Bottom line:
📉 Theta ≠ Retrieval
📈 Theta = Encoding/Updating
This subtle but important shift reframes how we think about the neural basis of memory, and why cholinergic drugs help some processes and not others.
Full details ⬇
www.biorxiv.org/content/10.1...
📉 Theta ≠ Retrieval
📈 Theta = Encoding/Updating
This subtle but important shift reframes how we think about the neural basis of memory, and why cholinergic drugs help some processes and not others.
Full details ⬇
www.biorxiv.org/content/10.1...
Cholinergic blockade reveals role for human hippocampal theta in encoding but not retrieval
Cholinergic dysfunction is a hallmark of Alzheimer's disease and other memory disorders. Yet, the neurophysiological mechanisms linking cholinergic signaling to memory remain poorly understood. In thi...
www.biorxiv.org
May 14, 2025 at 2:55 PM
Bottom line:
📉 Theta ≠ Retrieval
📈 Theta = Encoding/Updating
This subtle but important shift reframes how we think about the neural basis of memory, and why cholinergic drugs help some processes and not others.
Full details ⬇
www.biorxiv.org/content/10.1...
📉 Theta ≠ Retrieval
📈 Theta = Encoding/Updating
This subtle but important shift reframes how we think about the neural basis of memory, and why cholinergic drugs help some processes and not others.
Full details ⬇
www.biorxiv.org/content/10.1...
In analyses led by @ZabehErfan, we also show that neural dynamics under cholinergic blockade can be decoded from low-dimensional features of LFPs across electrodes.
May 14, 2025 at 2:55 PM
In analyses led by @ZabehErfan, we also show that neural dynamics under cholinergic blockade can be decoded from low-dimensional features of LFPs across electrodes.
This has big implications:
🧬 For memory models: Theta may unify encoding & re-encoding, not retrieval per se
🧠 For neurophysiology: Reinstatement might reflect reactivation of an encoding mode, not just stored content
🧪 For Alzheimer’s: Targets for modulating cholinergic tone may need rethinking
🧬 For memory models: Theta may unify encoding & re-encoding, not retrieval per se
🧠 For neurophysiology: Reinstatement might reflect reactivation of an encoding mode, not just stored content
🧪 For Alzheimer’s: Targets for modulating cholinergic tone may need rethinking
May 14, 2025 at 2:55 PM
This has big implications:
🧬 For memory models: Theta may unify encoding & re-encoding, not retrieval per se
🧠 For neurophysiology: Reinstatement might reflect reactivation of an encoding mode, not just stored content
🧪 For Alzheimer’s: Targets for modulating cholinergic tone may need rethinking
🧬 For memory models: Theta may unify encoding & re-encoding, not retrieval per se
🧠 For neurophysiology: Reinstatement might reflect reactivation of an encoding mode, not just stored content
🧪 For Alzheimer’s: Targets for modulating cholinergic tone may need rethinking
Our data show:
– Theta power & phase reset are disrupted by cholinergic blockade at retrieval
– But memory remains intact
– Reinstatement of spectral patterns from encoding is also impaired
→ Retrieval still works without theta, but maybe in a different form.
– Theta power & phase reset are disrupted by cholinergic blockade at retrieval
– But memory remains intact
– Reinstatement of spectral patterns from encoding is also impaired
→ Retrieval still works without theta, but maybe in a different form.
May 14, 2025 at 2:55 PM
Our data show:
– Theta power & phase reset are disrupted by cholinergic blockade at retrieval
– But memory remains intact
– Reinstatement of spectral patterns from encoding is also impaired
→ Retrieval still works without theta, but maybe in a different form.
– Theta power & phase reset are disrupted by cholinergic blockade at retrieval
– But memory remains intact
– Reinstatement of spectral patterns from encoding is also impaired
→ Retrieval still works without theta, but maybe in a different form.
This challenges long-held theories that hippocampal theta reflects retrieval-specific computations.
Instead, we propose a unifying framework: theta during retrieval reflects re-engagement of encoding-related neural states, perhaps to update or integrate memory—not retrieve it.
Instead, we propose a unifying framework: theta during retrieval reflects re-engagement of encoding-related neural states, perhaps to update or integrate memory—not retrieve it.
May 14, 2025 at 2:55 PM
This challenges long-held theories that hippocampal theta reflects retrieval-specific computations.
Instead, we propose a unifying framework: theta during retrieval reflects re-engagement of encoding-related neural states, perhaps to update or integrate memory—not retrieve it.
Instead, we propose a unifying framework: theta during retrieval reflects re-engagement of encoding-related neural states, perhaps to update or integrate memory—not retrieve it.
When scopolamine was present at encoding, patients had selective recollection deficits and disrupted hippocampal theta.
But when the drug was present only at retrieval, memory was spared—even though theta power, phase reset, and reinstatement were disrupted.
But when the drug was present only at retrieval, memory was spared—even though theta power, phase reset, and reinstatement were disrupted.
May 14, 2025 at 2:55 PM
When scopolamine was present at encoding, patients had selective recollection deficits and disrupted hippocampal theta.
But when the drug was present only at retrieval, memory was spared—even though theta power, phase reset, and reinstatement were disrupted.
But when the drug was present only at retrieval, memory was spared—even though theta power, phase reset, and reinstatement were disrupted.
We gave scopolamine (a muscarinic cholinergic blocker) to epilepsy patients with implanted hippocampal electrodes as they performed a memory task.
By injecting the drug before retrieval vs. before encoding we could tease apart the role of theta oscillations at each memory stage.
By injecting the drug before retrieval vs. before encoding we could tease apart the role of theta oscillations at each memory stage.
May 14, 2025 at 2:55 PM
We gave scopolamine (a muscarinic cholinergic blocker) to epilepsy patients with implanted hippocampal electrodes as they performed a memory task.
By injecting the drug before retrieval vs. before encoding we could tease apart the role of theta oscillations at each memory stage.
By injecting the drug before retrieval vs. before encoding we could tease apart the role of theta oscillations at each memory stage.