1. 5.4 The Molecular Problem of Memory

2. 1.Nature of knowledge is different. 2.Sites of storage is different. 3.Recall methods are different. Implicit and explicit memory have the following common features. 1.STM lasts for a few minutes to hours. LTM lasts for days, weeks, years and a life time. 2. Repetition converts STM to LTM.

3. 3. In both kinds of memory, long term storage requires new proteins. Implicit Memory Storage Eric kandel & his colleagues at Columbia University have studied the marine snail APLYSIA. They proved some points about Implicit Memory Storage.

4. Aplysia Californica - Brain has 20000 neurons - Easy to study Ganglia - A single group of cells. - contains 2000 nerve cells. - Committmence: Controls a no. of diff. Kinds of behaviour. -100 nerve cells: Controls a single kind of behaviour.

5. Aplysia body has a set of protective reactions(defensive reflexes). It has tail,gill and siphon. Gill- extracting the oxygen from the sea water. Siphon- dismiss the waste from the sea water. A tactile stimulus is applied to the siphon.

6. Gill Siphon Withdrawal(GSW) reflex is an example of essential defensive reflex. A simple reaction can be modified by diff. kinds of learning. 1. Sensitization(learned fear) 2. Habituation 3. Classical conditioning

7. Sensitization: 24 sensory neurons are inserted into siphon skin. Sensory neurons- six motor neurons(activate the gill). SN converts to MN via inter neuronal pathway. IN- inhibitory EN-excitatory SN is pick up from Siphon & transfer to motor neuron.