Alerting involves the brain's noradrenaline system, which originates in the locus coeruleus.


Neural mechanisms of alerting 

Alerting is readiness in preparation for an impending stimulus.  This includes tonic effects and phasic effects. 


University of Georgia

There are three different components of attention:

Alerting

Orienting

Conflict Monitoring (Executive Attention)

Components of Attention

Tonic sensory input adapts slowly to stimuli and continues to produce action potentials over the duration of the stimui. It conveys information about the duration of the stimulus. Tonic effects result from spending time on a task (vigilance).


Tonic Receptor Cells

Phasic receptors rapidly adapt to a stimulus. The response of the cell diminishes very quickly and then stops. It conveys information on rapid changes in stimulus intensity and rate. Phasic effects result from brain changes induced by warning signals or targets.


Phasic Receptor Cells

Tang, YY., Hölzel, B. & Posner, M. The neuroscience of mindfulness meditation. Nat Rev Neurosci 16, 213–225 (2015). https://doi.org/10.1038/nrn3916.

The Neuroscience of Mindfulness Meditation

Alerting

Orienting is the selection of specific information from multiple sensory stimuli.

Orienting

Conflict Monitoring (Executive Attention) is the monitoring and resolution of the conflict between computations in different neural areas.


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