Figure 4: Distance estimation in the parietal cortex utilizes dynamic Bayesian inference

Winkler bags are being hung to dry leaf litter. On this trip, bags were hung for 72 hours to dry. 

This diagram shows correlation between connectivity and distance of neurons in the human cortex. There are approximately 100,000 neurons in a square millimeter of cortex, as illustrated in the center box. The red gradation shows neuronal connectivity, with dark red indicating denser connectivity through synapses. While half of the synapses connect to neurons close to them, the other half connect with distant neurons, as so illustrated in the boxed area on the far left of this diagram. The differences in connectivity and distance between neurons require whole brain simulation in order to understand brain function.

Working in OIST’s interdisciplinary environment, Professor Shinobu Hikami, head of the Mathematical and Theoretical Physics Unit, has become especially interested in using random matrix theory to uncover correlations in complex biological systems, particularly in the intricate folding and entanglement of amino acid chains – an important process which eventually leads to a three-dimension protein, the building block of body tissue.  

The dendrite branches of spiny neurons are littered with spines, or receptor sites, for neurotransmitters, including dopamine. Spiny neurons play a crucial role in initiating and regulating movements of the body, limbs, and eyes by receiving signals from neurons in other parts of the brain that produce dopamine. The Brain Mechanism for Behaviour Unit is studying these cells in order to understand their role in Parkinson’s disease. Gordon Arbuthnott, head of the Unit, had previously found that half of these spines are lost from the dendrites when dopamine is removed, as is the case in Parkinson’s.