Behavioral Neuro Test 2 Flashcards
neuroscience approach behaviour methods
- stereotaxis surgery
- invasive electrophysiology
- immediate early gene (IEG) expression and tract tracing
stereotaxis surgery methods (3)
permanent lesions, electrode impanted in rat brain. and cannulation
bregma and lambda
bregma is an area on top of brain used as reference pooint. it is area on top of skull where two sutres (seams of in skull) intersect. lambda is another one of those reference points
stereotaxtic atlas
map of where a landmark is in brain.
IEG expression and tract tracing (3 types)
- double labelling
- optogenetics
- DREADDS
behavioural approach in methods for neuro
- open field test
- elevated plus maze
- radial arm maze
- morris water maze
- conditioned defensive burying
- conditioned taste aversion
intracellular unit recording
intracellular microelectrode records the membrane potential from a single neuron
extracellular unit recording
tip of microelectrode is in extracellular fluid next to neuron. records electrical disturbance each time a single neuron fires an action potential
multiple unit recording
electrode is larger than microelectrode- so it records the action potential of many nearby neurons; these are summed together
invasive EEG recording
a large implanted elctrode reocrds general changes in electrical brain activity; not specific to action potentials
in FG example, what were CS and US?
conditioned stumulus= light
unconditioned stimulus= food
why do we want to wait when using IEG expression and double labelling
wait 90 minutes because the protein (fos) takes about 90 minutes to be expressed
double labelled cells
cells that label for BOTH fg and fas
why do double labelled cells mater?
they are activated by a behavioural event and anatomically project from one brain region of interest to another.
this allows us to find behaviral functions of anatomical projections
fos vs fg
FG is a retrograde tracer and fos is a natural protein, IEG expression. Fos is present when neurons were fired/active.
direct method of labelling
flouresence
indirect method to label
antibodies. this is often the preferred method because there is more amplication
goat and rabbit antibody example (this is indirect method)
- an antigen is injected into a rabbit.
- the rabbit produces an antibody
- that antibody from the rabbit is injected into a goat
- the goat produces that antibody as well
optogenetics defintion
manipulating neural activity with light. this is done by using light sensitive algae and inserting it into the brain. light can depolarize or hyperpolarize channels.
opsin
a highly light sensitive ion channel. how? put genetic code to making opsin into a virus. virus is modified to tell cells to produce opsin. infuse virus into brain
2 types of opsin
channelrholdopsin and halorhodopsin
channelrholdopsin
opsin type- blue light depolarizes neuron because Na+ enters the cell. blue light causes Na+ to enter the cell
halorhodopsin
stimulated by yellow light. yellow light opens Cl- channels and hyperpolarizes cells
DREADDS
- **Engineered Receptors: **DREADDs are specially designed G protein-coupled receptors (GPCRs). Unlike natural receptors, DREADDs don’t respond to their usual, or endogenous, signaling molecules. For instance, if a DREADD receptor is derived from a receptor for acetylcholine (ACh), it will not be activated by ACh. These are specially engineered proteins that scientists put into certain brain cells.
- Designer Drug Activation: Scientists create a special drug that only activates these designer receptors. DREADDs are activated only by a unique synthetic drug, or designer drug, that’s created specifically for this purpose. This drug doesn’t interact with any other receptors in the body, so it won’t interfere with other brain or bodily functions.
- **Precise Control: **Because this synthetic drug only activates the engineered DREADD receptors, scientists can precisely control the activity of targeted neurons. This enables very specific manipulation of brain signaling without affecting other cells.
- Purpose: By turning specific brain cells on or off, researchers can study what those cells do, which helps in understanding behaviors, emotions, and even brain disorders. DREADDs are valuable in neuroscience research, helping to create precise effects without affecting the whole brain.