Psychology: Unit 4-Biological Basis of Behavior

Biological School

The Nervous System:

• Starts with an individual cell called a Neuron

Synapse: A structure that permits a neuron to pass a chemical or electrical signal to another call.

How does a neuron fire?

• It is an electrical process inside the neuron
• Chemical outside the neuron (in the synapse int he form of a neurotransmitter)
• The firing is called Action Potential
• Resting Potential: Sightly negative charge
• Reach the threshold when enough neurotransmitters reach dendrites

The All-or-None Response

• The idea that either the neuron fires or it does not--no part way firing
• Like a gun

Neurotransmitters: Chemical messengers released by terminal buttons through the synapse

4 Types

1. Acetycholine (ACH)
• Deals with motor movement and memory
• Lack of ACH has been linked to Alzheimer's disease
2. Dopamine
• Deals with motor movement and alertness
• Lack of dopamine has been linked to Parkinson's disease
• Too much has been liked to Schizophrenia
3. Serotonin
• Involved in mood control
• Lack of serotonin has been linked to clinical depression
4. Endorphin
• Involved in pain control
• Many of our most addictive drugs deal with endorphin

Drugs can be...

• Agonists: Make neuron fire
• Antagonists: Stop neural fire

3 Types of Neurons

1.  Sensory Neurons (Afferent Neurons)
• Take information from the senses to the brain
2. Inter Neurons
• Take messages from the Sensory neurons to other parts of the brain or to Motor Neurons
3. Motor Neurons
• Take information from the brain to the rest of the body

Central Nervous System

• The brain and the spinal cord

Peripheral Nervous System

• All nerves that are not encased in bone
• Everything but the brain and the spinal cord
• Is divided into 2 categories...Somatic and Automatic
1. Somatic Nervous System
• Controls voluntary muscle movement
• Uses motor (efferent) neurons
2. Automatic Nervous System
• Controls the automatic functions of the body
• Divided into 2 categories...The Sympathetic and Parasympathetic
1. Sympathetic Nervous System
• Fight or Flight Response
• Automatically accelerates heart rate, breathing, dilates pupils, slows down digestion.
2. Parasympathetic nervous System
• Automatically slows the body 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

Lesions

• Cutting into the brain and looking for change

Less invasive ways to study the brain

Brain Structures

Some scientists divide the brain into 3 parts:

• Hindbrain
• Midbrain
• Forebrain

Medulla Oblangata controls:

• Heart Rate
• Breathing
• Blood Pressure

Pons

• Connects hindbrain, midbrain, and forebrain together
• Involved in facial expressions

Cerebellum

• Located in the back of our head means little brain
• Coordinates muscle movement
• Like tracking a target

Midbrain

• Coordinates single movements with sensory information
• Contains the reticular formation: arousal and ability to focus attention

Thalamus

• In forebrain
• Received sensory information and sends them to appropriate areas of forebrain
• Like a switchboard
• Everything but small

Limbic System

• Emotional control center of the brain
• made up of Hypothalamus, Amygdala, and Hippocampus

Hypothalamus

• Pea sized in brain but plays a not so pea sized role
• Hunger
• Thirst
• Sexual arousal (libido)

Hippocampus is involved in memory processing

Amygdalal is vital for out basic emotions

Cerebral Cortex

• Top layer of our brain
• Contains wrinkles called fissures 
• The fissures increase surface are of our brain
• Laid out it would be about the size of a large pizza

Hemispheres

• Divided into a left and right hemispheres
• Contralateral controlled-left controls right side of body and viceversa
• Brain lateralization
• Lefties are better at spatial and creative tasks
• Righties are better at logic

Split-Brain Patients

• Corpus Collosum attaches the two hemispheres of cerebral cortex
• When removed, you have a split-brain patient

The cerebral cortex is made up of four lobes

• Temporal Lobe
• Process sound sensed by our ears
• Interpreted in auditory cortex
• Contains Wernike's Area: Interprets written and spoken speech
• Wernike's Aphosia: Unable to understand language: the syntax and grammar jumbled
• Parietal Lobe
• Contains sensory Cortex: Receives incoming touch sensations from rest of the body
• Most of the Parietal Lobes are made up of Association Area: Any are not associated with receiving sensory information or coordinating muscle movement
• Occipital lobe
• Deals with vision
• Contains Visual Cortex: Interprets messages from our eyes into images we can understand
• Frontal Lobe
• Abstract thought and emotional control
• Contains Motor Cortex: Sends signals to our body controlling muscle movements
• Contains Broca's Area: Responsible for controlling muscles that produce speech
• Damage to Broca's Area called Broca's Aphasia unable to make movements to talk

The Endocrine System

• A system of glands that secret hormones
• Similar to nervous system, except hormones work a lot slower than neurotransmitters

Thyroid Gland-affects metabolism among other things

Pituitary gland-secrets many different hormones, some of which affect other glands

Adrenal Gland-inner parts, called the medulla, helps trigger the "flight or fight" response

Pancreas-regulates the level of sugar in the blood

Ovary-secrets female sex hormones

Testes-secrets male sex hormones

Brain Injury Group Activity

Using the description of each person's behavioral symptoms, determine the probable cause locations of the damage and explain their function. You can include neurotransmitters, brain parts, cortical areas, glands, or anything else we have studied in this chapter that you believe might account for the damage. there is not necessarily always one correct answer. 

1. Katie had problems coordinating her movement and keeping her balance
2. David lost the ability to move his right arm
3. Molly and Samiyah suffered from an impaired ability to initiate, plan, and make good judgement 
4. Kelsey's eyes seemed fine, but she still had lost her vision in her left eye
5. Sara often kept falling asleep at odd times and in odd places
6. Ezekiel and Santos seemed to always be hungry and their temperatures ran high
7. Arlene suffered from an inability to from new memories
8. Chisom experience difficulty with analytic thinking science, and math reasoning
9. Kendall and Ciara both often flew into a rage and started picking fights with each other
10. Paco lost the feeling in his left leg
11. Jane and Asia seemed to constantly be experiencing a "runner's high"
12. Nathalie could no longer respond to her doctors soft tap in the knee
13. Kayla's speech was choppy, slow, and a grammatical mess
14. Bianca experience irregularities in heartbeat and respiration rates
15. Michelle started growing much, much larger
16. Mustafa and Abdul were uncontrollably thirsty.

Key

1. Cerebellum
2. Motor Cortex
3. Frontal Lobe
4. Occipital Lobe
5. Reticular Formation
6. Hypothalamus
7. Hippocampus
8. Cerebral Cortex
9. Amygdala
10. Sensory Cortex or Porietal Lobe
11. Pituitary Gland or Hypothalamus
12. Spinal Cord injury
13. Wernike's Area
14.  Medulla
15. Thyroid Gland
16. Hypothalamus