Delayed and Temporally Imprecise Neurotransmission in Reorganizing Cortical Microcircuits.
J Neurosci
; 35(24): 9024-37, 2015 Jun 17.
Article
em En
| MEDLINE
| ID: mdl-26085628
ABSTRACT
Synaptic neurotransmission is modified at cortical connections throughout life. Varying the amplitude of the postsynaptic response is one mechanism that generates flexible signaling in neural circuits. The timing of the synaptic response may also play a role. Here, we investigated whether weakening and loss of an entire connection between excitatory cortical neurons was foreshadowed in the timing of the postsynaptic response. We made electrophysiological recordings in rat primary somatosensory cortex that was undergoing experience-dependent loss of complete local excitatory connections. The synaptic latency of pyramid-pyramid connections, which typically comprise multiple synapses, was longer and more variable. Connection strength and latency were not correlated. Instead, prolonged latency was more closely related to progression of connection loss. The action potential waveform and axonal conduction velocity were unaffected, suggesting that the altered timing of neurotransmission was attributable to a synaptic mechanism. Modeling studies indicated that increasing the latency and jitter at a subset of synapses reduced the number of action potentials fired by a postsynaptic neuron. We propose that prolonged synaptic latency and diminished temporal precision of neurotransmission are hallmarks of impending loss of a cortical connection.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Córtex Cerebral
/
Transmissão Sináptica
/
Potenciais Pós-Sinápticos Excitadores
/
Rede Nervosa
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article