Other evidence, however, including neuroimaging and physiology converges on V4 as necessary to color perception. A recent meta-analysis has also shown a specific lesion common to achromats corresponding to V4. From another direction altogether it has been found that when synaesthetes experience color by a non-visual stimulus, V4 is active.
Other evidence from neuroscience and physiology supports the idea that V4 is essential for color perception. Furthermore, research has found a common lesion in individuals with color blindness (achromats) located in V4. Additionally, studies on synesthesia have shown that V4 is active when colors are perceived through non-visual stimuli.