EN
Secondary somatosenory cortex (SII) in rodents receives input from vibrissae trough reciprocal cortico-cortical connections from the barrel cortex and directly from thalamic sensory nuclei. In humans, SII is activated bilaterally during attentional tasks and it is consider to play a role in tactile memory and sensimotor integration. We examined it behavioral paradigms that modifi es SI evokes also plasticity in SII. We measured area of SII activation by stimulation of a row of vibrissae previously activated in classical conditioning paradigm, in which stimulation of a row of vibrissae was paired with a tail shock. The training consisted of 3 daily 10 min sessions, during which 40 pairings were delivered. Activation was mapped with [14C]-2-deoxyglucose (2DG) autoradiography one day after the end of conditioning. The autoradiograms were analyzed with computerized image analysis system, which aligned the 2DG uptake pattern with Nissl stain. We reported previously that conditioning results in enlargement of cortical representation of the “trained” row of vibrissae in SI. Here we found that in SII the representation of the “trained” row is increased bilaterally, by 37% on the average. The increase was observed in cortical layers II/III and IV. Clearly, plasticity in SII is not simply a refl ection of changes in SI. It may be supposed that in response to activation of a pathway involved in conditioning, structures involved in attention respond more strongly to sensory stimuli.