Biological Parallel Processing The Brain Biological Parallel Processing Computer Science and Software Engineering © 2014 Project Lead The Way, Inc.

The Brain: Massive Parallel Processing Presentation Name Course Name Unit # – Lesson #.# – Lesson Name The Brain: Massive Parallel Processing Brain = 100 billion neurons The brain is made of neurons. In some ways, each neuron is like a CPU. The neurons are wired to each other, organized into modules that are interconnected. The outer few millimeters of the brain is the cortex, a crinkled sheet of 20% of the brain's neurons. The sheet has parallel columns which are 3 to 6 layers thick. The cortex has four lobes on each side (hemisphere) of the brain. Each lobe performs many tasks. Although any one type of task is complicated to pin down to one location in the brain, it's nice to have a few placeholders. In our frontal lobe, we control our attention and make plans. Processing in our temporal lobes lets us hear speech and understand it. The occipital lobe processes our vision. We process our sense of touch across the parietal lobe, where it coordinates with the frontal lobe by connecting across the central fissure to plan our movements. One structure visible here outside the cortex is the cerebellum. The cerebellum coordinates the timing in sequences of movements like speech, walking, or playing a piano piece. Half the brain's neurons are in the cerebellum, where thousands of parallel sheets of neurons provide a sequence in time after some event.

Neurons Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Neurons A neuron is a cell that sends electrical output to muscles or other neurons based on sensory input or electrical input from other neurons. We say a neuron "fires" when it sends a pulse of electricity down its axon. Neurons can fire up to about 10 times per second. The input comes from the dendrites, and the processing happens in the cell body (also called the soma). Image courtesy Blaus ©2013

Synapse Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Synapse When the electrical synapse reaches the end of the axon, the axon discharges neurotransmitters into the synapse. The synapse is a small gap when the axon has grown onto another neuron's dendrite. Receptors on the dendrite detect this chemical signal and send (or stop sending) an electrical signal down the dendrite toward the post-synaptic cell's soma. Image courtesy Nrets (2006)

Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Vision Retina has 125 million neurons (rods and cones) 1 pixel = 1 rod or cone Our eyes detect light using millions of neurons. Image courtesy Fischer ©2013

What are the wiring routes? Presentation Name Course Name Unit # – Lesson #.# – Lesson Name The Brain: A CS Grand Challenge What are the wiring routes? fMRI 3D images of brain activity In MRI (magnetic resonance imaging) radio waves are sent into the brain, and molecule-specific echoes come out. Functional MRI (fMRI) tracks oxygen flow and tells us where neurons are sending electrical signals so that we can map the brain's activity in detail. Computation creates a 3D image we can sift through to see patterns of brain activity. This is a new technology. We are learning about the brain at an unprecedented rate. Our tools are getting better and better, detecting finer detail. These 3-D images are producing massive amounts of data. Like the sequencing of DNA, fMRIs are drowning scientists in data. Image courtesy Irving ©2004 Image courtesy Gray©2014

Extra Detail on Human Brain Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Extra Detail on Human Brain http://en.wikipedia.org/wiki/File:NIA_human_brain_drawing.jpg