[HN Gopher] Brain circuit that converts spatial goals to escape ...
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Brain circuit that converts spatial goals to escape actions
discovered in mice
Author : gmays
Score : 60 points
Date : 2022-12-25 05:11 UTC (17 hours ago)
(HTM) web link (www.sainsburywellcome.org)
(TXT) w3m dump (www.sainsburywellcome.org)
| psychphysic wrote:
| Wonder how they "disrupt" such a circuit in a mouse brain?
| Without collateral damage.
| feet wrote:
| >We used a chemogenetic approach where we targeted the
| inhibitory designer receptor hM4Di selectively to SC-projecting
| RSP neurons by injecting AAVretro-cre in the SC and Cre-
| dependent hM4Di in the RSP (Fig. 2a and Extended Data Fig. 3)
|
| https://www.nature.com/articles/s41586-022-05553-9
|
| My understanding of this is they used a virus to cause specific
| neurons to express the inhibitory hM4Di receptor which will
| modify the behavior of the desired target circuits with
| exogenous pharmacological manipulation when they introduce the
| agonist clozapine-N-oxide (CNO)
| psychphysic wrote:
| > virus to force specific neurons to express the inhibitory
| hM4Di receptor which will modify the behavior of the desired
| target circuits with exogenous pharmacological manipulation
| when they introduce the agonist clozapine-N-oxide (CNO)
|
| Wow reads like 22 century science.
| feet wrote:
| Using these viruses is currently pretty common for things
| like optogenetics and tract tracing, it's some pretty neat
| stuff because they can be so selective in outlining
| specific circuits
| prpl wrote:
| Optogenetics is similar, and crazier.
| feet wrote:
| IMO optogenetics can be a little more difficult to manage
| depending on the specific circuit you're studying and the
| recording method. Remember, you need to deliver the light
| to the actual neuron being manipulated and with _in vivo_
| models you 're kinda limited. There are some recording
| probes with light guides built in but again, this method
| is limited and doesn't work super well for longer term
| recording projects
|
| Personally I like pharmacological manipulation, but I'm
| probably a bit biased in that regard :)
| prpl wrote:
| yeah it seems much less practical, but it is pretty crazy
| from the standpoint of how it can be controlled - turn
| off and in by a literal switch.
|
| There's a dystopian black mirror future in here somewhere
| where people can take be administered viral vectors
| programmed with unique, proprietary methods of activation
| to stimulate a response - altering behavior, mood,
| hormones, etc... probably in a subscription model
| serviced by Comcast
| feet wrote:
| I think that would be an incredibly difficult task to
| accomplish. Currently these viral methods require a
| precise injection to a very specific part of the brain
| depending on what you're trying to modify or study, it's
| not like you can just give someone a pill that does this
| stuff. In optogenetics, light needs to be delivered
| inside the brain or to the neurons a brain slice or
| culture.
|
| That's on top of the fact that many behaviors are highly
| complex involving numerous circuits.
|
| You can already give someone drugs or take a drug
| yourself to modify behaviors and we get greater
| specificity with newer generation drugs as we learn more
| about the affinity of ligands with subunits expressed in
| various circuits naturally.
|
| Modification of behavior and thought processes is already
| a reality and it is in the field of psychological and
| behavioral neuropharmacology where we study these methods
| to help people with mental illnesses and neurological
| abnormalities
| valec wrote:
| another technique sometimes used is using Transcranial Magnetic
| Stimulation to create temporary "virtual lesions" to study how
| knocking out a particular region affects task peformance
| sedatk wrote:
| I'm fascinated that brain is compartmentalized enough, despite
| all cells being connected to each other, so a "local circuitry"
| can be identified for a specific action. I'd presume all cells
| would be firing more or less for any action. The existence of
| circuitry like structures makes it less organic and less
| mysterious for some reason. :)
|
| Now I wonder if artificial neural networks exhibit the same
| circuitry-like structures.
| feet wrote:
| Not all cells connect to each other remember and there are many
| different cell types with different functions which form
| functions specific circuits. Cell functionality goes far beyond
| the simple excitation-inhibition model
| red75prime wrote:
| They do. For example, training transformers on addition creates
| circuits that perform modular addition. See "A Mechanistic
| Interpretability Analysis of Grokking"
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