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 positiveto-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
12-79 years of age
Older = less accurately recognize fear and
more accurately recognize happiness
No significant differences in Amygdala + Basal
Ganglia activation due to age
- 20-29 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 = 242
- 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