A beacon molecule that prevents vision, behavioral problems in mice

Nestled deep in the middle of the vertebrate brain is a multi-sensory integration and movement control center called the superior colliculus. In rodents, this brain region integrates multi-sensory inputs—visual cues, sounds, ...

What makes us human? The answer may be found in overlooked DNA

Our DNA is very similar to that of the chimpanzee, which in evolutionary terms is our closest living relative. Stem cell researchers at Lund University in Sweden have now found a previously overlooked part of our DNA, so-called ...

New microscopy technique makes deep in vivo brain imaging possible

A pioneering technique developed by the Prevedel Group at EMBL allows neuroscientists to observe live neurons deep inside the brain – or any other cell hidden within an opaque tissue. The technique is based on two state-of-the-art ...

New fish species discovered after years of scientific studies

Scientists identify and name new fish species around the globe practically every week. Some turn up in unlikely places, and others display unusual characteristics and behaviors. But it's rare for an unidentified and unnamed ...

Team rewires a behavioral circuit in a worm using hydra parts

For two people to communicate in a loud, crowded room, they need to be standing side by side. The same is often true for neurons in the brain. But the same way a cell phone allows two people to communicate clearly across ...

Zebrafish predict the future to avoid virtual danger

Scientists from the RIKEN Center for Brain Science (CBS) and collaborators in Japan have discovered particular neurons in the brain that monitor whether predictions made by fish actually come true. By making use of a new ...

Decoding birds' brain signals into syllables of song

Researchers can predict what syllables a bird will sing—and when it will sing them—by reading electrical signals in its brain, reports a new study from the University of California San Diego.

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The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all. In vertebrates, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, balance, taste, and smell.

Brains can be extremely complex. The cerebral cortex of the human brain contains roughly 15-33 billion neurons depending on gender and age, linked with up to 10,000 synaptic connections each. Each cubic millimeter of cerebral cortex contains roughly one billion synapses. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body and target them to specific recipient cells.

The most important biological function of the brain is to generate behaviors that promote the welfare of an animal. Brains control behavior either by activating muscles, or by causing secretion of chemicals such as hormones. Even single-celled organisms may be capable of extracting information from the environment and acting in response to it. Sponges, which lack a central nervous system, are capable of coordinated body contractions and even locomotion. In vertebrates, the spinal cord by itself contains neural circuitry capable of generating reflex responses as well as simple motor patterns such as swimming or walking. However, sophisticated control of behavior on the basis of complex sensory input requires the information-integrating capabilities of a centralized brain.

Despite rapid scientific progress, much about how brains work remains a mystery. The operations of individual neurons and synapses are now understood in considerable detail, but the way they cooperate in ensembles of thousands or millions has been very difficult to decipher. Methods of observation such as EEG recording and functional brain imaging tell us that brain operations are highly organized, but these methods do not have the resolution to reveal the activity of individual neurons.

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