Neural Correlates of Learning and Memory

  • E. R. John


We have been studying changes in the electrical activity of the brain as cats learn and perform differentiated conditioned responses to flashes or clicks at different repetition rates. These studies involve long-term observation of unanesthetized freely moving animals in which 34 electrodes have been chronically implanted into a variety of cortical and sub-cortical locations. Presentation of an intermittent sensory stimulus causes a transient time-locked fluctuation in the voltage recorded from responsive brain regions. These voltage fluctuations can sometimes be seen as rhythmic waves or labeled responses at the repetition frequency of the stimulus appearing in the ongoing electrical activity, or EEG. By synchronizing the trigger of an oscilloscope to the stimulus presentation, it is possible to study the characteristic waveshape and latency of these time-locked oscillations, or evoked responses. Using computers, large numbers of evoked responses can be added to enhance the signal-to-noise ratio, providing a picture of the characteristic or average evoked response.


Conditioned Stimulus Conditioned Response Neural Correlate Firing Pattern Electrode Position 
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Copyright information

© Springer-Verlag Berlin · Heidelberg 1972

Authors and Affiliations

  • E. R. John
    • 1
  1. 1.Brain Research Laboratories Department of PsychiatryNew York Medical CollegeNew YorkUSA

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