Vibrissae-evoked behavior and conditioning before functional ontogeny of the somatosensory vibrissae cortex

J Neurosci. 1999 Jun 15;19(12):5131-7. doi: 10.1523/JNEUROSCI.19-12-05131.1999.

Abstract

The following experiments determined that the somatosensory whisker system is functional and capable of experience-dependent behavioral plasticity in the neonate before functional maturation of the somatosensory whisker cortex. First, unilateral whisker stimulation caused increased behavioral activity in both postnatal day (P) 3-4 and P8 pups, whereas stimulation-evoked cortical activity (14C 2-deoxyglucose autoradiography) was detectable only in P8 pups. Second, neonatal rat pups are capable of forming associations between whisker stimulation and a reinforcer. A classical conditioning paradigm (P3-P4) showed that the learning groups (paired whisker stimulation-shock or paired whisker stimulation-warm air stream) exhibited significantly higher behavioral responsiveness to whisker stimulation than controls. Finally, stimulus-evoked somatosensory cortical activity during testing [P8; using 14C 2-deoxyglucose (2-DG) autoradiography] was assessed after somatosensory conditioning from P1-P8. No learning-associated differences in stimulus-evoked cortical activity were detected between learning and nonlearning control groups. Together, these experiments demonstrate that the whisker system is functional in neonates and capable of experience-dependent behavioral plasticity. Furthermore, in contrast to adult somatosensory classical conditioning, these data suggest that the cortex is not required for associative somatosensory learning in neonates.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Newborn
  • Antimetabolites / pharmacokinetics
  • Association Learning / physiology
  • Behavior, Animal / physiology*
  • Conditioning, Psychological / physiology*
  • Deoxyglucose / pharmacokinetics
  • Electroshock
  • Female
  • Hot Temperature
  • Male
  • Neuronal Plasticity / physiology
  • Physical Stimulation
  • Rats
  • Rats, Long-Evans
  • Somatosensory Cortex / physiology*
  • Vibrissae / innervation
  • Vibrissae / physiology*

Substances

  • Antimetabolites
  • Deoxyglucose