PSY 210 Midterm 2.0 Flashcards
converging methods
putting together ideas from different areas of neuroscience ; asking same question from different methodologies
Neuroanatomy
physiological structure, staining, spatial, cytoarchitectonics
what is neuroanatomy not good for
system level physiology
where does neurophysiology occur
inside skull
where does electrophysiology occur
outside skull
Neurophysiology
electrical stimulation, electrode grids directly on cortex, Mapping (which parts of brain control body) , ANIMALS/DEAD
single-cell recording
extra and intracellular , correlation of firing w/ behavior of interest
lesions
cut and remove, learn what a particular area does
patient studies - neurophysiology & neuropsychology
SPATIAL
single dissociation
has A not B
double dissociation
group 1: A not B
group 2: B not A
Neurology & Neuropsychology
study of neurological disorders
hemorrhagic stroke
blood vessels bursts, pours blood into brain
ischemia stroke
blockage of vessel, no O2 to brain
tumor resection: glioma
glial gone bad; overgroth (microglia invovled in injury) - grown when not needed
tumor resection: meningioma
tumor on brain wall (pressure on brain) - NOT DEADLY
tumor resection: metastatic
cancer somewhere else in body, gets into bloodstream and spreads to brain
Kosakoffs
2 bumps (mammilary bodies) on basal surface - caused by alcholism
Cognitive Psychology
mental REPRESENTATIONS and trasnformations, processing
think of mind as computer (input, output)
Computational Modeling
testing theories
Electrophysiology: ERP
electroencephalogram (EEG), small snipet thats timelocked to an event; good temporal, poor spatial
Electrophysiology: MEG
magnetoenceophalograph, using magnetic field, expensive, better temp and spatial
Electrophysiology: TMS
transcranial magnetic stimulation, using wands, FLOW OF ELECTRICITY - stimulates neurons from outside of head
Neuroimaging: CT
structure;
Different tissues in the brain have different absorption rates when an x ray signal is passed through, based on the tissues density. CT scans send signals through the brain that are received by a detector on the other side. Based on how much of the signal is left to be read and is quantified on a scale of 0(less absorption)-1000(more absorption) , the scan can create a color image of the material that it passed through.
good spatial, poor temporal (seconds) not milli
Neuroimaging: PET
positron emission tracer is either injected/ingested/inhaled,
tracer is radioactive and the PET scan ultimately can track the degradation of the tracer - leaves behind positrons. A complicated mathematical model is used to observe where the tracer breaks down, and the tracking of the tracer breaking down creates the images.
PET uses radiation detectors to track what is known as an annihilation that occurs in the brain. This annihilation occurs when the positrons from the tracer attaches to the free flowing electrons in the brain, the annihilation sends two protons out in opposite directions. When the detectors register the protons leaving the explosion, it can show where the annihilation occured. Depending on what the tracker is looking for, the more annihilations that occur in a specific location the more of the target matter is present. For example, in a tracker that is looking for plaque that is present in a brain with alzheimer’s, the more annihilations in a specific location of the brain, the more plaque is present. A PET scan is most useful at detecting metabolic deficits in a particular region.
Neuroimaging: fPET
A functional PET scan is also a type of neuroimaging that is used to track blood flow across images across time. The functional PET tracks this by using a control task, and comparing that to the blood flow from a task of interest. Image is the count up of annihilations in a particular area.
Neuroimaging: MRI
Another form of neuroimaging is magnetic resonance imaging or a MRI. A MRI uses the naturally occurring nuclear spin of the nucleus of elements in the body to ultimately create a very detailed image. This is done using an extremely high powered magnet. When there are many nuclei spinning, the nuclear spins have angular momentum. This means that they are not spinning in synch or in the same direction. When the magnet used in an MRI is introduced, there is a magnetic dipole moment and all of the spinning nuclei align directionally, within the strength of the magnetic field. This is typically done by observing hydrogen nuclei because hydrogen is so prevalent in the human body. The magnet aligns the different nuclei directionally, but they are still spinning in an unsynced manner. Next, the MRI applies a radiofrequency pulse which shifts the direction yet again and syncs the spinning of all of the nuclei in the same wobble. This wobble is known as the procession which can be quantified as the Larmor. The Larmor equation multiplies the gyromagnetic constant and the magnetic strength of the magnet used which results in the frequency of the wobble. After the radiofrequency pulse is applied there is a period of relaxation in which the reorientation (T1) and desyncing (T2) is measured. The differences produced from the change of orientations and desyncing tells us about the different tissues and ultimately creates the image. The combination of the radiofrequency pulses and relaxation periods are known as the pulse sequence. Pulse sequences are created by a different combination of the (TR) or the time interval between two successive pulse cycles and the (TE) or the time interval from one pulse to the measurement of the MR signal. Much like the PET scan, there is also a functional MRI. The functional MRI subtracts a resting image from an image obtained while performing the target task which creates a statistical parameter map. Then, there is a statistical correction and the image is overlaid onto an anatomical image, creating a functional MRI image.
Explain the BOLD signal in fMRI.
In an fMRI there is a BOLD signal. BOLD stands for Blood Oxygenation Level Dependent. This uses the principle that blood flow is a correlate of neuronal activation. When there is neuronal activity in the brain, it needs oxygen to carry out the task at hand. Our body send oxyhemoglobin or oxygenated blood, and the blood that leaves the location of neuronal activity is deoxyhemoglobin or de-oxygenated blood. When you spark neural activity by performing a task, an increased amount of oxyhemoglobin floods to that area in preparation for use, leading to an excess amount of blood in the area of neural activation. This relative increase in oxyhemoglobin provides an increase in the magnetic resonance. So during a functional MRI, when a target task is performed, such a moving your pointer finger, there is an surplus (more than needed, overabundance - we don’t know how much blood neurons need) of oxyhemoglobin being sent to area of the brain that is being activated to move the finger, and that increase of oxyhemoglobin is the signal that is imaged. The detectors image by comparing looking at the amount of increase of blood - by looking at the amount of oxyhemoglobin of the condition of interest and the control interest.
Neuroimaging
mostly spatial
