The brain and spinal cord are made up of many cells, including neurons and glial cells. In this family of brain cells, scientists now have discovered a new brain cell i.e., a new neuron that is only present in humans.
Scientists discovered this neuron in the upper layer of the cortex in the slices of human brain tissue. They found that the cells are small, compact, dense and bushy in shape. In addition, when they transmit the signal to other cells, they become large, bulbous.
In order to a precise identification, scientists used gene expression and realized that a set of genes expressed in these inhibitory rosehip neurons doesn’t closely match any previously identified cell in the mouse. It means, they have no analog in the rodent often used as a model for humans.
According to scientists, this discovery could be the key to certain brain functions that separate us from mice. But, scientists are yet to find the functions of this particular neuron.
Rosehip neurons appear to make up just 10% to 15% of inhibitory neurons in the first layer of cortex and are likely even more scarce elsewhere. The locations of their points of contact on other neurons suggest they’re in a powerful position to put the brakes on other incoming, excitatory signals—by which complex circuits of neurons activate one another throughout the brain.
Scientists are now planning to study how rosehip neurons are organized in these larger circuits—and to explore whether their dysfunction might play a role in neuropsychiatric disease.
The discovery is published in the journal Nature Neuroscience.