+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Synaptic transmission from muscle afferents during fictive locomotion in the mesencephalic cat

, : Synaptic transmission from muscle afferents during fictive locomotion in the mesencephalic cat. Journal of Neurophysiology 51(5): 986-997

Modulation of synaptic potentials produced by electrical stimulation of low-threshold muscle afferents in lumbar alpha-motoneurons innervating knee and ankle muscles was studied by intracellular recording during "fictive locomotion" induced by stimulating the mesencephalic locomotor region (MLR) in paralyzed, mesencephalic cats. Averaging postsynaptic potentials in different phases of the fictive step cycle indicated that relatively little amplitude modulation occurred. In nearly half of the 38 motoneurons analyzed, there was a statistically significant tendency for excitatory postsynaptic potentials (EPSPs) to increase in amplitude during the depolarized phase of the oscillation in the membrane potential produced during fictive locomotion (locomotor-drive potential). In 8% the EPSPs decreased under the same conditions, while the rest displayed a constant amplitude during all phases of the fictive step cycle. Only three cells showed a distinct second peak in the EPSP at a latency consistent with transmission in a di- or trisynaptic pathway. Late inhibitory postsynaptic potentials (IPSPs) were also rarely observed. Thus oligosynaptic pathways from muscle afferents to the motoneuron groups studied are not prominent during the locomotor cycle in this preparation. We suggest that the marked modulation of monosynaptic reflex amplitude observed in mesencephalic cats (1) arises mainly from the effects of the locomotor-drive potential in bringing the cells closer to threshold during some phases of locomotion. Specific modulation during fictive locomotion of transmission in pathways from muscle afferents, which has been demonstrated for cutaneous pathways (28), was not observed. The implications of these results for the control of locomotion are discussed briefly.


PMID: 6327933

Other references

Hammer, M.; Leistritz, S.; Leistritz, L.; Schweitzer, D., 2001: Light paths in retinal vessel oxymetry. The oxygen utilization and, therefore, the metabolic state, of a distinctive area of the retina may be calculated from the diameter of the supplying artery and vein, the haemoglobin oxygenation, and the velocity of the blood. The first two paramet...

Gray, A.A., 1908: An investigation on the anatomical structure and relationships of the labyrinth in the Reptile, the Bird and the Mammal. London Proc R Soc ser, B. 80 507-528

Bulkley B.H.; Roberts W.C., 1973: Dissecting aneurysm limited to coronary artery a new cause. Circulation Supplement 48(4): IV-150

Hecker, G.; König, E.; Ney, P.; Schrör, K., 1987: Potent inhibition of PAF-stimulated human platelets and polymorphonuclear leukocytes by the PGE1 analog OP-1206. Progress in Clinical and Biological Research 242: 317-322

Hubbs, C.L., 1969: Message to the ashes of Matsubar. Japhthyol: 36-37

Kerley G.I.H., 1983: Relative population sizes and trends and hybridization of fur seals arctocephalus tropicalis and arctocephalus gazella at the prince edward islands southern ocean. Fur seals were counted at the Prince Edward Islands during the 1981/1982 austral summer. Classified counts, adjusted for pup undercounting and mortality, pregnancy rate and seasonal haulout patterns, of A. tropicalis and A. gazella are presented....

Bedford, M.E., 1993: Mechanoreceptors in knee ligaments of cats and callitrichids. American Journal of Physical Anthropology 0(SUPPL 16): 53-54

Novikov, A.N.; Pichugin, Y.I.; Linnik, T.P., 1992: The effect of cryoprotectants and some organic additives on the recrystallization in model systems. The cryoprotectants ethylene glycol, 1,2-propane diol, glycerol, formamide, acetamide, dimethyl sulfoxide, diethyl sulfoxide, polyethylene oxides of molecular weight 100 - 1500 and polyvinyl pirrolidone were studied. It has been shown that all the...

Whittier, D.P.; Moyroud, R., 1993: The promotion of spore germination and gametophyte development in Ophioglossum palmatum by low pH. American Fern Journal 83(2): 41-46

Casale T.B.; Kaliner M., 1982: Tritium labeled di hydro ergocryptine binding to platelet free intact mononuclear cells. Federation Proceedings 41(3): ABSTRACT 3045