lecture 10 Flashcards
3 ways to measure brain and behaviorf
measure brain and behavior
manipulate brain, measure behavior (neurosurgery/drugs
manipulate behavior, measure brain (restrict function)
what is the problem with testing humans
human behavior is very complex and its hard to isolate functions
ex. rare for someone to be impaired in all forms of memory because it is not a single function
corsi block tapping test
subject has to repeat sequence tapped out by examiner
- tests temporal lobe (hippocampus) short term recall of spatial position
mirror drawing task
trace the outline of an object by looking at mirror, difficult to do at first but you get better over time
- tests procedural memory (basal ganglia)
recency memory task
identify if objects have been seen previously and which was more recent
- tests temporal form of memory
3 human behavioraltests
corsi block tapping
mirror drawing
recency memory task
skilled reaching task
rats trained to reach through slot to obtain food
movements are differently affected by different types of neurological damage
- tests motor control and motor learning (M1)
morris water maze- place learning
rats find platform using external cues
morris water maze- matching to place learning
platformis in the same location each trial but a different location each day
morris water maze- cue learning
platform identified by a cue on the pool
two reasons to measure/manipulate brain and behavior
develop and test hypotheses about brain/behavioral relations
develop animal models of neurological and psychiatric disorders
karl lashley
used ablation to look for neural representation of memory but didnt find it
stereotaxic apparatus
surgical device permits targeting a specific part of brain for ablation
(karl lashley couldnt reach lower subcortical layers)
3 types of lesions
electrolyitic: lower electrode into brain at specific stereotactic coordinates and pass current through
neurotoxic: neuron killing chemical injected into brain
reversible lesions: regional cooling prevents synaptic transmission, administration of GABA agonist
brain stimulation
wilder penfield-
use electrode to stimulate areas of cortex
ex. hypothalamus stimulation causes rats to eat
deep brain stimulation
electrodes stimulate area with low-voltage current to facilitate behavior
- used for parkinsons, depression, OCD
transcranial magnetic stimulation
magnetic coil placed over the skull to stimulate the underlying behavior
- either induce or disrupt behavior
3 other manipulations of the brain
drugs- effects wear off when drugs metabolized but hard to pass through BBB
optogenetics- uses light to activate genetically modifued cells to activate ion channels, high temporal and spatial resolution
chemogenetics- genes code for receptors that respond to drugs with high specificity
measuring neuroanatomy
direct observation histology electrical activity imaging techniques chemical analysis
what can histology be used for
to look for modifications in the organization of cells in regions
- dendritic arburization or spine number
to look for newly generated cells
testing hippocampus- paired objects
healthy rats spend more time investigating object out of context
damaged ones treat new object at chance level which indicates that htey dont remember it is different
4 techniques for measuring brains electrical activity
- single cell recording
- electroencephalography
- eevnt related potentials
- magnetoencephalography
single cell recordinga
use fine electrodes to measure single-neuron AP
extra- next to cells (up to 40 neurons)
intra- inside cells
place cells
neurons in hippocampus vigourously fire when animal is in a specific place in the environment
head direction cell
fire when head is facing specific direction
EEG
changes as behavior changes
displays patterns of awake/drowsy/deep sleep
ERP
EEG is used to detect ERPs- graded potentials triggered by sensory stimulus
- in response to specific sensory event
- averaged to cancel noise
magnetoencephalography
generate electric field/magnetic field
- record magnetic potentials from detectors outside skull (SQUIDS)
- 3D localization of cell groups
- higher resolution then ERP but high cost
