Facial Affect Recognition in Bipolar Disorder- fMRI

Facial Affect Recognition in Bipolar Disorder- fMRI

Renee Andrews

5-7-14

Participants

-16 Bipolar I

-8 manic- inpatient

-8 depressed- 1 inpatient

-13 male

-all medicated w/ mood stabilizer and/or antidepressants

-at least 2 episodes of mania and depression

-8 controls (2 male)

-no history

Scanning Process

General Design

Explicit Task

-Young Mania Rating Scale and Hamilton Rating Scale for Depression

-day of scan-> all symptomatic

-Facial expressions: fear, sad, happy

-each presented explicit and implicit tasks

-intensities of emotion:

-0%- neutral

-50%- merged 0% and 100%

-100%- prototypical

-150%- exaggerated 100%

-1 of 4 color tone intensities

-Random neutral faces

-Counterbalanced implicit/explicit tasks across subjects

-8.75 minutes, 3.6-4 sec interval between faces

-Emotional expression

-Rate affective intensity ("How sad?", "How fearful?"- correspond with appropriate face)

-Indicate intensity by button press (4 point scale)

Neurological Understanding of Bipolar

Implicit Task

-Focus on color intensity

-Rate color intensity ("How red/green?"- corresponding color)

-Indicate intensity of coloring by button press (4 point scale)

-Large-scale frontolimbic networks- emergence of manic and depressive sxs

-Medial and ventrolateral PFC reciprocal connection with paralimbic, limbic, and subcortical regions- modulate emotional processing, bodily sensations, and response

-Over-activation of limbic/subcortical structures- emotional reactivity

-Dysfunctional frontal regions- explicit emotional regulation

Methods

and

Materials

Data Analysis

Behavioral Data

-Explicit- averaged ratings over all trials for each emotional type at each intensity for each participant

-Mixed effects ANOVA fit to intensity ratings

-estimate main effect of intensity and diagnostic group (manic/depressed)

-estimate interactive effect of group x intensity on emotional intensity ratings

-No detail about implicit task

fMRI Data

-Corrected or slice timing and head movement

-Anatomical standardization

-Design matrix: coded response to different intensity of facial affect (exclude neutral)

-ANOVA

-main effect of group

-main effect of task

-group by task interaction

-fit with imaging and tested for significance (p<0.005 )

-t-test for significance in regions of significant main effect of group or group x task interaction

What's the point?

Why?

-Compare implicit and explicit facial affect recognition

-Look at depressed AND manic phases

-Consider modulation of valence

What?

Question: How is the neural activity in currently symptomatic depressed and manic patients different from that of healthy subjects when completing both explicit and implicit facial affect recognition tasks with different valence?

Hypothesis: Different patterns of dysfuctional frontolimbic network activation potentially more salient at an implicit level of processing.

Level of Processing and Manic

Patients for Sad Faces

Limitations

Previous Studies

-Sample size

-No gender matching for controls

-Ignored gender differences in recognition traits

-Based on current state, not longitudinal

-No consideration for duration of illness/episode, age of onset, presence/absence of psychosis

-All patients medicated

-effect on BOLD responses seen?

-Patterns of abnormal brain activation can be strongly conditioned by level of explicit attentional engagement in processing emotional stimuli

-Underactivation by implicit processing

-amygdala, insula, superior and middle temporal gyri, hippocampus, dorsal anterior cingulate and medial superior frontal gyrus

-emotional arousal and perception

-emotional regulation

-other studies show underactivation in explicit processing

-Overactivation during implicit processing

-cingulate and superior FC

-Increased sensitivity to affective conflict

-Represents disparity between individual's current mood and perception of emotional external stim

Bipolar vs Unipolar

-depressed- bias toward negative stim

-manic- implicit processing of negative stim

-enhanced activation by +/- emotional expressions in depression phase (very different from unipolar/normal)

General Psychiatric Disorders

-abnormal activation patterns in auto processing of emotional stim (implicit)

Processing facial expressions and emotions

-facial expressions processed outside the focus of attention

-more limbic activation in implicit processing

Main Findings

Behavioral Data

1- Overactivation

-depressed: happy faces

-manic: sad faces

-both: fearful faces

-implicit and explicit tasks

2- Sad faces for manic patients

-modulated by attentional level of processing

-limbic and frontal regions

-implicit: overactivation

-explicit: underactivation

3- Implicit recognition results in higher activation for all emotional types and all groups

-Positive relationship between rating and level of exaggeration

-Main effect of group

-not significant for any emotional type

-sad faces only: marginally significant group x intensity interaction

-Manic- underestimate intensity of sad faces

Results

Discussion

Overactivation

Main effect of Group: Sad Faces

Main takeaways

-depressed: overactive for happy faces

-manic: overactive for sad faces

-both: increased response for fearful faces

-implicit and explicit taks

Other conclusions about/support for bipolar disorder

-existence of abnormal ventromedial PFC function

-abnormal activation of frontal and limbic pathways are key feature

-abnormal thalamic activation

-abnormal activity linked to cortico-striato-thalamic circuit

-bipolar and unipolar depressive syndromes are distinct in neuropsychological testing and functional neuroimaging

-Enhanced activation in manic state compared to healthy and depressed

-left fusiform gyrus

-No significant difference between healthy and depressed

Main effect of Task:

All Faces

So What?

-Enhanced activation with implicit recognition of sad faces

-lingual gyrus, lateral temporal cortex, supramarginal gyrus

-Enhanced activation with implicit recognition of fearful faces

-cerebellar vermis, brainstem, thalamus, caudate

-Enhanced activation with implicit recognition of happy faces

-supramarginal cotex, insula, cingulate gyrus, caudate

fMRI Data

-Supported hypothesis

-Implications for behavioral responses to facial affect stimuli

-Better understanding of overall behavior

-Potential for understanding mood state path

-Timing of swings

-Treatment ahead of time

-Implicit processing is extremely important in bipolar disorder

-Identified key features of biploar disorder

Implicit Tasks for

All Groups

Now What?

Main effect of Group:

Happy Faces

-Studies for predicting mood state switches based on mood-incongruent facial affect

-Longitudinal studies

-Specific differences between activation in bipolar and unipolar patients and other psychiatric disorders

-Gender effects on facial affect recognition

-All groups had increased activity in implicit tasks for all faces

-No overactivation with explicit tasks or limbic overactivation for implicit tasks-> different from

other studies

-Enhanced activation in depressed compared to healthy

-left superior frontal gyrus, bilateral precentral and ventral PFC, middle temporal gyrus, visual cortex, striatum, thalamus, and dorsal and posterior cingulate gyrus

-No significant difference between manic/healthy

Main effect of Group:

Fearful Faces

-Enhanced activation in manic and depressed compared to healthy

-precentral and postcentral gyri, middle temporal gyrus, parahippocampal gyrus, striatum, thalamus, brainstem

-No significant difference between manic and depressed

Group by Task Interaction:

Sad Faces

-Enhanced activation with implicitly recognized sad faces for manic compared to depressed and healthy

-Decreased activation with explicitly recognized sad faces compared to depressed and healthy

-Affected areas:

-amygdala, hippocampus, lateral temporal cortex, medial superior frontal cortex, anterior cingulate cortex

-No significant group x task interactions for fearful/happy