Figure 2.

Diagram of the traditional view of the function of the ascending reticular arousal system (ARAS), which provides a global activation of neocortex at the same time that somatic sensations are topographically routed via specific thalamic nuclei to the sensory cortex. Typically over-looked (and not illustrated here) are the feedback influences from neocortex to thalamus and brainstem reticulum. See comments below it item #6. (From Klemm, 2011).