• Question: I have couple of questions: 1. What is the neural mechanism for explicit memory to transfer into implicit memory? 2. How do we know we learned? 3. What is thought and thought process? 4. Is there a relation between the unimodal (in association cortices) and multimodal (in Hippocampal Pyramidal neurons) associations to thoughts/meanings/concepts? 5. What is the interpretation/physical meaning/ application in learning for low frequency stimuli ( 1Hz) - LTD activation; and High frequency stimuli (100 Hz)-activation of LTP. Help in understanding these is appreciated. Thanks.

    Asked by nchekuri to Paul, Masud, Lucy, Kathryn, Joni, Ian, Duncan, Catriona, Andy on 9 May 2015.
    • Photo: Duncan Astle

      Duncan Astle answered on 9 May 2015:

      Gosh – that is more than a couple of questions!! They are also some massive questions. I will have a crack at a couple at least (and may return to the others when I have had chance for a think).

      1) What makes you think that explicit memory always transfers to implicit memory? I wonder whether you mean ‘how do episodes become integrated within our knowledge base’. One account of that is the complimentary learning systems view – hippocampal activity is essential for those initial episodes, and with time a consolidation process occurs, whereby these initial hippocampal-dependent representations become integrated with activity elsewhere in the brain. This neural process mirrors a cognitive change, with subjects integrating this information with the rest of their knowledge base. Review article on this idea here: ftp://grey.colorado.edu/pub/oreilly/papers/McClellandMcNaughtonOReilly95.pdf

      It is interesting to consider what might hasten or impair this consolidation process. We know that sleep is beneficial for this – it hastens the integration process. We also know that the depth of the information provided can also influence this integration.

      2) How do we now that we have learned something?! Well that depends entirely upon what you mean by learning. I wonder whether you actually mean remember. I guess memory is an integral part of most learning processes…. but learning is clearly more than just memory. We can test someone’s memory for something in various different ways…. but learning really goes beyond this.

      Right.. I will return to the other questions when I have had chance to think more carefully! Thanks for such stimulating questions.