What pathways are involved in learning, and what species [and why] are most adept to learning?

Question: What pathways are involved in learning, and what species [and why] are most adept to learning?

Asked by snacks to Anne, Carolyn, Joe, Mariana, Nick on 20 Mar 2010 in Categories: Theories.
- Joseph Devlin answered on 20 Mar 2010:
  
  Hi Snacks,
  
  That’s a big question and a really good one. Learning is arguably the fundamental property all neural tissue. If a nervous system couldn’t learn, it wouldn’t be much good. The central function of the brain is to learn to predict its environment more accurately so it can respond appropriately. In fact, there is even a species of a simple kind of fish (can’t recall the name) that is born with a simple nervous system that allows it to swim to a nutrient rich area where it then clamps onto a rock to live the rest of it’s life. Once it does this, it’s essentially eats its own nervous system because it doesn’t need it anymore — it no longer will respond to its environment, so no need for nerve cells. So, in a very real sense, all of the brain is involved in learning, in one form or another and this is true for all species with any kind of nervous tissue. However, I’m guessing you were asking something a bit different.
  
  There are multiple memory systems in the human brain and we don’t understand them that well yet. There are lots of theories about them, so I’ll briefly tell you what I think are some of the good ones.
  
  The medial temporal lobes (MTL) are a part of the brain that are definitely important for certain types of memory like remembering things that happen in your life. Damage to this area produces amnesia of various sorts. The most famous example is a patient called HM who had surgery to remove his MTL because of severe epilepsy. After the surgery, he had enormous difficulties remembering new information although he was able to do things like learn new skills (e.g. juggling). Mariana and Nick both work directly on one of the central structures of the MTL — a region called the hippocampus, so I’ll let them say more about that.
  
  But the neocortical mantle (essentially all of the tissue on the outer edge of the brain) is also critical for memory like learning new skills and storing what are called “episodic” and “semantic” memories. Basically, the neocortex learns fairly slowly because by doing that, it is capable of storing new information without messing up previously learned information. The MTL, on the other hand, learns fast but forgets things fast too. So when you have a new experience or learn something new, it probably gets stored in the MTL areas first and then replayed over time to “train” the neocortex — that is, to store the memory properly. Some people refer to this process as “consolidating a memory.”
  
  If this theory is correct — and I think there is strong evidence supporting it — then both the MTL and neocortex are crucial components of memory and they play complementary roles.
  
  It is likely that these regions and their roles are maintained across most (all?) mammals and indeed, any critter with both of these systems. Lots of animals don’t really have a neocortex, though (it’s newer, evolutionarily speaking), so birds for instance, have a slightly different memory system.
  
  Long answer!
- Carolyn McGettigan answered on 21 Mar 2010:
  
  Much of the brain can be involved in learning new skills, and which areas used depend on what you’re learning to do – speak a new language, play the piano, juggle. The development of ‘long-term’ memories for the things we’ve learned involves interaction between the bits of the brain involved in doing the action, and a brain area called the hippocampus (named after the seahorse because of its shape!).
  
  Many studies show increases or decreases in functional activation and connectivity (the functional ‘working together’ of several brain areas) associated with learning a task. We ran an MRI study where adults learned to understand degraded speech. We found that the learning was associated with activation in parts of the inferior parietal and frontal lobes of the brain, which are involved in short-term memory (like repeating a list of digits) and linguistic processing. There is evidence that the adult human brain can show anatomical changes too, in grey (neuron cell bodies) and white matter (the long tracts of nerve fibres that are surrounded by fatty myelin). A recent study from last year trained adults to juggle over a period of 6 weeks. MRI brain imaging techniques before and after training showed increases in grey and white matter in the occipital and parietal lobes of the brain, which the researchers related to the motor and visual coordination involved in juggling. There is also evidence of neural re-organisation after brain injury – people can gradually regain abilities that were impaired through stroke, although they don’t go back to behaving exactly as before their injury. Of course, no adult’s brain is as plastic as that of a human infant, who brain is still developing and learning all the time!
  
  There is evidence of learned behaviours in all sorts of animal species. Songbirds learn to produce very complex songs by listening to a ‘tutor’ bird during their early development. Non-human primates can learn to do all sorts of tasks with amazing rapidity. I’ve seen videos of monkeys that have been trained do simple addition and subtraction tasks for rewards, and it’s startling how quickly and accurately they can do this. And of course, we know that even within a species there can be variation in learning – some varieties of dog can be trained to do more sophisticated tasks than others. I suppose where the differences emerge is in both the speed of learning, and the complexity of the task. While some animals can be trained to do pretty impressive things very quickly, they can’t achieve the complexity of language and higher-order conceptual processing, which human children can get to relatively quickly and without that much training. If you compare our brains with that of other species, you can see that the wrinkly bit on the outside (the cerebral cortex) is much more folded and wrinkled up than for other animals, which reflects the fact that our brains have just so much more cortical tissue packed into them. This is part of what supports the sophistication of the things we can learn to do.
- Mariana Vargas answered on 22 Mar 2010:
  
  Hello! great question. An area of the brain called the hippocampus is essential for learning new information (such as someones name or facts). Without the hippocampus, new memories are unable to be stored into long-term memory. However, it appears that once learnt, the memories are consolidated and stored in other parts of the brain (such as the brain cortex), but no one has been able to prove that yet!
  
  What species are more adept to learning? mammals are particularly good at this, because they have bigger brains. For primates, like us, as our brain is still developing after we are born there is a chance for many connections to be formed during our first years, and this seems to be a very important factor in the capacity of learning. But in general most animals can “learn”. A lot of the initial research into how neuronal connections get stronger with repeated stimuli was done in snails! which get sensitised to simple stimili such as touch.

Question: What pathways are involved in learning, and what species [and why] are most adept to learning?

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