# SL Psychology/Impact of biology
## Lesioning, EEGs, Neuro-imaging, experimental research, clinical research

In early psychology, researchers labeled the brain as a “black box” unable to be fully understood on a physical level. However with inventions and innovative technological methods established within the last few decades, these tools have allowed for researchers to ‘view’ the brain or/ and gain a better understanding of its processes.

### Lesioning

One method used by researchers is brain lesioning where he or she will purposefully destroy brain tissue in order to discover what action or brain process is affected and therefore unaffected by the damaged tissue. This procedure is practiced on animals considering that destroying human brain tissue is highly unethical. Using brain lesioning, researches have also discovered where the many localized functions of the brain are; for example, the language areas (Broca’s and Wernicke’s) are in the left frontal and in the left temporal lobes while maintaining homeostasis in the body as well as other processes such as regulating emotions is located in the hypothalamus which is in the middle of the base of the brain. One of the first cases that allowed researches to understand how damaged tissues can affect ones brain occurred when a man Phinius Gage suffered from a serious brain injury while working on his job. A pole went through his brain and though he survived the accident, physically unharmed, he seemingly became a totally new person with an abrasive attitude and a rude and vulgar personality. His severe and shocking change in personality led researchers to the conclusion that damaged brain tissue in the frontal lobe area was to blame and that the frontal lobe is a key component to a person’s personality.

### Electroencephlagram

An EEG or an electroencephalogram is an amplified tracing of such waves by an instrument called an electroencephalograph. Researchers use this instrument in order to localize functions of the brain as well. Researchers compare a subject’s EEG to a standard EEG of average data in order to discover any differences when the patient is performing a task. The EEG will show different pattern of lines when a certain brain process is occurring and the researchers can then use the graphs to correlate the data to an electrical wave evoked by the stimulus and thus, its relative position. More recent and advanced technology can even allow researchers to directly view the brain. CT (computed tomography) scans examine the brain by taking x-ray photographs that can reveal brain damage and even more accurate are PET (positron emission tomography) scans which show brain processes by using the sugar glucose in the brain to illustrate where neuron firing is taking place in the brain because active neurons use glucose as fuel. With PET scans, researchers can only locate areas of brain activity and not specific locations as they might with brain lesioning. The most advanced and helpful invention in brain physiology, however, is the MRI (magnetic resonance imaging) scan and especially the FMRI (functional magnetic resonance imaging). With a MRI, the patient’s head is put in a strong magnetic field, which aligns the spinning atoms then the atoms are disoriented from a radio wave and proceed to release detectable signs when they are realigned. In a FMRI a patient can perform mental tasks and the area of action can be detected through its blood flow from one part of the brain to another by taking pictures less than a second apart and showing where the brain “lights up”. For example, when a person processes visual information, blood rushes to the back of the brain. FMRIs make it possible to show when things happen, how brain areas change with experience, and what brain areas work together.

### Neuroimaging

Neuro Imaging refers to numerous methods employed psychologists and researchers to create an image of the structure or functioning of the brain. This is a fairly recent development in the field of medicine and psychological research. These new technologies have had a drastic impact on past and current research in the human brain. Researchers can now pair different brain functions with the area of the brain responsible for processing that function. These technologies also aids in diagnosis of brain disorders as well as numerous other areas of brain research.
CAT Computed Tomography (CT) or Computed Axial Tomography (CAT) scanning uses x-ray technology to give doctors an image of the structure of the brain. Because the image is available relative quickly, CAT scans are ideal for doctors evaluating brain injuries. The image can show the more dense areas of the brain to help doctors pinpoint areas of swelling in the brain. This form of neuroimaging does not show functioning of different areas of the brain, it is only capable of showing an image of the brain structure. The Image created from CAT scans is somewhat less detailed than that of the MRI.
MRI
fMRI
PET