The thalamic reticular nucleus (TRN) occupies a key position between cortex and thalamus, playing an important role in various functions such as sensory processing, the transition between sleep and wakefulness, attentional mechanisms and cognition Additionally, a multitude of genes implicated in sleep abnormalities and attentional deficits in neurodevelopmental disorders are highly expressed in the TRN. Computational modelling and simulation can offer insight into the interplay of TRN cellular and circuit mechanisms and their contributions to system-level function. The overall goal of my thesis is to extend TRN single cell modeling to account for its cellular, morphological and genetic heterogeneity, integrating it in a model of the thalamocortical loop. With that, I plan to explore some of the mechanisms through which TRN inhibition shapes changes in attentional focus across and within cortical areas and the role it plays in the transition between states of vigilance.