W12 - Valence Coding in the Amygdala 2/2 Flashcards
What topographic criteria allows to segregate the BLA into anterior and posterior regions?
Magnocellular and parvocellular pyramidal neurons segregate into aBLA and pBLA
What genetic expression system could be used to identify neurons mediating positive and negative affective experiences?
Immediate early genes like Fos
In the work of Kim et al., how did they temporally control the Fos gene-mediating flagging of neurons of interest?
Presence of Dox (expressed with a Dox diet) prevents the downstream cascade of Fox genes to express PABP-Flag -> therefore, stopping the Dox diet allows Fox genes and they downstream effectors to tag the neurons of interest
Under which conditions is the Dox diet relieved?
When mice undergo appetitive (exposure to a female) or aversive (footshock) experiences.
How can RNA molecules that were flagged can be profiled?
Immunoprecipitation isolates RNA molecules that are associated with a protein tagged with a Flag epitope
Why did Kim et al. looked for a different genetic marker separately in each population of neurons mediating affective responses (fear and reward)?
Because they hypothesized that ‘positive’ and ‘negative’ neurons would be non- overlapping
True or false: Rspo2+ and Ppp1rb+ BLA neurons define spatially intermingled populations of BLA pyramidal neurons
False: Rspo2+ and Ppp1rb+ BLA neurons define spatially segregated populations of BLA pyramidal neurons
What is FISH, what is it used for?
Fluorescent in situ hybridization allows to visually map gene expressions
What is the neuronal types of neurons expressing Rspo2+ and Ppp1rb+, respectively?
Rspo2+ neurons are magnocellular pyramidal neurons
Ppp1rb are parvocellular pyramidal neurons
Where are Rspo2+ and Ppp1rb+ neurons localized? What valence are they coding for respectively?
Rspo2+ neurons are enriched in aBLA, Ppp1rb+ neurons are enriched in pBLA
Aversive stimuli activate aBLA more than pBLA
Appetitive stimuli activate pBLA more than aBLA
Did Kim et al. found antagonist relationships between Rspo2+ and Ppp1rb+ neurons? How? At what level is the inhibition happening, if it occurs?
Yes, by modulating the activity of one neuronal population with optogenetics and recording the concomitant behavioural consequences in settings intrinsically coded by the other type of neuronal population
Local inhibition (in the BLA)
What behavioural consequences ensue photoinhibition of Rspo2+ neurons? Of Ppp1rb+ neurons? Is photoexcitation provoking opposite responses?
Optogenetic inhibition of Rspo2+ cells reduces freezing in a contextual fear conditioning task
Optogenetic inhibition of Ppp1b+ cells reduces nose poking for reward
Yes
What did Kim et al. find about the topographic distribution of downstream projections in the BLA? What technique did they use?
Retrograde tracing reveals distinct projection patterns across BLA A-P axis
What are the projection patterns like for
What are the projection patterns like for
