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Advanced Neurology Evaluating plausibility of thalamic model

projecting inhibitions onto REs and, consequently, defining When examining the response of the 81 Rs in our
the number of PCs forwarded to the cortex in burst mode. network to three distinct moments of current input
This phenomenon, observed in studies by Mulle (Figure 9B), we observe the three scenarios presented in
et al., is also essential for the biocompatible functioning the experiments by Mulle et al. (Figure 9C). The initial
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of the computational thalamic model. The effects of 70 ms replicate the first scenario without current, while
hyperpolarization on Rs firings, which shape the overall from 80 ms to 140 ms, we observe the second scenario
wave during oscillations, are illustrated in Figure 9A. In of waveform shaping. Concluding with the last scenario
the first scenario without current, there were significant reproduced approximately from 145 ms until the end of
changes in the waveform’s shape. In the second case, the the experiment, we notice the truncation of the activity
applied hyperpolarizing current of 1 nA increased the size from the intermediate scenario with the new current.
of the slow-wave component underlying burst discharges, In summary, these results collectively indicate that the
but its amplitude and duration were reduced by additional Rs of the computational thalamic model function similarly
inward current. In the last scenario, we observe peak to their biological counterparts. The capacity to have their
amplitudes being truncated, as seen in the second example. response waves sculpted by the excitatory inputs from

A B

C
D

Figure 8. Activity of reticular neurons (Rs) over relay neurons (REs) of our computational thalamic model. Consistent responses from artificial Rs (Ret.
neuron [green line]) were observed across all tested frequencies, dependent on the utilized frequency and time interval (grey line). Artificial REs (Rel.
neuron [black line]) exhibited progressively increasing sustained inhibition with higher stimulation frequencies.

A B

C

Figure 9. The sculpting effects of hyperpolarization of reticular neurons (Rs) over oscillation waves. (A) In the first scenario (1 sce.) without current, in
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addition to the baseline oscillation, it is possible to observe the concurrent reticular firings – “spindles” – and the subsequent hyperpolarizing effects that
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sculpt the overall shape of the oscillations. In the second case (2 sce.), a hyperpolarizing current of 1 nA increased the size of the slow-wave component
underlying burst discharges, but additional inward current reduced its amplitude and duration. In the last scenario (3 sce.), peak amplitudes were
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truncated, as observed in the second example. (B) Activity of the 81 Rs at three distinct moments: 1 sce. From 0 to 70 ms, 2 sce. from 80 to 140 ms, and
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3 sce. from approximately 145 ms to the end. (C) Representation of the activity of only one artificial Rs under the previous conditions. Copyright © 1999
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Society for Neuroscience.
Volume 3 Issue 3 (2024) 10 doi: 10.36922/an.3188