulsivity is linked to poorer performance on tasks that require model-based planning, but it is unclear what precise mechanisms underlie this deficit. Do compulsive individuals fail to engage cognitive control at the time of choice? Or do they have difficulty in building and maintaining an accurate representation of their environment, the foundation needed to behave in a goal-directed manner? 

This collaboration between the Gillan Lab and O'Connell Lab examined reaction time and EEG measures in 192 individuals who performed a two-step decision-making task. The study found that compulsive individuals are less sensitive to surprising action–state transitions, where they slow down less and show less alpha band suppression following a rare transition. These findings implicate failures in maintaining an accurate model of the world in model-based planning deficits in compulsivity.

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You can find the full publication here.

Seow, T. X., Benoit, E., Dempsey, C., Jennings, M., Maxwell, A., O'Connell, R., & Gillan, C. M. (2021). Model-based planning deficits in compulsivity are linked to faulty neural representations of task structure. Journal of Neuroscience, 41(30), 6539-6550.

The Whelan Lab introduces β-burst volume as a key measure of human inhibition
Journal of Neuroscience

Enz et al. identified a novel neural measure "β-burst volume" that predicts successful response inhibition, which can become impaired during normal aging and in a wide range of psychiatric diseases.

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You can find the full publication here.

Enz, N., Ruddy, K. L., Rueda-Delgado, L. M., & Whelan, R. (2021). Volume of β-Bursts, But Not Their Rate, Predicts Successful Response Inhibition. Journal of Neuroscience, 41(23), 5069-5079.

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