imprinting in animals (Introduction)

by David Turell , Friday, February 12, 2016, 20:07 (3206 days ago)

Horses are born to avoid humans. It takes weeks of imprinting to overcome it. New research how this happens in C. elegans, a tiny nematode work with 302 neurons as its nervous system:-http://www.the-scientist.com/?articles.view/articleNo/45311/title/Neuroscience-of-Early-Life-Learning-in-C--elegans/&utm_campaign=NEWSLETTER_TS_The-Scientist-Daily_2016&utm_source=hs_email&utm_medium=email&utm_content=26197263&_hsenc=p2ANqtz--Ov97ztHSKo6EE-GZJ1YRJD2zPhtjwOc1x6qe7aJ_Oa2uf9lrxexbNbJ5veZrcqFeYMLjUmIPdpaRUi7zzEMjzXkRdMg&_hsmi=26197264/-"Early-life exposure to pathogenic bacteria can induce a lifelong imprinted olfactory memory in C. elegans through two distinct neural circuits, according to a study published today (February 11) in Cell. Researchers from Rockefeller University in New York City have shown that early-life pathogen exposure leads the nematode to have a lifelong aversion to the specific associated bacterial odors, whereas later-in-life exposure spurs only transient aversion.-***-"A classic example of imprinting is how geese form attachments to the first moving object they see after birth; Nobel laureate Konrad Lorenz famously showed that the “moving object” could be himself instead of a mother goose. During the critical period at the start of life, animals often have unusual abilities to create and maintain long-term memories.-"For the present study, Rockefeller's Xin Jin and colleagues described a form of aversive imprinting in their C. elegans: newly hatched nematodes exposed to Pseudomonas aeruginosa PA14 or toxin-emitting Escherichia coli BL21 established a long-term olfactory aversion to it. Animals that experienced the pathogen immediately after hatching were able to synthesize and maintain the aversive memory for the whole of their four-day lifespans, while animals trained in adulthood only retained the aversive memory for up to 24 hours.-***-"The principle of separate neural circuits for memory formation and retrieval is far from unique to C. elegans. It was shown in humans through cases such as the famous patient “H.M.” who, following surgery that removed his medial temporal lobe, was able to retrieve old declarative memories but unable to form new ones.-“'[The] idea that the transient learning signal would later be dispensable at the time of memory goes back as far as Pavlov. We're just developing the idea at a different level of resolution to map it onto a physical site and not just a conceptual site,” said study coauthor Cori Bargmann. “It's a surprise all over again that you can actually implement this in such a compact, little brain.”-"Of course, memory formation and retrieval circuits must communicate with each other for learning to occur. The researchers found one molecular bridge between the circuits in the neurotransmitter tyramine, a homologue of adrenaline in mammals. Tyramine was released by the memory-formation neuron RIM and detected by the memory-retrieval neuron AIY; the neurotransmitter alone could replace the requirement for RIM activity in the C. elegans learning process."-Comment: This supports my contention that many instincts can be learned fixed processes, not involving 'thought'. This study is a reaction to chemical exposure.