Denial, dissociation, suppression, and repression reduce to inhibition, and thus to gamma-aminobutyric acid (GABA), for example, amblyopia (dim vision).
Putting thoughts to the back of the mind, giving undivided attention, and suspension of disbelief, are expressions that imply inhibition, and thus GABA.
“Differential Roles of Neuronal Activity in the Supplementary and Presupplementary Motor Areas: From Information Retrieval to Motor Planning and Execution” illustrates lack of differentiation between the presence of inhibition and the absence of activation: the researchers demonstrated that during movement execution, the activity of pre-SMA neurones decreased, as shown in their Fig 2A; the researchers stated in the abstract and in the discussion that the activity of pre-SMA neurones tended to be ‘suppressed’, but without evidence of what they meant by ‘suppressed’. Behaviourally, there are major differences between lack of activation, lack of activation due to depletion, lack of activation due to inhibition of activation before it occurs, and lack of activation due to inhibition of activation after it has occurred. The same caveats apply to any presumption that subadditive responses are due to ‘suppression’.
“Experience-Dependent Neural Integration of Taste and Smell in the Human Brain” includes a paragraph entitled Suppressive Interaction, wherein the authors describe “depressed responses” and “weak depression”.
Irreversible inhibition means deactivation.

Unintended motor actions include somnambulism and automatisms, which require medication that inhibits activation by dopamine.

Unexpected irritability may be due to a low blood sugar.

Pins and needles in the hands and feet, muscle cramps and numbness around the mouth result from low levels of calcium, which can be due to the overbreathing of anxiety.

Histamine released from mast cells contributes to, or causes, skin rashes.

Iridescent cosmetics contain multiple layers of molecules which fractionate light into its component waveforms and thus produce sensations of colour and movement, all of which can be stage-managed by the wearer of the cosmetics through control of audience position and illumination: if you see it being effective, sit tight and hold the light.

Fear sweat contains fatty acids and proteins, which smell when metabolised by skin bacteria.

Intestinal bacteria may produce alcohol, and thus cause intoxication without the consumption of alcohol.