Extended temporal gradient for the retrograde and anterograde amnesia produced by ibotenate entorhinal cortex lesions in mice

Cho, Yoon H.; Béracochéa, Daniel; Jaffard, Robert

doi:10.1523/jneurosci.13-04-01759.1993

Cited by 114 publications

(79 citation statements)

References 16 publications

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“…Inactivation of the dorsal hippocampus by lidocaine 1 day after training impaired performance, whereas inactivation 30 days after training had no effect (Maviel et al, 2004). Spared remote memory after hippocampal (or fornix) lesions has also been reported in other tasks in which animals must use spatial information to discriminate between multiple arms of a maze (Cho et al, 1993;Ramos, 1998). …”

Section: Discussionmentioning

confidence: 85%

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Impaired remote spatial memory after hippocampal lesions despite extensive training beginning early in life

2005

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Damage to the hippocampus typically produces temporally graded retrograde amnesia, whereby memories acquired recently are impaired more than memories acquired remotely. This phenomenon has been demonstrated repeatedly in a variety of species and tasks, and it has figured prominently in theoretical treatments of memory and hippocampal function. A striking exception to the finding of temporally graded retrograde amnesia comes from studies with rodents using spatial tasks like the water maze. In these studies, recent and remote memory were similarly impaired following hippocampal lesions. In contrast to work with rodents, studies of patients with medial temporal lobe lesions, including complete hippocampal lesions, indicate that remote spatial memory can be intact. One difference between studies in humans and studies in rodents is that spatial memory in animal studies is acquired during a limited period of time when the animals are adults. In contrast, the spatial memory studied in humans was acquired beginning at an early age and learning continued for a considerable period of time. We initiated training in a standard water maze immediately after rats had been weaned at 21 days of age and continued training until the rats were young adults (90 days old). Large hippocampal lesions were made 100 days after the completion of training. After recovery from surgery, control rats exhibited good retention on the first retention probe trial, but rats with hippocampal lesions performed at chance. Thus, even after extended training beginning early in life, and with a prolonged training-surgery interval, hippocampal lesions impair performance in the water maze task. Possible reasons for these findings are discussed in the context of the specific performance requirements of the water maze task.

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Section: Discussionmentioning

confidence: 85%

“…In contrast, in tasks where animals must use spatial information only to discriminate between arms of a maze (Cho et al, 1993;Ramos, 1998), remote spatial memory has been spared after hippocampal lesions.…”

Section: Discussionmentioning

confidence: 95%

Impaired remote spatial memory after hippocampal lesions despite extensive training beginning early in life

2005

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“…Wiig et al (1996) reported a temporally graded retrograde amnesia for learned object discriminations after lesions of perirhinal cortex, and Cho et al (1993Cho et al ( , 1995 and Cho and Kesner (1996) reported temporally graded impairments in spatial memory after lesions of entorhinal cortex. The discrepant results could be caused by differences in the lesions, tasks, or species.…”

Section: Discussionmentioning

confidence: 99%

Rhinal Cortex Removal Produces Amnesia for Preoperatively Learned Discrimination Problems But Fails to Disrupt Postoperative Acquisition and Retention in Rhesus Monkeys

1997

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To test whether the rhinal cortex (i.e., entorhinal and perirhinal cortex) plays a time-limited role in information storage, eight rhesus monkeys were trained to criterion on two sets of 60 object discrimination problems, one set at each of two different time periods separated by 15 weeks. After the monkeys had learned both sets, two groups balanced for preoperative acquisition rates were formed. One group received bilateral ablation of the rhinal cortex (n ϭ 4), and the other was retained as an unoperated control group (n ϭ 4). After a 2 week rest period, monkeys were assessed for retention of the object discrimination problems. Retention was significantly poorer in monkeys with removals of the rhinal cortex relative to the controls (68 vs 91%). Although both groups showed slightly better retention of problems from the more recently learned set, there was no evidence of a differential effect of the cortical removal across sets (i.e., no temporal gradient). In addition, the monkeys with rhinal cortex lesions subsequently learned three new sets of 10 object discrimination problems as quickly as the controls did, thus ruling out the possibility of a gross impairment in visual perception or discrimination abilities. Furthermore, they retained these postoperatively learned object discriminations as well as the controls did. The findings indicate that the rhinal cortex is critical for the storage and/or retrieval of object discrimination problems that were learned up to 16 weeks before rhinal cortex ablation; however, in the absence of the rhinal cortex, efficient learning and retention of new discrimination problems can still occur. Key words: visual discrimination; stimulus memory; retrograde amnesia; entorhinal cortex; perirhinal cortex; rhesus monkeyBilateral damage to the medial temporal lobe in humans typically results in a temporally graded retrograde amnesia, in which recent memories are lost although remote memories are spared, as well as severe anterograde amnesia, which is characterized by rapid forgetting of new information (e.g., Scoville and Milner, 1957). The phenomenon of temporally graded retrograde amnesia is consistent with the idea of memory consolidation (see McGaugh and Herz, 1972) and with the idea that the role of medial temporal lobe structures is only temporary. Presumably, as time passes after the original learning episode, memories that were initially dependent on these areas are eventually consolidated into a more permanent state elsewhere (for review, see Squire and Alvarez, 1995).Z ola-Morgan and Squire (1990) found that monkeys with damage to the hippocampal formation, entorhinal cortex, and parahippocampal cortex exhibited temporally graded retrograde amnesia, and they concluded that the hippocampal formation has a time-limited role in memory. Furthermore, similar findings have now been reported in rats (Winocur, 1990;K im and Fanselow, 1992; cf. Bolhuis et al., 1994;Cho et al., 1995) and rabbits (Kim et al., 1995) after lesions of the hippocampal formation. Thus, it seems that the ...

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“…If the accumbens plays a role in action selection [68,124,163], and the entorhinal cortex plays a role in memory formation [28,138,214,218,244], then it is possible that the same internal information is redistributed in different ways across the two pathways. Navigation models extending to anatomical structures beyond hippocampus have tended to include models of accumbens as the 'next stage downstream' [19,22,53,177], while memory models have tended to emphasize the entorhinal-hippocampusentorhinal loop [4,24,33].…”

Section: Space and Memorymentioning

confidence: 99%

The hippocampal debate: are we asking the right questions?

Redish

2001

Behavioural Brain Research

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For years, the debate has been: 'Is the hippocampus the cognitive map?' or 'Is the hippocampus the core of memory?' These two hypotheses derived their original power from two key experiments-the cognitive map theory from the remarkable spatial correlates seen in recordings of hippocampal pyramidal cells and the memory theory from the profound amnesias seen in the patient H.M. Both of these key experiments have been reinterpreted over the years: hippocampal cells are correlated with much more than place and H.M. is missing much more than just his hippocampus. However, both theories are still debated today. The hippocampus clearly plays a role in both navigation and memory processing. The question that must be addressed is rather: 'What is the role played by the hippocampus in the navigation and memory systems?' By looking at the navigation system as a whole, one can identify the major role played by the hippocampus as correcting for accumulation errors that occur within idiothetic navigation systems. This is most clearly experimentally evident as reorientation when an animal is lost. Carrying this over to a more general process, this becomes a role of recalling a context, bridging a contextual gap, or, in other words, it becomes a form of recognition memory. I will review recent experimental data which seems to support this theory over the more general spatial or memory theories traditionally applied to hippocampus.

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Extended temporal gradient for the retrograde and anterograde amnesia produced by ibotenate entorhinal cortex lesions in mice

Cited by 114 publications

References 16 publications

Impaired remote spatial memory after hippocampal lesions despite extensive training beginning early in life

Impaired remote spatial memory after hippocampal lesions despite extensive training beginning early in life

Rhinal Cortex Removal Produces Amnesia for Preoperatively Learned Discrimination Problems But Fails to Disrupt Postoperative Acquisition and Retention in Rhesus Monkeys

The hippocampal debate: are we asking the right questions?

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