The relationship between neuropsychological characteristics and emotional expressivity in mood- congruent attention bias

Abstract

Dispositional (self-reported) and objective (facial-display) emotional expressivity typically corresponds in healthy populations, however it remains unclear if this agreement holds in the context of emotion dysregulation and/or Chinese culture. Aberrant emotional expressivity is a hallmark signature of depression, clarifying the conceptual correspondence between expressivity facets may therefore organise similarities and differences in the literature. Study 1 (Chapter 2) adopted a proof-of-concept approach to examine the relationship between dispositional and facial expressivity, through the lens of self-reported depressive symptom severity (Study 1A, N = 100), and resting-state fMRI connectivity (Study 1B, N = 32). While dispositional expressive suppression (assessed by Emotion Regulation Questionnaire; Gross & John, 2003) was associated with intensity difference of selective facial muscles between expressions, their relationship was contingent upon emotional valence (sad/anxious vs. happy) of facial expressions, more prominently at higher depressive somatic symptoms and neural metastability of the sensorimotor network (SMN), highlighting the two emotional expressivity facets as conceptually related but unique in nature.

Emotional expressive alterations often coincide with attentional deficits, both of which have been linked to impairments with cognitive resources. Since mood-congruent attention bias represents a leading cognitive-affective vulnerability for depression, exploring the expressivity-attention bias connection may thus inform emotional expressive changes as a meaningful marker of depressive risk in non-clinical populations. Considering the unique conceptual properties of dispositional and observed expressivity, their contributions to attention bias were respectively investigated in Study 2 (Chapter 3, N = 46) and Study 3 (Chapter 4, N = 32), wherein both expressivity facets predisposed sad mood and attentional bias towards negative over positive stimuli, these relationships were strengthened by depressive somatic severity (Study 2; Study 3), moderate-to-higher resting-state synchrony and static connectivity globally (Study 2) and within SMN (Study 3, wherein SMN connectivity also concurred with fearful vs. neutral/happy facial expressiveness).

Provided the heterogenous nature of depressive vulnerability, Study 3 further elucidated the neuropsychological interplay between emotional expressivity and attention bias, by proposing three conceptual models with distinct combinations of neural, depressive, dispositional and facial expressive bases. Final models were of slightly different compositions than proposed, respectively comprising neuropsychological (Model 1), facial expressive (2), and facial expressive + neural underpinnings (3). Moreover, dispositional and observed expressivity did not co-exist in the same model, again substantiating their conceptual independence. Building upon incidental sex differences in facial emotions and neural connectivity found in Study 1A and Study 2, model analyses were repeated varying sex as covariate. Results yielded salient sex effects with neural synchrony-based models, and relatively sex-invariant observations with static connectivity- and facial expressivity-based models.

Overall, thesis results disentangled the interrelated yet distinctive relationship between dispositional and observed expressivity in the affective dysregulation context, and facilitated understanding of the associated neuropsychological mechanisms and sex/cultural profiles underlying mood-congruent attention bias. This thesis emphasises the need to recognise self-perceived and facial changes in expressivity as integral but separate markers of mood disturbance, and that depression heterogeneity lies not only in the regulation but also expression of (negative vs. non-negative) emotions, with implications to improve depression screening and intervention initiatives.