Unitary Components in the Activation of Clarke's Column Neurones

Eide, Erling; Fedina, L.; Jansen, J. K. S.; Lundberg, A.; Vyklický, Ladislav

doi:10.1111/j.1748-1716.1969.tb04559.x

Cited by 40 publications

(22 citation statements)

References 26 publications

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“…This contrasts with synaptic action on spinal motoneurones in which the maximum monosynaptic e.p.s.p.s rarely exceed 12 mV (Eccles, Eccles & Lundberg, 1957). In addition, the mean amplitude of monosynaptic e.p.s.p.s evoked by activation of a single afferent fibre is also greater in DSCT neurones than in motoneurones (Eide, Fedina, Jansen, Lundberg & Vyklicky, 1969b; also, cf. Kuno & Miyahara, 1968).…”

Section: Introductionmentioning

confidence: 76%

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Synaptic action on Clarke's column neurones in relation to afferent terminal size

Kuno¹,

Muñoz-Martínez²,

Randić³

1973

The Journal of Physiology

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SUOMMARY1. Excitatory post-synaptic potentials (e.p.s.p.s) were recorded intracellularly from Clarke's column neurones (DSCT neurones) of the cat in response to adequate stimuli applied to a variety of sensory receptors.2. The amplitude of e.p.s.p.s so produced varied from less than 0-2 mV to more than 2-3 mV. The M. KUNO AND OTHERS and motoneurones were examined with the electron microscope after chronic section of the dorsal roots.7. Dendritic degenerating terminals showed no significant difference in size between motoneurones and DSCT neurones. Degenerating 'giant' terminals were found on DSCT neurones, but they were located only on or very close to the cell body.8. It is concluded that the major factor responsible for a large number of 'quanta' of transmitter released at synapses on DSCT neurones is the number of multiple synaptic contacts formed by one afferent fibre rather than the size of individual synapses.

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Section: Introductionmentioning

confidence: 76%

“…amplitude between the two groups of neurones. Thus, it has been postulated that large e.p.s.p.s evoked in DSCT neurones are at least in part due to a large number of 'quanta' of transmitter released by impulses in individual afferent fibres (Kuno & Miyahara, 1968;Eide et al 1969b).…”

Section: Introductionmentioning

confidence: 99%

Synaptic action on Clarke's column neurones in relation to afferent terminal size

Kuno¹,

Muñoz-Martínez²,

Randić³

1973

The Journal of Physiology

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“…Birks, Huxley & Katz, 1960), the difference in m value between the neuromuscular junction and the central synapse may be accounted for by the difference in the size of their presynaptic terminals (Eccles, 1961). It has recently been shown that m values of the monosynaptic response observed in Clarke's column neurones are significantly greater than those measured in spinal motoneurones (Kuno & Miyahara, 1969;Eide, Fedina, Jansen, Lundberg & Vyklicky, 1969). A substantial number of synaptic endings on Clarke's column neurones are 5-15 # in diameter (Szentagothai & Albert, 1955), whereas those on spinal motoneurones usually range from 0-5 to 3 ,t (Haggar & Barr, 1950).…”

Section: Introductionmentioning

confidence: 99%

Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog

Kuno¹,

Turkanis²,

Weakly³

1971

The Journal of Physiology

286

134

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SUMMARY1. End-plate potentials were recorded intracellularly at the frog neuromuscular junction bathed in a solution containing a low concentration of calcium and a high concentration of magnesium.2. The muscle was subsequently subjected to 'cholinesterase staining', and the area of the individual end-plates, studied with intracellular electrodes, was measured.3. A positive correlation was found between the end-plate area and the diameter of muscle fibres.4. The mean quantum content (m) showed a positive correlation with the size of end-plates.5. The frequency of spontaneous miniature end-plate potentials was positively correlated with m as well as with end-plate area.6. It is concluded that the amount of transmitter released following nerve stimulation is related to the size of nerve endings.

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“…Here, the timing of the input and output spikes is correlated . This model may be applicable to the Clarke's column cells where single IA fibers may produce EPSP in the 2-5 my range (11) and, by analogy, to the LCN cell where presynaptic profiles are large and probably establish multiple contacts with postsynaptic Deafferenied Animals . After dorsal rhizotomies, two distinct phases of abnormal neuronal activity are associated temporally with morphological alterations in LCN ( Table 1) .…”

Section: Resultsmentioning

confidence: 99%

Deafferentation effects in lateral cuneate nucleus of the cat: Correlation of structural alterations with firing pattern changes

Kjerulf

O'Neal

Calvin

et al. 1973

Experimental Neurology

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A correlated anatomical and physiological investigation of the effects of unilateral cervicothoracic dorsal rhizotomies upon lateral cuneate nucleus of the cat (LCN) is reported. Pairs of adult cats with identical survival times were selected to correlate structural and functional changes . Two phases are described in the development of alterations of neuronal firing patterns . In the first phase, a relative silence within LCN was associated with depletion of round synaptic vesicles in the presynaptic profiles (LR boutons) of primary dorsal root afferents . The second phase was characterized by a development of spontaneous electrical hyperactivity which corresponded anatomically to the presence of denuded postsynaptic specializations, transient increase of adjacent extracellular space and an apparent decrease in the number of dendritic spines . There was a persistence of an unaltered population of small presynaptic boutons with flattened vesicles (SF boutons) . The LCN neuronal membrane is viewed as having an intrinsic tendency for repetitive firing which is enhanced by the functional effects of denuded postsynaptic specialization . A marked similarity was found between some of the spontaneous firing patterns of normal animals (doublets) and the high frequency bursting firing pattern in deafferented preparation. Three models for repetitive spike production are considered in our analysis : oscillator-produced spikes ; EP SP-produced spikes ; and spike-evoked spikes . The spike-evoked spikes model is considered to be the 1 The authors thank

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Unitary Components in the Activation of Clarke's Column Neurones

Cited by 40 publications

References 26 publications

Synaptic action on Clarke's column neurones in relation to afferent terminal size

Synaptic action on Clarke's column neurones in relation to afferent terminal size

Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog

Deafferentation effects in lateral cuneate nucleus of the cat: Correlation of structural alterations with firing pattern changes

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