In vivo activity-dependent plasticity at cortico-striatal connections: Evidence for physiological long-term potentiation

AUTOR(ES)

Charpier, S.

FONTE

The National Academy of Sciences of the USA

RESUMO

The purpose of the present study was to investigate in vivo the activity-dependent plasticity of glutamatergic cortico-striatal synapses. Electrical stimuli were applied in the facial motor cortex and intracellular recordings were performed in the ipsilateral striatal projection field of this cortical area. Recorded cells exhibited the typical intrinsic membrane properties of striatal output neurons and were identified morphologically as medium spiny type I neurons. Subthreshold cortical tetanization produced either short-term posttetanic potentiation or short-term depression of cortically-evoked excitatory postsynaptic potentials. When coupled with a postsynaptic depolarization leading the membrane potential to a suprathreshold level, the tetanus induced long-term potentiation (LTP) of cortico-striatal synaptic transmission. Induction of striatal LTP was prevented by intracellular injection of a calcium chelator suggesting that this synaptic plasticity involves an increase of postsynaptic free calcium concentration. Contrasting with previous in vitro studies our findings demonstrate that LTP constitutes the normal form of use-dependent plasticity at cortico-striatal synapses. Since excitation of striatal neurons produces a disinhibition of premotor networks, LTP at excitatory striatal inputs should favor the initiation of movements and therefore could be critical for the functions of basal ganglia in motor learning.

Documentos Relacionados

• "Latent" inhibitory connections become functional during activity-dependent plasticity.
• Neurotrophin release by neurotrophins: Implications for activity-dependent neuronal plasticity
• Long-term potentiation and long-term depression: a clinical perspective
• Decreased probability of neurotransmitter release underlies striatal long-term depression and postnatal development of corticostriatal synapses
• Multiple forms of activity-dependent intrinsic plasticity in layer V cortical neurones in vivo