Episodic memory, amnesia, and the hippocampal–anterior thalamic axis

  title={Episodic memory, amnesia, and the hippocampal–anterior thalamic axis},
  author={John P. Aggleton and M. W. Brown},
  journal={Behavioral and Brain Sciences},
  pages={425 - 444}
By utilizing new information from both clinical and experimental (lesion, electrophysiological, and gene-activation) studies with animals, the anatomy underlying anterograde amnesia has been reformulated. The distinction between temporal lobe and diencephalic amnesia is of limited value in that a common feature of anterograde amnesia is damage to part of an “extended hippocampal system” comprising the hippocampus, the fornix, the mamillary bodies, and the anterior thalamic nuclei. This view… 
The anterior thalamus provides a subcortical circuit supporting memory and spatial navigation
The electrophysiological properties of cells in the anterior thalamic nuclei are discussed with an emphasis on their role in spatial navigation and neuroanatomical and functional relationships between the ATN and hippocampal formation are described.
The role of the thalamus in amnesia: A tractography, high-resolution MRI and neuropsychological study
Dynamic Cortico-hippocampal Networks Underlying Memory and Cognition: The PMAT Framework
It is argued that the PMAT framework is an important advance over memory systems theories in that it can explain a larger breadth of phenomena and provides a larger number of predictions and testable hypotheses.
Long-term retrograde amnesia… the crucial role of the hippocampus
Lateral and anterior thalamic lesions impair independent memory systems.
These findings provide the first direct evidence of a double dissociation between the LT and AT neural aggregates, as the lateral and the anterior medial thalamus influence parallel independent memory processing systems, and they may each contribute to memory deficits, depending on lesion extent.
Amnesia and the hippocampus
The available evidence favours the view that the hippocampus, in conjunction with other cortical areas, is critical for the retrieval of remote episodic memories and for both recollection and familiarity anterograde memory processes.
The role of the anterior thalamic nuclei for properties of episodic memory: what, when, where
The results suggest that the contributions of the rodent anterior thalamic nuclei to episodic memory, as part of the extended-hippocampal system, primarily reflect the involvement of these nuclei in allocentric spatial learning.
Looking beyond the hippocampus: old and new neurological targets for understanding memory disorders
  • J. Aggleton
  • Biology, Psychology
    Proceedings of the Royal Society B: Biological Sciences
  • 2014
Anatomical findings now reveal that nucleus reuniens and the retrosplenial cortex provide parallel, disynaptic routes for prefrontal control of hippocampal activity, underlines the importance of redressing the balance and the value of looking beyond the hippocampus when seeking to explain failures in learning new episodic information.


The relationships between temporal lobe and diencephalic structures implicated in anterograde amnesia.
It is proposed that a common feature of anterograde amnesia is damage to part of an "extended hippocampal system" comprising the hippocampus, the fornix, the mammillary bodies, and the anterior thalamic nuclei, which results in deficits in the recall of episodic information.
The contribution of the anterior thalamic nuclei to anterograde amnesia
Damage limited to the hippocampal region produces long-lasting memory impairment in monkeys
These findings show that, first, the hippocampal region itself is essential for normal memory function; and second, the adjacent entorhinal and parahippocampal cortices, either alone or in combination, are also an essential component of the medial temporal lobe memory system.
Human amnesia and the medial temporal region: enduring memory impairment following a bilateral lesion limited to field CA1 of the hippocampus
This is the first reported case of amnesia following a lesion limited to the hippocampus in which extensive neuropsychological and neuropathological analyses have been carried out.
A contribution to the anatomical basis of thalamic amnesia.
The mamillothalamic tract and the ventral portion of the lamina medullaris interna are the most likely candidates in the mediation of memory processes and a combined lesion of these structures may be responsible for thalamic amnesia in man.
Memory in monkeys severely impaired by combined but not by separate removal of amygdala and hippocampus
A discrepancy between the clinical and animal literature could indicate a true evolutionary shift in the functions of the hippocampus, or, at the other extreme, it could simply reflect the use of incommensurate measures across species.
Contributions of the left intralaminar and medial thalamic nuclei to memory. Comparisons and report of a case.
A comparison among the patient's performances and those of alcoholic Korsakoff patients, patient NA, and amnestic patients with circumscribed diencephalic lesions suggests that there are two distinct behavioral and anatomic types of memory impairment associated with diencecephalic lesions.
Severity of memory impairment in monkeys as a function of locus and extent of damage within the medial temporal lobe memory system
It is suggested that, whereas damage to the hippocampal region produces measurable memory impairment, a substantial part of the severe memory impairment produced by large medial temporal lobe lesions in humans and monkeys can be attributed to damage to entorhinal, perirHinal, and parahippocampal cortices adjacent to the hippocampusal region.
On the relationship between knowledge and memory for pictures: Evidence from the study of patients with semantic dementia and Alzheimer's disease
It is demonstrated that patients with semantic dementia can show relatively preserved new learning on a forced-choice recognition memory test, while patients in the early amnestic phase of Alzheimer's disease show severely impaired learning on the same test, providing support for the view that new learning is primarily dependent upon the hippocampus and related structures.
Memory, amnesia, and the hippocampal system
A cognitive neuroscience theory of memory is offered that accounts for the nature of memory impairment exhibited in human amnesia and animal models of amnesia, that specifies the functional role played by the hippocampal system in memory, and that provides further understanding of the componential structure of memory.