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Psychology (10,000)
PSYB64H3 (200)
Chapter 1

all chapter notes for midterm (chapters 1,2,3,5,9) - very detailed !


Department
Psychology
Course Code
PSYB64H3
Professor
Janelle Leboutillier
Chapter
1

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Chapter 1
Biological Psychology as an interdisciplinary Field
Biologically psychology is the branch of psychology in which biological foundations of
behaviour, emotions, and mental processes are studied.
Historical Highlights in Biological Psychology
Trephining or trepanation was evidence of brain surgery 7000 years ago by drilling holes in the
skull. Edwin Smith Surgical Papyrus represents the oldest known medical writing in history – did not
consider the brain to be important. Hippocrates proposed that the brain was the source of intelligence and
correctly identified epilepsy as originating in the brain. Aristotle believed that the heart was the source of
intellect, whereas Herophilus (father of anatomy) believed that the ventricles played this important role.
Descarte’s mind body dualism – the body is mechanistic, whereas the mind is separate and nonphysical.
Biological psychology is based on monism – the mind is viewed as the product of the activity in the brain
and nervous system. Transmission of information along nerves is typically a one way street. Phrenology is
the pseudoscientific notion that the skull contours indicate personality and character traits.
Research Methods In Biological Psychology
Histology – refers to the study of microscopic structures and tissues and provide means for observing the
structure, organization, and connections of individual cells. The first step in the histological process is to
β€˜fix’ the tissue, either by freezing it or by treating it with formalin. Once the tissue is fixed, it is sliced by
microtome which works like a mini meat slicer. Golgi silver stain is best to make a detailed structure
analysis of a small number of single cells. Nissl stain should be used when you want to identify clusters of
cell bodies. A myelin stain would allow you to follow pathways carrying information from one part of hte
brain to another. Horseradishh peroxidise is when you know where a pathway ends and want to discover
it’s origin.
Autopsy – examination of the body following death. This is a correlational method and must be
interpreted carefully and precisely. Therefore , INAH-3 is correlated with sexual oreination, but we cannot
conclude whether the structure causes or is caused by sexual orientation.
Imaging:
Computerized Tomography (CT) – computers that enhance x-ray images. Provides excellent
structural information but cannot distinguish between a living or deal cell which means there is no
information regarding activity levels in the brain.
Positron Emission Tomography (PET) – allows researchers to observe brain activity for the first
time and was made possible by gamma camera. PET brain studies combine radioactive tracers with a wide
variety of molecules like oxygen, water, and drugs. Gamma ray resulting from the breakdown of the tracer
is recorded by detectors and fed to a computer in which the data constructs an image.
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Magnetic Resonance Imaging (MRI) – uses powerful magnets to align hydrogen atoms within a
magnetic field. Then, radio frequencies are directed at the part of the body to be imaged, producing
β€˜resonace’ or spinning of the hydrogen atoms. When the RF pulses cease, the hydrogen atoms return to
their natural aligment and as the atoms relax, each becomes a miniature radio transmitter emitting a pulse
that is detected. Voxel (volume pixel) is a three dimensional version of a pixel and the darkness or
coloration of each voxel represents the level of activity in an area. fMRI assess brain activity. fMRI uses
the fact that active neurons require more oxygen than less active neurons, and that variations in blood flow
on a particular area will reflect this need. Hemoglobin, the protein molecule that carries oxygen within the
blood has different magnetic properties when combined with oxygen or not and signals from a voxel will
change depending on the oxygenation of the blood in that area – this is known as the blood oxygenation
level dependent (BOLD) effect. MRI is better than CT and PET because it can provide images taken at
any angle without any movement of the individual. fMRI is also better than PET scans.
Recording:
The electroencephalogram (EEG) – measure the activity of a large number of cells, known as a
field potentials. Most influenced by the cortical cells closest to the electrodes.
Evoked potentials – allows researchers to correlate the activity of cortical sensory neurons
recorded through scalp electrodes with stimuli presented to the participant. ERP – average of 100 or more
EEG recordings.
Magnetoencephalography (MEG) – record the brain’s magnetic activity. Active neurons put out
tiny magnetic fields. The skull bones and tissues allow magnetism to pass through without any reduction
and thus this is better than EEG in this way. MEG data can be superimposed on three dimensional images
obtained with MRI and this combo can provide simultaneous information about brain activity and
anatomy.
Single cell recordings –both extracellular and intracellular events from a single neuron can be
assessed using tiny mircoelectrodes surgically implanted in the area of interest.
Brain stimulation: the tissues of the brain lack receptors for brain and therefore local anaesthesia is
usually used. For ethical reasons, brain stimulation is done on animals rather than on humans. Repeated
transcranial magnetic stimulation (rTMS) is a technique for stimulating the cortex at regular intervals by
applying a magnetic pulse through a wire coil encased in plastic and placed on the scalp – this can help
temporarily change brain activity immediately below the stimulation site – can inhibit or disinhibit certain
behaviours.
Lesion – injury to neural tissue and can either be naturally occurring or purposefully produced –
primary purpose is to assess the probable function of an area. Ablation is when large areas of brain tissue
are surgically removed. Chemically produced lesions have the advantage of harming only the cell bodies
of neurons while leaving the nerve fibres travelling through the area intact. A reversible type of lesion can
be produced by cooling an area using a probe – the neurons are unable to function when chilled but return
to normal function when it returns to normal temperature.
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Biochemical Methods: its hard for most chemicals to bybass the bloodbrain barrier and therefore
chemicals can be directly administered to the brain through the surgical implantation of micropipettes.
Microdialysis – small amounts of fluid are filtered from the area of the brain surrounding the tip of the
pipette for analysis and this allows the researchers to identify which neurochemicals are active in a precise
location.
Genetic Methods:
Twin studies- compare identical and fraternal twins. Monozygotic have an identical set of genes
and fraternal twins have on average about 50 percent of their genes in common just like any other siblings.
Adoption studies –compare the similarities of an adopted individual to his or her biological and
adoptive parents. Similarities to the biological parents suggest a role for heredity while similarities to the
adoptive parents suggest a role for the environment. Heritability – the amount that a trait varies in a
population due to genetics, is still influenced by the environment.
Studies of genetically modified animals – knockout genes takes the place of the normal genes but
fail to produce the specific protein. Researchers can assess the roles of particular genes and the proteins
they encode.
Stem cells – one of the most promising approaches to the problem of repairing brain and spinal
cord damage is the use of stem cells – undifferentiated cell that can divide and differentiate into other
types of cells. stem cell lines from three sources: adult stem cells, stem cells from umbilical cord blood,
and embryonic stem cells. Embryonic stem cells are pluripotent meaning that they can differentiate into
any type of tissue and are virtually immortal, but these cells will provoke an immune reaction in the
recipient. Adult stem cells are less flexible than the embryonic cells and can only differentiate into cells
similar to their source and lack the immortality of the embryonic cells also, but are less likely to cause
rejection by a tissue recipient.
Research Ethics
Things are hardly as plain as right or wrong.
Human Participants Guidelines – far more protective of the safety and well being of research
participants. Coercion of research participants is to be avoided at all costs.
Animal subjects guidelines – there must be a necessity to use animal subjects. The knowledge
gained should balance and justify the use of animals. Avoidance of pain and distress as well as excellent
food, housing, and vet care.
Emerging issues in research ethics:
Ethics of research on the internet – privacy issues, obtaining informed consent from
participants, and difficulties in debriefing participants are among the many ethical considerations that
researchers face.
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