Greater Insula Research Articles

Brain mechanisms of rumination and negative self-referential processing in adolescent depression

BackgroundDepression is linked to cognitive biases towards more negative and less positive self-relevant information. Rumination, perseverative negative thinking about the past and the self, may contribute to these biases. Methods159 adolescents (12–18 years), with a range of depression symptoms, completed the SRET during fMRI. Multiple regressions tested associations between conventional self-report and ecological momentary assessment (EMA) measured rumination, and neural and behavioral responses during a self-referent encoding task (SRET). ResultsHigher rumination (conventional self-report and EMA) was associated with more negative and fewer positive words endorsed and recalled. Higher self-reported (but not EMA) rumination was associated with higher accuracy in recognizing negative words and greater insula and dorsal anterior cingulate activity to negative versus positive words. LimitationsThe sample included mostly non-Hispanic White participants with household incomes above the national average, highlighting the need for replication in more diverse samples. Word endorsement discrepancies required fMRI analyses to model neural response to viewing negative versus positive words. ConclusionsAdolescents with higher rumination endorsed and recalled more negative and fewer positive words and recognized more negative words during the SRET. Higher insula reactivity, a key region for modulating externally-oriented attention and internally-oriented self-referential processes, may contribute to links between rumination and negative memory biases. These findings provide insight into neurocognitive mechanisms underlying depression.

Neighborhood Disadvantage and Neural Correlates of Threat and Reward Processing in Survivors of Recent Trauma

Differences in neighborhood socioeconomic characteristics are important considerations in understanding differences in risk vs resilience in mental health. Neighborhood disadvantage is associated with alterations in the function and structure of threat neurocircuitry. To investigate associations of neighborhood disadvantage with white and gray matter and neural reactivity to positive and negative stimuli in the context of trauma exposure. In this cross-sectional study, survivors of trauma who completed sociodemographic and posttraumatic symptom assessments and neuroimaging were recruited as part of the Advancing Understanding of Recovery After Trauma (AURORA) study between September 2017 and June 2021. Data analysis was performed from October 25, 2022, to February 15, 2023. Neighborhood disadvantage was measured with the Area Deprivation Index (ADI) for each participant home address. Participants completed separate threat and reward tasks during functional magnetic resonance imaging. Diffusion-weighted and high-resolution structural images were also collected. Linear models assessed the association of ADI with reactivity, microstructure, and macrostructure of a priori regions of interest after adjusting for income, lifetime trauma, sex at birth, and age. A moderated-mediation model tested whether ADI was associated with neural activity via microstructural changes and if this was modulated by PTSD symptoms. A total of 280 participants (183 females [65.4%]; mean [SD] age, 35.39 [13.29] years) completed the threat task and 244 participants (156 females [63.9%]; mean [SD] age, 35.10 [13.26] years) completed the reward task. Higher ADI (per 1-unit increase) was associated with greater insula (t274 = 3.20; β = 0.20; corrected P = .008) and anterior cingulate cortex (ACC; t274 = 2.56; β = 0.16; corrected P = .04) threat-related activity after considering covariates, but ADI was not associated with reward reactivity. Greater disadvantage was also associated with altered microstructure of the cingulum bundle (t274 = 3.48; β = 0.21; corrected P = .001) and gray matter morphology of the ACC (cortical thickness: t273 = -2.29; β = -0.13; corrected P = .02; surface area: t273 = 2.53; β = 0.13; corrected P = .02). The moderated-mediation model revealed that ADI was associated with ACC threat reactivity via cingulum microstructural changes (index of moderated mediation = -0.02). However, this mediation was only present in individuals with greater PTSD symptom severity (at the mean: β = -0.17; standard error = 0.06, t= -2.28; P = .007; at 1 SD above the mean: β = -0.28; standard error = 0.08; t = -3.35; P < .001). In this study, neighborhood disadvantage was associated with neurobiology that supports threat processing, revealing associations of neighborhood disadvantage with neural susceptibility for PTSD and suggesting how altered structure-function associations may complicate symptoms. Future work should investigate specific components of neighborhood disadvantage that may be associated with these outcomes.

A pilot study investigating changes in neural processing after mindfulness training in elite athletes

The ability to pay close attention to the present moment can be a crucial factor for performing well in a competitive situation. Training mindfulness is one approach to potentially improve elite athletes’ ability to focus their attention on the present moment. However, virtually nothing is known about whether these types of interventions alter neural systems that are important for optimal performance. This pilot study examined whether an intervention aimed at improving mindfulness [Mindful Performance Enhancement, Awareness and Knowledge (mPEAK)] changes neural activation patterns during an interoceptive challenge. Participants completed a task involving anticipation and experience of loaded breathing during functional magnetic resonance imaging recording. There were five main results following mPEAK training: (1) elite athletes self-reported higher levels of interoceptive awareness and mindfulness and lower levels of alexithymia; (2) greater insula and anterior cingulate cortex (ACC) activation during anticipation and post-breathing load conditions; (3) increased ACC activation during the anticipation condition was associated with increased scores on the describing subscale of the Five Facet Mindfulness Questionnaire; (4) increased insula activation during the post-load condition was associated with decreases in the Toronto Alexithymia Scale identifying feelings subscale; (5) decreased resting state functional connectivity between the PCC and the right medial frontal cortex and the ACC. Taken together, this pilot study suggests that mPEAK training may lead to increased attention to bodily signals and greater neural processing during the anticipation and recovery from interoceptive perturbations. This association between attention to and processing of interoceptive afferents may result in greater adaptation during stressful situations in elite athletes.

Serotonin transporter gene alters insula activity to threat in social anxiety disorder

Amygdala and insula hyper-reactivity to threat is implicated in social anxiety disorder (SAD) yet inconsistencies in activation have been reported. One source of variance are individual differences in 5-HTTLPR genotype where the short (S), relative to long (L) allele, corresponds with greater amygdala activation. However, the impact of genotype on insula to threat in SAD is not known. During functional MRI, 34 SAD patients and 28 healthy controls completed a perceptual assessment task comprising angry, fear, and happy faces. Results showed no diagnostic group differences in limbic/paralimbic regions but within SAD, greater insula, but not amygdala, activation to fearful faces was observed in patients with SS genotype compared with LaLa genotype. Findings indicate genotype influenced insula activation to threat in SAD.