How quickly fruit flies "count" odors, the new model tells you

Imagine you're sitting at home and hear someone knocking on the front door
.
You see through the window that there is a stranger
outside.
Almost immediately, your brain knows you've never seen the person
before.
Maybe you feel scared and pretend not to be home
.

Now, imagine a close friend or family member out there instead of a stranger
.
Almost as soon as you see them, your brain knows you've seen this person many times
in the past.

Your brain constantly calculates your experiences
with specific sights or smells.
Even if you don't remember all the details, those details can influence your initial reaction to the situation – whether to avoid it or accept it
.
From an evolutionary perspective, this instantaneous reaction can mean the difference between
life and death.

Scientists aren't entirely sure how this process works
in our brains.
But now, Sackt Navrakhar, a researcher at Cold Spring Harbor Laboratory (CSHL), has created a new computational model based on fruit fly brain data that may bring us closer to the answer
.

"We've been studying the brains of fruit flies for some time," Navlakha said
.
"It has about 100,000 neurons, and many connections are known
at the level of individual neurons and synapses.
They give us a perspective
on how the brain works.
”

In a paper published in Nature Communications, Navlakha and his team reviewed data from a 2017 study that imaged
the brains of fruit flies when exposed to new and familiar odors.

Navrakka hypothesized that insects can distinguish between four categories: what they smell for the first time, what they smell the second time, what they smell for the third time, and what
they have encountered many times before.

He created what he called a "1-2-3-many" count sketch
.
Count sketches are used in computer science to provide fast, approximate counts
.
For example, YouTube uses counting sketches to track the number
of views a video receives.
Navrakka suspects that creatures might do
the same.
He said:

"We took inspiration from a classical computer science approach to solving this problem
.
A variant of this method is actually used by fruit flies to solve the same problem
of tracking the number of times they experience different odors.
”

Humans may use similar, but more complex, counting systems
.
Navlakha explains that this is an area of future research:

"People haven't done similar memory tests
in humans.
We wanted to see if this model could also explain the memory counts (abilities) of humans and how this calculation might be affected
in people with Alzheimer's or Parkinson's.
”