Conduction properties of identified neural pathways in the central nervous system of mice in vivo.
Various lines of transgenic or knockout mice are now available that have abnormalities in neuron, glial cells or neuron-glial interaction. However, the techniques for quantitative analysis of their pathophysiological functions are still limited. We established an experimental model system to measure the properties of nerve conduction of identified neural pathways in the CNS using anesthetized and immobilized mice. Dorsal column (DC), vestibulospinal/reticulospinal tracts (VRST) and pyramidal tract (PT) were stimulated by inserting stimulating electrodes into the dorsal column nuclei, medial longitudinal fasciculus, and the medullary pyramid, respectively. Volleys were recorded at various segments in the cervical spinal cord with surface electrodes, and their conduction velocities (CVs) and relative refractory periods (RRPs) were measured. The CVs of the DC, VRST and PT were 26.25 +/- 4.96 m/s (n = 7), 51.55 +/- 4.65 m/s (n = 7), 8.89 +/- 1.81 m/s (n = 7), respectively. Data from paired stimulation indicated that the median values of RRPs of the DC, VRST and PT were 10, 2 and 4 ms, respectively, which suggested marked difference among individual tracts. This is the first attempt to measure the conduction properties of the central tracts in mice in vivo. This experimental procedure will give us a physiological measure of CNS functions in normal and genetically manipulated mice and contribute to clarifying the molecular mechanisms and pathophysiology of neurodegenerative diseases such as multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS).
Tanaka
Hisataka
H
Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan.
Ono
Katsuhiko
K
Shibasaki
Hiroshi
H
Isa
Tadashi
T
Ikenaka
Kazuhiro
K
D000818:Animals; D002490:Central Nervous System / Q000502:physiology* / Q000528:radiation effects; D004558:Electric Stimulation / Q000379:methods; D008526:Medulla Oblongata / Q000033:anatomy & histology / Q000502:physiology / Q000528:radiation effects; D051379:Mice; D018345:Mice, Knockout; D009431:Neural Conduction / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D009434:Neural Pathways / Q000502:physiology* / Q000528:radiation effects; D011930:Reaction Time / Q000528:radiation effects; D013997:Time Factors; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics
D014157:Transcription Factors