Psychology: Definitions, Structuralism and Behaviorism

Definitions of Psychology

• Psychology is the science of the mind and behavior.

Structuralism

• Structuralism is the science of the mind that looks for the elements of thought.
• In 1879, Wilhelm Wundt developed the "Science of Mind" which was the first psychology lab and separated psychology from philosophy in Leipzig, Germany.
• Wilhelm taught Titchener who had his own view as structuralism as the content of conscious thought: an example is the thought of an apple and all its elements.
• Titchener believed the thoughts were based on images, but others did not, and his views conflicted with behaviorism.

Behaviorism

• Behaviorism is the science of behavior
• In 1913, John Watson/Broadus says we need psychology to be an observable science where data is objective.

Cognitivism

• Cognitivism is the science of mind and behavior.
• It began in 1967 and concluded the definition of mind and behavior.
• Ulric Neisser published a cognitive psychology textbook, which focused on attention, perception, language, and memory.
• The focus is similar to a computer which inputs information.

The Science of Experimental Epistemology

• Experimental Epistemology explores where knowledge originates.
• Nativism is based on nature (Rationalism): you are born with innate knowledge.
• Empiricism is based on nurture (associationism): knowledge comes from experience, and people are born as a clean slate (tabula rasa).
• Everything comes from experience.

How Knowledge is Learned

• Rationalism:
  • Manipulation of concepts and ideas comes from thinking and making inferences
• Associationism:
• Knowledge is learned by connecting experiences together.

The Science of Knowing and Experiencing

• Knowing is not just storing information but understanding it and being aware of how to behave.
• Experiencing:
  • Computers cannot experience things like people through color or listening.
  • Experiencing is different from knowledge and information.
  • You can only taste salt to experience it.
  • Making experiences motivates people.

Mind and Body Problem

• Mind and Body Problem explores how they are related:
  • Dualism:
  • Descartes believed there are two kinds of stuff that makes up the universe and they interact: physical and non-physical made of soul, mind, and thought.
  • Materialism:
  • Everything is made up of the physical world, and thoughts are a part of the physical world.
  • Electrical signals and thoughts are electric signals

The Neuron

• Neurons receive and pass along information all around the body.
• Cell body (soma): contains the nucleus
• Dendrites: receive input from the previous presynaptic neuron.
  • You can think of dendrites as a big hand grabbing/receiving something
• Axon: sends the signal away from the cell body to the next neuron (which is sent down the axon as an action potential - AP)
• Myelin Sheath: fatty material that insulates the axon for the information to pass more quickly and efficiently.
• Nodes of Ranvier: breaks in the myelin sheath where the exchange of ions along the axon can happen.
• Axon terminals: where the neuron connects (with a gap in between) to another neuron to send signals (neurotransmitters)
• Synapse: gap in between the first and second neuron where the signal must jump to pass along.

Multiple Sclerosis (MS)

• MS is an autoimmune disease where the Nervous System treats myelin sheath as a foreign substance and attacks it.
• Demyelination: is when not many action potentials correctly fire, creating a signal that has a difficult time traveling or happening at all.
• This can make it hard for someone to walk, move around, or see.

How a Neuron Fires (Action Potential)

• Resting State: -70mV
  • Na+ ions are outside of the neuron.
  • Fewer K+ ions and Cl- ions are inside of the neuron, making it more negative ions that are inside than outside, which makes it more negative inside the neuron than outside, so it remains at -70mV.
• Neuron is stimulated by a neurotransmitter from another neuron
  • Na+ ions start slowly going inside the neuron.
  • The resting state of -70mV goes up and up and up then to -55mV.
  • -55mv is the threshold that must occur to allow the action potential (AP) to happen.
• Depolarization: occurs when the neuron becomes more positive.
  • Na+ gates are opened once the threshold is reached and Na+ rushes into the neuron.
  • This makes it more positive inside the neuron at +40mV.
  • Action potential is all or none: it does not matter the level of stimulus- it will either fire or not at all.

Repolarization/hyperpolarization

• Potassium (K+) ions flood out of the neuron because the cell become too positive through polarization.
• This makes it more negative in the neuron.
• It even overshoots the resting state (hyperpolarization).
• Back to Resting State:
  • More Na+ outside the cell, making the outside positive.
  • Less K+ inside the cell, making the inside more negative than the outside at -70mV.
  • This means that it is at the resting potential.

Action Potential

• Action Potential travels down the axon.
  • This depolarizes at each part of the axon.
  • Nodes of Ranvier allow the exchange of ions.
  • The AP travels at about 50 to 100m/sec

Neurotransmitters

• Vesicles are in the axonal buttons and contain neurotransmitters.
• Vesicles release neurotransmitters at the action potential.

Receptor Molecules

• Receptor Molecules are "the lock," which is located on the dendrites of the postsynaptic neuron.
• The neurotransmitters (the keys) land on the receptors, which opens ion gates for ions to come into the neuron.
• When neurotransmitters bind to the receptor molecules it opens the channels for Na+ to enter or leave (depending on if its excitatory or inhibitory).

Reuptake

• Neurotransmitters are taken back up into the presynaptic neuron to be used again.
• Some drugs can stop this reuptake, such as Selective Serotonin Reuptake Inhibitors (SSRI's- inhibits the reuptake of serotonin.
  • They keep the serotonin in the synapse for longer to have more serotonin to use, which helps with depression.
  • An example of an antidepressant is SSRIs.

Excitatory and Inhibitory Potentials

• EPSP - Excitatory Postsynaptic Potential:
  • This makes an action potential more likely to fire in the postsynaptic neuron.
  • Neurotransmitters are open Na+ channels, which starts an action potential.
  • It makes it more likely to fire because it starts to get more positive (-65, -60, -50), as it approaches the required -55mV to fire.
• IPSP - Inhibitory Postsynaptic Potential:
  • Less likely to fire an action potential in the postsynaptic neuron.
  • The neurotransmitters can open the gates of the K+ ions and have them flood out of the neuron.
  • Neurotransmitters can have Cl- come into the neuron, and Na+ leave the neuron as well.
  • Both make the neuron less likely to fire because it starts to get more negative now (-71,-75, -80).

Charles Sherrington

• Sherrington discovered the existence of the synapse without looking at the actual neuron.
• Experiments using dogs showed that:
  • Scratching a dog in an area makes them itch, but they eventually stop.
  • Stopping is an example of inhibition where you stop a behavior coming down from the brain to stop the scratching .
  • Snipping the spinal column causes disinhibition and stops your ability to stop the scratching or other unwanted behaviors.
• Sherrington stimulated a specific area:
  • Stimulating one area repeatedly over time creates the reaction to scratch, which is temporal summation.
  • Stimulating three areas all comes together to create the same, which is spatial summation, meaning that there must be one area where they all come together at the synapse.

Central Nervous System

• Brain: Receives and processes sensory information, initiates responses, and stores memory.
• Spinal Cord: conducts signals to and from the brain and controls reflex activities.

Peripheral Nervous System (PNS)

• Somatic nervous system: controls voluntary movement (muscles, senses)
• Autonomic nervous system: controls involuntary movements (vital functions: heart rate, breathing, and digestion).
  • Sympathetic: nervous system (fight or flight):
    • Uses all energy to survive, increased heart rate, and inhibits parasympathetic systems
  • Parasympathetic nervous system (rest or digest)
    • Calm state, slow heart rate, inhibits sympathetic system, allows sex, reproduction and digestion.

The Brain: Hindbrain

• Medulla: breathing, heart rate, and blood circulation.
• Pons: arousal and attention and coordinates facial expressions.
• Cerebellum: integration of fine motor movements (not in charge of movements) and balance.
  • Playing piano helps muscles work together to make movements.
  • Neuroplasticity is when other parts of the brain can take over functions of damaged parts of the brain.
  • Without the cerebellum:
    • Other parts of the brain can carry out functions.
    • Some aspects of language function is lost and some aspect language would be lost

Forebrain

• The Hindbrain being the only part of the brain connected can still function if the Forebrain is damaged.
  • A cat can move its limbs without purpose or intention.
  • They cannot act without purpose, as they will need the forebrain and midbrain to have the purpose put into place.
• Midbrain:
  • The movement is put into action.
  • A cat can walk because it is not reliant on the forebrain.

The Forebrain

• Thalamus: sends sensory and motor information to specific parts of the cortex
• Hypothalamus: controls responses to basic needs (motivation) such as fighting, fleeing, feeding, fornicating.
  • Regulates temperature and tells the body to sweat.
  • Removing the Hypothalamus of a rat causes it to never stop eating
• Limbic System
  • The rat is given warm air when it presses the panel in a cage.
  • The wire implanted cools the hypothalamus.
  • A rat presses the button to feel warm because the feel is voluntary.
  • Is responsible for memory through the hippocampus and emotion using the amygdala. Classical Conditioning
  • Missing amygdala: causes no fear when there is a loud noise.
  • The person is scared but does not remember why they are scared.
• Cortex Transected off of a Cat: Because of midbrain and hindbrain, a cat can put movements together with purpose with the thalamus, because it’s near the hypothalamus.

Cerebral Cortex

• Is responsible for planning, social behavior, and motor control.
  • The front part of the brain controls all those functions.
• Parietal Lobe:
  • Touching part of the brain will cause senses of touch
  • This part controls touch but it is at the top of the somatosensory
• Occipital lobe: enables sight and controls vision
• The temporal lobe: controls language and comprehension controls memory with the side of the brain known as hippocampus
• Corpus Callosum connects the two hemispheres on the right and left shares motor information between the two sides one hemisphere controls opposite, Ex: my right brain control my left hemisphere

Legitimate Brain Discoveries

• Cortex ( functioning tissue, and not just a protective coveiring)
• Commissures (connecting pathways betwenn brain hemispheres, other than the corpus callosum
• Crossing of ascending nerve pathways from spical cord the contralateral hemisphere of the brain
• The distubution of grey and white matter traits

Phineas Gage

• An iron to his head
• This changed the front of his frontal lobe
• Personality was exaggerated

Wilder Penfield

• Found specific regions of the body where in specific parts of the body
• He Drew the "little man" on the brain
• Showed that greater activity meant larger amount of tissue:
  • Motor and somatosensory areas
  • the Hands are bigger
  • Face is bigger

Cortical Function

• Left: is language
• Borca's area
• Wernicke's Area Right: Spatial Front parts of brain: expression, creating plans, initiating actions Back part of brain: receiving information, perceptions and interpretations

Damage to Non-primary areas

Prefrontal damage: lose all the function that relates to topic Damage to people might impact the ability to initiate actions Apraxia means: not using hands, meaning inabilities to put moments together "not doing". Damage to Auditory might not recognize the sounds they have learned Neglect damage to the right parietal leads to the lack of body parts in the right/or the left sides of the brain Might also forget, damage to their body.

Aphasia

Broca's - left hemisphere damage - broca's area damage - cannot produce speech, very difficult to say - but can comprehend - Paul broca identified his regions Wernicke's - also left hemisphere damage - damage in this area makes it so cannot comprehend speech- (they dont understand what others or being spoken to)