Related Experiment Video
Updated: May 17, 2026
12:51
Voltage-sensitive Dye Recording from Axons, Dendrites and Dendritic Spines of Individual Neurons in Brain Slices
Published on: November 29, 2012
Excitatory synapses onto axonic spines jump-start action potentials and route information flow
Hongkun Yang1, Kun Wang1, Yijie Chen2
1Department of Neurology, Huashan Hospital, Institute for Translational Brain Research, State Key Laboratory of Brain Function and Disorders, MOE Frontiers Center for Brain Science, MOE Innovative Center for New Drug Development of Immune Inflammatory Diseases, Fudan University, Shanghai, China.
Nature Neuroscience
|May 15, 2026
Summary
Axon initial segment (AIS) spines in adult mice receive glutamate signals, boosting action potential (AP) generation. These axonic spines preferentially activate specific neurons, influencing information flow in the brain.
Area of Science:
- Neuroscience
- Cellular Biology
- Synaptic Plasticity
Background:
- Action potentials (APs) are initiated at the axon initial segment (AIS).
- While GABAergic inputs to the AIS are known, glutamatergic synapses at the AIS are poorly understood.
- The structure and function of glutamatergic synapses at the AIS remain largely unexplored.
Purpose of the Study:
- To investigate the presence and function of glutamatergic synapses at the AIS.
- To determine the role of axonic spines in AP generation and information processing.
- To elucidate how these structures influence neuronal communication in specific brain regions.
Main Methods:
- Electrophysiological recordings in adult mice.
- High-resolution imaging to identify axonic spines.
- Analysis of synaptic receptor expression and structural plasticity.
- Investigation of neuronal circuit connectivity using hippocampal CA3 stimulation.
Main Results:
- Axonic spines expressing ionotropic glutamate receptors were found on the AIS in approximately half of neurons in the dorsal lateral septum (dLS), bed nucleus of the stria terminalis, and striatum.
- These axonic spines undergo structural plasticity in the dLS.
- Voltage-gated Na+ channels at the AIS amplify synaptic responses from axonic spines, facilitating AP generation.
- Hippocampal CA3 neurons preferentially activate axonic spine neurons (ASNs), leading to feedforward inhibition of non-ASNs.
Conclusions:
- Axonic spines at the AIS play a crucial role in initiating action potentials in dLS neurons.
- These structures are key components of synaptic integration and plasticity at the AIS.
- Axonic spines contribute to routing information flow from the hippocampus to downstream brain regions.
Related Concept Videos
01:41Action Potentials
Overview
02:47The Synapse
Neurons communicate with one another by passing on their electrical signals to other neurons. A synapse is the location where two neurons meet to exchange signals. At the synapse, the neuron that sends the signal is called the presynaptic cell, while the neuron that receives the message is called the postsynaptic cell. Note that most neurons can be both presynaptic and postsynaptic, as they both transmit and receive information.
01:14Action Potential
Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information to the nervous system. An action potential is a specific "all-or-none" change in membrane potential that results in a rapid spike in voltage.
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
01:14Action Potential
Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information to the nervous system. An action potential is a specific "all-or-none" change in membrane potential that results in a rapid spike in voltage.
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
01:23Propagation of Action Potentials
The propagation of an action potential refers to the process by which a nerve impulse, or "action potential," travels along a neuron.
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
01:21Neurons: The Axon
Axons are long, cytoplasmic processes of nerve cells capable of propagating electrical impulses known as action potentials. The cytoplasm or axoplasm of an axon contains neurofibrils, neurotubules, small vesicles, lysosomes, mitochondria, and various enzymes, all encased within the axolemma, the plasma membrane of the axon.
The axon attaches to the cell body at a cone-shaped elevation called the axon hillock. The initial part of the axon, closest to the hillock, is known as the initial segment.
The axon attaches to the cell body at a cone-shaped elevation called the axon hillock. The initial part of the axon, closest to the hillock, is known as the initial segment.