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Updated: Feb 24, 2026
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High-resolution In Vivo Manual Segmentation Protocol for Human Hippocampal Subfields Using 3T Magnetic Resonance Imaging
Published on: November 10, 2015
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The hippocampus: myth, memory and magnetic resonance imaging
D Lindsay1,2
1University of Cambridge, UK.
Annals of the Royal College of Surgeons of England
|February 23, 2026
Summary
Propofol sedation alters hippocampal functional connectivity in a multiphasic pattern, impacting memory performance. These changes reveal an underlying amnesic signature, even at low sedation levels.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Pharmacology
Background:
- The hippocampus is crucial for explicit memory.
- Understanding its function under sedation is vital.
- Advances in neuroimaging and anesthesia offer new insights.
Purpose of the Study:
- To investigate hippocampal functional connectivity during propofol-induced sedation.
- To correlate these changes with memory performance.
- To characterize the effects of sedation on brain function.
Main Methods:
- 25 healthy volunteers underwent fMRI under varying propofol sedation levels.
- Participants performed a semantic decision task.
- Hippocampal connectivity was analyzed in relation to memory recall.
Main Results:
- Hippocampal connectivity patterns remained stable during sedation and recovery.
- Memory performance decreased progressively with sedation.
- Functional connectivity showed multiphasic changes, with asymmetric alterations linked to memory performance.
Conclusions:
- Sedation-induced amnesia is associated with specific intra-hippocampal connectivity signatures.
- Functional connectivity changes during sedation are multiphasic.
- A core amnesic signature exists even at low sedation levels.
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