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Chapter 2

PSYC 3460 Chapter Notes - Chapter 2: Medulla Oblongata, Vasodilation, Autonomic Nervous System


Department
Psychology
Course Code
PSYC 3460
Professor
Stephen Kosempel
Chapter
2

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Chapter 2
Current Paradigms and the Role of Cultural Factors
May 13, 2008
Paradigm: a set of basic assumptions, a general perspective, that defines who to conceptualize
and study a subject, how to gather and interpret relevant data, even how to think about a
particular subject
The Role of Paradigms
Paradigm: a set of basic assumptions that outline the particular universe of scientific inquiry
it injects usual biases into the definition and collection of data and may also affect the
interpretation of facts
meaning or importance given to a data may depend on a paradigm
The Biological Paradigm
it is a continuation of the somatogenic hypothesis (mental disorders are caused by irregular
biological processes
aka. Medical model or disease model
the germ theory was once very pervasive but then it was found that it cannot account for all
diseases (ex. Diabetes)
medical illness are common in that; there is some biological process that is disrupted or not
functioning normally
this paradigm was dominant from late 1800s to the middle 20th century
Ex. Hall’s removed ovarian cysts or the whole ovary to treat melancholia, mania, and delusions
Contemporary approaches to the biological paradigm
There are research supporting heredity having to increase the risk of certain mental disorders and
may result from a chemical imbalance within the brain (depression), defect within the autonomic
nervous system (anxiety disorder) and impairment in brain structure (dementia)
Behaviour Genetics
Behaviour genetics: study of individual differences in behaviour that are attributable part to
differences in genetic make up
Genotype: his or her unobservable genetic constitution (fixed at birth)
Phenotype: totality of his or her observable behavioural characteristics (changes over time & a
product of interaction between genotype and environment)
Various clinical syndromes are disorders of the phenotype, not genotype
Diathesis: a predisposition, may be inherited, but not the disorder itself
Behaviour genetics relied on 4 basic methods for whether psychopathology is inherited
oComparison of members of a family
People who share 50% of genes with a given individual are called first-degree
relatives
Nephews and nieces share 25% of an uncles and is called second-degree
relatives
Index cases/probands: are the individuals under investigation
oComparison of pairs of twins
Concordant: when twins are similar diagnostically are said to be this
When MZ concordance rate is higher than DZ rate, the characteristic being
studied is said to be heritable
But sometimes it’s not heritable but the rearing practises of parents
Equal environment assumption: the environmental factors that are partial cause
of concordance are equally influential for MZ and DZ pairs

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Sometimes results maybe similar because of the environment rather than biology
oInvestigation of adoptees
Eliminates the effect of being raised by disordered parents
oLinkage analysis
Tries to specify the particular gene involved
Collect diagnostic information and blood samples from affected individuals and
relatives and use the blood sample to study the inheritance patter of
characteristics who genetics are fully understood
Biochemistry In The Nervous System
Each neuron has 4 major parts: cell body, dendrites, axons, and terminal buttons
It is stimulated through the cell body or dendrites, the nerve impulse (electrical potential) travels
down the axon into the terminal endings
The gap between the sending axon and receiving neuron there is a synapse
The terminal buttons contain synaptic vesicles (filled with NT; a chemical substance that allow a
nerve impulse to cross the synapse)
The nerve impulse causes the synaptic vesicles to release molecules of their transmitter
substances, and these molecules flood the synapse and diffuse toward the postsynaptic neuron
Postsynaptic cell contain proteins (receptor sites); sometimes excitatory or inhibitory
Then the last step is the presynaptic neuron is returned to normal state
Sometimes what remains is broken by enzymes, or pumped back by reuptake
Key Neurotransmitters
oNorepinephrine: from the peripheral sympathetic NS, involved in produced high arousal
states (must be involved in anxiety disorders)
oSerotonin: brain NTs, involved in depression
oDopamine: brain NT, involved in schizophrenia
oGamma-aminobutyric acid (GABA): inhibits some nerve impulses, involved in anxiety
disorders
This theory proposes that a given disorder is caused by too much or too little of a NT
Too much or too little of a particular transmitter could result from an error in these metabolic
pathways
It may also be a problem in the reuptake process or the number of receptors
oDelusions and hallucinations may result from too much dopamine receptors (increase in
stimulation of the receptors)
Focus On Discovery 2.1: Structure and Function of the Human Brain
3 layers envelop the skull called the meninges; divided by a midline fissure
Cerebrum is the thinking part of the brain
Connecting the two hemisphere is the corpus callosum
There are 10-15 billion neurons that make up the grey matter
The cortex is vastly convoluted; ridges are called gyri and depressions are called sulky or
fissures
Deep fissures divide the brain into 4 lobes
Left hemisphere: controls right half of body, speech
Right hemisphere: control left half of body, spatial relations and patterns, is involved in emotion
and intuition
They communicate via the corpus callosum
The grey matter is around the surface of the brain, the interior is mainly white matter (made up of
large tracts or bundles of mylinated fibres)
Nuclei: centres and pockets of grey matter. Serve as connecting tracts from the cortex with other
ascending and descending tracts and as integrating motor and sensory control centers
Basal ganglia: 4 masses of cortical cells are deep within each hemisphere
Ventricles: cavities deep within the brain and has cerebrospinal fluid

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Diencephalon: contains the thalamus and hypothalamus (both consisting of groups of nuclei)
oThalamus: a relay station for all sensory pathways except olfactory (receives almost all
impulses arriving from different sensory areas)
oHypothalamus: highest center of integration for many visceral processes, regulating
metabolism, temperature, perspiration, blood pressure, sleeping and appetite
Midbrain: mass of nerve fibre tracts connecting the cerebral cortex with the pons, the medulla
oblongata, the cerebellum and the spinal cord
Brain stem: comprises the pons, and medulla oblongata; functions as a neural relay station
oPons: contains tracts that connect the cerebellum with the spinal cord and with motor
areas of the cerebrum
oMedulla oblongata: main line of traffic for tracts ascending from the spinal cord and
descending from the higher centres of the brain
Medulla: contains nuclei that maintain regular life rhythms of the heart beat, rising and falling
diaphragm, and constricting and dilating blood vessels
Reticular formation: RAS (reticular activating system); plays a role in arousal and alertness
Cerebellum: consists of 2 deeply convoluted hemispheres; receives sensory information from the
inner ear and from muscles, tendons, and joints; the information received and integrated relates
to balance, posture, equilibrium and to smooth coordination of the body when in motion
Limbic system: developed earlier than mammalian cerebral cortex; control visceral and physical
expression of emotion (quickened heart beat and respiration, trembling, sweating, and alterations
in facial expression, appetite, mating, defence, flight, hunger and thirst
oCingulated gryus, septal area, and amygdale
Biological Approaches to Treatment
Clear connections exist between the cause of a disorder (a biological defect) and its treatment
Psychoactive drugs has been increasing
Tranquilizers: (valium) can be effective in reducing tension associated with some anxiety
disorders
oIt stimulates GABA neurons to inhibit other neural systems that create the physical
symptoms of anxiety
Antidepressants: (Prozac)increase neural transmission in neurons that use serotonin as a NT by
inhibiting the reuptake of serotonin
Antipsychotic drugs: (Thorazine) use in treating schizophrenia; it reduces the activity of
neurons that use dopamine as a NT by blocking their receptors
Stimulants: used in treating children with ADHD (attention, deficit, hyperactivity disorder); it
increase the level of several NT that help the child pay attention
Evaluating the Biological Paradigm
Reductionism: the view that whatever is being studied can and should be reduced to its most
basic elements or constituents
they assert that psychology and psychopathology will ultimately be nothing more than biology
they propose that reducing complex mental and emotional responses to simple biology
Focus On Discovery 2.2: The Autonomic Nervous System
Nervous System = Somatic (voluntary) NS + Autonomic (involuntary) NS
Autonomic NS is important in emotional behaviour
It stimulates the endocrine gland, the heart, the smooth muscles found in the walls of the blood
vessels, stomach, intestines, kidneys, and other organs
Autonomic NS = Sympathetic NS + Parasympathetic NS
Sympathetic NS
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