How and Why Do We Study It? The Brain How and Why Do We Study It?

Fact or Falsehood? Electrically stimulating a cat’s brain at a certain point can cause the animal to cower in terror of a tiny mouse. We ordinarily use only 10 percent of our brains. If a blind person uses one finger to read Braille, the brain area dedicated to that finger expands. Adult humans cannot generate new brain cells. Left-handedness is more common among musicians, mathematicians, and professional baseball players. By observing our brain activity, researchers can tell which of ten similar objects (hammer, drill, etc.) we are viewing. 1) True 2) False 3) True 4) False 5) True 6) True

Phineas Gage: Neuroscience’s Most Famous Patient Accidents and the resulting brain damage from them are used to study brain function. Case studies such as the story of Phineas Gage

Noninvasive Ways to Study the Brain Electrical stimulation of the brain (ESB) – milder electrical current that causes neurons to react as if they had received a message. EEGs record electrical activity called brain waves using electrodes. It studies the function of the brain. Picture from http://www.medtek.ki.se/medicaldevices/album/Ch%206%20Measurement%20methods%20&%20values/slides/F%206-18%20EEG%20electrode%20placement.jpg

Other Noninvasive Methods to Stimulate the Brain TMS (transcranial magnetic stimulation) is applied to the cortex using copper wire coils positioned over the head. It is referred to as rTMS if used repetively.

Other Noninvasive Methods Transcranial Direct Current Stimulation (tDCS) uses scalp electrodes to pass very low amplitude direct current to the brain to change the excitibility of the neurons. This method and rTMS are being evaluated for use with the treatment of PTSD and depression. tDCS is not the same as ECT (electroconvulsive therapy), which is used for treatment of depression and bipolar disorders and involves much higher levels of current through the entire brain. Does that SHOCK you?

Invasive Ways to Study the Brain Invasive methods are only tried after noninvasive methods fail or only partially succeed. Deep Brain Stimulation (DBS) is a type of ESB but requires the electrodes to be placed INSIDE the patient’s brain. It is used to treat Parkinson’s disease, seizure disorders, etc. Deep lesioning involved the insertion of a thin, insulated wire into the brain through which an electrical current is sent that destroys the brain cells at the tip of the wire.

Imaging Scans: CAT Scans In CAT scans (computerized axial tomography), a moving ring passes X-ray beams around and through the head to create a 3-D image of the brain. It is used to study the structure of the brain.

Imaging Scans: MRI In an MRI scan (magnetic resonance imaging) , a person lies in a magnetic field. Radio waves cause parts of the brain to give off extra energy. It is used primarily to distinguish soft tissue problems like tumors, strokes, or infections. It also focuses on the structure of the brain. To get a clear picture, you must lie perfectly still. An MRI scan of the brain

f MR I An fMRI is an MRI that studies the brain’s function instead of its structure. It uses magnetism of blood based on its oxygen levels to determine activity. The more oxygen in the blood, the more active the area. Unlike a regular MRI, you are asked to perform a task that increases oxygen levels to a certain part of your brain.

An “Active” MRI – An fMRI s done while you are performing a simple activity. A standard MRI requires immobility. In an fMRI, the computer makes a sort of “movie” of changes in the activity of the brain using images from different time periods .

Imaging Scans: PET Scans In a PET scan (positron emissional tomography), a person is injected with radioactive glucose (blood sugar). The glucose indicates which areas of brain activity exhibit greater productivity. These scans are active brain scans that show the brain at work, so they show its function, not its structure. The above slide shows a PET scan of a normal brain and a brain on cocaine. Red indicates positive usage of glucose (sugar). The brain on cocaine does not perform as effectively, as indicated by more yellow and blue. Lighter colors indicate more activity.

PBS NOVA: Mapping the Brain This interactive video shows use how different brain scans highlight different areas of the brain.

Why is it important to study the brain? Five reasons it is important to study the brain. 1. why/how your brain controls/affects other parts of your body 2. Why we behave the way we do 3. Why we are intelligent (or not) 4. How our brain develops and changes How to treat brain injuries Causes of diseases

For More Info: Nova episode, “How Does the Brain Work?” Nova interactive, “Diagnosing Brain Damage” Nova video short, “Brain Trauma”