A brain mechanism for attention

Attention is directed or focussed consciousness. Consciousness is a subjective sensation produced by the simultaneous activation of discrete neurophysiological systems. These are the alerting, awareness, affect, arousal, and attention systems. The process begins with the subcortical scanning of sensory stimuli for affect and significance via pleasure, pain and tension systems. The perceptions then pass to the Thalamus for further scanning and concentration into one sensory modality by Thalamic-Prefrontal-Thalamic reflex inhibition. The unimodal, significant perceptions then activate engrams in the Posterior Inferior Temporal Cortex, the Posterior Inferior Parietal Cortex, and the Posterior and Anterior Association Cortex. These areas project to the Prefrontal Association Cortex (PAC). The PAC inactivates sensory scanning systems causing fixation. The PAC also sends signals to the Hippocampus, which are gated by Septal and Hippocampal generated theta activity in the Hippocampus. This transiently interrupts the blanket inhibition of orientation, alertness, awareness, and arousal produced by the theta activity via the Hypothalamus. As a result of the above mechanisms, only one sensory stimulus activates the orientation, alerting, awareness, arousal, and cognitive systems and hence focussed attention occurs. Focussed attention can also be used to explain the initiation of voluntary movements.