Related Experiment Video
Updated: Sep 10, 2025

Electrophysiological Investigations of Retinogeniculate and Corticogeniculate Synapse Function
Published on: August 7, 2019
Synaptic transmission is dispensable for selecting the winner input but is crucial for the subsequent events of
Tzu-Huei Kao1,2, Yuto Okuno1,3, Kyoko Matsuyama1
1Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
Abstract:
Synaptic transmission has long been thought to regulate neuronal wiring during postnatal development, but this assumption remains largely untested. Selective strengthening of a single "winner" climbing fiber (CF) afferent to each Purkinje cell (PC) and elimination of the other "loser" CF axons in the cerebellum has been a representative model of neural circuit refinement. Here, we examined the role of neurotransmission at CF-PC synapses in their postnatal development. We labeled a subset of CFs in neonatal mice with fluorescent markers and the tetanus toxin light chain to ablate neurotransmitter release from these CFs. Surprisingly, we found that such neurotransmitter release-deficient CFs were able to become the winners. However, synaptic transmission was crucial for the winning CF to extend its synaptic territory along the PC dendritic arbor and eliminate the loser CFs. These findings reveal how synaptic transmission governs multiple steps of synapse elimination but not the selection of the winner input that persists throughout life.
Related Concept Videos
Synaptic Signaling
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
The Synapse
Integration of Synaptic Events
Overview of Synapses
The Role of Ion Channels in Neuronal Computation
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...

