Day old chicks used to study the effect of Memantine on memory
Samartgis, J. R., Schachte, L., Hazi, Agnes., Crowe, S. F. (2012). Memantine facilitates memory consolidation and reconsolidation in the day-old chick. Neurobiology of Learning and Memory 97 (2012), 380–385.
Research into the neurological correlates of memory using young male chickens has been used widely by research groups across the world for the last 30 or so years. Chicks will innately peck at beads as food, researchers coat a certain different coloured bead in a bitter tasting substance, and after showing disgust when it pecks this bead, the chick will avoid pecking further beads of the same colour.
This is called a one-trial passive-avoidance learning task.
To look for neurological agents involved in memory, researchers will inject various substances into the chicks brains to see what effects they have on their ability to remember not to peck the nasty tasting bead. This task has continued to be popular because it is very simple and highly reproducible.
Furthermore, chicks are used for this task because unlike rodents, “chicks do not respond to brain needle stick injury with electrical seizures and their brain is covered by a soft unossified skull (lacking bony structure); this permits rapid injections without the necessity for anaesthesia” which would interfere with the experiment.(1) Chicks are also used because of “their ready availability as rejects in the egg laying poultry industry” (1)
In a study published in 2012, Samartgis et al at LaTrobe university tested the effects of Memantine on 1160 male day-old chicks.
Memantine is a medication for Alzheimer’s disease that operates on the glutamatergic system. Glutamate is an important neurotransmitter that has been shown to be involved in learning and memory.
The control group of chicks were injected with a saline solution and the experimental group were injected with differing doses of Memantine to see what affect it would have on their ability at the one-trial passive-avoidance learning task mentioned above.
The steps of the one-trial passive-avoidance learning task in this experiment are explained in simple enough terms in the experiment for the layperson to understand:
"Pretraining: in which chicks are presented twice with a water-coated chrome bead to encourage a pecking response; baseline, in which a water-coated red bead is presented and pecks recorded as a baseline measure; training, in which a second red bead coated with the aversive substance methyl anthranilate (MeA) is presented to the chicks; reminder (Experiment 4 only), in which chicks are shown a dry red bead but are not allowed to peck, in order to elicit recall for the training event; and test, in which chicks are exposed to a dry red bead as a measure of retention of the training." (See page 381 of the original publication)
The researchers found that 0.1mM of Memantine was the most effective dose at facilitating success at the learning task in the day-old chick.
The researchers also investigated the effect of time of injection of drug relative to training and drug injected, the effect of the time of test after training and drug injected, and the effect of time of reminder trial post-training and drug injected.
As it is not relevant to the instrumental purposes of the scientific papers, in none these publications is information provided regarding what happens to animals after the research is completed. Chicks were most likely incinerated at the conclusion of the research.
This study was supported by an Australian Research Council Discovery Projects grant.
As mentioned in the paper itself, Memantine has already been approved for the treatment of Alzheimers Disease (AD) in Europe and the United States. Human clinical trials have already shown it to improve cognition in AD as well as vascular dementia. In some studies, various doses of memantine have been shown to have either no effect or to impair memory of rats(3) and chicks(4). Other studies have shown it to improve memory functioning. Considering these differing results within the same species, do the researchers believe that data obtained from the brains of day old chicks can be extrapolated to the more advanced human brain?
Why could this testing not have been observed in human patients using non-invasive imaging techniques?
What you can do:
Please write to the following, asking that they no longer fund unscientific animal-based experiments.
Australian Research Council
GPO Box 2702
1 - Gibbs, M. E. (2008) Memory systems in the chick: Regional and temporal control by noradrenaline. Brain Research Bulletin 76. 170–182
2 - Samartgis, J. R., Schachte, L., Hazi, Agnes., Crowe, S. F. (2012). Memantine facilitates memory consolidation and reconsolidation in the day-old chick. Neurobiology of Learning and Memory 97 (2012), 380–385.
3 – Réus, G., Valvassori, S., Machado, R., Martins, M., Gavioli, E., & Quevedo, J. (2008). Acute treatment with low doses of memantine does not impair aversive, non-associative and recognition memory in rats. Naunyn-Schmiedeberg's Archives of Pharamacology, 376(5), 295-300. http://dx.doi.org/10.1007/
4 – Barber, T. A., Meyers, R. A., & McGettigan, B.F. (2010). Memantine improves memory for taste-avoidance learning in day-old chichks exposed to isolation stress. Pharmacology, Biochemistry & Behavior, 95(2), 203-208. http://dx.doi.org/10.1016/j.