Memory and Resting-State Connectivity in Acute Transient Global Amnesia: A Case-Control fMRI Study
Elias El Otmani1, Emmanuel Barbeau2, Béatrice Lemesle3
1ToNIC, Toulouse NeuroImaging Center, UMR 1214, Universit. De Toulouse, INSERM, Paul Sabatier University (UT3), Toulouse, France.
Annals of Clinical and Translational Neurology
|April 10, 2026
Summary
Transient global amnesia (TGA) involves temporary memory loss due to reduced connectivity in the episodic memory network. This condition, characterized by anterograde amnesia, resolves within three months, sparing semantic memory.
Area of Science:
- Neuroscience
- Cognitive Neurology
- Neuroimaging
Background:
- Transient global amnesia (TGA) presents as isolated amnesia, with debated network-level mechanisms and neuropsychological profiles.
- Hippocampal lesions are known, but the broader functional network involvement requires further characterization.
Purpose of the Study:
- To characterize the functional and neuropsychological correlates of acute TGA.
- To investigate the longitudinal evolution of these correlates over three months.
Main Methods:
- A prospective case-control study involving 20 TGA patients and 20 healthy controls.
- Neuropsychological testing and structural/functional MRI were performed at acute, day 3, and 3-month follow-up.
- Analysis focused on episodic, semantic, and metamemory domains, and resting-state fMRI connectivity within the episodic memory network and large-scale brain networks.
Main Results:
- TGA patients exhibited profound, isolated anterograde amnesia in the acute phase, which resolved by 3 months.
- Acute-phase MRI revealed hypoconnectivity within the extended hippocampal system (parahippocampal-cingulate cortices), normalizing by 3 months.
- Small bilateral lesions were noted in TGA patients; semantic memory and metamemory remained intact.
Conclusions:
- TGA is linked to transient, selective hypoconnectivity within the mesiotemporal-cingulate episodic memory network.
- The study clarifies the recovery time course of anterograde amnesia and confirms preserved semantic memory and metamemory.
- TGA appears to be a transient limbic dysconnectivity syndrome, not a diffuse network disorder.
More Related Videos
09:38Generalized Psychophysiological Interaction PPI Analysis of Memory Related Connectivity in Individuals at Genetic Risk for Alzheimer's Disease
Published on: November 14, 2017
15.9K
12:09Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy
Published on: August 5, 2014
18.7K
Related Concept Videos
01:13Amnesia
861
Amnesia is a condition marked by long-term memory loss, which impairs the ability to recall past events or create new memories.
The severity and duration of memory loss vary depending on the type and underlying cause. Amnesia is classified into two main types: retrograde and anterograde.
Retrograde amnesia is marked by the loss of memories formed before the onset of the condition. Patients may recall distant past events but often forget those occurring shortly before the incident.
Anterograde...
The severity and duration of memory loss vary depending on the type and underlying cause. Amnesia is classified into two main types: retrograde and anterograde.
Retrograde amnesia is marked by the loss of memories formed before the onset of the condition. Patients may recall distant past events but often forget those occurring shortly before the incident.
Anterograde...
861
01:26Higher Mental Functions of Brain: Learning and Memory
2.3K
Memory is one of the most vital higher mental functions of the brain. Memory is closely related to learning because it enables us to retain information and experiences from our past to use them in our present life. It also helps us to remember facts, events, and skills, such as riding a bike or swimming. There are two types of memory — declarative memory, which involves memorizing facts or events, and procedural memory, which enables us to remember how to do something like writing or...
2.3K
01:19Role of Hippocampus in Memory
2.1K
The hippocampus, a critical brain structure, plays an essential role in memory processing, particularly in the formation and retrieval of memory. This small, seahorse-shaped region is located within the medial temporal lobe, with one hippocampus in each brain hemisphere. Experimental studies involving lesions in the hippocampi of rats have demonstrated significant impairments in tasks such as object recognition and maze navigation, indicating the hippocampus involvement in both recognition and...
2.1K
01:20Traumatic Memory
733
Emotionally traumatic events often lead to memories that are exceptionally vivid and enduring, sometimes persisting with remarkable clarity throughout an individual's life. A classic example of this phenomenon is a person who survives a car accident. Even years later, they may recall every detail of the event with startling accuracy — the screeching of the tires, the jarring impact, and the acrid smell of burning rubber. Such vividness contrasts sharply with how an individual...
733