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Data
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Ventral medial entorhinal cortical stellate neuron model: the role of T-type Ca2+ and persistent Na+
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Michele Migliore
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Dorsal and ventral medial entorhinal cortex (mEC) regions have distinct neural network
firing patterns to differentially support functions such as spatial memory. Correspondingly,
mEC layer II stellate neuron action potential frequencies vary across the dorsal-ventral axis,
with dorsal neurons exhibiting lower firing rates than ventral neurons. This has been partly
attributed to higher densities of inhibitory conductances in dorsal compared to ventral
neurons. We asked whether additional conductances might also impact this dorsal-ventral
gradient in spike firing. We report that T-type Ca 2+ current amplitudes increased three-fold
along the dorsal-ventral axis in mEC layer II stellate neurons. Twice as much Ca V 3.2 mRNA
was also detected in ventral mEC compared with dorsal mEC. Unusually, as T-type Ca 2+
currents are only transiently active, long depolarizing stimuli applied to ventral, and not
dorsal, stellate neurons triggered these currents to cause a sustained rise in membrane voltage
and spike firing. This effect was due to T-type Ca 2+ currents acting in concert with persistent
Na + currents. T-type Ca 2+ currents themselves prolonged excitatory post-synaptic potentials
(EPSPs) to enhance the summation of EPSP trains and augment EPSP-spike coupling in
ventral neurons. In contrast, T-type Ca 2+ currents had no effect on dorsal EPSP spike-
coupling. These findings indicate that by preferentially regulating ventral neuron spike firing
and synaptic potential integration, T-type Ca 2+ currents critically influence the dorsal-ventral
gradient in mEC stellate neuron excitability and associated circuit activity.
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Topczewska A, Giacalone E, Pratt WS, Migliore M, Dolphin AC, Shah MM (2023) Show
Other
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Giacalone, Elisabetta [elisabetta.giacalone at pa.ibf.cnr.it] Show
Other
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Migliore, Michele [Michele.Migliore at Yale.edu] Show
Other
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michele.migliore@pa.ibf.cnr.it
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