Ch 5 The Research Methods of Biopsychology Flashcards
What is the purpose of contrast X-rays in brain imaging?
Contrast X-rays highlight the difference in X-ray absorption between different tissues, improving the visibility of brain structures.
What is cerebral angiography used for?
It involves injecting a radiopaque dye into a cerebral artery to visualize the cerebral circulatory system and detect issues like vascular damage or tumors.
How does Computed Tomography (CT) work?
CT uses a computer-assisted x-ray procedure where an x-ray tube rotates around the head, producing images of horizontal sections of the brain, which are then combined into a 3D image.
Positron emission tomography (PET)
a radioactivity based technique
Provide images of functional brain images (activity) rather than structural image of the brain
tracks movement of FDG as it is taken up by brain cells
MRI
structural imaging
high resolution images from measuring radio-frequency waves from hydrogen atoms as they align with the magnetic field
different brain structures have diff amounts of water
Why does fluorodeoxyglucose (FDG) accumulate in active neurons during a PET scan?
FDG is similar to glucose but cannot be metabolized, so it accumulates in neurons as they consume energy, allowing PET to track brain activity.
How does Diffusion Tensor Imaging (DTI) work?
DTI measures the movement of water molecules, identifying pathways along which they diffuse, allowing visualization of major brain tracts and the connectome.
tracts (bundles of axons) are major routes for water diffusion
fMRI
structural (better) and functional
oxygen levels measured
what is an ultrasound based technique
functional ultrasound imaging (fUS)
ultrasound measures changes in blood volume to different areas of the brain - more active=more blood = alters the waves
what is special about transcranial stimulation (TMS)
shows causation
TMS (magnetic)
inactivates area for a minute, can see effect
tES (electrical)
increases activity using currents
tUS (ultrasound)
subcortical structures
can make small permanent lesions. - less invasive treatment
What does electroencephalography (EEG) measure?
gross electrical activity of the brain by recording electrical events through large electrodes placed on the scalp.
waveforms are associated with particular states of consciousness and cerebral pathology, such as alpha waves for relaxed wakefulness.
waves decrease in strength away from source, so we can pinpoint location
how to reduce noise when looking at EEG
Signal averaging can be used to reduce the noise of background EEG
allows for analysis of average evoked potentials (AEPs) focuses on the various waves in the averaged signal
Characterized by direction, positive or negative, and by its latency
What is an event-related potential (ERP)?
A: ERPs are changes in the EEG signal elicited by sensory stimuli, used to study brain responses to specific events.
Far-field potentials
Attenuated signals that originate far away in the sensory nuclei of the brain stem
What is Magnetoencephalography (MEG)?
MEG measures changes in magnetic fields produced by neural activity on the scalp’s surface, providing better spatial resolution than EEG and allowing localization of subcortical activity.
costly, large machines, have to be still
psychophysiological measures of somatic nervous system activity
muscle tension (aroused- more tension)
eye movement
psychophysiological measures of autonomic nervous system activity
skin conductance (level - situation, response - experience)
sweat gland activity associated with arousal increases conductance
cardiovascular activity
-HR, BP, Blood volume
what is stereotaxic surgery
Means by which experimental devices are precisely positioned in the brain
uses axis (locates brain structures like a map) and instrument (holds head and holds electrode)
lesion methods
aspiration (suction)
-peels off cortical tissue
radio-frequency
-heat destroys
knife cuts (sectioning)
-cuts conduction ni nerve/tract
reversible lesions
-anesthetic or cooling
electrical stimulation vs lesioning effects
tend to be opposite of each other
Intracellular Unit Recording:
Key Concept: Records the membrane potential of a single neuron as it fires.
How It Works: Uses a microelectrode inserted into a neuron to measure electrical activity on a moment-by-moment basis.
Usage: Commonly used in animal studies where the animal is immobilized to minimize movement.
Pros: High precision in capturing neuron activity.
Challenges: Animals must be immobilized, which limits real-world application.
extracellular unit recording
records firing activity for 1000 neurons at a time
the ways drugs can be injected
the peritoneal cavity of the abdomen
§ Intraperitoneally (IP)
A large muscle
§ Intramuscularly (IM)
The fatty tissue beneath the skin
§ Subcutaneously (SC)
A large surface vein
§ Intravenously (IV)
since drugs do not easily pass the blood brain barrier, how can we overcome this
To overcome this are administered in small amounts through a fine hollow tube called a cannula that is stereotaxically implanted in the brain
