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High synaptic threshold for dendritic NMDA spike generation in human layer 2/3 pyramidal neurons
Guilherme Testa-Silva1, Marius Rosier2, Suraj Honnuraiah1
1John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia.
Cell Reports
|December 14, 2022
Summary
Human neurons can generate NMDA spikes, but less effectively than rodent neurons. This reduced capacity is linked to the wider diameter of human dendrites, increasing the synaptic threshold for spike generation.
Area of Science:
- Neuroscience
- Cellular Electrophysiology
- Comparative Neuroanatomy
Background:
- Dendrites are crucial for neuronal integration of synaptic inputs.
- Electrical properties of human dendrites are less understood than those in rodents.
- NMDA-receptor-dependent spikes (NMDA spikes) are a key form of dendritic computation.
Purpose of the Study:
- To investigate the capacity of human dendrites to generate NMDA spikes.
- To compare NMDA spike generation in human versus rodent neurons.
- To elucidate the biophysical mechanisms underlying differences in NMDA spike generation.
Main Methods:
- Dendritic glutamate iontophoresis in human brain slices.
- Local dendritic synaptic stimulation.
- Morphologically realistic and simplified computational modeling.
Main Results:
- Human layer 2/3 pyramidal neurons can generate dendritic NMDA spikes.
- The capacity to evoke NMDA spikes is significantly reduced in human neurons compared to rodents.
- Wider dendritic diameter in human neurons increases the synaptic threshold for NMDA spike generation.
Conclusions:
- Human dendrites possess the capability to generate NMDA spikes.
- Human neurons exhibit a reduced capacity for NMDA spike generation relative to rodent neurons.
- The wider diameter of human dendrites is a primary factor contributing to the higher threshold for NMDA spike generation.
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