Visual System

A weekly deep dive into the hidden architecture of your mind. V3: Where Vision Starts Going Global Where It Lives V3, sometimes referred to as the tertiary visual cortex, is an extrastriate visual area located just beyond V2 in the visual processing hierarchy. It lies adjacent to V2 within the occipital lobe and receives most of its input from V2. Compared to V1 and V2, V3 represents a slightly later stage of visual processing and serves as an early higher-order visual area.

A weekly deep dive into the hidden architecture of your mind. V2: Where Early Vision Starts Becoming Interpretation Where It Lives V2, also known as the secondary visual cortex, the prestriate cortex, or Brodmann area 18, is located immediately adjacent to V1 in the occipital lobe. It forms a thin, horseshoe-shaped band that surrounds V1 on both the medial (toward the midline) and lateral (away from the midline) surfaces of the brain. While V1 lines the calcarine sulcus, V2

Retinal Waves and Early Visual Development Before a baby is born, its eyes are already preparing for vision. The fetal brain begins organizing how sight will work long before the eyes ever open. Rather than waiting for experience, the visual system starts wiring itself early so that, at birth, its basic circuits are already in place. Without objects to see or light entering the eyes, the developing visual system relies on internally generated activity to build its structure.

Understanding How Our Brain Sees When you open your eyes or encounter something new, your brain quickly creates a picture of what you are seeing. In about 100 milliseconds (ms), your brain has already formed a basic image of your surroundings. This image isn't complete, but it gives you a clear outline of what is there. Here is what actually happened in that brief moment: 0-10 ms: Light hits the retina. At the back of the eye is the retina, which contains photoreceptors. Pho

A weekly deep dive into the hidden architecture of your mind. The Primary Visual Cortex: Your Brain’s First Draft of Reality Where It Lives The Primary Visual Cortex, also known as V1, Brodmann's area 17, or the striate cortex, is located at the rear of your brain in the occipital lobe, positioned along the sides of the calcarine sulcus. What It Does V1 is the first place in the brain’s cortex where visual signals are analyzed. It’s the starting point for turning raw input fr

A weekly deep dive into the hidden architecture of your mind. The Superior Colliculus : The Reflex Engine Behind Your Gaze Where It Lives The superior colliculus (SC) lives in the back of the midbrain. It sits above the inferior colliculus and behind the pineal gland. Together, the superior and inferior colliculi form the tectum (“roof”) of the midbrain. This location is important because it places the SC right in the path of fast visual and auditory information entering the

A weekly deep dive into the hidden architecture of your mind. The Lateral Geniculate Nucleus: How Your Brain Sees Before You Do Where It Lives The lateral geniculate nucleus (LGN) sits inside the dorsal thalamus. There is one LGN in each hemisphere. Each LGN receives visual information from the opposite half of visual space. What It Does The LGN receives visual signals from the retina, sorts them into parallel information streams, and sends the organized output to the primary