Explore Module

Fototrasduzione e adattamento.
The cascade occurring within photoreceptors (activation of photopigment, transducin, modulation of cGMP and ion channels) explains how light becomes current. Adaptation (to light and darkness) recalibrates the system’s sensitivity, enabling operation across multiple orders of magnitude in luminance.

Resolution and contrast.
Acuity does not depend solely on optics: retinal and cortical circuits select spatial frequencies and orientations, enhancing contour contrast. The different pathways (parvocellular/magnocellular) prioritize detail/color or motion.

Visual pathways and integration.
Beyond V1, processing splits into networks that emphasize “what” (form, color) and “where/how” (space, action). Color perception emerges from the integration of L/M/S cone responses and chromatic opponencies, while motion perception requires temporal integration and binocular disparity for depth.

Why do we perceive motion better than fine details under low light?
Because in scotopic vision, pathways sensitive to global and temporal variations dominate, with reduced spatial resolution.

Why can a small pupil sometimes improve sharpness?
Because it reduces aberrations and increases depth of field (within the limits of diffraction).