The Brain: Introduction, Brain Scans and Imagery

Scanning of a human brain by X-rays

Scanning of a human brain by X-rays

The brain enables the mind: seeing, hearing, remembering, thinking, feeling, speaking and dreaming.

Science now enables us to know about the living brain through lesions. Lesions are destroyed tissue. A brain lesion is naturally or experimentally caused destruction of brain tissue, which selectively removes tiny clusters of normal or defective brain cells without harming the surroundings. We can also probe the brain with tiny electrical pulses. Scientists can look upon on the messages of individual neurons and on mass action of billions of neurons. We can see colour representations of the brain’s energy – their consuming activity. These tools facilitated the neuroscience revolution.

The oldest method of studying the brain-mind connection is to observe the effects of brain disease and injuries. This has been going on for more than five thousand years. In the past two centuries, physicians have been recording the results of damage to specific brain areas. Some noticed that damage to one side of the brain often caused numbness or paralysis on the opposite side of body. This suggested that that somehow the right side of the body is wires to the left side and vice versa.

Other scientists noticed that damage of the back of brain disrupted vision and that damage to the left front part of the brain caused speech difficulties. These discoveries have helped scientists map the brain. Today scientists are able to electrically, chemically or magnetically stimulate various parts of the brain to record the effects. Modern electrodes are so small that they can detect the electro pulse in a single neuron.

scan2An electroencephalogram or EEG is an amplified recording of the waves of electrical activity that travels across the brain’s surface. These waves are measured by electrodes placed on the scalp when presented with a stimulus.

A positron emission tomography or PET scan is a visual display of brain activity. It detects where a radioactive form of glucose travels to whists the brain performs a given task.

A magnetic resonance imaging system or an MRI is a technique that uses magnetic fields and radio waves to produce computer generated images that distinguish among different types of soft tissue. It also allows us to see structures within in the brain. MRIs align the spinning atoms in our brain through the use of a magnetic field as well as causing a pulse of radio waves that disorients them momentarily. When the atoms return to normal spin the release detectable signals. MRIs can also detect oxygen-laden blood flow.


Myers, David G. Psychology . 6. Worth Publishers, 2001. Print.Myers, David G. Psychology . 6. Worth Publishers,2001. Print.