The Action of Temperature on the Excitability, Spike Height and Configuration, and the Refractory Period Observed in the Responses of Single Medullated Nerve Fibers

Schoepfle, Gordon M.; Erlanger, Joseph

doi:10.1152/ajplegacy.1941.134.4.694

Cited by 82 publications

(29 citation statements)

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“…There are two reasons why temperature changes give opposite effects on the population spike and the cell discharge probability. First, warming causes shorter action currents with decreased amplitudes (Schoepfle and Erlanger, 1941;Hodgkin and Katz, 1949; Thompson et al, 1985). Increased temperature speeds up the action currents so that the onset of the repolarizing potassium currents occurs earlier than bcforc.…”

Section: Population Potentialsmentioning

confidence: 99%

Brain temperature and hippocampal function

1995

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Even though homeothermic animals regulate the body temperature, fluctuations up to 2-3 degrees C may occur during physiological conditions. In many species, including the rat, a similar variation can be measured in the brain temperature. Such changes are expressed throughout the brain with a preserved gradient between the warmer basal and cooler dorsal parts. In spite of these recordable physiological changes, spatial learning is quite robust, in that it occurs at brain temperatures between 30 and 39 degrees C. Even drastic cooling (to below 15 degrees C) fails to affect consolidation or storage of information when the animal is tested after rewarming. The physiological temperature fluctuations have significant consequences for electrophysiological responses in the brain. Various bioelectrical signals are more sensitive during warming, axonal conduction is speeded up, and stimulus-elicited transmitter release becomes faster and more synchronized. Action potentials have shorter rise and decay times in warm conditions, and the amplitude becomes slightly smaller. Population responses are differently affected by these changes. Dentate field potentials in response to stimulation of perforant-path fibers appear with shorter latency in warm conditions, and the rate of rise in the field EPSP is increased. Paradoxically, the amplitude of the population spike is reduced. This is due to a combination of reduced amplitude of individual action potentials and reduced efficiency of the summation of groups of action potentials. Due to the large effects of temperature on hippocampal field potentials, it is mandatory that brain temperature changes are monitored and/or controlled whenever such responses are recorded in freely moving and anesthetized animals.

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Section: Population Potentialsmentioning

confidence: 99%

Brain temperature and hippocampal function

1995

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“…This should be consulted for details about the method used for 802 A. S. PAINTAL determining ARP and how artifacts inherent in earlier work (cf. Erlanger & Gasser, 1937;Schoepfle & Erlanger, 1941) were eliminated. Except for one aberrant point at 84 m/sec all the other points at 200 C (of Fig.…”

Section: Mechanism Underlying Arp the Relation Of Conduction Velocitmentioning

confidence: 99%

The influence of diameter of medullated nerve fibres of cats on the rising and falling phases of the spike and its recovery

Paintal¹

1966

The Journal of Physiology

144

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SUMMARY1. The relation of conduction velocity, i.e. fibre diameter (Hursh, 1939a) to certain temporal dimensions of the nerve impulse recorded monophasically was studied in medullated fibres of cats in vivo at temperatures mostly ranging between 21 and 370 C.2. Contrary to existing belief, it was demonstrated unequivocally that spike duration varies inversely with the conduction velocities of the fibres; so also the durations of the rising and the falling phases (rise-time and fall-time) of the impulse. The fall-time is linearly related to conduction velocity at all recorded temperatures. The rise-time varies steeply with conduction velocity at the lower levels of conduction rate, and very gradually at the higher conduction rates.3. The spike duration of preganglionic sympathetic fibres is identical with that of somatic medullated fibres with similar conduction velocities. There is therefore little justification for classifying them separately as so-called B fibres.4. The rate of recovery of spike amplitude following a preceding impulse also varies inversely with conduction velocity, and in the same manner as the absolute refractory period (ARP). In fact the relation of time for 40 % recovery of spike amplitude to conduction velocity is identical with the relation of conduction velocity to ARP. The Qlo for 40 % recovery of spike amplitude is 4*7 between 13 and 290 C.5. Rise-time increases exponentially with fall in temperature in all medullated fibres, fast (say 64 m/sec) and slow (say 16 m/sec), the Qlo being 2-5. Fall-time varies exponentially with temperature in slow fibres (Qlo = 3.5); in fast fibres it varies linearly. The Qlo for spike duration is the same in all fibres between 27 and 370 C only, its value being about 3-4. Below 270 C the Qlo depends on the conduction velocity of the fibres.Only in slow fibres does spike duration tend to vary exponentially with temperature.6. Only abortive spikes are generated during the interval between the end of a preceding spike and the end of the ARP which is about 1i times spike duration in fast fibres and about twice spike duration in slow fibres.

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“…A wealth of information now exists concerning the modification of various parameters of nervous activity by temperature changes (Lucas, 1908;Garten & Sultze, 1913;Adrian, 1921;Gasser, 1931;Schoepfle & Erlanger, 1941;Lorente de No, 1947;Tasaki & Fujita, 1948;Lundberg, 1948;Hodgkin & Katz, 1949, to mention only a few of the many investigations relevant to the present work). Most of this information applies, however, to the temperature dependence either of the membrane potential or of the different phases of the nerve impulse; little is known of the effect of temperature on the receptor potential, although it has been reported by Burkhardt (1959) that the amplitude of the receptor potential in the stretch receptor of the crayfish increases with decreasing temperature.…”

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confidence: 97%