Structural and Functional Neuroanatomy of Core Consciousness A Primer for Disorders of Consciousness Clinicians

Understanding the structural and functional neuroanatomy of core consciousness (ie, wakefulness and awareness) is an asset to clinicians caring for persons with disorders of consciousness. Although the neuroscience of wakefulness and awareness remain active areas of investigation, consistent evidence regarding several brain-behavior relationships informs this area of study. Wakefulness (arousal) is supported by brainstem-forebrain-diencephalic systems; its development reflects the integrated and coordinated activation within and between brainstem neuronal groups (eg, the ARAS) and basal forebrain cholinergic neurons innervating the thalamus and other neocortical regions; and widespread excitatory efferents to the neocortex, with corre-sponding desynchronized cortical activity (a hallmark of wakefulness). Awareness reflects the integrated and coordinated activity within and between systems serving wakefulness with cortical areas to and within which ascending sensory, interoceptive, and motor information is presented and associatively processed. Its development reflects anterior forebrain dynamics and corresponding activity within frontal-subcortical circuits in which the central thalamus is a key node for global cortical activation.Predictable and clinically evaluable relationships follow on disruption of the structure and function of the neural systems subserving wakefulness and awareness, and the nature of those disruptions informs not only the clinical presentation of disorders of consciousness but also the interventions (especially pharmacologic agents and/or neurostimulation methods) that may be offered to modify or remediate them. Additionally, distinguishing between the absence of wakefulness and the active process of sleep permits consideration of the interaction between the neural systems supporting consciousness and those producing sleep in relation to clinical presentation and treatment.The current state of the science provides clinicians with deeper insights into the nature of these conditions and their clinical, ethical, and neurophilosophical implications than at any prior time. Although increasing access to practical, reliable, advanced neurodiagnostic methods will no doubt continue to further the scientific study and clinical assessment of the neural systems supporting core consciousness, it is hoped that the present primer on the structural and functional neuroanatomy of wakefulness and awareness will provide clinicians with information that enhances their medical knowledge about the disorders of consciousness and provides a context into which extant and emerging findings from the assessment and treatment literature can be placed.

Automated summary

Understanding the neuroanatomy of wakefulness and awareness is crucial for clinicians dealing with disorders of consciousness. Wakefulness is supported by brainstem-forebrain-diencephalic systems, while awareness is a result of integrated activity within and between wakefulness systems and cortical areas. Disruptions in these neural systems can inform the clinical presentation and treatment options for disorders of consciousness.