<unk>  refers to<unk> ic interactions between<unk>  and<unk>  regions of the receptive fields of photoreceptor cells in the retina.<unk>  enables edge detection and contrast enhancement within the visual cortex.
Center-surround antagonism
Microbial synergy
Antineoplastic resistance
Cross-resistance
Transmarginal inhibition
Accommodative convergence
Uncoupling 
Co-stimulation