Brain Lesions That Disrupt Understanding Another's Emotions
Brain Lesions That Disrupt Understanding Another's Emotions
Functional imaging studies have typically revealed temporal pole activation in association with 'mentalizing' or cognitive perspective taking (Meyer et al., 2013). However, voxel-based morphometry studies of behavioural variant FTD, a neurodegenerative disease that is manifest primarily by changes in comportment and social behaviour (Rascovsky et al., 2011) reveals a specific role of right temporal pole in emotional empathy—both in emotional contagion and affective perspective-taking. Emotional empathy has been reported to be more impaired in patients with behavioural variant FTD than in other dementias (Rankin et al., 2005). Voxel-based morphometry allows identification of structure–function relationships by determining the correlation between volumes of grey matter (loss) in particular areas and performance on behaviours that depend on those areas. Rankin et al. (2006) carried out a voxel-based morphometry study of 123 patients with Alzheimer's disease, progressive supranuclear palsy, corticobasal degeneration, and FTD using caregivers' ratings on the IRI (Davis, 1983) to evaluate empathy. They found that impairments in empathy measured by the sum of empathetic concern (reflecting emotional contagion) and perspective-taking significantly correlated with the volume of grey matter right temporal pole, fusiform gyrus and medial inferior frontal region. The empathetic concern subscale alone correlated with volume of grey matter in the right temporal pole, caudate/subcallosal gyrus and inferior frontal gyrus; whereas perspective-taking correlated with atrophy in the right temporal pole, right and posterior fusiform, and right caudate/subcallosal gyrus. Therefore, the right temporal pole might be critical for both emotional contagion and affective perspective-taking, or integrating the two, or it might have a more general role in representing social concepts, which enables one to understand the emotions of others in a social interaction. For, in the example of David hearing about Catherine at the restaurant, to recognize David's anger or jealousy, one would have to have access to social representations of tact, honour, and so on. A specific role of the superior right temporal pole in representing social concepts has been demonstrated both with functional imaging study of healthy control subjects (Zahn et al., 2007) and in a PET study of individuals with frontotemporal lobar degeneration (Zahn et al., 2009). In the latter study, hypometabolism in right superior segment of anterior temporal cortex (Brodmann areas 38 and 22) was associated with impairment in understanding social concepts or traits (e.g. loyal, tactless, and honourable) relative to animal concepts or traits (e.g. trainable, useful, and nutritious).
Case studies Two patients with FTD had impaired empathy measured by caregiver ratings on the IRI and impaired recognition of emotions through prosody and facial expression, associated with right temporal pole atrophy (Perry et al., 2001). A detailed report (Narvid et al., 2009) revealed a significant impairment in emotional comprehension and contagion, perspective-taking, and attribution of intentions despite generally preserved cognitive abilities associated with right and medial orbital frontal and anterior temporal regions, but sparing of dorsolateral frontal cortex.
Group study The area most strongly associated with acute stroke among 27 patients in the Leigh et al. (2013) study described earlier was the right temporal pole. All six patients with right temporal pole lesions had impaired empathy. There was also a significant correlation between the volume of lesion in the right temporal pole and the percentage of errors on the affective perspective-taking task.
Evidence from voxel-based morphometry in focal neurodegenerative disease and one recent focal lesion study together indicate that right anterior temporal cortex likely plays a critical role in emotional empathy. It either has a role in both emotional contagion and affective perspective taking or a more general process, such as representing social concepts (Zahn et al., 2007, 2009).
Right Temporal Pole
Functional imaging studies have typically revealed temporal pole activation in association with 'mentalizing' or cognitive perspective taking (Meyer et al., 2013). However, voxel-based morphometry studies of behavioural variant FTD, a neurodegenerative disease that is manifest primarily by changes in comportment and social behaviour (Rascovsky et al., 2011) reveals a specific role of right temporal pole in emotional empathy—both in emotional contagion and affective perspective-taking. Emotional empathy has been reported to be more impaired in patients with behavioural variant FTD than in other dementias (Rankin et al., 2005). Voxel-based morphometry allows identification of structure–function relationships by determining the correlation between volumes of grey matter (loss) in particular areas and performance on behaviours that depend on those areas. Rankin et al. (2006) carried out a voxel-based morphometry study of 123 patients with Alzheimer's disease, progressive supranuclear palsy, corticobasal degeneration, and FTD using caregivers' ratings on the IRI (Davis, 1983) to evaluate empathy. They found that impairments in empathy measured by the sum of empathetic concern (reflecting emotional contagion) and perspective-taking significantly correlated with the volume of grey matter right temporal pole, fusiform gyrus and medial inferior frontal region. The empathetic concern subscale alone correlated with volume of grey matter in the right temporal pole, caudate/subcallosal gyrus and inferior frontal gyrus; whereas perspective-taking correlated with atrophy in the right temporal pole, right and posterior fusiform, and right caudate/subcallosal gyrus. Therefore, the right temporal pole might be critical for both emotional contagion and affective perspective-taking, or integrating the two, or it might have a more general role in representing social concepts, which enables one to understand the emotions of others in a social interaction. For, in the example of David hearing about Catherine at the restaurant, to recognize David's anger or jealousy, one would have to have access to social representations of tact, honour, and so on. A specific role of the superior right temporal pole in representing social concepts has been demonstrated both with functional imaging study of healthy control subjects (Zahn et al., 2007) and in a PET study of individuals with frontotemporal lobar degeneration (Zahn et al., 2009). In the latter study, hypometabolism in right superior segment of anterior temporal cortex (Brodmann areas 38 and 22) was associated with impairment in understanding social concepts or traits (e.g. loyal, tactless, and honourable) relative to animal concepts or traits (e.g. trainable, useful, and nutritious).
Focal Lesions of Right Temporal Pole
Case studies Two patients with FTD had impaired empathy measured by caregiver ratings on the IRI and impaired recognition of emotions through prosody and facial expression, associated with right temporal pole atrophy (Perry et al., 2001). A detailed report (Narvid et al., 2009) revealed a significant impairment in emotional comprehension and contagion, perspective-taking, and attribution of intentions despite generally preserved cognitive abilities associated with right and medial orbital frontal and anterior temporal regions, but sparing of dorsolateral frontal cortex.
Group study The area most strongly associated with acute stroke among 27 patients in the Leigh et al. (2013) study described earlier was the right temporal pole. All six patients with right temporal pole lesions had impaired empathy. There was also a significant correlation between the volume of lesion in the right temporal pole and the percentage of errors on the affective perspective-taking task.
Summary
Evidence from voxel-based morphometry in focal neurodegenerative disease and one recent focal lesion study together indicate that right anterior temporal cortex likely plays a critical role in emotional empathy. It either has a role in both emotional contagion and affective perspective taking or a more general process, such as representing social concepts (Zahn et al., 2007, 2009).
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