AP Psych Unit 1: Biological Basis of Behavior

nature vs. nurture

false dichotomy

The Jim Twins Minnesota 1979

Three Identical Strangers

genetic determision

genetically determined (ex: eye color, ear shape)

genetic predisposition

genetic “push” or inclination in a certain direction (no certainity)

(Psych are genetically predisposed,

but not genetically determined)

epigenetics

genes can get “turned on/off” as a result of interacting with environment, “experiences after the activity of genes” (epi= above or in addition)

How do we know stuff about the brain

• open skull (people who die)

• case studies → injury to brain regions

• brain scans

Phineas Gage Case Study 1848

Brain specificity/Brain localization

certain brain parts have specific functions

Brain plasticity/neroplasicity

the brain wires and re-wires itself in response to new experiences (the brain adapts and motifs itself)

Type 1: Structural- experiences or memories change a brains physical structure

Type 2: Functional- brain functions move from damaged area to undamaged area

neurogenesis→ nuero-regrowth

Hemispherectomy

lose whole half of brain

Long Term Potentiation (LTP)

persistent strengthening of neural synapses based on frequent activity

(intertwined with brain plasticity)

Brain Scans

Function:

• EGG- measure electrical activity in the brain

• FMRI- structure and function in high resolution using magnetics

• PET- function radioactive glucose injected, tracks as flows to active brain area, and structure

Structure:

• CAT: read soft tissue (cross-section view) → only structure computerized x-ray

• MRI: reads with magnets- images of structure and potential damage

Jody Case Study

The Nervous System

Fight or Flight Response

1. Heart rate: Increase

2. Respiration: Decrease

3. Adrenaline: Increase

4. Endorphin: Increase

5. Pupils: Increase

6. Salvation: Decrease

7. Digestion: Decrease

8. Bladder: Release

Limbic System

emotion and drive

• Amygdala: Aggression and Fear

• Hippocampus: new memories

• Hypothalamus: Fighting, Fleeing, Feeding, Fornication

• Pituitary gland: “master gland”

Case Study HM 1953

Aphasis

loss of ability to understand or speak language

Brain Stem

1. Thatamus: Relay Station/Sensory Switchboard

2. Reticular Formation: Alertness and Attention

3. Pons: (no need to know)- sleep

4. Medulla: Heart beat, breathing, blood circulation, digestion (MIKE THE CHICKEN)

Left vs. Right Brain

• Left: math and logic, language centers

• Right: visual/spatial, non-verbal, facial recognition, artistic/creative

(not processed through words) → can draw, “I saw nothing”

Corpus Callosum

• think bundle of nerve fibers that link the two hemispheres

• Sperry and Gazzaniga: split brain procedure

• Endocrine system: glands and hormones, travel through bloodstream and secreted by glands

“The Neural Chain”

• How neurons in the human brain communicate

• about 86 billion nuerons in the brain

Glial Cells

• “Glue” neurons in place

• Support and provide nutrients

• Form myelin around axons

There are two categories of “message sending neurons”

• Sensory: Afferent neurons carry messages in to the CNS →

  • Afferent = Approach

The CNS

• Motor: Efferent neurons carry messages out from the CNS to the muscles and glands →

  • Efferent = Exit

Reflex Arc

neural pathway that controls the bodies automatic response (does not need to be processed in the brain)

Neural Specificity

Some neurons have specific functions

Nuerons (in breif)

• Cells fire in patterns

• Binary… “The all or none law”

• Specificity

  • Feature detectors, motion detectors, mirror neurons

A Typical Neuron

• Nucleus: 

• Cell Body (Soma): the cells life-support center

• Dendrites: receiving messages form other cells

• Axon: passes messages away from the cell body to other neurons, muscles, or glands

• Myelin Sheath: covers the axon of some neurons and helps speed neural impulses

• Axon Terminal Branch: form junctions with other cells

• Neural Impulse: action potential, electrical signal traveling down the axon

Multiple Sclerosis

autoimmune disease, body attacks the myelin and disrupts the neural firing

Presynaptic Neuron

sending message

Postsynaptic Neuron

receiving message

Resting State

neuron is negatively charged, the neuron could “fire” but it’s not (aka resting potential)

Firing State

when then neuron receives enough of an electrical charge, it “fires” in an all-or-none manner

All-Or-None Law

the neuron fires fully or not at all

“Toilet”

Action Potential

• the electrical charge that skips down the axon of the neuron

• polarized → depolarized → polarized state

Re-Uptake

recollecting/recycling excess neurotransmitter left out in the synapse

Refractory Period

a brief period in which the neuron cannot fire while it “reloads”

Polarized Neuron

a neuron that has a distinct structural and functional asymmetry between its two main processes: the axon (output) and the dendrites (input)

Depolarized Neuron

a process in which the membrane potential of a neuron becomes less negative, or more positive

How neurons communicate

synaptic transmission

Agonists

Drugs that mimic or encourage the activity of a specific neurotransmitter

Antagonists

Drugs that block the effect of a particular neurotransmitter

Neurotransmitters (in brief)

• Chemical messengers

• Excite or inhibit?

• Neurotransmitters vs. hormones?

There are 2 basic categories of neurotransmitter activity

• Excitatory: Neurotransmitters that stimulate neural activity, Think of the accelerator in a car

• Inhibitory: Neurotransmitters that slow neural activity; Think of the brakes in a car

Opiates

artificial endorphins, body stops producing natural endorphins

Myasthenia Gravis

Autoimmune neuromuscular disorder of any voluntary muscle movement. Body attacks acetylcholine receptors making muscle contraction difficult.

→ causes paralysis

Rem Sleep

sleep with eyes open

What is the neurotransmitter involved with sleep

• Serotonin

• Adenosine (inhibitory neurotransmitter)

What brain structures are involved with sleep and alertness

• Medulla

• RAS

Hormone that secretes sleep

Melatonin

The Pineal Gland

secretes melatonin, the “sleep hormone” which helps regulate internal bodily rythms

Hypothalamus

sleep control center monitoring day/night changes, especially in the suprachiasmatic nucleus (SCN)

Circadian Rythms

24hr sleep/wake cycle, governed by the SCN and Pineal gland

Why do humans sleep?

• Restorative Theory: Humans sleep to replenish physical energy

• Memory Consolidation Theory: Human sleep helps in sorting and filing info, and in strengthening some neural connections, while pruning others away

• Adaptive Theory/Evolution Theory: Humans sleep at night because it’s historically been best for their survival to do so

D.J. Peter Tripp (1959)

REM (“Paradoxical Sleep”)

While your major muscle groups are essentially shut down, your brain is nearly as active as when awake

The dream stage?

• Paralysis

• Tetris Study (link to info processing)

• REM deprivation 

• REM rebound

• Babies and REM: (bodies natural response to sleep deprivation leading to an increase in REM sleep)

Insomnia

a common sleep disorder characterized by difficulty falling or staying asleep, despite having adequate opportunity to do so

Hypersomnia

sleep disorder characterized by excessive daytime sleepiness (EDS) that cannot be relieved by adequate sleep

Sleep Disorders

1. Sleep Apnea- frequent stoppages of breathing during sleep

2. Narcolepsy- a sudden, involuntary drop into REM sleep

3. Night Terrors- screaming, sweating, can’t link to dream, no recall in AM

4. Somnambulism and Somniloquy- sleepwalking and talking

5. Rem sleep disorder- the muscles don’t shut down as they should, potentially dangerous