👁️ Your Eyes May Have Evolved From an Ancient “Cyclops” Organ

Every vertebrate eye — including yours — may trace its origins to a single light-sensitive organ that sat in the middle of the head of a distant ancestor nearly 600 million years ago.

In a new Current Biology study, researchers from Lund University and the University of Sussex propose that an early worm-like ancestor lost its paired eyes after adopting a sedentary lifestyle. What remained was a simple median light-sensitive organ.

Millions of years later, as its descendants became active swimmers, evolution may have repurposed this central organ to form the paired retinas of vertebrates. The same ancestral system also appears to have given rise to the pineal gland, which today regulates our circadian rhythms and melatonin production.

If correct, this model could explain why vertebrate eyes are fundamentally different from those of insects and squid — and why the systems controlling vision and sleep may share a common evolutionary origin.

One important caveat: this is an evolutionary reconstruction, supported by anatomy, developmental biology, and neuroscience, rather than the discovery of a fossil “cyclops.”

📄 Paper: https://www.cell.com/current-biology/fulltext/S0960-9822(25)01676-8

#Evolution #Biology #Vision #Neuroscience #Science

👁️ Scientists Have Mapped the Wiring Behind Human High-Resolution Vision

Researchers have created the first complete cell-by-cell and synapse-level wiring map of the human fovea — the pinhead-sized region of the retina that lets us read, recognize faces and see fine detail in color.

The team reconstructed roughly 3,000 neurons and more than 300,000 connections, tracing how signals move through this tiny patch of nervous tissue. What they found was unexpectedly elegant: while much of the retina uses many overlapping pathways, the human fovea funnels visual information through just three major circuits.

That streamlined architecture may be one reason human central vision is so precise. The researchers describe it as more like an expressway than a maze of side streets — sacrificing redundancy for speed and efficiency.

The fovea is technically part of the central nervous system, which makes this the first complete connectivity map of a human CNS structure at this level of detail. Beyond basic neuroscience, the map could become a reference for treatments aimed at retinal diseases that destroy central vision.

We often talk about the brain as the organ that “sees.” But the first stage of high-resolution vision may already be doing far more sophisticated processing than we realized.

#Neuroscience #Vision #HumanBrain #Retina #Connectome #Science

https://www.pnas.org/doi/10.1073/pnas.2603286123