Research Spotlights: November 2021

Development of brain’s emotion circuitry is altered by early-life abuse

Childhood abuse is a major contributor to the development of psychopathology, but the impact of abuse on particular brain circuit development and its combined contribution to later psychopathology is not well known. In a study funded by NIMH, NCATS, NSF, and other funders, researchers found that girls who experienced childhood abuse had altered brain development patterns depending on whether they developed psychiatric symptoms later in life.

Researchers examined 234 girls (ages 8-18) for their maltreatment histories and presence of psychiatric symptoms. Girls were identified as “typically developing” (no abuse nor psychiatric symptoms), “resilient” (abuse history with no psychiatric symptoms), or “susceptible” (abuse history with psychiatric symptoms). The girls had MRI brain scans to determine the level of maturation across all brain structures, brain circuits involved in emotion, and brain circuits involved in language. Brain age gap estimations (BrainAGEs; predicted age minus true chronological age) were calculated for each brain circuit as a measure of its maturation compared to other similarly aged girls.

Girls who experienced physical neglect had advanced maturation across all brain structures, regardless of whether they demonstrated psychiatric symptoms. Conversely, girls that had experienced childhood abuse had delayed maturation specifically of the brain circuity associated with emotion, regardless of whether they were resilient or susceptible to psychiatric symptoms. Girls that were not demonstrating psychiatric symptoms (“resilient”) showed altered brain activity in the fronto-parietal cortex and hippocampus which are critical brain regions for emotion regulation. Girls with delayed maturation of the emotion circuitry were also more likely to have hyperarousal symptoms that are common in anxiety disorders and post-traumatic stress disorder.

The researchers hypothesized that the acceleration of brain wide circuitry development may be related to a lack of stimuli associated with social and emotional processes during the period of neglect and that the delay in structural maturation of emotion circuits in abused girls may initially be adaptive in response to a threat. However, chronic hyperarousal can lead to long-lasting psychopathology. By better understanding the impact of adversity on the maturation of brain circuitry, testing and treatment strategies can be better targeted to compensate for atypical brain development.

Keding TJ, Heyn SA, Russell, JD, Zhu X, Cisler J, McLaughlin KA, Herringa RJ. Differential Patterns of Delayed Emotion Circuit Maturation in Abused Girls With and Without Internalizing Psychopathology. Am J Psychiatry. 2021; doi: 10.1176/appi.ajp.2021.20081192.

Promoting physical exercise by applying engineering tools to personalize fitness tracker messages

Is it possible to create a personalized approach to health messaging that will promote more physical activity based on individual (or person-specific) behavior? Sponsored by the NHLBI and the NSF, a recent study tested this question by studying physical activity of 45 young adults in response to a variety of messaging approaches. The novelty of this paper is that the researchers were able to evaluate new mathematical models of human behavior through controlled system engineering tools to design feedback based on the current state of the individual. With accumulating data feedback, the model determined the best time to send a message to impact physical activity.

Participants wore an activity monitor that recorded step counts and heart rate, and the data were sent to the researchers. Additionally, geo-location services in the participants smartphone were used to collect data on local weather indices, time, and location where participants received the message. Researchers focused on the timing, frequency, and context of the messaging – known as correct dosing - in order to identify the best time, point to send a message to ensure that the message was not a distraction and impacted physical activity. By individualizing the messaging, the researchers were able to deliver precision behavioral medicine.

In conclusion, although the mathematical models were not able to perfectly predict behavior, the researchers found that as more data is gathered across new environments and experiences, prediction algorithms will continue to improve.

Hojjatinia S, Hojjatinia S, Lagoa CM, Brunke-Reese D, Conroy DE. Person-specific dose-finding for a digital messaging intervention to promote physical activity. Health Psychol. 2021 Aug;40(8):502-512. doi: 10.1037/hea0001117. PMID: 34618498; PMCID: PMC8514055.

Certain personality traits linked to Alzheimer’s disease risk

In a recently published research, researchers supported by the NIA found that changes in the brain associated with Alzheimer's disease (AD) are correlated with an individuals’ personality traits. In this study, the researcher looked at the underlying neuropathological changes in the brain and examined how these changes were related to personality traits prior to any clinical diagnosis of dementia. Based on previous research, they focused on two personality traits previously linked to the risk of dementia: neuroticism, which measures a predisposition for negative emotions, and conscientiousness, which measures the tendency to be responsible, careful, and goal oriented.

The study used data from the Baltimore Longitudinal Study of Aging (BLSA) and combined it with previously published research in a meta-analysis that summarized 12 studies on personality and AD neuropathology. Combined, these studies included over 3,000 participants, which allows for a more robust estimation of associations between personality and neuropathology than the typical individual study. Results from both the BLSA and meta-analysis showed an association between increased amyloid and tau deposits, a biological indicator of AD, in participants who scored higher in neuroticism and lower in conscientiousness. Additionally, these associations found in people experiencing cognitive deficits were even stronger in studies of people experiencing normal cognition, indicating that the personality traits preceded the disease state instead of being an effect of altered cognition.

These findings suggest that certain personality traits, low neuroticism, and high conscientiousness, may help protect against AD and other neurological diseases by delaying or preventing the emergence of neuropathology. This effect could be due to certain personalities being linked to healthier lifestyles and behaviors, such as high conscientiousness being linked to more physical activity and low neuroticism being linked with better stress management techniques. Over the lifespan, more adaptive personality traits may support better metabolic and immunological functions, consequentially preventing or delaying neurodegenerative process.

In conclusion, this study shows that even before clinical dementia, personality traits can predict the likelihood for the accumulation of pathology associated with dementia. There are limitations to this study, including the study samples coming from across four different high-income countries, with overall higher educational attainment, so studies need to be extended to populations and areas that are at higher-risk, lower-resourced, and will need to be replicated in a prospective longitudinal study. However, these results from the meta-study expands on the current knowledge of the associations between personality and dementia risks.

Terracciano A, Bilgel M, Aschwanden D, Luchetti M, Stephan Y, Moghekar AR, Wong DF, Ferrucci L, Sutin AR, Resnick SM. Personality Associations with Amyloid and Tau: Results From the Baltimore Longitudinal Study of Aging and Meta-analysis. Biol Psychiatry. 2021 Sep 3:S0006-3223(21)01566-3. doi: 10.1016/j.biopsych.2021.08.021. Epub ahead of print. PMID: 34663503.