3 lecture 8 Flashcards
what are the parts to planing false memories
1) We need a behavior so that mice can tell us what they remember
2) We need a way to determine which cells encode that memory
3) We need a way to activate those cells
4) Then, we’ll put it all together and create a false memory
why is it mice that we plant the false memories in
Everything else I’ve been telling you about has been in rats and birds
Currently, scientists have the best genetic control over mice
It is possible to create strains of mice with particular genotypes and particular patterns of gene expression
This is a critical aspect of the studies I’ll be talking about
Basically, we’ll be using some of what you’ve learned about genetics and biotechnology to answer questions about the brain
How do you get a mouse to remember something? And, how do you get them to tell you about it?
One way is through behavioral conditioning
how can you do conditioning
You can do conditioning by pairing anything rewarding or aversive (unconditioned stimulus) with anything neutral (conditioned stimulus)
For example:
Chocolate followed by a light Cocaine followed by a tone
A needle prick followed by a smell
And so on. . .
explain the proof of fear conditioning in mice
Put a mouse in a blue room, it will wander around and explore
While it’s in the blue room, let’s say you give a mild foot-shock, then return it to its home cage
Later on, when you put the mouse back into the blue room
It will behave as though it expects there to be a foot-shock (even if you don’t give one)
That is, it will act scared
What do mice do when they’re scared? They freeze i.e. they stand very very still
This means mice can quickly learn to associate a place (blue room) with an experience (foot shock)
and demonstrate that they remember the experience by displaying a conditioned response (freezing)
this is known as fear conditioning
what is conditioned place preference
There is also what’s called conditioned place preference
You have a mouse spend time in two different locations
In one, this green room, you just leave it alone
In another, this blue room, she gets a mild foot-shock
Then, you let her pick which room she wants to spend time in
Not surprisingly, she’ll generally pick the green room
** side note; that was all to get the behaviour under control**
btw
Now that we have the behavior under control in the mouse, we need a way to identify the what
the memory circuit
what is used as a marker of neural activity
c-fos
how is c-fos used as a marker
high expression = high activity (lots of action potentials)
give an example of how c-fos is used as a marker in birds
Example: Birds
Cells in the basal ganglia fire a lot of action potentials when males sing by themselves
This activity results in c-fos expression when males sing by themselves
–lots of c-fos is transcribed and translated when the male starts singing by himself
Less activity & less c-fos (less transcription and translation of c-fos) when he sings to a female
In the hippocampus, experiences result in what
a particular group of cells being activated
Cells active during an experience –> express c-fos: these cells do what
Cells active during an experience –> express c-fos These cells hold the memory of the experience
give an example of “Cells active during an experience –> express c-fos These cells hold the memory of the experience”
Example: You have a particular group of cells that are active for your 6th birthday party
During your 6th birthday party, these cells would express c-fos
They also become active again when you remember your 6th birthday party
And you might have another group of cells that are active. And maybe that combination is the memory for that time you ate too many candy bars and got sick in the car
Those cells would express cFOS while you were getting sick
And they would be active again when, say, you ride in the back seat of a car and smell candy
what activates a group of cells
experiences like foot-shock
These cells will express c-fos after the foot shock
