PSYC 241 Lecture Notes - Lecture 2: Neurotransmitter, Dementia, Existentialism
11 Oct 2019
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Lecture 2 – Theoretical perspectives
Goals of the theory perspective (a good theory)
- explain etiology (what causes X, why others don’t have X)
- identify maintaining factors (what makes symptoms persist, these factors can be the same OR
different from causal factors)
- predict course of disorder
- design effective treatment (intervention targets factors that cause and or maintain a disorder)
In the past theories were single factor / unidimensional
- this is where the nature versus nurture debate stems from
interactionist theories (today)
- Both nature and nurture influence mental health
models and theories outline
1. biological models
2. psychosocial models
3. integrated theories (both)
biological models (5)
- damage to the brain
o structural damage to the brain leads to disorder
▪ direct head injury
▪ diseases
• childhood cancer influences adult brain
• dementia, deterioration of cog functioning linked to loss of brain cells
▪ toxins (lead, etc.)
- neurotransmitters
o focus on box 2.1
▪ Know generally how neurotransmitters work? (Na and K involved)
▪ nerve impulses received by dendrites of neighbouring neuron (excite or
inhibition signals)
▪ travels down axons, and excites/inhibits the next neuron
▪ messages travel through synapse
o Neurotransmitter definition: Chemical messengers released from the propagating
neuron and move through the synapse to the postsynaptic neuron
o Research attention on: DA, 5-HT, NE, GABA
o Neurotransmitters act together (ie: DA and 5-HT act together to create balance in brain)
▪ DA = pleasure seeking /exploring
▪ 5-HT: constraint and inhibition behaviour
▪ NE: excite neurons/agitate
▪ GABA: gamma aminobutyric acid, relax/inhibit neurons
o different neurotransmitters are concentrated in different brain areas, and relate to
different functions
o neurotransmitter disturbances (also how drugs work)
▪ (quantity of NT produced) produce too much/too little at synapse
▪ (quantity of receptors) too many/too little Receptors (reabsorption )
▪ (amount of transmitter deactivation) too much or too little deactivation via
enzymes
▪ (quantity of NT in synapse)
▪ (time of reuptake process) too fast or too slow, ie SSRI drugs inhibit reuptake,
make it slower
o Abnormal behaviour can result from any of the 5 things above, (excessive or reduced
activity), ie: schizo happens when too much excitation in dopamine system
o Unlikely single neurotransmitters determine behaviour
o behaviour & neurotransmitter's impact each other (bidirectional relationship)
- PNS (SNS and ANS)
o somatic nervous system: controls muscles (cuz soma = body).
▪ GAD: chronic muscle tension .
o autonomic nervous system: controls automatic body functions (breathing, digestion,
heart rate, etc.) to produce homeostatic (balanced) activity.
▪ sympathetic: fight or flight .
• increased HR/breathing, vision acuity, movement, adrenalin, decreased
digestion, salivation, constrict bladder (so easier to run)
• individuals defer in duration, intensity, and return to baseline
o quicker/slower f/f response.
o different intensity experienced.
o quicker/slower return to baseline.
• the body still activates sympathetic system in face of both true and false
fears (ie, scared of flying, no imminent danger of dying but u still
stressed).
▪ Parasympathetic: rest and digest.
- endocrine system
o chemicals released into blood stream
o hormone imbalance can lead to disrupted behaviour/thoughts/feelings (make sure u
don’t misdiagnose a mood disorder, that is in fact a hormonal disorder)
▪ hypoglycemia: hard for pancreas to regulate blood sugar cuz too much insulin
converting glucose away. (too low sugar),
• mimics anxiety, easy to misdiagnose with anxiety if you don’t do
hormonal test
▪ cretinism: dwarf and intellectual deficits (defective thyroid)
o hypothalamus releases (releasing hormones), which travel to dif pituitary, which then
release other hormones that affect our behaviour in adrenals or gonads (tests/ovaries),
HPA and HPG axes.
- genetics
o genetics definition: inherited characteristics/behaviours
