2026-04-13T00:11:51Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/990352026-01-16T09:21:25Zcom_2072_1033col_2072_452950

00925njm 22002777a 4500 dc Barardi, Alessandro author García Ojalvo, Jordi author Mazzoni, Alberto author 2016-09-06 The thalamus is a key brain element in the processing of sensory information. During the sleep and awake states, this brain area is characterized by the presence of two distinct dynamical regimes: in the sleep state activity is dominated by spindle oscillations (7 - 15 Hz) weakly affected by external stimuli, while in the awake state the activity is primarily driven by external stimuli. Here we develop a simple and computationally efficient model of the thalamus that exhibits two dynamical regimes with different information-processing capabilities, and study the transition between them. The network model includes glutamatergic thalamocortical (TC) relay neurons and GABAergic reticular (RE) neurons described by adaptive integrate-and-fire models in which spikes are induced by either depolarization or hyperpolarization rebound. We found a range of connectivity conditions under which the thalamic network composed by these neurons displays the two aforementioned dynamical regimes. Our results show that TC-RE loops generate spindle-like oscillations and that a minimum level of clustering (i.e. local connectivity density) in the RE-RE connections is necessary for the coexistence of the two regimes. We also observe that the transition between the two regimes occurs when the external excitatory input on TC neurons (mimicking sensory stimulation) is large enough to cause a significant fraction of them to switch from hyperpolarization-rebound-driven firing to depolarization-driven firing. Overall, our model gives a novel and clear description of the role that the two types of neurons and their connectivity play in the dynamical regimes observed in the thalamus, and in the transition between them. These results pave the way for the development of efficient models of the transmission of sensory information from periphery to cortex. Peer Reviewed Postprint (published version) Àrees temàtiques de la UPC::Física Àrees temàtiques de la UPC::Informàtica Àrees temàtiques de la UPC::Ciències de la salut::Medicina::Neurologia Thalamus Neural networks (Neurobiology) Dynamics Neurons Neural networks Action potentials Single neuron function thalamus Gamma-aminobutyric acid Membrane potential Network analysis Tàlem Xarxes neuronals (Neurobiologia) Dinàmica Transition between functional regimes in an integrate-and-fire network model of the thalamus