Home▸Perception & Optical Illusions▸2D Motion Aftereffect — Direction-Selective Neuron Adaptation (2D)

2D Motion Aftereffect — Direction-Selective Neuron Adaptation

A flat 2D companion to the 3D waterfall-illusion spiral: a real translating grating you adapt to, plus an explicit two-pool direction-selective neuron model (leaky adaptation + recovery ODE) whose live firing-rate chart shows why the static test pattern feels like it drifts backward. Adjust drift speed, direction and adaptation rate.

Perception & Optical Illusions2DEasy60 FPS📱 Mobile-adapted⇄ 3D version

Details

CategoryPerception & Optical Illusions

RenderingCanvas 2D

DifficultyEasy

Target FPS60

ControlsSliders for drift speed (0.5-4x), bar width, adaptation duration (3-20s) and fatigue rate; direction toggle (leftward/rightward); Start adapting, Stop now and Reset buttons; live phase, adaptation %, net signal and perceived-direction readouts plus a firing-rate strip chart.

motion aftereffectwaterfall illusionneural adaptationdirection-selective neuronsopponent processcanvas 2dvisual perception

Related simulations

Colour Contrast IllusionsThree classic colour perception illusions: simultaneous lightness contrast, Mach bands at…

Optical Illusions — Visual Perception GalleryInteractive gallery of 8 classic optical illusions: Müller-Lyer, Ebbinghaus, Café Wall,…

Gestalt Grouping PrinciplesInteractive demos of how the visual system organises elements into wholes: proximity,… ⊞ All 160 in Perception & Optical Illusions →

This is the flat, translating-grating companion to the 3D rotating-spiral motion aftereffect. A vertical-bar grating genuinely drifts left or right while you fixate on it, driving an explicit two-pool direction-selective neuron model: one pool tuned to the drift direction, one tuned to the opposite direction. The driven pool's gain fatigues over the adaptation period following a real leaky-integrator differential equation. When the grating freezes for the test phase, the fatigued pool's spontaneous firing is suppressed relative to the fresh opposite pool, so the net direction signal — computed and charted live, not scripted — points backward, exactly matching opponent-process motion-adaptation theory for the waterfall illusion.

⚙ Under the hood

A genuine 2D companion to the 3D rotating-spiral motion aftereffect: a translating vertical-bar grating you actually adapt to for a real timed period, driving an explicit two-pool direction-selective neuron model whose fatigue and recovery are integrated live as a differential equation, not implied by a frozen shader. When the grating truly freezes for the test phase, the fatigued pool's suppressed spontaneous firing versus the fresh opposite pool produces a live-computed net signal — shown as both a directional arrow and a real-time firing-rate strip chart — that points backward, exactly matching opponent-process motion-adaptation theory for the waterfall illusion. Adjust drift speed, bar width, adaptation duration and fatigue rate.

motion aftereffectwaterfall illusionneural adaptationdirection-selective neuronsopponent processcanvas 2dvisual perception

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install