The Amygdala and Facial Expression PSYC275: Neuroanatomy Amy Couture-Rizzo April 21, 2005

The Amygdala

The Amygdala

The Amygdala

The Amygdala Motivation Motivation Memory Memory Emotional behavior Emotional behavior Instinctive and acquired Instinctive and acquired Mediates conscious and unconscious emotional responses Mediates conscious and unconscious emotional responses Fear responses and pleasure Fear responses and pleasure Anxiety, autism, narcolepsy, depression, phobias and PTSD are all suspected of being linked to malfunctions of the amygdala Anxiety, autism, narcolepsy, depression, phobias and PTSD are all suspected of being linked to malfunctions of the amygdala

Amygdala Damage Impairs Emotion Recognition from Scenes Only when they Contain Facial Expressions Ralph Adolphs and Daniel Tranel Neuropsychologia 41 (2003) 1281–1289

Main Findings “Bilateral amygdala damage impairs recognition of negative emotions from facial expressions” (p. 1287). “Bilateral amygdala damage impairs recognition of negative emotions from facial expressions” (p. 1287). “Bilateral amygdala damage does not in general impair recognition of emotions from complex static visual stimuli, provided those stimuli contain cues in addition to facial expression” (p. 1287). “Bilateral amygdala damage does not in general impair recognition of emotions from complex static visual stimuli, provided those stimuli contain cues in addition to facial expression” (p. 1287). “When facial expressions of anger are present, the introduce cues that subjects with bilateral amygdala damage mistake for incorrect emotions” (p. 1288). “When facial expressions of anger are present, the introduce cues that subjects with bilateral amygdala damage mistake for incorrect emotions” (p. 1288).

fMRIs

The Amygdala Processes the Emotional Significance of Facial Expressions: An fMRI Investigation Using the Interaction between Expression and Face Direction Wataru Sato, Sakiko Yoshikawa, Takanori Kochiyama, and Michikazu Matsumura NeuroImage 22 (2004) 1006– 1013

Main Findings “Activity in the amygdala showed the interaction between emotional expression and face direction, indicating higher activation for angry expressions looking toward the subject than angry expressions looking away from the subject” (p. 1011). “A positive relation was found between the amygdala activity and experienced emotion” (p. 1011). “The amygdala is involved in emotional but not visuoperceptual processing for emotional facial expressions, which specifically includes the decoding of emotional significance and elicitation of one’s own emotions corresponding to that significance” (p. 1011).

Differential Amygdala Responses to Happy and Fearful Facial Expressions Depend on Selective Attention Mark A. Williams, Francis McGlone, David F. Abbott, and Jason B. Mattingley NeuroImage 24 (2005) 417– 425

Fig. 3. BOLD signal change in the amygdala overlaid on MNI template sections. (a) Bilateral amygdala activity to happy faces in the attend face versus attend house condition. (b) Mean activity for runs containing happy faces plotted separately for attend face and attend house conditions within clusters revealed in a, showing an increase in amygdala activity when participants attended to the faces.

Fig. 3. BOLD signal change in the amygdala overlaid on MNI template sections. (. (c) Unilateral amygdala activity to fearful faces when participants attended to the houses compared to the faces. (d) Mean activity for runs containing fearful faces plotted separately for attend face and attend house conditions within clusters revealed in c, showing an increase in amygdala activity to fearful faces when participants attended to the houses.

Main Findings “The influence of selective attention on amygdala activity depended on the valence of the facial expression. Threatening stimuli (fearful faces) that were actively ignored resulted in a significant increase in amygdala activity, whereas nonthreatening stimuli (happy faces) that were ignored resulted in a significant decrease in amygdala activity, relative to conditions in which the face was attended. Thus, activity in the amygdala seems to depend on both the current focus of attention and the emotion portrayed by the face. These results are broadly consistent with the proposed role of the amygdala as a warning system (LeDoux, 2000). On this view the amygdala is likely to be most important when an individual is either unaware of a potential threat or is actively ignoring such a threat” (p. 424).

Human Amygdala Responses to Fearful Eyes J. S. Morris, M. deBonis, and R. J. Dolan NeuroImage 17, 214–222 (2002)

FIG. 1. (a) Prototypical and chimerical faces. FF and NN are prototypical faces, fearful and neutral, respectively. FN is a chimerical face in which the upper half (eyes) is derived from the fearful prototype and the lower half (mouth) from the neutral prototype. NF is a chimerical face with neutral upper half and fearful lower half.

Main Findings “Fearful eyes alone are sufficient to evoke increased neural responses in human amygdala” (p. 219). “The specifically increased response to FF faces (relative to FN faces) in left anterior amygdala suggests that this region is sensitive to the configural conjunction of fearful eye and fearful mouth” (p. 219). “Simple, context-independent responses to fearful eyes were observed in right amygdala, superior colliculus, and pulvinar” (p. 219).

The Dynamics of Cortico-Amygdala and Autonomic Activity over the Experimental Time Course of Fear Perception Leanne M. Williams, Kerri J. Brown, Pritha Das, Wolfram Boucsein, Evgeni N Sokolov, Michael J. Brammer, Gloria Olivieri, Anthony Peduto, and Evian Gordon Cognitive Brain Research 21 (2004) 114– 123

Main Findings “Persistence of amygdala engagement across repeated trials” (p. 119). “The persistence of SCRs and amygdala activity might reflect a sustained form of emotional ‘priming’ for complex or cognitively interpreted fear signals” (p.121). “The left amygdala in particular may subserve the maintenance of vigilance to threat signals” (p.121).

Activity in the Human Brain Predicting Differential Heart Rate Responses to Emotional Facial Expressions Hugo D. Critchley, Pia Rotshtein, Yoko Nagai,d John O’Doherty,aChristopher J. Mathias, and Raymond J. Dolan NeuroImage 24 (2005) 751– 762

Fig. 1. Experimental design and cardiac responses. A) Subjects performed 80 trials of an emotional forewarned reaction time task. Each trial began with a 1-s presentation of a face stimulus depicting a happy, sad, angry, or disgusted facial expression. The subject maintained fixation over an ensuing 7-s interval then made a cued four-choice, reaction-time, buttonpress judgement of the facial emotion. There then followed a variable intertrial interval of mean duration 7.5 s. This trial procedure is associated with and orienting cardiac acceleration to the emotional face, followed by cardiac deceleration in anticipation of the cued motor response. The figure illustrates diagrammatically an experimental trial and, beneath this, average heart rate responses (interpolated pulse oximetry data, zeroed at trial onset) of one subject during trials judged to depict happy (black), sad (blue), angry (red), and disgusted (green) facial expressions. This color convention is used in other figures.

Fig. 1. Experimental design and cardiac responses. (B) The peak heart rate in the first 4 s of each trial, relative to the trial onset, was computed and used in the analyses of functional imaging data. Across subjects, different emotional judgements were associated with different magnitude of heart rate increase. Compared to the average response, facial expressions judged as happy or disgusted were associated with a relative blunting of heart rate, whereas there was a relative increase in heart rate increase evoked by sad and angry facial expressions. Error responses (where there was a face wrongly categorized, depicted in gray) also produced a relative enhancement of heart rate increase. Group data in the evoked change in heart rate (mean F SE) are shown, representing changes from an average heart rate of 66.1 beats per minute across subjects (range 54–76 beats per minute).

Main Findings “Amygdala activity predicted heart rate increases… evoked by face stimuli within each category of emotion. However, sad and angry expressions elicited on average greater heart rate increases than happy and disgusted facial expressions. In this regard, a greater amygdala response will be seen to sad and angry, compared to happy and disgusted,expressions.” (p. 757).

In Summary Damage to the amygdala impairs effective detection of emotion from facial expression. Damage to the amygdala impairs effective detection of emotion from facial expression. The amygdala is involved in the processing of facial expressions for emotional content. The amygdala is involved in the processing of facial expressions for emotional content. In judging fear expressions, the amygdala may serve as a warning system of a dangerous stimulus. In judging fear expressions, the amygdala may serve as a warning system of a dangerous stimulus. Fearful eyes are enough to activate the amygdala. Fearful eyes are enough to activate the amygdala. The amygdala also is predictive of visceral and autonomic reactions of the body in response to facial expression. The amygdala also is predictive of visceral and autonomic reactions of the body in response to facial expression.