Which bit of our brains do we need to recognise fear, disgust and happiness?
Reviewed by Anna Volkmer

Recognising other people’s emotions is a useful life skill for human interaction in both social and vocational situations. Yet there remains significant debate about which areas of the brain are required to enable us to read and understand these facial expressions in others. Historically there has been discussion in the research literature that attributes this skill to the right hemisphere, yet others who suggest primary emotions such as fear and anger are recognised by the right hemisphere whilst social emotions such as affection and embarrassment are recognised by the left hemisphere. More recently brain scanning techniques have provided more information on the specific areas involved. However, studies using functional imaging can only reveal what areas are engaged, rather than which are critical. Other structural imaging studies have examined people with chronic lesions where functions have perhaps recovered and potentially been adopted by other areas. In this study, the researchers recruited 30 people in the acute phase following a right hemisphere lesion, with MRI scans from within the first 24 hours of their hospital admission. The researchers also recruited 30 control participants to participate in the study. Each participant was presented with 56 photographs of actors expressing one of seven basic emotions:happy; surprise; angry; disgust; fear; sad and neutral. The participants were then asked to identify the emotion label. Results show that people with right hemisphere lesions were significantly less accurate than the control group. In fact, participants with amygdala or anterior insular damage were most impaired on testing, and the degree of the damage in these areas was associated with increased error rate. These types of studies are useful for all clinicians working with individuals with different types of right hemisphere damage. Interventions targeting the recognition of emotions from facial expression are few and far between, yet there is significant scope for the applicability of such therapies for people following stroke, brain injury, dementia and mental health diagnoses. Further investigation examining the potential for people to make improvements through behavioural interventions in this area seems warranted given the significant impact this can have on relationships, mood and quality of life.

Impaired recognition of emotional faces after stroke involving right amygdala or insula.
Tippett DC, Godin BR, Oishi K, et al.
SEMINARS IN SPEECH AND LANGUAGE
2018;39(1):87-99.