RT Journal Article
SR Electronic
T1 Local Dendrodendritic Inhibition Regulates Fast Synaptic Transmission in Visual Thalamus
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2513
OP 2522
DO 10.1523/JNEUROSCI.4402-11.2012
VO 32
IS 7
A1 Shane R. Crandall
A1 Charles L. Cox
YR 2012
UL http://www.jneurosci.org/content/32/7/2513.abstract
AB Inhibition from thalamic interneurons plays a critical role in modulating information transfer between thalamus and neocortex. Interestingly, these neurons yield inhibition via two distinct outputs: presynaptic dendrites that innervate thalamocortical relay neurons and axonal outputs. Since the dendrites of thalamic interneurons are the primary targets of incoming synaptic information, it has been hypothesized that local synaptic input could produce highly focused dendritic output. To gain additional insight into the computational power of these presynaptic dendrites, we have combined two-photon laser scanning microscopy, glutamate uncaging, and whole-cell electrophysiological recordings to locally activate dendritic terminals and study their inhibitory contribution to rat thalamocortical relay neurons. Our findings demonstrate that local dendritic release from thalamic interneurons is controlled locally by AMPA/NMDA receptor-mediated recruitment of L-type calcium channels. Moreover, by mapping these connections with single dendrite resolution we not only found that presynaptic dendrites preferentially target proximal regions, but such actions differ significantly across branches. Furthermore, local stimulation of interneuron dendrites did not result in global excitation, supporting the notion that these interneurons can operate as multiplexors, containing numerous independently operating input–output devices.