George, S, Wise, A, Fallon, J & Shepherd, R 2015, ‘Evaluation of focused multipolar stimulation for cochlear implants in long-term deafened cats ‘, Journal Of Neural Engineering, 12, 3.
Associated Institution(s): Royal Victorian Eye and Ear Hospital, the Bionics Institute, and The University of Melbourne
The Experiment
The experiment from 2015 aimed to test four different cochlea implant stimulation methods on kittens with artificially induced chronic deafness. They aimed to discover which provides the highest clarity with the lowest electrical current, as well as the effect of different positions of the implant on its performance.
Six kittens underwent an experimental deafness procedure, which involved daily injections of neomycin sulphate, an antibiotic that has hearing loss side effects. These injections commenced the day after birth and continued for 20 days. Injections were continued if necessary until the kittens registered as profoundly deaf. Kittens were deaf for a period of 10-12 months before the experiment commenced.
The experiment was conducted over 2-3 days where the cats were anaesthetised, intubated, and kept unconscious throughout. The cochlea implants were surgically inserted after which the cats were placed in a restrictive metal frame called a stereotaxic frame, which positions their head with metal rods in the ears and a metal clamp on the nose.
A craniotomy, which is invasive brain surgery, was performed on the cats where a segment of their skill was removed followed by removal of the cerebral cortex, so that the section of brain associated with auditory processing could be exposed.
Different currents were then used to stimulate the electrodes in the implants to determine the effectiveness and clarity of the different models. Brain activity of the auditory processing region was also monitored through a silicon-recording device that was implanted during the craniotomy.
After data was collected for the cochlea implants, the cats were killed and the implants removed for analysis.
Background
The Bionics Institute, in conjunction with The University of Melbourne, is continuing to conduct invasive cochlea experiments involving the deafening of cats. The facility has conducted numerous studies in the past 10 years that have comparable methods which all involve the deafening and killing of the cat subjects. The following is a non-exhaustive summary of some of the other research involving cats used in studies on human hearing, and what the cats were subjected to. The institute has also performed similar research on guinea pigs and uses cats in vision studies.
| Reference – Bionics Institute | Year | Animal use |
| Fallon, J, Irvine, D, & Shepherd, R 2009, ‘Cochlear implant use following neonatal deafness influences the cochleotopic organization of the primary auditory cortex in cats’, The Journal Of Comparative Neurology, 512, 1, pp. 101-114 | 2009 | 17 kittens deafened the day after birth, then killed after completion of experiment |
| Wise, A, Fallon, J, Neil, A, Pettingill, L, Geaney, M, Skinner, S, & Shepherd, R 2011, ‘Combining cell-based therapies and neural prostheses to promote neural survival’, Neurotherapeutics: The Journal Of The American Society For Experimental Neurotherapeutics, 8, 4, pp. 774-787 | 2011 | 17 cats deafened and total of 24 cats killed at the conclusion of the experiment |
| George S S, Wise A K, Shivdasani M N, Shepherd R K and Fallon J B, 2014, ‘Evaluation of focused multipolar stimulation for cochlear implants in acutely deafened cats’ Journal of Neural Engineering, 11 065003 | 2014 | 6 cats were deafened and then killed after completion of experiment |
| Irving, S, Wise, A, Millard, R, Shepherd, R, & Fallon, J 2014, ‘A partial hearing animal model for chronic electro-acoustic stimulation’, Journal Of Neural Engineering, 11, 4, p. 046008
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2014 | 21 kittens were deafened at 5 days of age, 10 other kittens were deafened at 7 moths. All 31 cats were killed at the end of the experiment. |
| Fallon, J, Shepherd, R, Nayagam, D, Wise, A, Heffer, L, Landry, T, & Irvine, D 2014, ‘Effects of deafness and cochlear implant use on temporal response characteristics in cat primary auditory cortex’, Hearing Research, 315, pp. 1-9 | 2014 | 15 kittens were deafened one day after birth, 2 others at a later date. A total of 17 cats killed at the completion of the experiment |
| Fallon, J, Shepherd, R, & Irvine, D 2014, ‘Effects of chronic cochlear electrical stimulation after an extended period of profound deafness on primary auditory cortex organization in cats’, The European Journal Of Neuroscience, 39, 5, pp. 811-820 | 2014 | 10 kittens were deafened one day after birth. All cats were killed at the completion of the experiment |
| George, S, Shivdasani, M, Wise, A, Shepherd, R, & Fallon, J 2015, ‘Electrophysiological channel interactions using focused multipolar stimulation for cochlear implants’, Journal Of Neural Engineering, 12, 6, p. 066005 | 2015 | 7 cats were deafened and a total of 8 cats were killed after completion of experiment |
| Featured experiment: George, S, Wise, A, Fallon, J, & Shepherd, R 2015, ‘Evaluation of focused multipolar stimulation for cochlear implants in long-term deafened cats’, Journal Of Neural Engineering, 12, 3, p. 036003 | 2015 | 6 kittens were deafened from one day after birth. All cats were killed after the completion of the experiment |
| Fallon, J, Irving, S, Pannu, S, Tooker, A, Wise, A, Shepherd, R, & Irvine, D 2016, ‘Second spatial derivative analysis of cortical surface potentials recorded in cat primary auditory cortex using thin film surface arrays: comparisons with multi-unit data’, Journal Of Neuroscience Methods, Apr. 5, 2016. ISSN: 0165-0270. | 2016 | 13 cats were deafened, 14 cats were killed after completion of experiment |
| Senn, P, Shepherd RK, Fallon JB 2015 “Focused electrical stimulation using a single current source” J Neural Eng Oct 15(5):056018 doi:10.1088/1741-2552/aad0a5 | 2018 | Electrical stimulation in cat |
As well as the question of the research being relevant to human medicine, the sheer number of cats subjected to these invasive experimental procedures from one day of age is quite shocking, and only seems to be increasing over the years. With such similar experiments being conducted each year, the institute appears to be abusing their use of cats in a wasteful manner. With such similar experimental methods in place for all the studies there is the question of what new information is being obtained with each new experiment that could not be deduced from any of the previous studies? Continually and persistently deafening and killing cats and receiving large amounts of tax-payer funding to do so is something that needs to be addressed.
Typical grants from the NHMRC for these types of studies are in the hundreds of thousands. Here are just a few grants that have been awarded to researchers of the Bionics Institute over the past few years to conduct their cochlea experiments:
- Professor Rob Shepherd received $437,213.00 for research over 2009-2012 on cochlear implants
- Professor James Fallon received $560,267.00 for research over 2011-2014 on cochlear implants
- Professor Rob Shepherd received $506,725.00 for research over 2011-2013 on auditory nerves and deafness.
- Professor James Fallon received $958,739.00 for research over 2015-2018 on bilateral cochlea implants (NHMRC, 2016)
Should this much tax payer money be dedicated to research that involves deafening and killing cats?
Source of funding data: National Health and Medical Research Council (NHMRC), 2016, ‘NHMRC Grants 2000-2015’, Australian Government, Canberra, viewed 18th April 2016,
Relevance of Results
Cats and humans are vastly different species, and these differences extend to the structure and function of the ears. A recent study by Rattay et al. (2013) compared the anatomical auditory nerve differences between the two species in order to determine if results from the cat ear are really transferrable to humans. The study found a number of differences, as expected, and states the following:
“Shorter total lengths of SGNs in cat, thinner processes, smaller cell bodies and fundamental differences in myelination are obvious reasons not to rely on a cat model when signalling in human auditory nerve is discussed as these differences between the species may lead to important differences in auditory nerve function.”[1]
With the looming question of how relevant research on cats is to humans, should such large amounts of invasive experiments be permitted?
[1] Rattay, F, Potrusil, T, Wenger, C, Wise, A, Glueckert, R, & Schrott-Fischer, A 2013, ‘Impact of Morphometry, Myelinization and Synaptic Current Strength on Spike Conduction in Human and Cat Spiral Ganglion Neurons’, Plos ONE, 8, 11, p. 1
Funding
The featured experiment was funded by the National Health and Medical Research Council (NHMRC) the Australian Research Council (ARC) ($350,000), and The Garnett Passe and Rodney Williams Memorial Foundation. The Bionics Institute is also supported by the Victorian Government through its Operational Infrastructure Support Program.
What You Can Do
Please write to the following to voice your concerns about the number of cats subjected to this research every year, to question the relevance of the research to human medicine and to question the decisions of the Animal Ethics Committee who approved this research::
Vice Chancellor, University of Melbourne
Email : vc@unimelb.edu.au
Please also write to the following funding bodies to ask why they are funding the use of animals in experimental procedures when these animals do not appropriately model humans, and to voice your concerns about the number of cats subjected to this research every year.
Professor Anne Kelso
National Health and Medical Research Council
GPO Box 1421
Canberra ACT 2601
Email: nhmrc@nhmrc.gov.au
And
Australian Research Council
GPO Box 2702
Canberra ACT 2601
Email: info@arc.gov.au
