Lit Review: A RELATIONSHIP BETWEEN SMELL IDENTIFICATION AND EMPATHY

Authors: Spinella, Marcello1
Source: International Journal of Neuroscience; June 2002, Vol. 112 Issue: Number 6 p605-612, 8p
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Olfaction is achemical sense that has powerful relationships with " emotion " . The central olfactory system has projections to limbic and paralimbic structures, including pyriform cortex, mediodorsal thalamus, the basolateral amygdala, laterral hypothalamus, and orbitofrontal cortex.

Orbitofrontal cortex is activated during olfactory identification tasks, and smell tests are used to demonstrate anosmia in people with orbitofrontral dysfunction. Orbitofrontal cortex may be more strongly activated ipsilaterally, depending on the nostril presented and hedonic value of the odor. Given this extensive limbic representation of olfaction, it is not surprising that olfaction related to mood and some personality characteristics.

Empathy is defined as a vicarious feeling of others' emotional states. It serves as a strong motivator for prosocial behavior and is seen as a important component for appropriate moral development. The emotion component of empathy, in contrast, involves emotional and visceral experiance in response to another's state, or feeling another's emotions.
Although orbitofrontal cortex has been the focus of the neuroanatomical substrate of empathy, it has neuroanatomical connections and close functional relationships with other limbic structures such as basolateral amygdala and mediodorsal thalamus. Thus, it is likely that these sense structures plar some role in empathy as well. For example, an analysis of cases of frontotemporal dementia suggests tht dysfunction of right anterior temporal cortex causes a decrease in empathy. Given the common neuroanatomical regions subserving olfaction, emotion and empathy, it was hypothesized that there is a relationship between on smell tests and rating of empathy.

Alberta Smell Test
The Alberta Smell test (AST) is a measure of olfactory identification. It employs eight scented markers as stimuli, presented monorhinally and blind to the subject. Subjects are presented with a list of the eight possible scents from which to choose. The makersare capped between uses and retain their scent well across multiple uses. The results also indicate that right-sides smell identification and smell improvement correlate with empathy measures better than left-sided smell measures. Another finding in this study is the correlation between the emotion aspect of empathy with smell measures, but not the cognitive aspect. The cognitive component of empathy concerns comprehending another's emotional state, more so than " feeling " their emotional state.
This study is the first to demonstrate a relationship between empathy and smell in normal subjects. It is suggested that the reason for the relationship between these two seemingly disparate functions is a consequence of their common neuroanatomical substrates.