Place and modality analysis in caudal reticular formation.

1. Evoked potentials and unit responses were studied under chloralose anaesthesia in a restricted region of the caudal bulbar reticular formation of the cat which is known anatomically to receive a preferential spinal input.2. Responses were analysed in terms of place and sensory modality and show varying degrees of place and modality convergence, as well as preferential responses for certain loci of stimulation.3. Evidence is presented which suggests that some unit responses are generated in dendrites.4. The response properties of the whole population are compared with those obtained from other reticular regions in previous identical experimental series. It is shown that the integrated activity of the ascending reticular formation acting as a whole would enable the organism to discriminate, to a greater or lesser degree, place and modality from the convergent peripheral input to the reticular formation.