Chapter 2: PowerPoint #3 Brain Imaging Techniques CT Scan: Computerized Topograph Scan MRI: Magnetic Resonance Imaging fMRI: Functional Magnetic Resonance Imaging PET Scan: Positron Emission Tomograph Scan EEG: Electroencephalogram

CT Scans: An x-ray of the brain. A CT scan is essentially a computerized assembly of several x-ray images taken from a series of different angles. With a CT, the resolution is much better than conventional x-rays, and the detail that can be seen is much greater. 

Tumor in Wernicke’s Area         MRI is a noninvasive imaging technique that does not use x-rays.   The process involves passing a strong magnetic field through the head.  The magnetic field used is 30,000 + times that of the earth's magnetic field.  It's effect on the body, however, is harmless and temporary.  The MRI scanner can detect radiation from certain molecules, which are present in different concentrations in different tissues. 

P E T S C A N PET measures the emission of positrons from the brain after a small amount of radioactive isotopes, or tracers,  have been injected into the blood stream.  A common example is a glucose-relative with embedded fluor-18.   With this molecule, the activity of different regions of the brain can be measured.  The result is a three-dimentional map with the brain activity represented by colors. 

After Implant of Dopamine-secreting Tissue Normal Brain ADHD Brain After Implant of Dopamine-secreting Tissue Brain Development in First Year of Life

EEG of Mouse with Epileptic Seizure EEG Cap Alert Deep Sleep

The Evolution of the Brain

THALAMUS It relays to the cerebral cortex information received from diverse brain regions. Sort of a requisite 'last pit stop' for information going to cortex. Axons from every sensory system (except olfaction) synapse here as the last relay site before the information reaches the cerebral cortex

CEREBELLUM Alcoholims causes brain shrinkage to the cerebellum

Emotion and Memory are closely connected. Amygdala A little almond shaped structure, connects with the hippocampus. Hippocampus Is particularly involved with memory phenomena, specially with the formation of long-term memory (the one that, sometimes, lasts forever).

The pituitary gland may be king, but the power behind the throne is clearly the hypothalamus.

Lobes of the Cerebral Cortex

Motor Area Sensory Area

Speaking the Heard Word LANGUAGE CENTERS Disrupts Understanding Disrupts Speaking Speaking the Heard Word Speaking the Written Word Angular Gyrus Speak & Understand, Unable to Read