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1. Computational modeling of long-term depression of synaptic weights: insights from STDP, metaplasticity and spontaneous activity

Creator:
Beňušková , Lubica and Jedlička, Peter
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
LTP, LTD, STDP, metaplasticity, and spontaneous activity
Language:
English
Description:
Using the STDP rule with metaplasticity, we show that to evoke long-term depression (LTD) or depotentiation of synaptic weights in the spiking model of granule cell is not easy. This is in accordance with a number of experimental studies. On the other hand, heterosynaptic LTD which accompanies homosynaptic long-term potentiation (LTP) is induced readily both in the model as well as in experiments. We offer possible explanation of these phenomena from STDP, metaplasticity and spontaneous activity. We suggest conditions under which it would be possible to induce homosynaptic LTD and depotentiation.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2. Effects of acoustic stimuli on neuronal activity in the auditory cortex of the rat

Creator:
Zhang, Y., Han, L., Xiao, X., Hu, B., Ruan, H., and Xiong, Y.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, zvukové signály, acoustic signals, rhythmic discharges, auditory cortex, intracellular recording, depolarization, spontaneous activity, 14, and 612
Language:
English
Description:
Spontaneous activity of cortical neurons exhibits alternative fluctuations of membrane potential consisting of phased depolarization called "up-state" and persistent hyperpolarization called "down-state" during slow wave sleep and anesthesia. Here, we examined the effects of sound stimuli (noise bursts) on neuronal activity by intracellular recording in vivo from the rat auditory cortex (AC). Noise bursts increased the average time in the up-state by 0.81±0.65 s (rang e, 0.27-1.74 s) related to a 10 s recording duration. The rise times of the spontaneous up-events averaged 69.41±18.04 ms (range, 40.10-119.21 ms), while those of the sound-evoked up-events were significantly shorter (p<0.001) averaging on ly 22.54±8.81 ms (range, 9.31- 45.74 ms). Sound stimulation did not influence ongoing spontaneous up-events. Our data suggest that a sound stimulus does not interfere with ongoing spontaneous neuronal activity in auditory cortex but can evoke new depolarizations in addition to the spontaneous ones., Y. Zhang ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Gain-of-function mutations in the transient receptor potential channels TRPV1 and TRPA1: how painful?

Creator:
Štěpána Boukalová, Filip Touška, Marsakova, L., Hynkova, A., Lucie Surá, Chvojka, S., Ivan Dittert, and Viktorie Vlachová
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, mutace (biologie), funkce, mutation (biology), functions, TRPV1, TRPA1, gain-of-function mutation, spontaneous activity, gating, nociception, 14, and 612
Language:
English
Description:
Gain-of-function (GOF) mutations in ion channels are rare events, which lead to increased agonist sensitivity or altered gating properties, and may render the channel constitutively active. Uncovering and following characterization of such mutants contribute substantially to the understanding of the molecular basis of ion channel functioning. Here we give an overview of some GOF mutants in polymodal ion channels specifically involved in transduction of painful stimuli - TRPV1 and TRPA1, which are scrutinized by scientists due to their important role in development of some pathological pain states. Remarkably, a substitution of single amino acid in the S4-S5 region of TRPA1 (N855S) has been recently associat ed with familial episodic pain syndrome. This mutation increases chemical sensitivity of TRPA1, but leaves the voltage sensitivit y unchanged. On the other hand, mutations in the analogous regi on of TRPV1 (R557K and G563S) severely affect all aspects of channel activation and lead to spontaneous activity. Comparison of the effects induced by mutations in homologous positions in different TRP receptors (or more generally in other distan tly related ion channels) may elucidate the gating mechanisms conserved during evolution., S. Boukalova ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Randomness of spontaneous activity and information transfer in neurons

Creator:
Lubomír Košťál and Lánský, P.
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, neurofyziologie, entropie, neuron, neurophysiology, entropy, neuronal coding, spontaneous activity, randomness, 14, and 612
Language:
English
Description:
The analysis of information coding in neurons requires methods that measure different properties of neuronal signals. In this paper we review the recently proposed measure of randomness and compare it to the coefficient of variation, which is the frequently employed measure of variability of spiking neuronal activity. We focus on the problem of the spontaneous activity of neurons, and we hypothetize that under defined conditions, spontaneous activity is more random than evoked activity. This hypothesis is supported by contrasting variability and randomness obtained from experimental recordings of olfactory receptor neurons in rats., L. Košťál, P. Lánský., and Obsahuje biblografii a biblografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public