neurosock
@neurosock.bsky.social
#BrainChips monthly recap. I make #neuro papers easy to understand. To make #Neuralink possible. Neuro PhD. AI🤖ML👾Data Sci 📊 Monkeys🐵Future🚀Cyberpunk⚡🦾🌌
If you like this, and think I should keep doing these every week, hit a like on the first post.
It motivates me to spend 5-6 hours a week preparing each summary 😇.
It motivates me to spend 5-6 hours a week preparing each summary 😇.
November 13, 2025 at 11:58 AM
If you like this, and think I should keep doing these every week, hit a like on the first post.
It motivates me to spend 5-6 hours a week preparing each summary 😇.
It motivates me to spend 5-6 hours a week preparing each summary 😇.
Disclaimers:
1) This is a simplification from a very complex paper. Sorry if I omitted some details, it is all for clarity 😸
2) As any paper, this study has to be further REPLICATED to know if its true.
1) This is a simplification from a very complex paper. Sorry if I omitted some details, it is all for clarity 😸
2) As any paper, this study has to be further REPLICATED to know if its true.
November 13, 2025 at 11:58 AM
Disclaimers:
1) This is a simplification from a very complex paper. Sorry if I omitted some details, it is all for clarity 😸
2) As any paper, this study has to be further REPLICATED to know if its true.
1) This is a simplification from a very complex paper. Sorry if I omitted some details, it is all for clarity 😸
2) As any paper, this study has to be further REPLICATED to know if its true.
Limitations:
The model has not yet been validated in experiments.
It also abstracts the basal ganglia into a simple loop, omitting direct and indirect pathways.
The model has not yet been validated in experiments.
It also abstracts the basal ganglia into a simple loop, omitting direct and indirect pathways.
November 13, 2025 at 11:58 AM
Limitations:
The model has not yet been validated in experiments.
It also abstracts the basal ganglia into a simple loop, omitting direct and indirect pathways.
The model has not yet been validated in experiments.
It also abstracts the basal ganglia into a simple loop, omitting direct and indirect pathways.
Implications:
This framework connects molecular defects directly to cognitive symptoms and behavioral issues.
It suggests future psychiatric treatments could target specific circuit dynamics rather than just global chemistry.
This framework connects molecular defects directly to cognitive symptoms and behavioral issues.
It suggests future psychiatric treatments could target specific circuit dynamics rather than just global chemistry.
November 13, 2025 at 11:58 AM
Implications:
This framework connects molecular defects directly to cognitive symptoms and behavioral issues.
It suggests future psychiatric treatments could target specific circuit dynamics rather than just global chemistry.
This framework connects molecular defects directly to cognitive symptoms and behavioral issues.
It suggests future psychiatric treatments could target specific circuit dynamics rather than just global chemistry.
Overactive D2 receptors caused the thalamic circuit to fail, mimicking schizophrenic symptoms (Fig 7).
Restoring activity in the mediodorsal thalamus rescued the behavior, validating the circuit mechanism.
Restoring activity in the mediodorsal thalamus rescued the behavior, validating the circuit mechanism.
November 13, 2025 at 11:58 AM
Overactive D2 receptors caused the thalamic circuit to fail, mimicking schizophrenic symptoms (Fig 7).
Restoring activity in the mediodorsal thalamus rescued the behavior, validating the circuit mechanism.
Restoring activity in the mediodorsal thalamus rescued the behavior, validating the circuit mechanism.
They found that inhibitory interneurons gate learning based on the thalamus's confidence level (Fig 4).
Uncertainty suppresses plasticity to prevent errors, while certainty releases the brakes to encode new rules.
Uncertainty suppresses plasticity to prevent errors, while certainty releases the brakes to encode new rules.
November 13, 2025 at 11:58 AM
They found that inhibitory interneurons gate learning based on the thalamus's confidence level (Fig 4).
Uncertainty suppresses plasticity to prevent errors, while certainty releases the brakes to encode new rules.
Uncertainty suppresses plasticity to prevent errors, while certainty releases the brakes to encode new rules.
The biological model consistently outperformed standard "ideal" algorithms like Thompson Sampling (Fig 3a-c).
Biological heuristics like dynamic sparsity modulation allowed for faster adaptation than rigid mathematical formulas.
Biological heuristics like dynamic sparsity modulation allowed for faster adaptation than rigid mathematical formulas.
November 13, 2025 at 11:58 AM
The biological model consistently outperformed standard "ideal" algorithms like Thompson Sampling (Fig 3a-c).
Biological heuristics like dynamic sparsity modulation allowed for faster adaptation than rigid mathematical formulas.
Biological heuristics like dynamic sparsity modulation allowed for faster adaptation than rigid mathematical formulas.
They demonstrated that the PFC-MD circuit learns a generative model to infer hidden contexts (Fig 4c).
This circuit maintained a low-dimensional representation of likelihood that tracked the changing environment.
This circuit maintained a low-dimensional representation of likelihood that tracked the changing environment.
November 13, 2025 at 11:58 AM
They demonstrated that the PFC-MD circuit learns a generative model to infer hidden contexts (Fig 4c).
This circuit maintained a low-dimensional representation of likelihood that tracked the changing environment.
This circuit maintained a low-dimensional representation of likelihood that tracked the changing environment.
This is how we learned that from their results:
They showed the basal ganglia encodes uncertainty as a probability distribution used for exploration (Fig 2f).
Synapses representing different value quantiles allowed the model to balance risk and reward efficiently.
They showed the basal ganglia encodes uncertainty as a probability distribution used for exploration (Fig 2f).
Synapses representing different value quantiles allowed the model to balance risk and reward efficiently.
November 13, 2025 at 11:58 AM
This is how we learned that from their results:
They showed the basal ganglia encodes uncertainty as a probability distribution used for exploration (Fig 2f).
Synapses representing different value quantiles allowed the model to balance risk and reward efficiently.
They showed the basal ganglia encodes uncertainty as a probability distribution used for exploration (Fig 2f).
Synapses representing different value quantiles allowed the model to balance risk and reward efficiently.
But how?
They built "CogLinks," a model using realistic neurons that approximates ideal mathematical algorithms.
This allowed them to mathematically prove the biological circuit performs near-optimal decision-making.
They built "CogLinks," a model using realistic neurons that approximates ideal mathematical algorithms.
This allowed them to mathematically prove the biological circuit performs near-optimal decision-making.
November 13, 2025 at 11:58 AM
But how?
They built "CogLinks," a model using realistic neurons that approximates ideal mathematical algorithms.
This allowed them to mathematically prove the biological circuit performs near-optimal decision-making.
They built "CogLinks," a model using realistic neurons that approximates ideal mathematical algorithms.
This allowed them to mathematically prove the biological circuit performs near-optimal decision-making.
That's the gist of it.
But why?
Previous models were either too abstract to map onto biology or too opaque to understand.
Researchers needed a bridge between mathematical theory and the messy reality of neurons and synapses.
But why?
Previous models were either too abstract to map onto biology or too opaque to understand.
Researchers needed a bridge between mathematical theory and the messy reality of neurons and synapses.
November 13, 2025 at 11:58 AM
That's the gist of it.
But why?
Previous models were either too abstract to map onto biology or too opaque to understand.
Researchers needed a bridge between mathematical theory and the messy reality of neurons and synapses.
But why?
Previous models were either too abstract to map onto biology or too opaque to understand.
Researchers needed a bridge between mathematical theory and the messy reality of neurons and synapses.
Here is another way to put it:
A broken thermostat makes a furnace switch on and off wildly.
By damaging the thalamic detector, the brain loses its stability and hallucinates change in a stable world.
A broken thermostat makes a furnace switch on and off wildly.
By damaging the thalamic detector, the brain loses its stability and hallucinates change in a stable world.
November 13, 2025 at 11:58 AM
Here is another way to put it:
A broken thermostat makes a furnace switch on and off wildly.
By damaging the thalamic detector, the brain loses its stability and hallucinates change in a stable world.
A broken thermostat makes a furnace switch on and off wildly.
By damaging the thalamic detector, the brain loses its stability and hallucinates change in a stable world.
This causes the mouse to perceive constant volatility, leading to erratic switching even after successful choices.
This behavior has been observed in schizophrenia subjects.
This behavior has been observed in schizophrenia subjects.
November 13, 2025 at 11:58 AM
This causes the mouse to perceive constant volatility, leading to erratic switching even after successful choices.
This behavior has been observed in schizophrenia subjects.
This behavior has been observed in schizophrenia subjects.
Here's what could be happening in schizophrenia:
Hyperactive D2 receptors in BG unbalance activity in Thalamus, making the "Belief keeper" unstable.
This results in a unstable attractor, sensitive to noise and that cannot hold onto evidence.
Hyperactive D2 receptors in BG unbalance activity in Thalamus, making the "Belief keeper" unstable.
This results in a unstable attractor, sensitive to noise and that cannot hold onto evidence.
November 13, 2025 at 11:58 AM
Here's what could be happening in schizophrenia:
Hyperactive D2 receptors in BG unbalance activity in Thalamus, making the "Belief keeper" unstable.
This results in a unstable attractor, sensitive to noise and that cannot hold onto evidence.
Hyperactive D2 receptors in BG unbalance activity in Thalamus, making the "Belief keeper" unstable.
This results in a unstable attractor, sensitive to noise and that cannot hold onto evidence.
The Detective acts as a master switch, engaging the specific Gambler circuit that matches the current context.
This hierarchy allows the mouse to instantly swap strategies without unlearning everything when the world changes.
E.g. PFC has evidence of a wrong choice.
This hierarchy allows the mouse to instantly swap strategies without unlearning everything when the world changes.
E.g. PFC has evidence of a wrong choice.
November 13, 2025 at 11:58 AM
The Detective acts as a master switch, engaging the specific Gambler circuit that matches the current context.
This hierarchy allows the mouse to instantly swap strategies without unlearning everything when the world changes.
E.g. PFC has evidence of a wrong choice.
This hierarchy allows the mouse to instantly swap strategies without unlearning everything when the world changes.
E.g. PFC has evidence of a wrong choice.
A "Detective" circuit in the PFC tracks clues to infer the current context or "hidden state".
PFC helped by the mediodorsal (MD) thalamus "belief keeper" who uses attractor dynamics to hold a stable belief until enough evidence pushes it to a new conclusion.
PFC helped by the mediodorsal (MD) thalamus "belief keeper" who uses attractor dynamics to hold a stable belief until enough evidence pushes it to a new conclusion.
November 13, 2025 at 11:58 AM
A "Detective" circuit in the PFC tracks clues to infer the current context or "hidden state".
PFC helped by the mediodorsal (MD) thalamus "belief keeper" who uses attractor dynamics to hold a stable belief until enough evidence pushes it to a new conclusion.
PFC helped by the mediodorsal (MD) thalamus "belief keeper" who uses attractor dynamics to hold a stable belief until enough evidence pushes it to a new conclusion.
A "Gambler" circuit is formed by:
The basal ganglia "notebook": stores payout probabilities as full distributions, not just averages.
Premotor cortex: samples from these notes to explore options when the outcome is uncertain.
Motor cortex: compares values and takes action.
The basal ganglia "notebook": stores payout probabilities as full distributions, not just averages.
Premotor cortex: samples from these notes to explore options when the outcome is uncertain.
Motor cortex: compares values and takes action.
November 13, 2025 at 11:58 AM
A "Gambler" circuit is formed by:
The basal ganglia "notebook": stores payout probabilities as full distributions, not just averages.
Premotor cortex: samples from these notes to explore options when the outcome is uncertain.
Motor cortex: compares values and takes action.
The basal ganglia "notebook": stores payout probabilities as full distributions, not just averages.
Premotor cortex: samples from these notes to explore options when the outcome is uncertain.
Motor cortex: compares values and takes action.
The mouse faces two puzzles:
which arm pays out right now?, and
have the hidden rules changed?
which arm pays out right now?, and
have the hidden rules changed?
November 13, 2025 at 11:58 AM
The mouse faces two puzzles:
which arm pays out right now?, and
have the hidden rules changed?
which arm pays out right now?, and
have the hidden rules changed?
Imagine a mouse in a T maze with a red 🟥 and a blue 🟦 side.
In this world the rules flip between:
Context A: get a reward 70% of the times if go 🟥
Context B: gets a reward 70% of the times if go 🟦.
In this world the rules flip between:
Context A: get a reward 70% of the times if go 🟥
Context B: gets a reward 70% of the times if go 🟦.
November 13, 2025 at 11:58 AM
Imagine a mouse in a T maze with a red 🟥 and a blue 🟦 side.
In this world the rules flip between:
Context A: get a reward 70% of the times if go 🟥
Context B: gets a reward 70% of the times if go 🟦.
In this world the rules flip between:
Context A: get a reward 70% of the times if go 🟥
Context B: gets a reward 70% of the times if go 🟦.
Core result:
They found the brain uses specialized circuits for different types of uncertainty, linked hierarchically by the thalamus.
Disrupting this link mimics schizophrenia symptoms, causing the mouse to perceive volatility where none exists.
Let's unpack this:
They found the brain uses specialized circuits for different types of uncertainty, linked hierarchically by the thalamus.
Disrupting this link mimics schizophrenia symptoms, causing the mouse to perceive volatility where none exists.
Let's unpack this:
November 13, 2025 at 11:58 AM
Core result:
They found the brain uses specialized circuits for different types of uncertainty, linked hierarchically by the thalamus.
Disrupting this link mimics schizophrenia symptoms, causing the mouse to perceive volatility where none exists.
Let's unpack this:
They found the brain uses specialized circuits for different types of uncertainty, linked hierarchically by the thalamus.
Disrupting this link mimics schizophrenia symptoms, causing the mouse to perceive volatility where none exists.
Let's unpack this:
Traditionally, the basal ganglia and cortex were seen as separate systems for habit and planning.
This study proposes the thalamus acts as a critical bridge, orchestrating how these systems interact to handle uncertainty.
This study proposes the thalamus acts as a critical bridge, orchestrating how these systems interact to handle uncertainty.
November 13, 2025 at 11:58 AM
Traditionally, the basal ganglia and cortex were seen as separate systems for habit and planning.
This study proposes the thalamus acts as a critical bridge, orchestrating how these systems interact to handle uncertainty.
This study proposes the thalamus acts as a critical bridge, orchestrating how these systems interact to handle uncertainty.
Thanks😊. I enjoy making this little silly drawings. Helps me understand the paper much more and remember better.
October 31, 2025 at 10:12 PM
Thanks😊. I enjoy making this little silly drawings. Helps me understand the paper much more and remember better.