Vision - Part 1

Right side of your brain controls your Left body functions

Left side of your brain controls your Right body functions

•Each eyeball is divided into 2 parts –Right Visual Field

–Left Visual Field

•Right Hemisphere receives visual info from LVF only•Left Hemisphere receives visual info from RVF only

Vision - Part 2Left Visual Field is

illustrated in REDRight Visual Field

is illustrated in BLUE

Lesson Outline

Split-Brain Discoveries

Ways to study the Brain!!!

Accidents: damage to brain regions can tell us about their functions

Phineas Gage.

Lesions: tissue destruction

Cutting into the brain and looking for change.

Brain tumors also lesion brain tissue.

Seizures

3 basic types – Grand Mal

•Involves total body convulsions, aka “tonic-clonic”

– Petit Mal•Involves isolated body part convulsion, aka “focal”

– Absence•Patient becomes unresponsive, and has no memory of occurrence. Appears to be day-dreaming but cannot awake. Very rare.

What is a seizure?

1. Abnormal discharge of electrical impulses within the brain

2. Rather than smooth constant production of Action Potentials, neurons fire without any regulation, causing disruption tobrain function at the biochemical level

3. Seizures generally have 3 parts: Aura - period of warning, usually olfactory or visualIctus - actual seizure periodPostictal state - time where body “resets” itself

Causes of Seizures

Alcohol Poisoning

Drug Overdose/Reaction

Head Injury

Fever (especially in children)

Neurological Defect (usually genetic)

Sepsis (in brain)

Brain Tumor

Stroke

Epilepsy

Lesson Outline

Epilepsy A seizure disorder in which reoccurring seizures are the

main symptom caused by an abnormal discharge of electrical activity from the neurons in the cerebral cortex.

• In the US more than 4 million people have some form of epilepsy• Risk of epilepsy is greatest in early childhood and late adulthood.• Seizures have been found depicted as early as in cavepaintings!

• 4,000 yr. old writings depict epileptics as “possessed by demons”

• Julius Caesar, King Charles II, Vincent Van Gogh and novelist Dostoyevsky all reportedly suffered from seizures.

Treatments for Epilepsy

3 major courses of treatment: Drugs

Generally first line of attack because it is effective, relatively inexpensive, and safe

DietKetogenic diet - lots of fat and almost no carbohydratesThis diet drastically alters the way our bodies get

energy from food - instead of making glucose, it makes ketones

SurgeryCommissurotomy

Commissurotomy

For patients with frequent and violent epileptic seizures, surgically splitting the corpus callosum was the only relief - known as a “commissurotomy”

Corpus callosum is a bundle of nerve fibers which serve to connect the right and left cerebral hemispheres

Less Invasive ways to study the Brain

Electroencephalogram (EEG)

Computerized Axial Tomography (CAT)

Positron Emission Tomography (PET)

Magnetic Resonance Imaging (MRI)

Functional MRI

Electroencephalogram (EEG)

Electrodes placed on the scalp create an amplified recording of the waves of electrical activity that sweep across the brain’s surface

CT scan CT (computed tomography) Scan

a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body; also called CAT scan

PET Scan

PET (positron emission tomography) Scan a visual display of brain activity that

detects where a radioactive form of glucose goes while the brain performs a given task

MRI Scan MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain

MRI scan of a healthy individual (left) and a person with schizophrenia (right) Note the enlarged fluid - filled brain region in the image on the right.

fMRI Scan• Functional MRI• Reveals blood flow, and therefore,

brain activity by comparing successive MRI scans.

• “Reading Your Mind” – 60 Minutes

Brain Restoration – Plasticity

• The ability for our brains to form new connections after the neurons are damaged.

• Evidenced by brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development

• The younger you are, the more plastic your brain is.

• Plasticity of sensory cortex

Brain Restoration

cells in the nervous system that support, nourish, and protect neurons

Glial Cells