Studying Memory
What are 3 methods for altering brain function
1) Stereotaxic Surgery 2) intercranial Injection 3) Genetic Engineering (knock in/out)
LTP electrically induced in tissue slices or in the brain does not represent ____
A bahevioural experience. Its not experiencing a memory.
Describe intercranial injections
A cannula guide is implanted into the rats brain. Drugs can then be delivered to specific regions of an awake and moving rat by inserting the cannula into the guide.
Describe genetic engineering
Affects the genome (knock in/ out)
In eyeblink conditioning , what happens once training has occurred ?
Animals will begin to blink once they hear the stimulus
What is the window to the memory trace ?
Behavior
What are 2 ways to turn on/off brain regions?
Chemogenetics and optogenetics
What do DREADDs stand for ?
Designer receptor exclusively activated by designer drugs
What decreases as a function of training trials in the morris water escape task?
Escape latency
Describe the steps used to infer a memory has formed
Experience Observable > memory trace inferred > behavioral change observable (Window to the memory trace)
In fear conditioning, a 15 sec tone is presented followed by a shock. Rats are then tested for their fear of the context-place where shock occurred and later for their fear of the tone. Shocked (S) rats display more ____ than rats that were not shocked (NS).
Freezing
What is chemogenetics ?
Getting a receptor expressed inside a cell that is normally not there. DREADD (created receptor), virus that contains receptor is injected. Nothing endogenously activates it... CNO is given to activate receptor. Receptors are activated to turn on or off brain regions.
What is an unpaired classical conditioning group ?
Group experiences both CS and US but at random, no association
Describe viral vectors
Have express on of different receptor sites , activate or deactivate
What is engram?
Hypothesized place for memory in the brain
Describe eyeblink conditioning
Light fear conditioning. Present a stimulus (shorter duration in eyeblink 1/2 sec) followed by a shock. Wires placed behind the eye that stimulate cells to blink. Can also use air.
We take short term memory and put it into _______. This is NOT the same as ______, which takes a ______ and the first takes ______
Long term. LTP consolidation, a couple hours. A day.
LTP is a _____, not memory itself.
Memory mechanism
Common subjects in memory research include
Mostly rodents (rats and mice), finch's and macaques
Describe optogenetics as well as channelrhodopsin and halorhodopsin
Rat got injected with rhodopsin (light sensitive cells) which makes the brain light sensitive. It can then be excited/inhibited based on light. Channelrhodopsin- excite neurons Halorhodospin- inhibit neurons
What would the results be for a probe trial with the platform removed from the pool?
Rats spending a larger percent of time in the T quadrant
In inhibitory avoidance learning, rats are shocked when they crossover from the light side of a cage to the dark. Shocking varies from no shock, weak shock, moderate shock, and strong shock. As shock intensity increases, what else increases?
Response latency (crossover latency).
Who created Morris water escape maze?
Richard Morris
What does Clozapine-N-Oxide (CNO) do?
Selectively activated the receptors (DREADDs)
Describe the dimensions of memory traces for both short and long term
Short term mem > "active" memory > rapid decay and vulnerable to disruption Long term mem > "inactive state" > slow decay and less vulnerable to disruption
Describe the two ways memories can be disrupted
Storage failure > the amnesia is permanent Retrieval failure > the amnesia is temporary
What are the 4 quadrants in a morris water escape tank?
T- training quadrant A- 2 adjacent quadrant O- the quadrant opposite of the training quadrant
What are behavioral paradigms ?
The apparatus that is used
A longer latency is inhibitory avoidance means what?
The more learning that has occurred
What is the morris water escape tank ?
The place-learning version of the morris water escape task.
What is escape latency
The time it takes a rodent to find hidden platform in morris water escape tank
What is delay conditioning?
The unconditioned stimulus directly follows the conditioned stimulus (shock right after tone)
What is trace conditioning?
There's a trace interval between cessation of the conditioned stimulus (tone) and the onset of the unconditioned stimulus (shock)
Describe a stereotaxic device
Used during surgery for precise placement of a fine wire (electrode) or a small injection needle (cannula) for targeting current or a chemical solution into a specific brain region. Holds head still while electrode or cannula is precisely lowered.
What is a paired classical conditioning group ?
When the CS and US are paired together, they are bounded , building an association
