Kate McLean is an artist who has mapped the smellscapes of several cities. She aims to capture the ephemeral qualities of a city by conducting “smellwalks” and creating visualizations of these data sets.
Her walks have taken her to the toxic sludge-filled Gowanus Canal in Brooklyn, the fresh sea air of Newport, Rhode Island, and a particularly aromatic block in New York City.
Maps of the sense of smell
In the past, smell maps were a way for people to record the distinctive odors of their city or region. Now, scientists have mapped the pathways that olfactory information takes through brain circuits. These maps show how sensory signals are routed from the nose to the primary smell-processing hub of the piriform cortex, and how those signals can be decoded by the brain.
CSHL neuroscientists have used new technology to track tens of thousands of olfactory neurons in the fly brain. The scientists uncovered a map that shows how sensory transmissions seem coordinated and organized, revealing how the brain detects, characterizes, and identifies smells.
In a similar study, researchers have created the first map of all olfactory, thermosensory, and humidity-sensing projection neurons in the brain of the vinegar fly. The study provides an important step toward understanding how these neurons work together to produce complex behaviours. It is the first map of its kind for a living organism.
Maps of the human sense of smell
The human sense of smell can detect a trillion different odors. Yet, city officials and urban planners typically deal with less than ten bad ones. These smells often have negative consequences, such as air pollution or over-development. However, the ability to sense odors can be used for positive purposes, such as providing navigational information.
As a multisensory artist and designer, Kate McLean aims to celebrate the role that smell plays in our cities by mapping the urban “smellscape.” She does this through scent walks where she leads groups of people to experience the olfactory qualities of a city. These data are then translated into a map of the city’s aromas.
Neuroscientists have discovered maps that depict how sensory neurons are arranged based on their function to effectively process information from a particular stimulus. They have also shown that sensory transmissions between olfactory brain regions appear to be coordinated, which is why we can identify many different smells.
Maps of the human brain
In the early 1900s, neurologist Korbinian Brodmann drew some of the first maps of the human brain by hand, based on differences in the cellular architecture that he could see under a microscope. For over a century, scientists have used these maps to gain insight into the function of different regions of the cortex.
Researchers at Washington University in St Louis recently created a more intricate map of the cortex. They combined scans of brain structure, function and connectivity, identifying 180 distinct areas in each half of the cortex—confirming 83 known areas and identifying 97 new ones.
The new map will help scientists be more certain about which areas of the brain they’re seeing activity in or noticing problems with when scanning patients and healthy volunteers. And it will also help neurosurgeons be more sure about which areas they should avoid during operations. But the most important thing that this new map will show is how individual brains differ.
Maps of the human olfactory system
In recent years, there has been a renewed interest in the human sense of smell. While the olfactory system receives less attention than the visual, auditory, and somatic senses, it plays a critical role in our lives. It is also an example of a neural map, an organisation of neurons that transmit sensory information in the brain.
One approach is to create olfactory maps, which record the odours encountered in a particular location or region. These olfactory maps can be used to understand how the olfactory system works and to detect abnormalities in olfaction.
A smell map is not the same as a visual one, as it only captures odours that exist at a particular moment in time. In a project called Scratch ‘N Sniff NYC, designer Nicola Twilley created two smell maps of New York City, one based on dominant odor perception frameworks in each neighbourhood and the other based on crowd-sourced selections of people’s smell biases.