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Intrinsic properties of rat striatal output neurones and time‐dependent facilitation of cortical inputs in vivo
Author(s) -
Mahon Séverine,
Delord Bruno,
Deniau JeanMichel,
Charpier Stéphane
Publication year - 2000
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2000.t01-1-00345.x
Subject(s) - excitatory postsynaptic potential , prepulse inhibition , neuroscience , depolarization , chemistry , membrane potential , postsynaptic current , long term potentiation , facilitation , neural facilitation , inhibitory postsynaptic potential , electrophysiology , postsynaptic potential , time constant , biophysics , biology , psychology , receptor , biochemistry , schizophrenia (object oriented programming) , engineering , psychiatry , electrical engineering
1 In vivo intracellular recordings were performed from striatal output neurones (SONs) ( n = 34 ) to test the role of their intrinsic membrane properties in the temporal integration of excitatory cortical synaptic inputs. 2 In a first series of experiments, intracellular injection of a test depolarising current pulse was preceded by a 200 ms suprathreshold prepulse, the two pulses having the same intensity. An increase in intrinsic excitability was observed as a decrease (55 ± 21 ms, n = 13 ) (mean ± s.d.) in latency to the first action potential of the test response compared to the prepulse response. This value decayed exponentially as a function of the time interval between the current pulses (τ= 364 ± 37 ms, n = 5 ). The voltage response of SONs was not modified by a prepulse that induced a membrane depolarisation < −62 mV. 3 The effect of the suprathreshold prepulse was tested on monosynaptic cortically evoked excitatory postsynaptic potentials (EPSPs). The ability to induce suprathreshold EPSPs was markedly increased by the prior depolarisation ( n = 11 cells). This facilitation decayed progressively as a function of the time intervals between prepulses and cortical stimuli. The potentiation was not observed on small EPSPs reaching a peak potential < −65 mV ( n = 3 ). 4 We conclude that SONs can optimise cortical information transfer by modifying their intrinsic excitability as a function of their past activation. It is likely that this time‐dependent facilitation results, at least in part, from the kinetics of a striatal slowly inactivating potassium current available around −60 mV that recovers slowly from inactivation.