BIOLOGICAL BASIS OF BEHAVIOR - NATURE VS NURTURE DEBATE

The influence of biology (sometimes called the neuroscience or bio-psychological perspective) is growing. Some researchers predict that someday psychology will be a specialty within the field of biology. An understanding of the biological principles relevant to psychology is needed to understand current psychological thinking.

Roots: Charles Darwin: Origin of Species :

• Evolution is the gradual process of biological change that occurs in a species as it adapts to its environment
• Natural Selection is the driving force behind evolution by which the environment selects the fittest organisms
  • Example of an adaptive behavior would be phobias - we are afraid of snakes or we sleep at night / our distaste for bitter foods

How are genes and behavior linked?

GENOTYPE - genetic pattern

PHENOTYPE - physical structure

DNA - genetic code

GENE - is a segment of a chromosome that encodes our physical and mental characteristics -Each gene has smaller molecular units called nucleotides (4)

CHROMOSOME: The threadlike structures along which genes are organized - 46 chromosomes / Every cell in your body has 23 pairs of chromosomes.

How does the body communicate internally?

CommunicatIon System - Endocrine and Nervous System

What is a Neuron?

A neuron is a nerve cell. The brain is made up of about 100 billion neurons.

• Neurons have specialized projections called dendrites and axons. Dendrites bring information to the cell body and axons take information away from the cell body.
• Neurons communicate with each other through an electrochemical process.
• Neurons form specialized connections called "synapses" and produce special chemicals called "neurotransmitters" that are released at the synapse. - When synapses are strengthened this is called Long Term Potentiation

MAKE A MAD NEURON

Types of Neurons (SAME - SENSORY AFFERENT MOTOR EFFERENT) Mnemonics :)

• Sensory / Afferent
• Motor / Efferent
• Interneurons

TUTORIALS

ACTION POTENTIAL

HOW DOES ACTION POTENTIAL WORK?

Action Potential - A change in the overall balance of the charge of the neuron

The nerve impulse caused by the electric charge across the cell membrane of the axon. When the neuron fires this charge travels down the axon and causes neurotransmitters to be released at the terminal buttons of the neuron

Resting Potential - Neuron is inactive it is waiting for an action potential -The electric charge of the axon is in an inactive state when the neuron is ready to fire

Polarization - Negatively charges chloride (CL-) ions exist within the axon -

Depolarization - Positively charged sodium ions (NA+) and Potassium ( K+) channels open - causing the electrochemical charge across the axon

Threshold - A point of excitation in the neuron for an action potential to occur

All or Nothing - once the threshold is reached the neuron will fire at full strength - If the threshold is not reached the neuron will not fire

Neurotransmitters-– chemicals in the endings of nerve cells that send information across the synapse

Acetylcholine – neurotransmitter that regulates basic bodily processes such as movement, memory, and learning

Dopamine – a neurotransmitter also involved in the control of bodily movements / associated with rewards( involved in Parkinson’s diseasseand Alzheimer’s)

How do we know what the Brain Does? Neuroimaging

EEG -Electroencephalograph

• Brain Wave Activity / Electric Patterns / What parts of the brain are most active / Seizures / Epilepsy
• William Penfield - see that the brain was divided into areas / different functions when he exposed the brain to electrodes

PET SCAN - Positron Emission Tomography -

• Shows what part of the brain is active during certain tasks - It measures a chemical a part of the brain is using - Using low radioactive glucose which shows up in the scan of the brain

CT Scan - Computerized Tomography

• X Ray of the Brain - images are seen from different angles - does not show activity
• MRI - Magnetic Resonance Imaging
• Similar to a CT Scan - Pictures of the brain but more detail
• Uses magnetic field so patient is exposed to less radiation
• Structure of the brain not function

fMRI - Functional Magnetic Resonance Imaging

• Combo MRI and PET Scan
• Shows brain structure and blood flow in the brain allows us to see brain activity during cognitive activities
• Brain structure and Brain Function

Brain Structure and Function

Brain Stem - Medulla - Little brain / Automatic Nervous System

Pons - Bridge - connects brain stem to cerebellum / sleep

Reticular Formation

Thalamus - On top of the Brain Stem - Brain's Relay Station

Cerebellum - Motor Skills / Balance / Procedural Memory - Implicit memory / Series of steps - order / involved in classical conditioning / habitual responses

Limbic System - Emotional Center and Memory Center (HAH)

Hippocampus - connect your present to your past and new ideas / consolidation of memory / HM - anterograde amnesia

Amygdala - emotion especially fear and aggression

Hypothalmus - Hypo - under / under the thalamus

• Control circuit for motivation and drives
• body temperature
• sex drive / libido
• hunger / thirst
• sleep / circadian rhythm

Cerebral Cortex - Cerebrum / 4 Lobes - Location and Function

• Occipital - vision
• Temporal - Auditory / Wernicke Area
• Frontal - Prefrontal - Thought Processes (CEO) / Motor Cortex / Broca Area / Phineas Gage
• Parietal - Sensory Cortex

Homunculus - Visual representation of the sensory (parietal) and motor cortex (frontal)

Brain has 2 Hemispheres: Divide by Corpus Callosum / Role of Split Brain Patients- corpus callosum has been severed

• Each hemisphere controls the opposite side of the body
• Studies done by Sperry and Gazzaniga on split brain patients
• Cerebral Dominance - are you right or left brained? We use both
• Right Brain is associated with spatial orientation and emotional tone (how you say it)
• Left is associated with language (what you say)
  • Broca - Transferring thoughts into words - Damage would cause an ability to speak properly - Aphasia / Think of Boca as Mouth
  • Wernicke - transferring words into thoughts / Damage would cause an inability to understand speech - Aphasia
  • Broca is to speech as Wernicke is to comprehension
• White Matter
• Gray Matter
• Anterior - front
• Posterior - back