Lecture 7: Olfactory Social Neuroscience (NSBED, UU)

We have this bias that smell is not important to us, probably because we find it hard to name them.

What’s remarkable about the smell brain autonomy?

• There is limbic overlap, which is not surprising since smells can carry emotional value
• Ipsilateral projection
• No thalamic intermediary: the thalamus is processed without thalamic relay
• Feedback to the bulb: top down modulation

We can quickly learn the importance of a smell.

Smell functions:

• Judging whether food is edible
• Avoid environmental hazards
• Social communication

Summary part 1:

• Human sense of smell is better than initually realized
• Share smell skills with outher animals
• Neuroanatomy: limbic (emotion), plastic (learning)
• Social (sommunication) function

Humans seem to smell odors of fear and disgust following an all or nothing principle: they either smell it or they don’t (not quantified).

Damage in the amygdala stops odor-driven behavior, but leaves learned olfactory responses intact.

Summary part 2:

• The smell of fear partially induces fear in a recipient: sender and receiver become on the same page
• It biases perception, physiological and neural responses
• Hardwired neural networks may be involved

Sickness affects your body odor.

There is a distinct network of regions activated when a person smells the body odor of a sick person.

Loss of smell is a better predictor of COVID-19 than fever+cough+shortness of breath.

Our ACE-2 receptors in the nose get infected by Covid-19.

High anxious subjects show a greater startle response to the smell of fear than non-anxious subjects.

ASD patients have more trouble detecting smells.

There have been found negative relations between psychopathic traits and smell ability. Lower smell ability has also been linked to low empathy.

Summary part 3:

• Sickness affects your body odor
• Smell loss is one of the best COVID-19 predictors
• Psychopathology, hormones are related to smell ability
• Trust your nose!

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