Understanding the Brain

Electroencephalograph (EEG) Monitors the electrical activity of the brain EEG recordings are translated into line tracings called brain waves Used in clinical diagnosis of various neurological disorders

Electroencephalograph (EEG)

Brain Imaging- CAT Scan In a CAT scan machine, the X-ray beam moves all around the patient, scanning from hundreds of different angles. The computer takes all this information and puts together a 3-D image of the body. Portrays only brain structure. Used to diagnose and treat a wide variety of ailments (head trauma, cancer, tumors).

Brain Imaging- PET Scan These scans examine brain function They monitor chemical processes such as neurotransmitters Person receives an injection of radioactive substance Brain structures that are active absorb the substance and this is color coded onto a computer screen.

Brain Imaging- PET Scan

Brain Imaging- MRI Similar to CAT scan but better picture due to high resolution Person’s head is surrounded by a magnetic field and the brain is exposed to radio waves, which cause hydrogen atoms in the brain to release energy. The energy released by different structures generates an image on a computer screen.

Brain Imaging- MRI

Brain Imaging- fMRI Similar to PET but less invasive and collects precise images rapidly. It measures the movement of blood molecules (an index of neural activity). Provides both functional and structural information in the same image.

Lesioning & ESB Lesioning- destroying a piece of the brain Insert an electrode into a brain structure and pass a high electric current which burns tissue ESB (electrical stimulation of the brain) - sending an electric current into a brain structure to activate it

Three Main Regions of the Brain  Hindbrain- lower part of brain stem (pons & medulla), & cerebellum  Midbrain- upper brainstem (reticular formation)  Forebrain- largest & most complex part, limbic system (hippocampus, hypothalamus, thalamus, amygdala) at the center, cerebrum, cerebral cortex & lobes.

Cerebrum is divided into 4 Lobes

Frontal Lobe Prefrontal cortex Reasoning, planning, paying attention, getting organized, decision making Motor cortex- movement of muscles Broca’s Area (only left side) – production of speech

Phineas Gage- example of prefrontal cortex damage

Parietal Lobe Somatosensory Cortex- controls sensory information Process info from body parts Sense of touch, feeling temperature & pain Phantom Limb syndrome

Temporal Lobe Primary auditory cortex Involves hearing, speaking, understanding written & verbal words Wernicke’s Area- comprehension of language

Occipital Lobe Primary visual cortex Visual processing begins

Brain Plasticity Experience can change/sculpt certain brain structures (ex: musicians) The brain can go through neural reorganization after damage- healthy neurons attempt to compensate for the loss of nearby neurons The adult brain can generate new neurons Brain’s plasticity declines with age