Sex differences in the neural correlates of emotional responses and episodic memory encoding for positive and negative emotional stimuli Pubblico

Abstract

Evidence from both cognitive and clinical psychology literatures suggests that women and men differ in emotional functioning. Women show greater emotional responses than men in expression and physiological activation, and are more likely than men to be diagnosed with disorders involving emotion, such as depression, anxiety, and PTSD. The goal of the current research was to characterize differences in how women and men respond to emotional stimuli, at the neural level. This issue is critical to understanding basic individual differences in human mental health and in emotion more generally. We conducted three studies: Study 1 was a meta-analysis of neuroimaging studies of emotion in women and men, Study 2 was a neuroimaging experiment investigating sex differences in responses to emotionally-arousing visual stimuli, and Study 3 was a neuroimaging experiment investigating how sex differences in emotional brain regions might influence episodic memory. The meta-analysis combined the results of studies which explicitly examined sex differences with the much larger number of studies that examined only women or men, using activation likelihood estimation (ALE). For studies of negative emotion, women showed greater activation of the amygdala than men. For studies of positive emotion, men showed greater activation of the amygdala than women. The findings provided novel evidence that sex differences depend on affective valence. In study 2, we replicated the finding that women showed greater amygdala responses to negative stimuli, and found greater hypothalamus responses to positive stimuli in men than women. In addition, women showed greater functional connectivity than men between the amygdala and anterior cingulate cortex, a circuit involved in emotion regulation. Men showed greater functional connectivity than women between the amygdala and nucleus accumbens, a circuit involved in reinforcement learning and appetitive motivation. In study 3, we found that the amygdala plays a greater role in encoding emotional stimuli in women than men, and that functional connectivity between the amygdala and hippocampus during encoding was predictive of later memory in women but not men. Findings provide converging evidence for important differences in women's and men's brain processing of emotional stimuli, and highlight the need for greater consideration of gender in the study of emotion.

Table of Contents

Chapter 1, Introduction
1.1 The emotional brain 5
1.2 Sex differences in brain structure 6
1.3 Sex differences in emotion-related brain function 7
1.4 Sex differences in amygdala responses to emotional stimuli 9

1.5 Sex differences in emotional processing networks 11

1.6 Sex-specific hemispheric asymmetry in amygdala contribution to episodic encoding 12

1.7 Hypotheses 12

1.8 References 14

Chapter 2, Sex differences in brain activation to emotional stimuli: A meta-analysis of neuroimaging studies

2.1 Abstract 29
2.2 Introduction 31
2.3 Methods 33
2.4 Results 44
2.5 Discussion 55
2.6 Conclusions 67
2.7 References 69

Chapter 3, Sex differences in neural activity and amygdala connectivity associated with emotion processing

3.1 Abstract 76
3.2 Introduction 77
3.3 Methods 79
3.4 Results 83
3.5 Discussion 103
3.6 References 108

Chapter 4, Sex influences the role of the amygdala in memory for positive and negative stimuli

4.1 Abstract 114
4.2 Introduction 115
4.3 Method 117
4.4 Results 124
4.5 Discussion 131
4.6 References 138

Chapter 5, General Discussion

5.1 Relations between the findings of the meta-analysis and the neuroimaging studies 144
5.2 Future directions 146
5.3 Clinical implications 148
5.4 Conclusions 148
5.5 References 150

About this Dissertation

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School	Laney Graduate School
Department	Psychology
Degree	PhD
Submission	Dissertation
Language	English
Research Field	Psychology, General Psychology, Physiological Psychology, Cognitive
Parola chiave	gender differences fMRI emotion amygdala sex differences
Committee Chair / Thesis Advisor	Hamann, Stephan, Emory University
Committee Members	Wallen, Kim, Emory University Barsalou, Lawrence, Emory University Bauer, Patricia, Emory University Rilling, James K, Emory University

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