RESPIRATORY NEURON ACTIVITY IN THE MESENCEPHALON, DIENCEPHALON AND CEREBELLUM OF THE CARP

The functional properties, localization and connections of neurons with a respiratory-rhythmic firing pattern in the mesencephalon, diencephalon and cerebellum of the carp were studied. Some neurons acquire respiratory rhythm only as a side effect of respiration via sensory stimulation by movements or water current. In other neurons, however, the rhythm is the result of nervous input from the respiratory center. These were studied in more detail. Three categories were distinguished: 1. Plain respiratory neurons. None of the stimuli used could influence the firing pattern of these neurons. 2. Respiratory-optical neurons, which receive both respiratory and visual input. 3. Respiratory-movement-sensitive neurons, the firing pattern of which is sensitive to stimuli influencing the respiratory movements. The respiratory-optical neurons are argued to be components of a system correcting the visual image for respiration-induced displacements of the eyes. The movement sensitive neurons appear to process proprioceptive information at a level, where the demands on the cranial muscles of respiratory and other movements are integrated. The plain respiratory neurons, at least partly, can be regarded as interneurons between the respiratory center and the systems mentioned above. © 1979 Springer-Verlag.