Long-range retrograde spread of LTP and LTD from optic tectum to retina.
Neural activity can induce persistent strengthening or weakening of synapses, known as long-term potentiation (LTP) or long-term depression (LTD), respectively. As potential cellular mechanisms underlying learning and memory, LTP and LTD are generally regarded as synapse-specific "imprints" of activity, although there is evidence in vitro that LTP/LTD may spread to adjacent synapses. Here, we report that LTP and LTD induced in vivo at retinotectal synapses of Xenopus tadpoles undergo rapid long-range retrograde spread from the optic tectum to the retina, resulting in potentiation and depression of bipolar cell synapses on the dendrites of retinal ganglion cells, respectively. The retrograde spread of LTP and LTD required retrograde signaling initiated by brain-derived neurotrophic factor and nitric oxide in the tectum, respectively. Such bidirectional adjustment of the strength of input synapses in accordance to that of output synapses may serve to coordinate developmental refinement and learning functions of neural circuits.
Du
Jiu-lin
JL
Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA.
Wei
Hong-ping
HP
Wang
Zuo-ren
ZR
Wong
Scott T
ST
Poo
Mu-ming
MM
D000818:Animals; D007814:Larva / Q000502:physiology; D007858:Learning / Q000502:physiology; D017774:Long-Term Potentiation / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D018408:Patch-Clamp Techniques; D012160:Retina / Q000502:physiology*; D051245:Retinal Bipolar Cells / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000378:metabolism; D013477:Superior Colliculi / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D014982:Xenopus laevis