Figure 4: Amount of cortical representation is a basis for the strength of auditory memory. Animals trained as in Figure 3. Memory strength was determined by how long animals continued to barpress when water was no longer delivered (“extinction”) following attainment of a high level of performance during reward training (“acquisition”): the greater the duration of barpressing, the stronger the memory. Note that stronger memories are related to the amount of gain in representational area during acquisition. Cartoons show training protocols with frame denoting that the strength of acquisition memory was tested. Figure modified from [28].