Answer:
Olfactory fatigue, or nose blindness.
Explanation:
This is inability of an individual to perceive a particular smell after prolong exposure to the molecules of the odours substance.It due to gradual loss of sensitivity of the olfactory receptor cells after long exposure.
Olfactory fatigue is an adaptive process of the brain to prevent overloading of two many sensory inputs in the olfactory memory.
Therefore it blocks sensitivity of the olfactory receptors in the nasal membrane to the molecules of the usually exposed odours substances,so that new neural pathways for the newly acquired stimuli exposed to, will be created-(this is refers to as changed of neuron)
Thus it is the blockage of sensitivity of the olfactory receptors by the brain that explains reasons for lack of perception after prolong exposure.