Topic 1: Intro to biopsychology Flashcards
Three R’s of animal welfare
reduction replacement (computer models) refinement (reduce pain and discomfort)
extreme views= abolishionist all animals have the same rights as humans, no animal trials are permissible. Minimilists think its ok but we shoudl minimise harm and use three R’s
Mind-brain problem
consciousness, is it real should we avoid the question, is consciousness a fundamental property like mass or charge - but its not constant. Mind body problem different to mind brain problem. Monism = mind and brain same thing, mental activity is the same a brain activity
Physical V Ontogenetic V evolutionary V functional explanations
Physical; other parts of the body influence on brain e.g. hormones
Ontogenetic; how a structure/function develops e.g. inclduign reference to genes nutrition, experiences and interactions between
Evolutionary; reconstructs the evolutionary history of a behaviour or structure
functional; describes why something evolved as it did
evo v functional = what v why
Brain size and intelligence
The proportion of the brain dedicated to carrying out higher-order cognitive processes is more important than the size of the brain itself
brains have decreased in size over the last 10’000 years (reducing energy needs of the brain)
also wrinkles increase surface area increases number of possible neurons
Theory and modern understanding of the pineal gland
Descartes - thought it was where the mind and body interacted, also thought the brain and body was hydrolic, hence fluid filled ventricles full of animal spirits
actual - part of endocrine system making melatonin
Stereotaxic instrument
used in animal trials to stimulate record from or damage any part of the brain. An electrode is inserted to the location and passes a current sufficient to damage the area
to control this research a sham lesion is also made in a control group where the skull cut and surgery is the same but no current is passed. Differences between these two measured
considered crude, new methods more specific include chemicals that only turn off neurons not axons, and sometimes only temporarily, or use gene knockout
Ablation = removal
lesion = damage
After death the brain slices are stained to record the precise location of damage
TMS
Trans-cranial Magnetic Stimulation; a magnet can stimulate the neurons under it or stop them creating a virtual lesion (which seems to go away again after)
e.g. Michael Mosley
temporarily activating or inactivating neurons in the brain using magnetic stimulation/
Blind sight
primitive visual pathways track movement (like a snake does)
primary visual area (V1) can be damaged (in people with blind sight) and movement can still be processed by the primitive pathway that goes to the superior calliculus
unilateral neglect
Hemineglect, also known as unilateral neglect, hemispatial neglect or spatial neglect, is a common and disabling condition following brain damage to the RIGHT PARIETAL LOBE in which patients fail to be aware of items to one side of space. (wont eat food of left side, or apply lipstick on the left side)
optogenetics
instead of the old pump a current randomly that stimulates all neurons and axons in an area, they do optogenetics
they got microbes that respond to light by producing proteins which react to light (some by opening sodium channels (excitation) or chlorine channels (inhibition))
they then got a virus to insert those proteins into neurons (or part of e.g. the axon or dendrites)
they invented thin optical fibres that could shine just the right amount of light onto the right brain area
EEG
Very fast, very safe, poor spatial resolution
measures electrical impulses in the brain using electrodes on the scalp.
Electroencephalography records the overall activity of neurons under a certain electrode (within about 1cm accuracy)
can show wake v sleep wave states
epileptic fit state
can show evoked potentials/evoked responses An evoked potential or evoked response is an electrical potential in a specific pattern recorded from a specific part of the nervous system, especially the brain, of a human or other animals following presentation of a stimulus such as a light flash or a pure tone.
after action potential transmission there is depolarisation which is measured
its the post synaptic dendritic currents from cortical pyramidal cells (pyramidal neurons, are a type of multipolar neuron found in areas of the brain including the cerebral cortex, the hippocampus, and the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract.)
EOG - electroocculargram measures the eye movement
the line data (looks like earthquake) each line is an electrode
measured in microvolts, gamma beta alpha theta and delta waves
MEG
Magneto encephalo graph, the big huge helmet on the cute baby
measures the faint magnetic fields generated by brain activity (within about 1cm accuracy)
can trace the propagation of a message from one part of the brain to another
different wave types measured in EEG
GBATD Good Boys Always Talk Dirty
Gamma brainwaves (39 – 42 Hz) are the fastest and most subtle brain waves. Gamma rhythms modulate perception and consciousness.
Beta brainwaves (13 – 38 Hz) are small, faster brainwaves associated with a state of mental, intellectual activity and outwardly focused concentration. This is basically state of alertness.
Alpha brainwaves (8-12 Hz.) are slower and larger. They are associated with a state of relaxation and represent the brain shifting into an idling gear, waiting to respond when needed. If we close our eyes and begin picturing something peaceful, there is an increase in alpha brainwaves.
Theta brainwaves (4-7 Hz) brain waves represent a day dreamy, spacey state of mind that is associated with mental inefficiency. At very slow levels, theta brain wave activity is a very relaxed state, representing the twilight zone between waking and sleep.
Delta brainwaves (1-3 Hz) are the slowest, highest amplitude brain waves, and are what we experience when we are asleep. In general, different levels of awareness are associated with dominant brainwave states.
PET
positron emission tomography
radioactive glucose is injected
and when the glucose is used by busy brain areas, they emit 2 gamma rays 180degrees apart, the difference in time received to both senses tells the exact location
detected by gamma ray detectors.
fMRI
advantages
less expensive or risky than PET. doesn’t use ionizing radiation,
magnet limits who and what can go in
claustrophobia
expensive
results are not necessarily generalisable, one persons results dont generlaise to all, very individualised, also one activitiy on one day might stimulate basal ganglia, on others it doesnt
records the energy released by water molecules after the removal of a magnetic field. Or blood
protons of hydrogen atoms aling when magnet is on, then radiofrequency current distrubs the alignment and they return to their resting state, they then emit a radio signal, received by the scanner, which shows the relaxation rates of the different tissues
hydrogen protons everywhere in the body, in fat and water
they spin causing an electrical current
receiver coil is wrapped around the patients body
blood oxygen level is measured in fMRI (functional MRI) showing blood flow
looking for the susceptibility (magnetic-ness of parts of the brain)
oxygenated hemoglobin
de-oxygenated hemoglobin becomes paramagnetic (more magnetic) inside a big magnet
its an indirect measure of brain activities
more blood flow to areas = more oxygenated hemoglobin which then becomes de-oxygenated by being used in an area.
Has been used predictivly! sleepy patients repeatedly reporting imagry, visual cortex activation mapped
