Transcript The Brain - ISD 2135 Maple River Schools / Homepage
The Brain
Using lesions helps to understand the working of the brain. What are lesions?
Older Brain Structures
•
Earliest ancestors had a less complex brains system
The Brainstem
•
Oldest, innermost
•
Begins where the spinal cords swells slightly after entering the skull, medulla
Function
Controls heartbeat and breathing
•
Above the medulla, pons
Function
Helps coordinate movements
•
Brainstem is the crossover point
The Thalamus
•
Above the brainstem
Function:
Receives info from the senses, except smell
Sends info to higher brain regions that deal with the senses Receives the higher brain replies, sends info to the medulla and cerebellum
•
The Tools of Discovery – Having our Heads Examined
EEG
Reads electoral activity in your brain
•
PET
Shows brains use of glucose
Like a weather radar, shows the “hot spots” Injects radioactive sugar
•
MRI
Aligns atoms, then disorients them
Functional MRI Reveals brains functioning's as well as its structure
The Reticular (net-like) Formation
•
Inside the brainstem, between ears
•
Neurons which run from the spinal cord up through the thalamus
Function
Filters incoming stimuli Relays important info to together brain areas
Controls arousal
What happens if you stimulate it?
Cut it?
The Cerebellum (little brain)
•
Rear of brainstem
Function
Enables nonverbal learning and memory Judges time Modulates our emotions
Discriminates sounds and texture
Coordinates voluntary movement Alcohols affect
Not as coordinated
•
Injured
Hard to wake, keep balance, shake hands
Movements jerky or exaggerated
•
Occurs without conscious effort, brain processes most info outside of our awareness
The Limbic System
•
Between the new and old part of the brain
•
Made up of the
Amygdala
Hypothalamus Hippocampus
•
Function
Processes conscious memories
•
Injury
Can’t form new memories
•
Tied to emotions fear and anger and motives for food and sex
The Amygdala
•
Tied to aggression and fear
•
Discuss the rhesus monkey and cat
•
The Hypo (just below) thalamus
Bodily maintenance
Hunger
Body temperature Sexual behavior
Maintain a steady internal state (homeostatic)
Monitors the state of your body, tunes into your blood chemistry and any incoming orders from together brain parts. Discuss the examples
Unfortunately, it is possible for the hypothalamus to lose its ability to communicate with leptin. When this happens, the hypothalamus continuously instructs the cells of the body to increase fat storage by lowering the metabolism, by being hungry and by burning sugar for energy - the exact opposite of what should be happening for the body to function its best and maintain a normal weight.
What that means is that for the girl on the left, her hypothalamus is correctly sensing leptin and maintaining her body with normal weight, while for the girl on the right, her hypothalamus is not correctly sensing leptin and therefore, her body cannot lose weight, but continues to store fat, virtually regardless of how little she eats or how much she exercises.
The Hypothalamus Cont.d’
•
Rewards centers
Addictive disorders may be due to reward deficiency syndrome
The Cerebral Cortex
•
Like bark on a tree
•
Function
Perceiving, thinking speaking
Control and informational processing center
Structure of the Cortex
•
Unfolded size of what?
•
20 – 23 billion what?
•
300 trillion what?
•
Hemispheres’ cortex is subdivided into four lobes separated by fissures (folds)
Functions of the Cortex
Motor Functions
•
Right controls left and vice versa.
Mapping the Motor Cortex
•
Brain has no sensory receptors
•
Body areas requiring precise control like ? and ? occupy the greatest amount of cortical space
Discuss experiments with paralyzed patients
Sensory Functions
•
Receives information from the skin senses and movement of body parts
•
More sensitive the body region, the large the sensory cortex area. Discuss lips and whiskers.
•
Also have visual cortex in the occipital lobes
•
Helps identify words, detect emotions, recognize faces
•
Sound processed in auditory cortex in temporal lobe.
• •
Association Areas
Interprets, integrates, acts on sensory information and likes it with stored memories.
•
Hard to map
•
Parietal lobes
Enable mathematical and spatial reasoning Temporal lobe
Recognize faces
•
In all four lobes
•
Frontal lobe
Judgment, planning, processing new memories
Damage
Alter personality, no inhibitions, moral judgment unrestrained Discuss Phineas Gage
•
The Brain’s Plasticity
Ability to modify itself after damage.
•
May produce new brain cells, neurogenesis
•
Sever brain and spinal cord neurons usually do not regenerated
•
Some brain areas are reassigned to specific areas
•
Some neural tissue can reorganize in response to damage
•
Plasticity may occur, especially with kids
Discuss figure 4.17, blindness and deafness
•
Master stem cells found in the human embryo
Discuss possibilities
•
Left hemisphere slow-growing, right may pick up the language
Our Divided Brain
•
What is lateralization?
•
Thought the right side of the brain was minor.
•
Left side damage impairs reading, writing, speaking, arithmetic reasons, understanding
Splitting the Brain
•
Severed the corpus callosum which carries messages between them
•
Discuss the experiment by Gazzaniga, and bothersome left-hand independence
Right-Left Differences in the Intact Brain
•
Right hemisphere
Perceptual task
Self awareness
Discuss people with stroke
•
Speaks or calculates in the left hemisphere
•
Discuss sedative into the neck artery
•
Fetal Alcohol Syndrome
Brain of baby with no exposure to alcohol • Brain of baby with heavy prenatal exposure to alcohol