Biological Bases of psychological processes Date: 20/1/2013 and 27/1/2013

1. Chapter 2
Biological Foundations of
Psychology
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

2. The Study of the Biological Bases of
Psychology
• Pre-adaptation
– Describes the process by which an existing system (e.g.
physical disgust/physical pain) is co-opted (“hi-jacked”) in
order for new human functions to develop (e.g. moral
disgust/response to social exclusion)
• Nervous system
– Divided into Central Nervous System (CNS) and
Peripheral Nervous System (PNS)
– CNS includes the brain and spinal chord
– PNS includes the somatic system and autonomic system
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3. Neurons, the Building Blocks of the
Nervous System
• Basic unit of the nervous system = Neuron
– Specialized cell that transmits neural impulses or
messages to other neurons, glands and muscles
Figure 2.2 Schematic Diagram of a
Neuron.
Arrows indicate the direction of the
nerve impulse. Some axons are
branched; the branches are called
collaterals. The axons of many
neurons are covered with an insulating
myelin sheath that helps increase the
speed of the nerve impulse.
(Adapted from Human Anatomy by Anthony J. Gaudin
and Kenneth C. Jones. Copyright © 1988 by Anthony
J. Gaudin and Kenneth C. Jones. Reprinted by
permission of the authors.)
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
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4. Neurons, the Building Blocks of the
Nervous System
• Neurons vary greatly in size and shape
• Neurons are classified into three categories
– Sensory neurons – transmit impulses from receptors
to CNS
– Motor neurons – carry outgoing signals from CNS to
muscles and glands
– Inter-neurons – connect sensory and motor neurons
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5. Neurons, the Building Blocks of the
Nervous System
• Action Potentials
– Information travels along neuron in form of neural
impulse called an action potential
– Each action potential is the result of movement of
electrically charged particles (ions) in and out of
neuron
– Movement of ions controlled by ion channels - when
these are closed the neuron is referred to as “resting”
– When a neuron is depolarized above the excitation
threshold cell membrane is temporarily unstable,
resulting in action potential
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6. Neurons, the Building Blocks of the
Nervous System
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
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7. Neurons, the Building Blocks of the
Nervous System
• Synaptic transmission and neural coding
– All-or-none law – a neuron is either firing action
potential, or not, so how can the nervous system code
for/represent complexity of experience?
– Power of nervous system lies in the complexity of the
connections between neurons
– Lock-and-key action – the way a neurotransmitter and
receptor fit together, which causes a change in
permeability of ion channels, either excitatory or
inhibitory
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8. Neurons, the Building Blocks of the
Nervous System
• Neurotransmitters
– More than 70 identified
– Acetylcholine – involved in memory and attention and
transmits signals between nerve and muscle.
Prevalent in hippocampus. What problems result?
– Norepinephrine – an increase/decrease in brain
correlates with increase or decrease in mood level.
Reuptake blocked by cocaine/amphetamines, Lithium
speeds it up.
– Dopamine – mediates effects of natural rewards (e.g.
food) and effects of drugs of abuse (Schizophrenia)
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9. Neurons, the Building Blocks of the
Nervous System
• ...Neurotransmitters
– Serotonin – important role in mood regulation (SSRI).
Also important in sleep and appetite and used for ED.
– Glutamate – excitatory in nature – linked with learning
and memory. What area of brain is it mostly found in?
– GABA – inhibitory in nature – helps control muscle
movement. Anti anxiety drugs enhance GABA.
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ISBN 9781844807284 © 2009 Cengage Learning

10. The Organization of the Brain
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11. The Organization of the Brain
• The hindbrain
– Medulla
• Controls breathing & some reflexes which aid upright posture
– Pons
• Important in the control of attentiveness/timing of sleep
– Reticular formation
• Network of neurons that extend from lower brainstem up to
the thalamus in the forebrain and across other parts,
controls arousal, also plays role in ability to focus attention.
– Cerebellum
• concerned primarily with control of movement & important for
learning new motor responses to Psychology 15 edition
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12. The Organization of the Brain
• The midbrain
– Superior and inferior colliculus
• Important for transmitting sensory information to brain & in
movement control (including eye movement)
– Substantia nigra
• Key part of dopamine-containing pathway – deteriorates in
Parkinson’s disease
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13. The Organization of the Brain
• The forebrain
– Includes cerebrum (split into two hemispheres) and
sub-cortical structures
– Thalamus
• Directs incoming information from sense receptors to
cerebrum
– Hypothalamus
• Regulates eating, drinking & sexual behavior. Exerts control
over ANS & also role in sensation of emotions. Important in
homeostatsis.
– Pituitary gland
• Part of system of glands called endocrine system involved in
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hormones
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14. The Organization of the Brain
• ...The forebrain
– Limbic system
• Provides additional control over some instinctive behaviors
regulated by central core
• Hippocampus – special role in recent memory
• Amygdala – involved in emotional behavior, e.g. fear
– Cerebral cortex
• Receives information from sensory systems; controls motor
responses and contains association areas which are
concerned with memory, thought and language
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

15. The Organization of the Brain
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

16. The Organization of the Brain
• Mapping the brain
– Recent development of sophisticated computer
methods allow detailed images of human brain
without damaging or distressing patient
• Methods include computerized axial tomography (CAT or
CT), magnetic resonance imaging (MRI), and positron
emission tomography (PET)
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
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17. The Organization of the Brain
• Asymmetries in the brain
– Language
• Understanding about brain mechanisms for language largely
derived from studies of patients with brain damage.
• Aphasia – language deficit caused by brain damage
• Broca’s area – involved in speech production
• Wernicke’s area – involved in speech comprehension
– Split-brain research
• The brain normally acts as integrated whole but for some
epilepsy patients, the corpus callosum surgically severed -
these split-brain patients provide important insights into brain
function
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

18. The Organization of the Brain
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

19. The Organization of the Brain
• ...Asymmetries in the brain
– Hemispheric specialization – split-brain research
indicates two hemispheres function differently
• Left hemisphere – controls ability to express self through
language and skilled in mathematical abilities
• Right hemisphere – comprehends only simple language but
highly developed in spatial and pattern sense
• Specialization does not mean two hemispheres work
independently but rather they continually integrate activities
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

20. The Autonomic Nervous System
• Autonomic system
– System of nerves outside of the brain & spinal chord that
controls the glands and smooth muscles including the
heart, blood vessels and stomach lining.
• Autonomic nervous system (ANS)
– Activities it controls are autonomous or self-regulating
(e.g. digestion & circulation)
– ANS has two divisions – sympathetic & parasympathetic
– Sympathetic nervous system – active during excitement
– Parasympathetic nervous system – associated with rest
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
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21. The Endocrine System
• Endocrine system
– System of glands which secrete hormones to be
transported through the bloodstream to act in various
ways on cells of different types
– The Nervous system controls fast changing activities
of the body by directly activating muscles and glands.
– The endocrine system act more slowly indirectly
affecting the activities of cell groups in the body by
secreting hormones.
– Pituitary gland “master gland” which controls
secretion activity of other endocrine glands
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
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22. The Endocrine System
• Hormones are secreted by endocrine glands into the
bloodstream and transported to other parts of the body
where they have specific effects.
• Hormones act in various ways on various cells.
• Each cell has receptors particular to specific hormones.
• Receptors pull those molecules out of the bloodstream
and into the cell.
• One of the major endocrine glands is the pituitary gland
that is partly an outgrowth of the brain and lies just belw
the hypothalamus.
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

23. Evolution, Genes and Behavior
• Evolution of behavior
– Natural selection – process described by Charles
Darwin whereby variations on inheritable traits which
aid survival are passed on to future generations
– Examination of behavior needs to include ultimate
causes of behavior (why behavior evolved through
natural selection) and proximate causes (how
behavior generated)
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
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24. Evolution, Genes and Behavior
• Chromosomes and genes
– Genes – segments of deoxyribonucleic acid (DNA)
molecules that form fundamental hereditary unit
– Chromosomes – structures which carry genes in the
nucleus of each cell in the body
– Chromosomes and genes both exist in pairs
– Dominant & recessive genes – each gene in pair can be
dominant or recessive.
• Both dominant = dominant gene specifies form of trait developed
• One dominant, one recessive = dominant gene determines trait
• Both recessive = recessive gene determines trait
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

25. Evolution, Genes
and Behavior
...Chromosomes and
genes
Sex-linked genes
- Normal female has two X
chromosomes in pair 23
- Normal male has one X and
one Y chromosome in pair 23
- Men express more recessive
traits because gene carried on
one of chromosomes in pair 23
will not be countered by
dominant gene on other
- Genetically determined
characteristics linked to twenty-
third chromosome pair called
sex-linked traits
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

26. Evolution, Genes and Behavior
• Genetic studies of behavior
– Some traits determined by single gene but most
characteristics determined by many genes - polygenic
– Selective breeding
• Method for studying inheritance of particular traits by mating
animals high or low in particular behavioral/physical trait
• Been used to demonstrate inheritance of number of
behavioral characteristics
• If selective breeding does not alter a trait then assume that
trait is linked primarily to environmental factors
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

27. Evolution, Genes and Behavior
• ...Genetic studies of behavior
– Twin studies
• Method used to study relative influences of genetics and
environment in behavior
• Identical twins – monozygotic because develop from single
fertilised egg therefore share exactly same genes
• Fraternal twins – dizygotic as develop from two fertilised
eggs therefore same genetic similarity as other siblings
• Studies indicate some characteristics more similar between
identical twins (e.g. intelligence)
• Studies of adopted children indicate genetic influence may
become stronger with age
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

28. Evolution, Genes and Behavior
• ...Genetic studies of behavior
– Molecular genetics of behavior
• Some researchers suggest certain human traits influenced by
specific genes, which are thought to affect particular
neurotransmitter receptors
• Such analyses can be misleading and should be treated with
caution – further research needed
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

29. Evolution, Genes and Behavior
• ...Genetic studies of behavior
– Environmental influences on gene action
• An individual’s inherited potential at birth heavily influenced
by environment infant encounters (e.g. diabetes – genetic
disposition but obesity important variable)
• Genetics may set limits on individual’s potential, but what
happens to that potential depends on the environment in
which an individual grows up
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning