Brain Neurons: How They Work

Image by azizul hadi via FlickrThe interconnection of Neurons also known as nerve cells creates a massively parallel computer that is responsible for processing all our sensory data. It also holds information in memory cells for later recall.

It is convenient to compare the neural processing of information in the brain to the information processing in a computing device. However, the two of these devices process information in a very different manner. The computer is good at crunching numbers and working with the binary representation of the symbols. The computer can hold massive amount of information on storage devices. Human brain is not very good either at storing vast amount of information or doing quick number crunching. Its main strenght lies in being an excellent pattern recognizer. It can recognize things even if the presented with incomplete information. This observation has lead to the development of an area in computing also known as Neural Computing in which approximate model of neural network are simulated on a computer.

This short video shows a beautiful animation of neurons in the brain. How they are connected and how they function.


Brain Facts

The adult human brain weighs about 3 pounds (1,300-1,400 g).

The adult human brain is about 2% of the total body weight.

The average human brain is 140 mm wide.

The average human brain is 167 mm long.

The average human brain is 93 mm high.

The human brain has about 100,000,000,000 (100 billion) neurons.

The total surface area of the cerebral cortex is about 2500 sq. cm (~2.5 ft²)

Neurons multiply at a rate 250,000 neurons/minute during early pregnancy.

The weight of an adult human cerebellum is 150 g.

There are 12 pairs of cranial nerves.

There are 31 pairs of spinal nerves.

There are about 13,500,00 neurons in the human spinal cord.

The total number of human olfactory receptor cells is about 40 million.There are 1,000 to 10,000 synapses for a "typical" neuron.

The cell bodies of neurons vary in diameter from 4 microns (granule cell) to 100 microns (motor neuron in cord).

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Inspiring Last Talk by Randy Pausch

Image by moominsean via FlickrRandy Pausch, a professor of computer science at Carnegie Mellon University died from pancreatic cancer. He gave an inspiring talk titled Achieving your Childhood Dreams. The talk found its way as a video on Youtube. The video has been watched by millions of people. In the video he is has shown extreme courage in facing his upcoming death.

A talk like this forces us to rethink our priorities. We can go to the moon. We can create all kinds of the technological marvels but we still have not gained much control over life and death. None of us really know why we were born or how or when or why we will die. We can create all kind of explanation to answer these questions but the truth of the matter is that answer to these questions is unknowable.



There was an old Indian Movie titled "Anand" in which the lead character played by Rajesh Khanna, was dying of cancer. He also showed a playful side facing his death while everybody around him was sad and upset. However, he was just a fictional movie character. In Randy Paush we have a real human being who faced his death with courage and he will inspire us all to do the same

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Professor Dan Arieley author of "Predictably Irrational"

Image via WikipediaProfessor Dan Ariley

is the Alfred P. Sloan Professor of Behavioral Economics at MIT, where he holds a joint appointment between MIT's Media Laboratory and the Sloan School of Management. He is also a researcher at the Federal Reserve Bank of Boston and a visiting professor at Duke University. Ariely wrote this book while he was a fellow at the Institute for Advance Study at Princeton.

presented a talk at Google about his book "Predictably Irrational: The Hidden Forces That Shape Our Decisions." His main thesis refutes the original assumption that humans are "Homo Economus" i.e. rational human beings who always act in their best interest and who always try to maximize their profits. A youtube description of his talk:

In a series of illuminating, often surprising experiments, MIT behavioral economist Dan Ariely refutes the common assumption that we behave in fundamentally rational ways. Blending everyday experience with groundbreaking research, Ariely explains how expectations, emotions, social norms, and other invisible, seemingly illogical forces skew our reasoning abilities. Not only do we make astonishingly simple mistakes every day, but we make the same types of mistakes, Ariely discovers. We consistently overpay, underestimate, and procrastinate. We fail to understand the profound effects of our emotions on what we want, and we overvalue what we already own. Yet these misguided behaviors are neither random nor senseless. They're systematic and predictable—making us predictably irrational.

and the video
His work in the area of behavioral finance continues the work started by Amos Nathan Tversky, who was a cognitive and mathmatical psychologists. He worked very closely with Daniel Kahnemann a Noble Prize winning researcher to show conclusively about the hidden biases in the human decision making process. Their findings in the area of behavioral finance question the assumption of human beings acting totally in a rational manner.

The picture that emerges out of these findings portrays us more like "rationalizing beings" rather then "rational beings" or we could say that we use reason and logic as tools to create new knowledge but the process that leads to rational self consistent knowledge is not rational itself.

These findings of human behavior as non-rational are also being supported by the work in the area of Cognitive, Affective and behavioral Neuroscience.

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Right Brain Left Brain Functions

Image via WikipediaThe brain consists of two halves connected through the nerve bundles called Corpus Callosum. Both sides of brain work together to help us in creating a comprehensive picture of the world we experience. The brain works through modules that are specialized to perform specific functions. The right side of the brain is holistic and works through the entire pattern. The left side of the brain is analytic and acts as an interpreter of the experience.

The strong evidence to support this came from the studies of split brain patients. These patients were suffering from acute seizures and to stop the seizure from spreading to the entire brain the best course was to split the two halves of the brain through brain surgery.

The surgery was successful as anticipated in reducing the brain seizures but had some side effects. These patients were subjected to many scientific studies to see the effect of the surgery on their brain functioning by pioneering neuroscientist Dr. Michael Gazzaniga. Here is a video where Dr. Gazzaniga is interviewing a split brain patient:



The video clearly shows that the patient despite appearing completely normal has lost some of his ability to relate and interpret external items. Also, it shows how the left side brain acts as a interpreter and creates a story even if the story does not support the facts.

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