Psych Notes: The Brain

The Nervous System
-It starts with an individual nerve cell called a neuron

Synapse
a structure that permits a neuron to pass a chemical or electrical signal to another cell
How Does a Neuron Fire?
-Resting Potential: slightly negative charge
-reaches the threshold when enough neurotransmitters reach dendrites
-It is an electrochemical process: electrical inside the neuron and chemical outside the neuron (in the synapse in the form of a neurotransmitter)
-The firing is called Action Potential

The All-or-None Response
-the idea that either the neuron fires or it doesn't; no part-way firing

Neurotransmitters
-chemical messengers releases by terminal buttons through the synapse
We should know at least 4 types and what they do

1. Acetylchlorine (ACH)
• deals with motor movement and memory
• lack of ACH is linked to Alzheimer's Disease
2. Dopamine
• deals with motor movement and alertness
• lack of dopamine linked to Parkinson's Disease
• too much dopamine has been linked to schizophrenia
3. Serotonin
• involved in mood control
• lack of serotonin has been linked to clinical depression
4. Endorphins
• involved in pain control
• many addictive drugs deal with endorphins

Drugs can be...
-Agonists: make neurons fire
-Antagonists: stop neural firing

Three Types of Neurons

1. Sensory Neurons (Afferent Neurons)
• take info from the senses to the brain
2. Inter Neuron
• take messages from the sensory neurons to the other parts of the brain or to the motor neurons
3. Motor (Efferent) Neurons
• take information from the brain to the rest of the body

The Nervous System
-Central: brain and spinal cord
-Peripheral: all nerves not encased in bone; everything else that's not the brain or spinal cord
     -Two Types:

• Somatic: controls voluntary muscle movement
• uses motor or efferent neurons
• Automatic: controls automatic functions of the body
• sympathetic: fight or flight response
• automatically accelerates heart rate, breathing, dilates pupils, slows down digestion
• parasympathetic: automatically slows down after a stressful event
• heart rate and breathing slow down, pupils constrict, and digestion speeds up

Reflexes

-normally, sensory (afferent) neurons take info up through spine to the brain

-some reactions occur when sensory neurons reach just the spinal cord, doesn't need to go to the brain

Ways to Study the Brain

-Lesions: cutting into the brain and looking for change

-EEG

CAT scan

Brain Structures

1. Hindbrain
1. Medulla Oblongata: in charge of heart rate, breathing, and blood pressure
2. Pons: connects hindbrain, mindbrain, and forebrain together
• involved in facial expressions
3. Cerebellum: located in the back of the head.
• "Little Brain"
• coordinates muscle movements
• like tracking a target
2. Midbrain: coordinates simple movements with sensory information. Contains reticular information: arousal and ability to focus attention
3. Forebrain
• Thalamus: receives sensory information and sends them to appropriate areas of forebrain
• like a switchboard
• covers all senses except smell

Limbic System: emotional control center of the brain, made up of Hypothalamus, amygdala, and hippocampus

1. Hypothalamus
• pea sized 
• responsible for body temperature, hunger, thirst, sexual arousal (libido)
2. Hippocampus and Amygdala
• hippocampus is involved in memory processing
• amygdala is vital for our basic emotions
3. Cerebral Cortex
• top layer of our brain
• contains wrinkles called fissures, which increases surface area of our brain
• laid out, it would be about the size of a large pizza

Hemispheres: divided into left and right hemispheres. Conralateral controlled (left controls right and vice versa)

1. Lefties: better at spatial and creative tasks
2. Righties: are better at logic

Corpus Collosum: attaches the two hemispheres of cerebral cortex

-when removed, you have a split-brain