ISSN:0022-3034    

DOI:10.1002/neu.480040102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480040103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractA preparation of the desert locust,Schistocera gregaria, has been developed, in which it was possible to work with identified neurons while still allowing some behavior. A total of 26 motorneurons to the hind leg were studied singly, and in various pairs, both by direct stimulation, and by recording during spontaneous activity and various reflex actions. Motorneurons were identified by passing current into their somata and correlating the evoked somata spikes with extracellularly or intracellularly recorded events in the muscles. Tension of the muscle was also recorded and motor axons were stimulated to evoke antidromic spikes in the somata. Both epsp's and ipsp's can be seen clearly in recordings from the somata; spikes appear as electrotonically conducted remnants only. Somata exhibited little or no electrogenesis. It is inferred that impulses are initiated in a zone tentatively identified with the region of emergence of the motor axon from the neuropil. Integration occurs in the neuropilar segment, with the soma serving as a parallel RC element. Data was obtained on the central mechanisms of coordination of synergistic and antagonistic motorneurons and on the modes of excitation of slow and fast neurons to the same muscles.

ISSN:0022-3034    

DOI:10.1002/neu.480040104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractPreliminary studies are reported on the roles of some interneurons and motorneurons in generating simple behavior patterns in the locustSchistocerca gregaria. The neurons were penetrated by intracellular electrodes singly, or in pairs, whilst a variety of reflexes and spontaneous movements was observed. For example: large oscillations of membrane potential occurring at characteristic flight frequency were observed in flight motorneurons after blowing on the head. The pattern of impulses was directly determined by the amplitude and period of the oscillations. Similar oscillations were observed to occur spontaneously in leg motorneurons, where they caused bursts of impulses which closely resembled those occurring during walking.Both sensory‐integrating and pre‐motor interneurons were encountered, but none with the function of “commanding” motor output. Much of the input to leg motorneurons is already in programm

ISSN:0022-3034    

DOI:10.1002/neu.480040105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractMorphological and electrophysiological studies of the agranular cerebellar cortex of ferret after infection with panleukopenia virus have led to the following conclusions:A.At light microscopic level this agranular cerebellar cortex is shown to be totally disorganized when compared to its normal lamination.B.From an ultrastructural point of view, Purkinje cells are present throughout the thickness of the cerebellar cortex, demonstrating dendritic branches studded with unwed spines.C.Purkinje cells receive four different types of inputs‐climbing fibers, mossy fibers, stellate cell terminals, and Purkinje cell axon collateral terminals. The mossy fiber contacts which are generally not present in mammals are made in some cases to elongated, “dolichoderic” spines.D.Stellate, basket, and Golgi cell interneurons are present, and receive inputs from mossy and climbing fiber terminals, and probably from axon collaterals of Purkinje cells. The mossy fiber input to these neurons represents a true reorganization of the cerebellar circuit, since it has never been observed in any other vertebrate.E.Stellate and basket cells terminate in contact with dendrites and somata from Purkinje cells, while the Golgi cell terminals seem to be restricted to somata and dendrites of other Golgi cells.F.Electrophysiologically, Purkinje cells can show normal excitability following antidromic invasion, and may be activated by the mossy and climbing fiber afferent systems. Intra‐and extracellular recording from Purkinje cells demonstrates that the mossy fiber afferent system activates Purkinje cells with a latency of approximately 1 msec and its excitatory action is graded with relation to the amplitude of the white matter stimulation. Following an initial excitation, this input generates a longlasting inhibition (50 msec), which is attributed to mossy and climbing fiber activation of inhibitory interneurons.G.Climbing fiber activation generates the typical all‐or‐none burst response in Purkinje cells extracellularly. Intracellularly, large unitary EPSPs characteristic of this form of activation may be recorded with a latency of 1.5 to 3 msec. This large unitary EPSP seems to behave in the usual one‐to‐one relation (one climbing fiber to one Purkinje cell).H.Double climbing fiber activation reveals that a conditioning white matter stimulation produces a total inhibition of a climbing fiber burst at 15 msec interval, which indicates a rather strong inhibitory action on Purkinje cells following this form of activation.I.Climbing fiber activation is followed in most cases by a so‐called climbing fiber reflex, suggesting that the inferior olive in this agranular condition is functioning in a normal manner.J.Finally, some of the neurobiological implications of these findings are considered

ISSN:0022-3034    

DOI:10.1002/neu.480040106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480040101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY