[Morphometric investigation on the changes of the paramembranous structures of the CA 1 hippocampal synapses of trained rats, with special reference to the morphological plasticity of the synapses].

Albino rats aged 13 weeks experienced a single training for bright-dark discrimination in a Y-chamber. 24 hours later after a successful training the paramembranaceous structures of the synapses contrasted by phosphotungstic acid were morphometrically analysed. As a result of this investigation a signifikant reduction of the height and the width of the dense projections was to be stated compared to untrained rats. Likewise the length and the width of the postsynaptic ribbon were reduced in trained rats. But this alteration proved not to be significant.