Profound retrograde but absence of anterograde amnesia for cued place learning in rats with hippocampal lesions

2013 ◽  
Vol 236 ◽  
pp. 102-109 ◽  
Author(s):  
Juan M.J. Ramos
Keyword(s):  
Anterograde Amnesia ◽  
Place Learning ◽  
Hippocampal Lesions

The Role of the Perirhinal Cortex and Hippocampus in Learning, Memory, and Perception

2005 ◽  
Vol 58 (3-4b) ◽  
pp. 246-268 ◽  
Author(s):  
Mark J. Buckley
Keyword(s):  
Medial Temporal Lobe ◽  
Memory Loss ◽  
Anterograde Amnesia ◽  
Perirhinal Cortex ◽  
Memory System ◽  
Object Identity ◽  
Temporal Relationships ◽  
New Findings ◽  
Hippocampal Lesions

One traditional and long-held view of medial temporal lobe (MTL) function is that it contains a system of structures that are exclusively involved in memory, and that the extent of memory loss following MTL damage is simply related to the amount of MTL damage sustained. Indeed, human patients with extensive MTL damage are typically profoundly amnesic whereas patients with less extensive brain lesions centred upon the hippocampus typically exhibit only moderately severe anterograde amnesia. Accordingly, the latter observations have elevated the hippocampus to a particularly prominent position within the purported MTL memory system. This article reviews recent lesion studies in macaque monkeys in which the behavioural effects of more highly circumscribed lesions (than those observed to occur in human patients with MTL lesions) to different subregions of the MTL have been examined. These studies have reported new findings that contradict this concept of a MTL memory system. First, the MTL is not exclusively involved in mnemonic processes; some MTL structures, most notably the perirhinal cortex, also contribute to perception. Second, there are some forms of memory, including recognition memory, that are not always affected by selective hippocampal lesions. Third, the data support the idea that regional functional specializations exist within the MTL. For example, the macaque perirhinal cortex appears to be specialized for processing object identity whereas the hippocampus may be specialized for processing spatial and temporal relationships.

Anterograde amnesia with hippocampal lesions following glufosinate intoxication

Neurology ◽  
2006 ◽  
Vol 67 (5) ◽  
pp. 914-915 ◽  
Author(s):  
H. Y. Park ◽  
P. H. Lee ◽  
D. H. Shin ◽  
G. W. Kim
Keyword(s):  
Anterograde Amnesia ◽  
Hippocampal Lesions

scholarly journals Dissecting the fornix in basic memory processes and neuropsychiatric disease: A review

2019 ◽  
Author(s):  
Susan L. Benear ◽  
Chi Ngo ◽  
Ingrid R. Olson
Keyword(s):  
Diffusion Imaging ◽  
Memory Loss ◽  
Epileptic Seizures ◽  
Anterograde Amnesia ◽  
Brain Structures ◽  
Subcortical Structures ◽  
Hippocampal Lesions ◽  
Imaging Research ◽  
Loss Control ◽  
Deep Brain

The fornix is the primary axonal tract of the hippocampus, connecting it to modulatory subcortical structures. This review reveals that fornix damage causes cognitive deficits that closely mirror those resulting from hippocampal lesions. In rodents and non-human primates, this is demonstrated by deficits in conditioning, reversal learning, and navigation. In humans, this manifests as anterograde amnesia. The fornix is essential for memory formation because it serves as the conduit for theta rhythms and acetylcholine, as well as providing mnemonic representations to deep brain structures that guide motivated behavior, such as when and where to eat. Diffusion imaging research is revealing that the fornix plays a key role in mild cognitive impairment and Alzheimer’s Disease, and can potentially predict conversion from the former to the latter. Emerging imaging findings link perturbations in this structure to schizophrenia, mood disorders, and eating disorders, although more research is needed. Cutting-edge research is currently investigating how deep brain stimulation of the fornix can potentially halt memory loss, control epileptic seizures, and even improve mood.

The Effects of Hippocampal Lesions on Response, Direction, and Place Learning in Rats.

2005 ◽  
Vol 119 (4) ◽  
pp. 946-952 ◽  
Author(s):  
Krista G. Stringer ◽  
Gerard M. Martin ◽  
Darlene M. Skinner
Keyword(s):  
Place Learning ◽  
Hippocampal Lesions ◽  
Response Direction

scholarly journals The rhesus monkey hippocampus critically contributes to scene memory retrieval, but not new learning

2018 ◽  
Author(s):  
Sean Froudist-Walsh ◽  
Philip G. F. Browning ◽  
Paula L. Croxson ◽  
Kathy L. Murphy ◽  
Jul Lea Shamy ◽  
...  
Keyword(s):  
Anterograde Amnesia ◽  
Visual Object ◽  
Anatomical Structures ◽  
Memory Impairments ◽  
New Learning ◽  
Hippocampal Lesions ◽  
The Rich ◽  
Neurotoxic Lesions ◽  
Cortical Regions ◽  
And Storage

AbstractHumans can recall a large number of memories years after the events that triggered them. Early studies of humans with amnesia led to the hippocampus being viewed as the critical structure for episodic memory, but human lesions are imprecise, making it difficult to identify the anatomical structures underlying memory impairments. Rodent studies enable great temporal and anatomical precision in hippocampal manipulations, but not investigation of the rich assortment of interleaved memories that occurs in humans. Thus it is not known how lesions restricted to the hippocampus affect the retrieval of multiple sequentially encoded memories. Furthermore, disagreement exists as to whether hippocampal inactivations lead to a temporally graded, or ungraded amnesia, which could be a consequence of different types hippocampal disruption observed in rodent and human studies. In the current study, four rhesus monkeys received bilateral neurotoxic lesions of the hippocampus, and were compared to thirteen unoperated controls on recognition and new learning of visual object-in-place scenes. Monkeys with hippocampal lesions were significantly impaired compared to controls at remembering scenes that were encoded before the lesion. We did not observe any temporal gradient effect of the lesion on memory recognition, with recent and remote memories being equally affected by the lesion. Monkeys with hippocampal lesions showed no deficits in learning and later recognising new scenes. Thus, the hippocampus, like other cortical regions, may be engaged in the acquisition and storage of new memories, but its role can be taken over by spared regions following a lesion. These findings illustrate the utility of experimental paradigms for studying retrograde and anterograde amnesia that make use of the capacity of nonhuman primates to rapidly acquire many distinct visual memories.

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