ABSTRACT
There are three kinds of storage: short-term, medium, and long-term or permanent. Flexner, Flexner and Roberts proposed, in 1966, that short-term memory is dependent 'upon the reverberation of neuronal impulses'.2 Medium-term storage 'may be based upon changes in the concentration of ions or small molecules or on changes in the configuration or location of pre-existing macro-molecules'. This type of memory lasts one or two days, and may be an intermediate stage in the establishment of long-term memory.
