Circadian rhythmicity shapes astrocyte morphology and neuronal function in CA1 (McCauley et al 2020)

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Most animal species operate according to a 24-hour period set by the suprachiasmatic nucleus (SCN) of the hypothalamus. The rhythmic activity of the SCN modulates hippocampal-dependent memory, but the molecular and cellular mechanisms that account for this effect remain largely unknown. In McCauley et al. 2020 [1], we identify cell-type specific structural and functional changes that occur with circadian rhythmicity in neurons and astrocytes in hippocampal area CA1. Pyramidal neurons change the surface expression of NMDA receptors. Astrocytes change their proximity clustered excitatory synaptic inputs, ultimately shaping hippocampal-dependent learning in vivo. We identify to synapses. Together, these phenomena alter glutamate clearance, receptor activation and integration of temporally corticosterone as a key contributor to changes in synaptic strength. These findings highlight important mechanisms through which neurons and astrocytes modify the molecular composition and structure of the synaptic environment, contribute to the local storage of information in the hippocampus and alter the temporal dynamics of cognitive processing. [1] "Circadian modulation of neurons and astrocytes controls synaptic plasticity in hippocampal area CA1" by J.P. McCauley, M.A. Petroccione, L.Y. D’Brant, G.C. Todd, N. Affinnih, J.J. Wisnoski, S. Zahid, S. Shree, A.A. Sousa, R.M. De Guzman, R. Migliore, A. Brazhe, R.D. Leapman, A. Khmaladze, A. Semyanov, D.G. Zuloaga, M. Migliore and A. Scimemi. Cell Reports (2020),
1 . McCauley JP, Petroccione MA, D'Brant LY, Todd GC, Affinnih N, Wisnoski JJ, Zahid S, Shree S, Sousa AA, De Guzman RM, Migliore R, Brazhe A, Leapman RD, Khmaladze A, Semyanov A, Zuloaga DG, Migliore M, Scimemi A (2020) Circadian Modulation of Neurons and Astrocytes Controls Synaptic Plasticity in Hippocampal Area CA1. Cell Rep 33:108255 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Synapse; Channel/Receptor;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal GLU cell; Astrocyte;
Channel(s): I A; I h; I M; I K; I K,Ca; Ca pump; I Calcium; I CAN; I Na,t;
Gap Junctions:
Receptor(s): AMPA; NMDA;
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Synaptic Integration; Synaptic Plasticity; Detailed Neuronal Models;
Implementer(s): Migliore, Rosanna [rosanna.migliore at]; Migliore, Michele [Michele.Migliore at];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; AMPA; NMDA; I Na,t; I A; I K; I M; I h; I K,Ca; I CAN; I Calcium; Ca pump; Glutamate;
cacumm.mod *
cagk.mod *
cal2.mod *
can2.mod *
cat.mod *
h.mod *
kadist.mod *
kaprox.mod *
kca.mod *
kdrca1.mod *
kmb.mod *
ltpltd.mod *
naxn.mod *
netstims.mod *
: $Id: netstim.mod,v 2001/01/01 20:30:37 hines Exp $
: modified in such a way that the first event will never be before start
: M.Migliore Dec.2001
: modified in such a way to have the first event at start
: M.Migliore Sep. 2003

  RANGE interval, number, start
  RANGE noise

	interval	= 10 (ms) <1e-9,1e9>: time between spikes (msec)
	number	= 10 <0,1e9>	: number of spikes
	start		= 50 (ms)	: start of first spike
	noise		= 0 <0,1>	: amount of randomeaness (0.0 - 1.0)

	event (ms)
	end (ms)

PROCEDURE seed(x) {

	on = 0
	y = 0
	if (noise < 0) {
		noise = 0
	if (noise > 1) {
		noise = 1
	if (start >= 0 && number > 0) {
	: first spike occurs at start
		event = start
		net_send(event, 3)

PROCEDURE init_sequence(t(ms)) {
	if (number > 0) {
		on = 1
		event = t
		end = t + 1e-6 + invl(interval)*(number-1)

FUNCTION invl(mean (ms)) (ms) {
	if (mean <= 0.) {
		mean = .01 (ms) : I would worry if it were 0.
	if (noise == 0) {
		invl = mean
		invl = (1. - noise)*mean + noise*mean*exprand(1)

PROCEDURE event_time() {
	if (number > 0) {
		event = event + invl(interval)
	if (event > end) {
		on = 0

	if (flag == 0) { : external event
		if (w > 0 && on == 0) { : turn on spike sequence
			net_send(0, 1)
		}else if (w < 0 && on == 1) { : turn off spiking
			on = 0
	if (flag == 3) { : from INITIAL
		if (on == 0) {
			net_send(0, 1)
	if (flag == 1 && on == 1) {
		y = 2
		if (on == 1) {
			net_send(event - t, 1)
		net_send(.1, 2)
	if (flag == 2) {
		y = 0

Presynaptic spike generator

This mechanism has been written to be able to use synapses in a single
neuron receiving various types of presynaptic trains.  This is a "fake"
presynaptic compartment containing a spike generator.  The trains
of spikes can be either periodic or noisy (Poisson-distributed)

   noise: 	between 0 (no noise-periodic) and 1 (fully noisy)
   interval: 	mean time between spikes (ms)
   number: 	mean number of spikes

Written by Z. Mainen, modified by A. Destexhe, The Salk Institute

Modified by Michael Hines for use with CVode
The intrinsic bursting parameters have been removed since
generators can stimulate other generators to create complicated bursting
patterns with independent statistics (see below)

Modified by Michael Hines to use logical event style with NET_RECEIVE
This stimulator can also be triggered by an input event.
If the stimulator is in the on=0 state and receives a positive weight
event, then the stimulator changes to the on=1 state and goes through
its entire spike sequence before changing to the on=0 state. During
that time it ignores any positive weight events. If, in the on=1 state,
the stimulator receives a negative weight event, the stimulator will
change to the off state. In the off state, it will ignore negative weight
events. A change to the on state immediately fires the first spike of
its sequence.