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Cited by 362Memory and Neural MechanismsMemory Processes and InfluencesCognitive Functions and Memory

Severity of memory impairment in monkeys as a function of locus and extent of damage within the medial temporal lobe memory system

Zola‐Morgan, Stuart, Squire, Larry R., Ramus, Seth J.·1994·Hippocampus
DOI 10.1002/hipo.450040410
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Abstract

During the past decade, work with monkeys has helped identify the structures in the medial temporal lobe that are important for memory: the hippocampal region (including the hippocampus proper, the dentate gyrus, and the subicular complex) and adjacent cortical areas that are anatomically linked to the hippocampus, i.e., the entorhinal, perirhinal, and parahippocampal cortices. One idea that has emerged from this work is that the severity of memory impairment might increase as more components of the medial temporal lobe are damaged. We have evaluated this idea directly by examining behavioral data from 30 monkeys (ten normal monkeys and 20 monkeys with bilateral lesions involving structures within the medial temporal lobe) that have completed testing on our standard memory battery during the last 10 years. The main finding was that the severity of memory impairment depended on the locus and extent of damage to the medial temporal lobe. Specifically, damage limited to the hippocampal region produced a mild memory impairment. More severe memory impairment was produced when the damage was increased to include the adjacent entorhinal and parahippocampal cortices (the H+ lesion). Finally, memory impairment was even more severe when the H+ lesion was extended forward to include the anterior entorhinal cortex and the perirhinal cortex (H++ lesion). Taken together, these findings suggest 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 hippocampal region. © 1994 Wiley‐Liss, Inc.

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  • The entorhinal cortex lies in a critical path in neural systems related to memory.

    “The EC lies in a critical path in neural systems related to memory; it receives afferents from widespread association and limbic areas, projects to the dentate gyrus of the hippocampal formation, receives afferents from the hippocampus, and sends afferents back to association neocortex (Rosene and Van Hoesen, 1987;Zola-Morgan et al., 1994).”

    From Profound Loss of Layer II Entorhinal Cortex Neurons Occurs in Very Mild Alzheimer’s Disease (1996) · cites this paper as Zola-Morgan et al., 1994

  • Otherwise, non-episodic mechanisms can be used to solve memory tasks after repeated training.

    “Otherwise, non-episodic mechanisms can be used to solve memory tasks after repeated training [155,156].”

    From Is episodic-like memory <i>like</i> episodic memory? (2024) · cites this paper as [156]

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Related

Authors
Zola‐Morgan, S., Squire, L. R., & Ramus, S. J.
Affiliations
University of California San Diego (US)
ORCID
Squire, Larry R.
Venue
Hippocampus
Publisher
Wiley
Published
1994-08
Volume
4
Issue
4
Pages
483-495
ISSN
  • 1050-9631 (ISSN-L)
  • 1098-1063
DOI
10.1002/hipo.450040410
OpenAlex
W2100224172
Semantic Scholar
7707a32abffc33a1ad4c50e95c0cf81bd432b556
Cited by
362
References
60
Citations by year
2025: 1 · 2024: 26 · 2023: 2 · 2022: 5 · 2021: 4 · 2020: 7 · 2019: 5 · 2018: 4 · 2017: 7 · 2016: 4 · 2015: 8 · 2014: 4 · 2013: 5 · 2012: 5
FWCI
14.81
Type
journal article
Language
en
Open access
closed
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor, 3726 d)
Locations
  • Hippocampus (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (5r01ns019063-12)
  • National Institute of Neurological Disorders and Stroke (NS19063)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory Processes and Influences
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Functions and Memory
Keywords
memory impairment, medial temporal lobe, entorhinal cortex, perirhinal cortex, parahippocampal cortex, dentate gyrus, bilateral lesions, lesion extent, memory systems, monkeys
MeSH terms
Animals, Female, Hippocampus, Humans, Macaca fascicularis, Male, Memory, Memory Disorders, Pattern Recognition, Visual, Temporal Lobe, Entorhinal Cortex

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