The Mellow Years?: Neural Basis of Improving Emotional Stability over Age Williams et al. (2006) Amir Shams Tabrizi

Introduction Behavioral studies have reported that emotional functions improve with age: -Less negativity -Easing of emotional intensity - Reduction in trait neuroticism Older adults show a shift in the ratio of positive- to-negative emotion - in the experience, memory, and recognition of negative emotion - for positive emotion

Why? Possibilities -Environmental effects, i.e. retirement -Motivational priorities change with age: ‘knowledge acquisition finding emotional satisfaction’

Purpose of Study We know how behavior changes, but how exactly does the brain change? How does brain function/activity change over the lifespan with respect to emotional processing?

Regions of Interest Medial Prefrontal Cortex implicated in governing emotional functions + Sub cortical circuits associated with emotional processing

Materials & Methods Participants: 242 healthy individuals Divided into 4 age bands: Teens (12-19) Young (20-29) Middle (30-49) Older (50-79)

Materials & Methods Behavioral task - Blocks of 8 facial expressions representing: fear (negative emotion) happy (positive) neutral - Brain activity recorded using FMRI + ERP

Materials & Methods FMRI N = 80 Regions of Interest: -Medial Prefrontal cortex -Amygdala -Basal ganglia Functional maps constructed for activated voxels within each ROI for contrasts between ‘fear vs. neutral’ and ‘happiness vs. neutral’

Variables Independent Variable: age Dependent Variable: ROI activation

Results Increasing age = decrease in MPFC response to happiness, but increase in MPFC responses to fear - Brain has to work harder to register fear Happy Fear

Results Linear + significant decline of neuroticism over years of age Older = less accurately recognize fear and more accurately recognize happiness No significant differences in Amygdala + Basal Ganglia activation due to age years = greatest activation for fear and happiness

Discussion How? Step 1 - as age increases, the following things happen: Life experiences accumulate Motivational goals change Become aware of mortality Desire to maximize meaningfulness of events Chose quality over quantity So this causes greater selectivity in perception of positive emotions

Step 2 selectivity for positive emotions in life experiences = selectivity for positive emotions in the underlying medial prefrontal systems - MPFC learns (neural plasticity) from experience Result = better emotional well being

Implications Emotional brain function is one of the few things that improve with age. So it provides a platform to intervene other cognitive impairments

Strengths & Limitations - N = Wide spectrum of lifespan (12-79 years) - Brilliant methods section - Very very detailed and well written - Repetitive results and discussion - Integration of FMRI, RPE, MRI data made discussion very hard to understand