English to French Medical Medical (general) Ophtalmologie

Bonjour,

Merci de m'aider à trouver le sens du terme en objet dans le contexte suivant :

"A rod or cone photoreceptor actually releases less neurotransmitter when stimulated by light.
Neurotransmitter could either stimulate (depolarise) or inhibit (hyperpolarise) the bi-polar cell it synapses with, dependent on the nature of the receptor on the bi-polar cell.
This ability is integral to the centre on/off mapping of visual units."