title: Involvement of trigeminal mesencephalic nucleus in kinetic encoding of whisker movements.
abstract: In previous experiments performed on anaesthetised rats, we demonstrated that whisking neurons responsive to spontaneous movement of the macrovibrissae are located within the trigeminal mesencephalic nucleus (Me5) and that retrograde tracers injected into the mystacial pad of the rat muzzle extensively labelled a number of Me5 neurons. In order to evaluate the electrophysiological characteristics of the Me5-whisker pad neural connection, the present study analysed the Me5 neurons responses to artificial whisking induced by electrical stimulation of the peripheral stump of the facial nerve. Furthermore, an anterograde tracer was injected into the Me5 to identify and localise the peripheral terminals of these neurons in the mystacial structures. The electrophysiological data demonstrated that artificial whisking induced Me5 evoked potentials as well as single and multiunit Me5 neurons responses consistent with a direct connection. Furthermore, the neuroanatomical findings showed that the peripheral terminals of the Me5 stained neurons established direct connections with the upper part of the macrovibrissae, at the conical body level, with fibres spiralling around the circumference of the vibrissae shaft. As for the functional role of this sensory innervation, we speculated that the Me5 neurons are possibly involved in encoding and relaying proprioceptive information related to vibrissae movements to other CNS structures.
authors: Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy. Electronic address: fisiou@uniss.it.
authors: Ombretta
authors: O
authors: Mameli
authors: Department of Biomedical Sciences, Physiology Division, Catania University, 95125 Catania, Italy.
authors: Stefania
authors: S
authors: Stanzani
authors: Department of Biomedical Sciences, Physiology Division, Catania University, 95125 Catania, Italy.
authors: Antonella
authors: A
authors: Russo
authors: Institute of Neurological Sciences, National Research Council, Section of Catania, 95125 Catania, Italy.
authors: Rosalia
authors: R
authors: Pellitteri
authors: Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy.
authors: Paolo
authors: P
authors: Manca
authors: Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy.
authors: Pier Luigi
authors: PL
authors: De Riu
authors: Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy.
authors: Marcello Alessandro
authors: MA
authors: Caria
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials; D005154:Facial Nerve / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D008406:Masseter Muscle / Q000294:innervation / Q000502:physiology; D008839:Microelectrodes; D009068:Movement; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D056347:Neuroanatomical Tract-Tracing Techniques; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D012668:Trigeminal Ganglion / Q000033:anatomy & histology / Q000502:physiology*; D014278:Trigeminal Nuclei / Q000033:anatomy & histology / Q000502:physiology*; D014738:Vibrissae / Q000033:anatomy & histology / Q000294:innervation / Q000502:physiology*
keywords: Artificial whisking; Macrovibrissae proprioception; Rat; Trigeminal ganglion; Trigeminal mesencephalic nucleus; Whisker sensory innervation