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MIT engineers have designed a "brain-on-a-chip," smaller than a piece of confetti, that is made from tens of thousands of artificial brain synapses known as memristors—silicon-based components that mimic the information-transmitting synapses in the human brain. The researchers borrowed from principles of metallurgy to fabricate each memristor from alloys of silver and copper, along with silicon. When they ran the chip through several visual tasks, the chip was able to "remember" stored images and reproduce them many times over, in versions that were crisper and cleaner compared with existing memristor designs made with unalloyed elements. Their results, published today in...

Glanzman’s unpopular hypothesis was that they might reside in the nucleus of the neuron cell, where DNA and RNA sequences compose instructions for life processes. Glanzman’s team found that the RNA from trained donors induced learning, while the RNA from untrained donors had no effect. They had transferred a memory, vaguely but surely, from one animal to another, and they had strong evidence that RNA was the memory-transferring agent. The work of Douglas Blackiston, an Allen Discovery Center scientist at Tufts University... wanted to know if a butterfly could remember something about its life as a caterpillar, so he exposed...

The flip of a single molecular switch helps create the mature neuronal connections that allow the brain to bridge the gap between adolescent impressionability and adult stability. Now Yale School of Medicine researchers have reversed the process, recreating a youthful brain that facilitated both learning and healing in the adult mouse. Scientists have long known that the young and old brains are very different. Adolescent brains are more malleable or plastic, which allows them to learn languages more quickly than adults and speeds recovery from brain injuries. The comparative rigidity of the adult brain results in part from the function...

Findings challenge conventional wisdom of how neurons operateNeurons are complicated, but the basic functional concept is that synapses transmit electrical signals to the dendrites and cell body (input), and axons carry signals away (output). In one of many surprise findings, Northwestern University scientists have discovered that axons can operate in reverse: they can send signals to the cell body, too. It also turns out axons can talk to each other. Before sending signals in reverse, axons can perform their own neural computations without any involvement from the cell body or dendrites. This is contrary to typical neuronal communication where an...

Human brains appear to come in at least two flavours: male and female. Now variations in the density of the synapses that connect neurons may help to explain differences in how men and women think. Even when intelligence levels are equal, women and men excel at different cognitive tasks. But although brain size and neuron density differ between the sexes, these don't seem to correlate with cognitive differences. So, Javier DeFelipe at Complutense University in Madrid, Spain, and colleagues counted the number of synapses instead. The brain tissue they analysed came from the left temporal cortex, a region of the...