Connection Clusters

As our brains learn something, our neurons form new connections in clustered groups, says a new study. In other words, synapses – connections between neurons – are much more likely to form near other brand-new synapses than they are to emerge near older ones. As our neuroscience friends like to say: “Cells that fire together wire together” – and that process of rewiring never stops. From before you were born right up until this moment, the synaptic pathways in your brain have been transforming, hooking up new electrochemical connections and trimming away the ones that aren’t needed. Even when you’re sound asleep,…

Beyond Perfection

If you continue to practice a skill even after you’ve achieved mastery of it, your brain keeps learning to perform it more and more efficiently, says a new study. As we perform a task – say, dunking a basketball or playing a sweet guitar solo – over and over again, we eventually reach a point that some psychologists call “unconscious competence,” where we execute each movement perfectly without devoting any conscious attention to it at all. But even after this point, our bodies keep finding ways to perform the task more and more efficiently, burning less energy with each repetition. This story’s…

Taking Vision Apart

For the first time, scientists have created neuron-by-neuron maps of brain regions corresponding to specific kinds of visual information, and specific parts of the visual field, says a new study. If other labs can confirm these results, this will mean we’re very close to being able to predict exactly which neurons will fire when an animal looks at a specific object. Our understanding of neural networks has come a very long way in a very short time. It was just a little more than 100 years ago that Santiago Ramón y Cajal first proposed the theory that individual cells – neurons – comprised…

The Memory Master

A gene that may underlie the molecular mechanisms of memory has been identified, says a new study. The gene’s called neuronal PAS domain protein 4 (Npas4 to its friends). When a brain has a new experience, Npas4 leaps into action, activating a whole series of other genes that modify the strength of synapses – the connections that allow neurons to pass electrochemical signals around. You can think of synapses as being a bit like traffic lights: a very strong synapse is like a green light, allowing lots of traffic (i.e., signals) to pass down a particular neural path when the neuron fires. A…

Guiding Neuron Growth

Our neurons’ growth can be shaped by tiny cues from spinning microparticles in the fluids that surround them, a new study reports. The branching and growth of neurons is based on several kinds of guides, including their chemical environment, their location within the brain, and the dense network of glial cells that support and protect them. But as it turns out, they’re also surprisingly responsive to fluid dynamics, turning in response to the rotation of nearby microparticles – a bit like the way a vine can climb a fence-post. Since the early days of neuroscience, researchers have dreamed of growing and shaping neurons for specific purposes – to patch…

Synaptic Changes

Synapses – the junctions where neurons communicate – are constantly growing and pruning themselves – and those two processes occur independently of one another, says a new study. As a synapse sees more and more use, it tends to grow stronger, while synapses that fall out of use tend to grow weaker and eventually die off. Collectively, these processes are known as synaptic plasticity: the ability of synapses to change their connective properties. But as it turns out, the elimination of redundant synapses isn’t directly dependent on others being strengthened – instead, it seems to be triggered by its own independent chemical…

Silicon Synapses

A new kind of computer chip mimics the way a neuron learns, a new study reports. The 400-transistor chip simulates the activity of a single synapse – a connection between two neurons. Because of the chip’s complexity, it’s able to mimic a synapse’s plasticity – its ability to subtly change structure and function in response to new stimuli. For example, a synapse that repeatedly responds to an electric shock might, over time, become less sensitive to that shock. Thus, synaptic plasticity forms the basis of neural learning, well below the level of conscious processing. The human brain contains approximately 100 billion neurons, and more…