An action potential (AP) is a shift in the membrane voltage of a neuron generally caused by a sudden ion influx, resulting in excitation, allowing for the cell to send signals across its neural network. Spontaneous excitation can be crucial for organizing neural circuits, especially in sensory modalities. For hearing specifically, the auditory brainstem area contains a low-frequency subset of neurons best studied in the avian cochlear nucleus magnocellularis (NM) area termed NMc. Nearly 40% of NMc neurons exhibit spontaneity due to their intrinsic properties allowing for high excitability. Given that NM neurons receive glutamatergic (excitatory) input from the auditory nerve, we hypothesize that NMc neuron spontaneous activity is influenced by glutamate transmission. We used whole cell patch clamp electrophysiology and identified glutamate as our neurotransmitter of interest by recording spontaneous synaptic events when blocking non-glutamate receptors. Thus, we predicted that any spontaneous excitatory post synaptic currents (EPSCs) are AMPA (glutamate receptor) dependent. To test this, we used blocked AMPA and GABA receptors and observed resulting EPSCs after washout of the chemical. We found that while EPSC characteristics varied, the kinetics suggest expression of AMPA and GABA receptors in NMc neurons, supported by elimination of EPSCs with blocking of the AMPA and GABA receptors. Better understanding spontaneous synaptic events in NMc will help characterize their function in the avian auditory brainstem. Additionally, the relationship between spontaneous synaptic events and intrinsic activity allows insight into the modulation of spontaneous firing rates, a mechanism crucial in the development of sensory systems.

Last modified

• 06/30/2021

Creator

• Sriram, Shreya

DOI

• https://doi.org/10.21985/n2-0xny-pr68

Keyword

• Brains
• Activity
• Neuron

Date created

• 2021

Resource type

• Conference Proceeding

Rights statement

• In Copyright