A gene-by-gene, neuron-by-neuron search has turned up a new breed of brain cell that may serve as a fine-scale “volume control” for neural activity in humans.
The novel type of brain cell, known as a rosehip neuron, is described in a study published today by Nature Neuroscience.
“It’s very rare, and you only see it, so far, in a human,” study co-author Ed Lein, an investigator at the Seattle-based Allen Institute for Brain Science, told GeekWire.
Lein’s group at the Allen Institute and a Hungarian research team at the University of Szeged, headed by Gábor Tamás, narrowed in on the neurons using two different lines of inquiry.
Tamás’ team uncovered the neurons as they sifted through samples taken from the brains of two men in their 50s who had died and donated their bodies to science. Researchers found the rosehip neurons in the outermost layer of the human neocortex, known as Layer 1. That layer is proportionately thicker in humans than in other species, and it’s thought to play a key role in human consciousness.
The neurons were given the “rosehip” name because each cell’s central axon had the bulbous look of a rose after it has shed its petals. They’re inhibitory neurons, which means they can tamp down electrical impulses coming in from other brain cells.
In a news release, Tamás compared inhibitory neurons to the brake pedals in a car, and said that rosehip neurons appear to be a specialized kind of brake. “This particular cell type — or car type — can stop at places other cell types cannot stop,” he said. “The car or cell types participating in the traffic of a rodent brain cannot stop in these places.”