People may be literally led by their noses | Science News for Students

People may be literally led by their noses

A new study suggests senses of smell and navigation are linked in the brain
Nov 21, 2018 — 6:45 am EST
An artists interpretation of a person smelling and directions (arrows) in their brain

The brain tangles up senses of smell and direction, a new study suggests.

E. Otwell

Our sense of smell and sense of navigation are linked in our brains, a new study suggests. If true, we may truly be led by our noses.

Louisa Dahmani is a neuroscientist — someone who studies the brain. She works for Harvard University in Cambridge, Mass. Her team asked 57 young people to navigate through a virtual town on a computer screen. Afterward, each person was tested on how to get from one spot to another.

The researchers also tested each person’s smelling abilities. Participants sniffed one of 40 fragrant felt-tip pens. Then they had to match that smell to one of four words shown on a screen. These two tasks might have seemed unrelated. But the team found that the best smellers were also the best navigators.

Scientists linked both skills to certain spots in the brain. The left orbitofrontal (OR-bit-oh-FRUNT-ul) cortex and the right hippocampus (Hip-oh-KAMP-us) were both bigger in the better smellers and better navigators. The orbitofrontal cortex has been tied to smelling. The hippocampus is known to be involved in both our sense of smell and in navigation.

The researchers separately studied nine people who had damaged orbitofrontal cortices (KOR-tih-sees). Those people had more trouble with navigation and with identifying smells, the team found. The researchers shared their findings October 16 in Nature Communications. Dahmani did the work while at McGill University. That’s in Montreal, Canada.

A sense of smell may have evolved to help people find their way around. This idea is called the olfactory (Oal-FAK-tor-ee) spatial hypothesis. More specific aspects of smell, such as how good people are at detecting faint whiffs, might also be tied to navigation, the researchers suggest.

Power Words

(more about Power Words)

cortex     The outermost layer of neural tissue of the brain.

hippocampus     (pl. hippocampi) A seahorse-shaped region of the brain. It is thought to be the center of emotion, memory and the involuntary nervous system.

hypothesis     (v. hypothesize) A proposed explanation for a phenomenon. In science, a hypothesis is an idea that must be rigorously tested before it is accepted or rejected.

navigate     To find one’s way through a landscape using visual cues, sensory information (like scents), magnetic information (like an internal compass) or other techniques.

neuroscientist     Someone who studies the structure or function of the brain and other parts of the nervous system.

olfaction     (adj. olfactory) The sense of smell.

orbitofrontal cortex     A region of the brain located just behind your eye sockets. It’s part of the cortex — the area of the brain that is involved in planning and decision-making. The orbitofrontal cortex plays a role in emotions, in controlling your impulses and in decisions driven by the positive feelings that come from a reward of some kind. This brain area may also affect how we experience emotions, such as becoming anxious when preparing to take a risk.

spatial     An adjective for things having to do with the space where something is located or the relationships in space between two or more objects.

virtual     Being almost like something. An object or concept that is virtually real would be almost true or real — but not quite. The term often is used to refer to something that has been modeled — by or accomplished by — a computer using numbers, not by using real-world parts. So a virtual motor would be one that could be seen on a computer screen and tested by computer programming (but it wouldn’t be a three-dimensional device made from metal).


Journal:​​ L. Dahmani et al. An intrinsic association between olfactory identification and spatial memory in humans. Nature Communications. Published online October 16, 2018. doi: 10.1038/s41467-018-06569-4.