Home' Trinidad and Tobago Guardian : March 2nd 2016 Contents A24
body & soul
Guardian www.guardian.co.tt Wednesday, March 2, 2016
Advanced calcium imaging of zebrafish brains is
helping University of Queensland researchers dis-
cover how sensory stimuli such as sights and sounds
are integrated in the human brain.
The research into how fish interpret and integrate
sensory information, led by School of Biomedical
Sciences ARC Future Fellow Dr Ethan Scott, could
improve understanding of how humans combine
senses like sight, touch and sound to create a complete
The team s studies showed that the zebrafish s
tectum---a mid-brain structure known for its visual
processing---is more similar to its human counterpart,
the superior colliculus, than previously thought.
"In order to function efficiently, fish and humans
need a unified sensory view of the external world
contributed to by multiple senses," he said.
"Zebrafish are transparent and, since the larvae
also develop externally, we can observe the brain
from its earliest developmental stages through to full
function. Using fluorescent calcium imaging, we were
able to monitor neural activity across large populations
of neurons in a completely intact functional zebrafish
Dr Scott said the first step in laboratory tests was
to show the fish visual stimuli and observe the calcium
dynamics in the tectum.
"Visual processing in the zebrafish tectum is well
known and we found a predicted set of outcomes
that replicated previous studies," he said.
"We then introduced stimuli for other senses, such
as sound and the detection of water flow, which have
not been studied in the zebrafish tectum. When we
introduced sounds, we saw a small number of cells
within the tectum respond to these stimuli. There
were also responses in the tectum to the flow of
water across the body of the fish.
"Although the tectum in larval zebrafish was
Using functional magnetic resonance imaging,
a team of UCLA researchers has shown for the first
time that children with autism spectrum disorder
(ASD) who are overly sensitive to sensory stimuli
have brains that react differently than those with
the disorder who don t respond so severely to noises,
visual stimulation and physical contact.
The findings could lead to the development of
interventions that can help the more than 50 per
cent of individuals with ASD who have very strong
negative responses to sensory stimuli, a condition
called sensory over-responsivity (SOR). Interventions
for this condition could significantly improve the
lives of children with this form of ASD and their
families, said study first author Shulamite Green, a
postdoctoral fellow in the Semel Institute for Neu-
roscience and Human Behavior at UCLA.
"This condition is distressing and impairing for
individuals on the autism spectrum, as well as for
their parents, who often feel confined to their homes
because it s too difficult to take their children out
shopping, to the movies or to a restaurant. Our
research provides new insights into the brain differ-
ences that may cause sensory over-responsivity,
which helps us understand how to treat it' from
simple interventions like limiting exposure to multiple
sensory stimuli to more complex interventions like
cognitive-behavioral therapy," Green said.
ASD is a developmental disability that can cause
significant social, communication and behavioural
challenges. It occurs in all racial, ethnic and socioe-
conomic groups, but is almost five times more com-
mon among boys than among girls.
The study appeared in the peer-reviewed journal
JAMA Psychiatry. (www.sciencedaily.com)
Fish brains help explain human sensory perception
Because zebrafish are transparent, scientists use them
to observe how brains develop. This research may help
us better understand how human sensory perception
thought to be used solely for visual
processing, our research has shown
that it responds to at least three types
Dr Scott said the discovery had a
number of implications.
"The tectum was much less
responsive to a visual stimulus if other
stimuli were taking place at the same
time, and this suggests there was
some sort of sensory integration or
gating occurring," he said.
"Since similar processes take place
in the mammalian superior colliculus,
our research indicates the fish tectum
is more similar to the superior col-
liculus than has previously been
recognised. This is useful, because it
suggests that the zebrafish tectum,
with all of its great experimental
attributes, is an appropriate platform
for studying how the superior col-
liculus works, including how infor-
mation from different senses are inte-
to sensory stimuli
have different brains'
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