When processing information, whether it is interpreting sheet music or reading the words in this article, the neurons in the brain must communicate nearly instantly to determine what is being communicated. A new study from University College London (UCL) and the University of North Carolina (UNC) has suggested that each neuronal dendrite is capable of performing computations individually.
There are an estimated 100 billion neurons in the brain and there could be as many as one million billion dendrites to connect them and facilitate communication. Each neuron can be connected to as many as 1000 other neurons and the information being shared across many is thought to give us our brain power.
To begin neurotransmission, electrical signals, called action potential, are sent down through a presynaptic neuron. This triggers chemical neurotransmitters to be sent through a gap known as the synaptic space, where it is received by the dendrites. The dendrites relay the signal down through the rest of the neuron, and then release the neurotransmitters so that they can be used again by the presynaptic axon. Combining the signal patterns of several of these impulses allows us to see and have memories of images, although this part of the process is not well understood. But, as it turns out, this is not the complete story.
The study, published online on 27 October 2013 in Nature, challenges conventional knowledge and potentially breaks new ground with the understanding of dendrite function. It was previously believed that dendrites merely passed the information along to be processed elsewhere, and did not actually engage in data processing at all. When visual information is being processed, it produces distinct electrical signals that can be measured. By focusing on the neurons that process information collected by the eyes, researchers were able to collect electrical and visual data from the dendrites themselves from mouse test subjects.
The results of this study were completely unprecedented and show that the dendrites may play a role in reading the signal and sorting it so it may be relayed properly to the next neuron. It is thought that this process might remain constant for other areas of sensory perception in the brain and may even occur in human brains.