Comparison of synaptic transmission and plasticity between sensory and cortical synapses on relay neurons in the ventrobasal nucleus of the rat thalamus.
Relay neurons in the ventrobasal nucleus of the thalamus transmit somatosensory information to the cerebral cortex and receive sensory and cortical (feedback) synaptic inputs via, respectively, medial lemniscal (ML) and corticothalamic (CT) fibres. Here, we report that calcium-permeable AMPA receptors are expressed at CT synapses, but not ML synapses, and that the NMDA receptor (NMDAR)-mediated/non-NMDAR-mediated synaptic current ratio is significantly larger at CT synapses than at ML synapses. Moreover, NMDAR-dependent LTP and L-type voltage-gated calcium channel-dependent LTD are readily induced at CT synapses, but not ML synapses. In particular, LTD of CT synaptic transmission is induced by spiking of postsynaptic relay neurons in continuous mode, but not burst mode, in current-clamp recordings. These results show that the strength of the cortical input to thalamic relay neurons is selectively subjected to use-dependent modification, which could be a mechanism for regulation of thalamocortical-corticothalamic interactions and the underlying sensory processing.
Hsu
Ching-Lung
CL
Institute of Zoology, National Taiwan University, No.1, Roosevelt Road, Section 4, Taipei 106, Taiwan.
Yang
Hsiu-Wen
HW
Yen
Cheng-Tung
CT
Min
Ming-Yuan
MY
D000818:Animals; D015220:Calcium Channels / Q000502:physiology; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011984:Sensory Receptor Cells / Q000502:physiology*; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*; D020651:Ventral Thalamic Nuclei / Q000166:cytology / Q000502:physiology*
D015220:Calcium Channels