| Abstract: | Electrophysiological, morphometric and behavioural studies have been made on the role of parafascicular complex in regulation of nociceptive sensitivity in 45 rabbits from the 1st to the 16th day of their postnatal life. The evoked potential to nociceptive stimulation was recorded already in 1-day animals. Analysis of amplitude-temporal parameters of the EPs in acute experiments revealed a sharp increase in their positive phase at the 7-8th day of life. As it was shown in the behavioural experiments, that is just the period of maximum generalized reaction to nociceptive stimulation. It was found that to this age, the surface of neurones in the complex significantly increases, their density remaining still high. The data obtained are discussed in relation to factors which account for ontogenetic changes in electrophysiological correlates of neuronal responses in the parafascicular complex to peripheral nociceptive stimulation. |
