Brain’s Tree of Cell Types Demonstrates Neural Hierarchy

by Karishma Abhishek on Dec 4 2020 4:51 PM

 Brain’s Tree of Cell Types Demonstrates Neural Hierarchy
Brain's tree of cell types (neurons) describes the general building principle of neural circuits as per a study at Baylor College Of Medicine, published in the journal Nature.
A tree of life shows the evolution of life with relationships between species. Similar idea was explored to discover the brain's tree of cell types that aims to organize cells in the brain into groups and describe their relationships to each other.

Basic fundamental features of a neuron – their anatomy (how they look under a microscope), their physiology (how they respond when stimulated), and their transcriptome (the genes they express), were explored using a technique called Patch-seq.

Neural hierarchy : This technique provided a deeper understanding of how exactly the neurons in the motor cortex are related to each other with clarity on the tree of cell types. The neurons had different genetic families, within which, each family of the neurons exhibited extensive anatomical and physiological diversity.

"Our data support the view that the tree of cortical cell types may look more like a banana tree with few big leaves rather than an olive tree with many small ones. This view provides a simpler model to describe the diversity of neurons we find in the brain. We believe that this simpler view will lead to a more principled understanding of why we have so many cell types in the brain, to begin with, and what they are used for," said Tolias, Brown Foundation Endowed Chair of Neuroscience and director of the Center for Neuroscience and Artificial Intelligence at Baylor.

Thus, the neuron hierarchy consists of distinct, non-overlapping branches at the level of families, the large leaves of the banana tree. Within each family, neurons show continuous changes in their genetic, anatomical, and physiological features, and all three features within a family are correlated.

The concept was proved by scientists from the Allen Institute of Brain Science in Seattle, published simultaneously in the journal Cell, who obtained similar results from mouse visual cortex underscoring that this view of cell types may be a general building principle of brain circuits.