MECHANORECEPTOR ACTIVITY FROM THE MOUTH OF THE CARP IN TRIGEMINAL NERVE BRANCHES AND IN THE MESENCEPHALIC TRIGEMINAL NUCLEUS

Publisher Summary This chapter discusses the mechanoreceptor activity from the mouth of the carp in trigeminal nerve branches and in the mesencephalic trigeminal nucleus. The response characteristics of buccal mechanoreceptors innervated through trigeminal nerve branches to different stimuli were studied by recording from small isolated bundles of nerve fibers. These responses were compared with the firing patterns of neurons in the mesencephalic trigeminal nucleus in reaction to the same stimuli. The study results showed that both trigeminal branches investigated, that is, V2 and V3, carry touch information from different parts of the perioral region that is not important for respiratory movement regulation. A small fraction of the nerve fibers in one V2 branch is connected to slow adapting skin- and tissue receptors around the mouth and to fast adapting deep mechanoreceptors sensing lower jaw abduction. Activation of these receptors influences the respiratory pattern. The neurons recorded from in the mesencephalic trigeminal nucleus do not react to touch stimuli but respond to skin and tissue stretch, and to lower jaw abduction in the same manner as the fibers recorded from in the trigeminal V2 branch do.