Bursting and tonic modes displayed by the TC-RE network with RE-RE clustering as a function of external input on TC neurons for different corticothalamic inputs.

<p>(A) Firing rate of TC (red) and RE (blue) neurons as a function of the external driving input impinging on TC neurons for different corticothalamic input amplitudes. (B) Number of positive (depolarizing, red) and negative (rebound, blue) <i>w</i> values of TC spikes for different corticothalamic inputs. The <i>w</i> values are averaged across 100 trials for each external stimulus. (C,D) Mutual information carried by the firing rate of TC (red) and RE (blue) neurons with a cortico-thalamic input of (C) 1000 spikes/s and (D) 2000 spikes/s, calculated between the set of increasing sensory stimuli (10 − 150 spikes/s) and the neural response given by the firing rate. The white dashed lines in the bars refer to the significance threshold (<i>p</i> < 0.05, bootstrap test). Measures are averaged over 100 trials for each external stimulus. The synaptic strengths are respectively: <i>g</i>_{<i>RE</i> → <i>TC</i>} = 300 <i>μ</i>S, <i>g</i>_{<i>TC</i> → <i>RE</i>} = 200 <i>μ</i>S and <i>g</i>_{<i>RE</i> → <i>RE</i>} = 300 <i>μ</i>S.</p

Values of synaptic strengths for a network of 500 neurons.

<p>Values of synaptic strengths for a network of 500 neurons.</p

Dynamical properties of two-neuron loops.

<p>(A) Scheme of a two-neuron TC-RE loop. (B) Membrane voltage traces of the TC and RE neurons generated by this minimal TC-RE loop. (C) Interspike interval (ISI) distribution of the TC-RE loop as a function of the synaptic strength <i>g</i>_{<i>TC</i> → <i>RE</i>}. The value of <i>g</i>_{<i>RE</i> → <i>TC</i>} is appropriately set to 550 <i>μ</i>S in order to support self-sustained activity, while <i>g</i>_{<i>TC</i> → <i>RE</i>} varies between 10 <i>μ</i>S and 60 <i>μ</i>S. RE and TC ISI distributions are shown in the top and bottom plots, respectively. (D) ISI distribution of a TC-RE loop as a function of the synaptic strength <i>g</i>_{<i>RE</i> → <i>TC</i>}. The value of <i>g</i>_{<i>TC</i> → <i>RE</i>} is chosen equal to 32 <i>μ</i>S to reproduce the two-spike bursting dynamical regime of panel B while <i>g</i>_{<i>RE</i> → <i>TC</i>} varies between 200 <i>μ</i>S and 800 <i>μ</i>S. RE and TC ISI distributions are shown in the top and bottom plots, respectively. (E) Scheme of a minimal purely reticular RE-RE loop. (F) ISI distribution of this loop as a function of the synaptic strength <i>g</i>_{<i>RE</i> → <i>RE</i>}. <i>g</i>_{<i>RE</i> → <i>RE</i>} varies between 200 <i>μ</i>S and 800 <i>μ</i>S. (G) Scheme of an input-driven two-neuron TC-RE loop. (H) ISI distribution of this loop as a function of external sensory input strength. RE and TC ISI distributions are shown in the top and bottom plots, respectively. The synaptic strengths are respectively: <i>g</i>_{<i>RE</i> → <i>TC</i>} = 550 <i>μ</i>S, <i>g</i>_{<i>TC</i> → <i>RE</i>} = 32 <i>μ</i>S and <i>g</i>_{<i>EXT</i> → <i>TC</i>} = 1 <i>μ</i>S.</p

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Dataset associated to the article "Transition between functional regimes in an integrate-and-fire network model of the thalamus", by Alessandro Barardi, Jordi Garcia-Ojalvo and Alberto Mazzoni.<br

Four-neuron motifs in the form of coupled pairs of TC-RE loops.

<p>The two TC-RE oscillators are bidirectionally coupled through (A) TC-RE connections, (B) RE-TC connections, (C) RE-RE connections, and (D) all three connections. (E) Frequency of the power spectral peak and (F) phase coherence at that frequency for the four different motifs. The power spectral density and phase coherence during self-sustained activity were averaged across 50 trials for random values of the GABA decay time (see text). GABA rise time and AMPA rise and decay times are set constant (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161934#sec011" target="_blank">Materials and Methods</a> section). When the corresponding connections exist in the motifs, the synaptic strengths are respectively: <i>g</i>_{<i>RE</i> → <i>TC</i>} = 550 <i>μ</i>S, <i>g</i>_{<i>TC</i> → <i>RE</i>} = 32 <i>μ</i>S, and <i>g</i>_{<i>RE</i> → <i>RE</i>} = 20 <i>μ</i>S.</p

Spindle self-sustained activity generated by a full network of TC-RE neurons depending on RE-RE clustering.

<p>(A) Connectivity matrix of a random TC-RE network. The presynaptic neurons are represented in the x axis and the postsynaptic neurons in the y axis. The network is made of 500 neurons, of which the first 250 are RE neurons and the remaining ones are TC neurons. (B) Connectivity matrix in the presence of RE-RE clustering (rewiring probability <i>RP</i> = 0.25) (C) Membrane voltage dynamics of a couple of arbitrarily chosen TC and RE neurons in the case of random network. (D) Membrane voltage dynamics of a couple of arbitrarily chosen TC and RE neurons in the presence of clustering: evidence of typical spindle oscillations. (E,F) Distribution of inter-spike intervals (along the horizontal axis, color-coded and normalized to unit area) as a function of the rewiring probability (along the vertical axis) for RE (panel E) and TC (panel F) neurons. The synaptic strengths are respectively: <i>g</i>_{<i>RE</i> → <i>TC</i>} = 300 <i>μ</i>S, <i>g</i>_{<i>TC</i> → <i>RE</i>} = 200 <i>μ</i>S and <i>g</i>_{<i>RE</i> → <i>RE</i>} = 300 <i>μ</i>S.</p

Bursting and tonic modes displayed by a TC-RE network with RE-RE clustering as a function of external input on TC neurons.

<p>(A) Firing rate of TC (red) and RE (blue) neurons as a function of external driving input impinging on TC neurons. (B,C) ISI distribution as a function of external driving input on TC neurons of RE (B) and TC (C) neurons. (D) Mutual information between the set of increasing external stimulus (0-150 spikes/s) and the neural response given by the firing rate of TC and RE neurons. Different external sensory inputs are considered for the two regimes, following panel A: 0-50 spikes/s for the bursting mode and 60-150 spikes/s for the tonic mode. The white dashed line in the bar plots refers to significance threshold (<i>p</i> < 0.05, bootstrap test). The measures are averaged over 100 trials for each external stimulus. (E,F) Adaptation variable <i>w</i> of RE (E) and TC (F) neurons (color coded) as a function of the external input on TC neurons, averaged across 100 trials for each external stimulus. (G) Number of positive <i>w</i> values (depolarizing events, green) and negative <i>w</i> values (rebound events, black) of TC neurons. (H) Coefficient of variation of the ISI for both TC and RE cells as the input rate on TC neurons increases. The synaptic strengths are respectively: <i>g</i>_{<i>RE</i> → <i>TC</i>} = 300 <i>μ</i>S, <i>g</i>_{<i>TC</i> → <i>RE</i>} = 200 <i>μ</i>S and <i>g</i>_{<i>RE</i> → <i>RE</i>} = 300 <i>μ</i>S.</p

Simulated laminar recordings for excitatory synapses only in the lower dendritic bush

Simulated recordings (10101 ms) of the LFP generated by the 3D network described in the paper when excitatory synapses are located only in the lower dendritic bush, computed from LFPy. Each row is a different depth. Input intensity is 1.5 sp/ms

Simulated laminar recordings for homogeneous synaptic distribution

Simulated recordings (10101 ms) of the LFP generated by the 3D network described in the paper when both inhibitory and excitatory synapses are distributed homogeneously over the whole neuron surface, computed from LFPy. Each row is a different depth. Input intensity is 1.5 sp/ms

Performance of candidate LFP proxies.

<p>(A) Illustrations of predictions of LFP time courses from candidate LFP proxies. From top to bottom: firing rate (FR), membrane potential (V_m), AMPA currents, GABA currents (note: these have a negative sign), sum of absolute values of AMPA and GABA currents ∑|<i>I</i>|, sum of AMPA and GABA currents ∑<i>I</i>. Results are shown for a thalamic stimulation of 1.5 spikes/ms, and the proxies are normalized to have variance equal to one (see text),. (B-C) time course of the LFP signal (black) for reference depths 100 μm (B) and -100 μm (C) compared to the best matching proxy, ∑|<i>I</i>| (magenta). The title indicates the fraction of variance explained (85% in both cases). (D-E) Cross-correlation in time between the LFP and the ∑|<i>I</i>| proxy for the two depths. Note that the peaks corresponding to the highest cross-correlation magnitudes corresponded to a lag of 1 ms, i.e., the LFP was best predicted by the value of ∑|<i>I</i>| one millisecond in the past. (F-G) Fraction of LFP signal variance explained by different LFP proxies with optimal delay (same color code as (A)). as a function of depth. The sum of absolute values of the synaptic currents ∑|<i>I</i>| was the best proxy, followed by the use of GABA alone. The firing rate FR was a poor proxy, and the other three were moderately good proxies.</p