Can't find your keys? You need a chickadee brain
Scientists identify a link between spatial memory and genes in a bird


Date:
November 9, 2021
Source:
Cornell University
Summary:
Researchers have shown that there is a genetic component underlying
the amazing spatial memories of Mountain Chickadees. Although
the genetic basis for spatial memory has been shown for humans
and other mammals, direct evidence of that connection has never
before been identified in birds.



FULL STORY ==========================================================================
For the first time, researchers have shown that there is a genetic
component underlying the amazing spatial memories of Mountain
Chickadees. These energetic half-ounce birds hide thousands of food
items every fall and rely on these hidden stores to get through harsh
winters in the mountains of the West. To find these caches, chickadees
use highly specialized spatial memory abilities.

Although the genetic basis for spatial memory has been shown for humans
and other mammals, direct evidence of that connection has never before
been identified in birds.


========================================================================== These findings were just published in the journal Current Biology. The
research is a collaboration among scientists from the Cornell Lab of Ornithology, the University of Colorado Boulder, the University of Nevada, Reno, and the University of Oklahoma.

"We all use spatial memory to navigate our environment," says lead
author Carrie Branch at the Cornell Lab of Ornithology. "Without memory
there's no learning and an organism would have to start from scratch
for every task. So, it really is life and death for these birds to be
able to remember where they stashed their food. We've been able to show
that natural selection is shaping their ability to remember locations."
If natural selection (survival of the fittest) is shaping chickadee
memory, certain criteria have to be met. There has to be variation in
the trait: some chickadees are indeed better than others at re-finding
their stores. There has to be a fitness advantage: birds that perform
better on a spatial memory task are more likely to survive and produce offspring. Importantly, variation in the trait must have a genetic basis.

"Environment does still matter a lot in terms of shaping behavior, but
our work here suggests that genes may create the brain structures, and
then experience and learning can build on top of that," Branch explains.

How do you measure a chickadee's memory? Senior author Vladimir
Pravosudov and his team at the University of Nevada, Reno, designed
arrays of "smart" feeders to measure memory in a population of wild
Mountain Chickadees in California's Sierra Nevada mountains. Each feeder
is equipped with radio frequency identification sensors. The 42 birds
tested were fitted with leg tags the size of a grain of rice which give
off an identifying signal. Each bird was assigned to one of the eight
feeders in each array. The feeder sensor reads the bird's ID tag and if
it's the matching feeder for that individual, a mechanism opens the door,
and the bird gets a seed. The scientists then tracked how many tries it
took before the birds consistently went to the correct feeder.

"This is an effective system to test spatial learning and memory
in hundreds of wild chickadees in their natural environment," said
Pravosudov. "We have previously shown that even very small variations in performance are associated with differences in survival." To understand
the connection between spatial memory and genetic architecture, co-authors Georgy Semenov and Scott Taylor at the University of Colorado Boulder, sequenced Mountain Chickadee genomes.

"We used two methods to link genetic variation with spatial memory in chickadees," said Semenov. "In the traditional genome-wide approach,
we compared genetic data across individuals, from those that performed
well on the spatial learning and memory task to those that performed
poorly. We did the same comparison with a new machine learning
algorithm. Both methods showed hundreds of differences associated with
spatial memory. Many of the variations in the genomes turned up in areas
known to be associated with learning, memory, and neuron development in
the brain." The authors say many questions remain about the influence
of spatial memory itself, including what role it may play in the female's choice of a mate.

This research was supported by grants to the University of Nevada, Reno,
and to the University of Colorado Boulder, from the National Science
Foundation and by a Rose Postdoctoral Fellowship from the Cornell Lab
of Ornithology.

========================================================================== Story Source: Materials provided by Cornell_University. Original written
by Pat Leonard, courtesy of the Cornell Chronicle. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Carrie L. Branch, Georgy A. Semenov, Dominique N. Wagner,
Benjamin R.

Sonnenberg, Angela M. Pitera, Eli S. Bridge, Scott A. Taylor,
Vladimir V.

Pravosudov. The genetic basis of spatial cognitive variation
in a food- caching bird. Current Biology, 2021; DOI:
10.1016/j.cub.2021.10.036 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211109135455.htm

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