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Much of your brain is devoted to signals from the retina. Visual input is one of the greatest senses providing stimuli for the fight or light reflexes.  Animals also have these pathways because survval means escaping from predators.

 LEDs don’t just hurt your eyes. They quietly drain your nervous system.

Your eyes are not just cameras. They are sensors wired straight into the brain’s control centers.

Inside the retina are specialized cells called intrinsically photosensitive retinal ganglion cells. These cells do not help you see objects. They help regulate alertness, hormone release, body temperature, and the sleep wake cycle. They send signals directly…

Where do they go?

Besides the primary pathway to the visual cortex (via the Lateral Geniculate Nucleus), visual stimuli are sent to several subcortical structures for specialized processing, including reflex control, circadian rhythms, and rapid emotional responses. 

Key brain regions receiving visual input include:

Superior Colliculus (Midbrain): This structure controls rapid, reflexive eye and head movements (saccades) to direct gaze toward a visual stimulus. It is heavily involved in visual attention and orientation, particularly for stimuli in the peripheral field.

Suprachiasmatic Nucleus (Hypothalamus): This is the body's internal clock, which regulates circadian rhythms and sleep/wake cycles based on light intensity.

Pretectum (Midbrain): This area is responsible for the pupillary light reflex, managing the constriction of the pupil in response to bright light.

Amygdala (Limbic System): A direct, "fast-track" pathway from the retina (via the pulvinar nucleus of the thalamus) allows the amygdala to receive raw visual information quickly—often before the cortex conscious processes it—enabling rapid detection of potential threats, such as angry or fearful faces.

Pulvinar Nucleus (Thalamus): This nucleus connects with the superior colliculus and the amygdala, contributing to the "subcortical pathway" that enables rapid, non-conscious "blindsight" and emotional processing. 

Cortical Pathways Beyond V1

Once visual information reaches the primary visual cortex (V1), it is distributed to higher-order areas via two main streams: 

Dorsal Stream ("Where" or "How" pathway): Travels to the parietal cortex for spatial awareness, motion processing, and guiding motor actions.

Ventral Stream ("What" pathway): Travels to the inferior temporal lobe for object recognition, face recognition, and color processing.