Neuronal activity in sensory cortex predicts the specificity of learning

Learning to avoid dangerous signals while preserving normal responses to
safe stimuli is essential for everyday behavior and survival. Following
identical experiences, subjects exhibit fear specificity ranging from high
(specializing fear to only the dangerous stimulus) to low (generalizing
fear to safe stimuli), yet the neuronal basis of fear specificity remains
unknown. Here, we identified the neuronal code that underlies
inter-subject variability in fear specificity using longitudinal imaging
of neuronal activity before and after differential fear conditioning in
the auditory cortex of mice. Neuronal activity prior to, but not after
learning predicted the level of specificity following fear conditioning
across subjects. Stimulus representation in auditory cortex was
reorganized following conditioning. However, the reorganized neuronal
activity did not relate to the specificity of learning. These results
present a novel neuronal code that determines individual patterns in
learning. Keywords: fear conditioning, auditory cortex, sensory systems,
learning, computational model, imaging, sensory cortex, tuning curve,
neurobiology, population coding.