Monday
February 20, 2006
news@michigandaily. com
SCIENCE
SA
Sharks:
The
initial
frontier
'U' scientists explore the possibilities of controlling sharks via remote control
By Matt Beneke
Daily Science Writer
When most people hear the word
"shark," certain images come to mind:
a swiftly moving fin slicing through
the water with dramatic 1970's nail-
biting music in the background; or
maybe a giant pointed nose, a pair of
angry, flared nostrils and a row of dag-
ger-like teeth a league wide.
But researchers are adding a new
image to that list. Sharks are now the
guinea pig used to validate the design
of the next generation of electrical brain
stimulation devices.
A shark whose behavior is dictated by
a small wireless device implanted in its
head? Sounds like something out of the
next James Bond picture. But if all goes
well, a research team at the University
will make this areality.
A multi-disciplinary team, led by
biomedical engineering Prof. Darryl
Kipke, is in a competition with other
universities to create a wireless brain
recording and stimulation device to
transfer control of free-swimming
nurse sharks to a human operator.
Being able to model the dynamics
of the nurse shark's brain might also
help us learn more about the brain
plasticity of other animals, including
that of a certain advanced ground-
dwelling primate.
Sponsored by the Defense Advance-
ment Research Project Administration,
the team consists of Albion College
biology Prof. Jeff Carrier, researching at
Kipke's Neura, and Ann Arbor start-up
company NeuroNexus.
The Neuro Engineering Labora-
tory brings to the table experience in
neural implant recording and stimu-
lation experiments. Carrier captures
the sharks, houses them and brings
his expertise in shark husbandry and
behavior. NeuroNexus supplies the neu-
ral electrodes and electronics that will
be implanted into the sharks.
But why a nurse shark?
According to nurse shark expert Car-
rier, there are a number of reasons. First
of all, they are relatively easy to capture.
All it takes is a trip to the Florida
Keys, and Carrier is able to live-cap-
ture them using a variety of methods,
including nets, rod and reel, and long-
hooked lines.
The ideal size, for reasons of trans-
port and subsequent laboratory research,
is a shark between 2 to 4 feet long, but
the animals can grow up to 7 feet.
The nurse shark is also known to
adapt well to captivity. Most sharks need
to keep mobile in order to move water
across their gills, but nurse sharks can
keep a steady flow of oxygenated water
over their gills even if they are lying still
in a confined environment.
Additionally, nurse sharks are par-
ticularly docile, as they only eat small
aquatic invertebrates and are not as
likely to chomp off the arm of a careless
grad student.
"Nurse sharks are very intelligent
creatures and conditioning their behav-
ior with the use of food is not as daunting
of a task as it may seem," Carrier said.
As with any research involving ver-
tebrate animals, the research must be
approved by the University Commit-
tee on the Use and Care of Animals.
In addition, the research must follow
protocols established by the commit-
tee regarding the ethical treatment of
the animals.
According to University researcher
Mark Lehmkuhle, the first step toward
developing the device is to effectively
record brain signals from anesthetized
nurse sharks. The team does this by
implanting sensory electrodes into the
known olfactory and auditory brain cen-
ters of the shark.
DAVID TUMN/Daily
Albion College biology professor Jeff Carrier carefully places a shark back Into a tank at his research lab.
"It's going to be tricky to figure out how to
protect electronics from the harsh environment
that is sea water."
- Jeff Carrier,
Albion College biology professor
A brief
history of
neurological
experiments
The inspiration for this project
is not confined to a single disci-
pline; it draws from many areas
of science and has roots in vari-
ous notable experiments of the
past.
In the 1780's, the Italian
biologist Luigi Galvani first per-
formed an experiment that would
be repeated endless times in
biology laboratories to easily-
impressionable undergraduates.
Galvani found that the applica-
tion of electricity to a frog could
cause its muscles to contract,
even if the muscle is part of a
detached leg.
The work was furthered in the
early 1800s by a fellow Ital-
ian named Felice Fontana, who
advanced to human brains.
He applied electricity to the
brains of cadavers, which elic-
ited mysterious facial muscle
contractions. But Italian society
was not quite ready for this type
of experimentation with their
deceased.
Fontana avoided their wrath
by switching to the use of living
research subjects.
Russian scientist Ivan Pavlov
was a pioneering researcher
best known for his research in
the early 1900s involving condi-
tioned reflexes.
Pavlov's infamous experiment
involved ringing a bell before
feeding his dogs. The dogs then
associated the sound with a sub-
sequent food reward.
With time, he was able to get the
dogs to involuntarily drool with no
food being presented, as long as
they heard the bell ringing.
The idea that environmental
events (a ringing bell) that previ-
ously had no relation to a given
reflex (drooling), would trigger
that reflex proved to be a revo-
lutionary idea impacting not only
the field of animal research, but
also in human behavior.
The first quantitative recording
of electrical signals of the brain
was done in the mid-1920s by an
Austrian scientist named Hans
Berger.
Inspired by a telepathic encoun-
ter with his sister, he decided
to devote his life to develop a
scientific model to explain the
mechanism of his experience.
In a quest to determine how
blood flow to the brain fuels
mental and psychic energies, he
developed the first electroen-
cephalogram.
Though his psychic energy
models have yet to be validated
by anyone, his device continues
to be a valuable tool to non-inva-
sively measure brain function.
These electrodes are then connected
to wires that power the device as well as
deliver the electronic brain signals to a
data acquisition program on a computer.
But they're not looking for just any
brain activity. The team is interested in
recording representative signals from the
appropriate locations in the cortex while
exposing the sharks to specific scent and
auditory cues.
Previous research has shown that it is
possible to expose certain odors to lab
rats, and correlate each of the odors to
a specific pattern of neural activity. This
activity is sensed by electrodes placed in
olfactory centers of the animal's brain.
The next step would be to conduct the
same sensory experiments on conscious,
free-swimming nurse sharks.
The sharks will be trained to move to
the left or right side of their holding tank,
according to scent and auditory cues,
with the motivation of a food reward
when it moves in the desired direction.
The aim of this step.is to gather a set
of electrical brain signals that are valid
representations of the odors and sounds
used to train the sharks.
Once the sharks have been trained,
the team will attempt to direct the shark
to move to the left or right, but without
exposure to the scent and sound cues.
By using stimulating electrodes in
the appropriate areas of the shark's
brain (still with trailing power and
communication wires), they will
deliver the representative brain sig-
nals to mimic the real cues.
The idea is that if the scent and sound
information can be adequately repro-
duced by artificial stimulation in the
appropriate areas of the shark brain, the
behavior associated with the real scents
and sounds will be reproduced with the
artificial stimulation.
Finally, the previous tests would
be repeated on the same free-swim-
ming sharks, but this time without
wires attached.
A wireless device will be implanted
under the skin of the sharks, capable of
sensory recording and transmitting the
brain signal to a computer, as well as
receiving instructions from the computer
to stimulate the motor areas of the brain
to elicit the desired movement.
Going wireless has many obvious
advantages, especially in the electri-
cally-conductive and corrosive envi-
ronment of salt water that the nurse
shark needs to survive.
However, there are real problems
involving signal bandwidth and power
to overcome, as known to anyone with
a cellular phone who has experienced
broken or dropped signals and dead bat-
teries.
Carrier said mixing electronics
with water will also create some
inherent difficulties.
"It's going to be tricky to figure out
how to protect electronics from the harsh
environment that is sea water," he said.
This project is at its early stages,
oDvAI DTUAN /j Daiy
Albion College biology senior Amy Hupp and nurse shark expert Jeff
Carrier measure a shark in Carrier's lab.
and right now the team is at the tory cues, dictate shark behavior
first step. With its lofty ambitions within the brain.
and scope, they anticipate that it The development of this device will
will take years to progress to the result in a valuable tool to understanding
wireless controller. At present, it how animal behavioral responses change
is not clear how sensory system when they originate from artificial, ver-
input, such as olfactory and audi- sus natural, neural stimulation.
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