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 … Continue reading The Memory Master

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 … Continue reading Synaptic Changes

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, … Continue reading Silicon Synapses

Diff’rent Vesicles

A new discovery shows that the rules of synaptic transmission are very different from what we’d thought. In each neuron, tiny sacs called vesicles store neurotransmitter chemicals, and help transport them to other neurons. For decades, scientists had thought all the vesicles of a particular neurotransmitter were more or less identical – but now, they’ve discovered that only one set of vesicles are marked for transmission, while a much larger set lay mysteriously dormant. What causes these differences, you ask? A protein with an awesome name: We now find that the v-SNARE tetanus toxin-insensitive vesicle-associated membrane protein (VAMP7) differs from other … Continue reading Diff’rent Vesicles