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