Biochemistry. in the Article ‘‘The Effects of Sequence Context Immunology
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8796 Corrections Proc. Natl. Acad. Sci. USA 93 (1996) Biochemistry. In the article ‘‘The effects of sequence context Immunology. In the article ‘‘A synthetic random basic copol- on DNA curvature’’ by Mensur Dlakic´and Rodney E. Har- ymer with promiscuous binding to class II major histocompat- rington, which appeared in number 9, April 30, 1996, of Proc. ibility complex molecules inhibits T-cell proliferative responses Natl. Acad. Sci. USA (93, 3847–3852), the authors request that to major and minor histocompatibility antigens in vitro and the following be noted. In Fig. 2, on the abscissa, the fifth base confers capacity to prevent murine graft-versus-host disease in from the left should be an ‘‘a’’ instead of a ‘‘t.’’ The correct vivo,’’ by Paul G. Schlegel, Rina Aharoni, Yanfei Chen, Jun figure and its legend are shown below. Chen, Dvora Teitelbaum, Ruth Arnon, Michael Sela, and Nelson J. Chao, which appeared in number 10, May 14, 1996, of Proc. Natl. Acad. Sci. USA (93, 5061–5066), the authors request that the following corrections be noted: In the Ab- stract, line 6, and in Materials and Methods, p. 5062, line 17, of the left hand column, inadvertently the ratio of two amino acids within GLAT has been reversed. It should read: 1.9:4.7:6.0:1.0. In the Abstract, line 6, a printer’s error resulted in the incorrect molecular weight range of GLAT. It should be changed to Mr, 6000–8500. Psychology. Regarding the article ‘‘Electroconvulsive shock and lidocaine reveal rapid consolidation of spatial working memory in the water maze’’ by Ve´ronique Bohbot, Pavel FIG. 2. Cutting frequencies for complementary strands of se- Ota´hal,Zheng Liu, Lynn Nadel, and Jan Bures, which ap- quences 42–1, 42–4, and 42–5 (Fig. 1A) with DNase I. The GAGAG peared in number 9, April 30, 1996, of Proc. Natl. Acad. Sci. motif, where most of the differences are observed, is shown in capitals. USA (93, 4016–4019), it is requested that the following cor- Physiology. In the article ‘‘Spectrum of HERG K1-channel rection be noted. This article, which was listed in the Table of dysfunction in an inherited cardiac arrythmia’’ by Michael C. Contents under the heading of Plant Biology, should have been Sanguinetti, Mark E. Curran, Peter S. Spector, and Mark T. listed under the heading of Psychology. Keating, which appeared in number 5, March 5, 1996, of Proc. Natl. Acad. Sci. USA (93, 2208–2212), the authors request that the following be noted. Reference 11 should read: 11. Liman, E. R., Hess, P., Weaver, F. & Koren, G. (1991) Nature (London) 353, 752–756. Biochemistry. In the article ‘‘A functional peptide encoded in the Escherichia coli 23S rRNA’’ by Tanel Tenson, Alexandra DeBlasio, and Alexander Mankin, which appeared in number 11, May 28, 1996, of Proc. Natl. Acad. Sci. USA (93, 5641– 5646), the authors request that the following be noted. The first sentence of Results should read ‘‘Phenotypic selection of the random gene fragment libraries was originally described by Holzmayer et al. (18).’’ Downloaded by guest on September 29, 2021 Proc. Natl. Acad. Sci. USA Vol. 93, pp. 4016-4019, April 1996 Psychology Electroconvulsive shock and lidocaine reveal rapid consolidation of spatial working memory in the water maze VERONIQUE BOHBOT*, PAVEL OTAHALt, ZHENG LIUt, LYNN NADEL*, AND JAN BUREStt *Arizona Research Laboratories, Neural Systems Memory and Aging, and Department of Psychology, University of Arizona, Tucson, AZ 85721; and tlnstitute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic Contributed by Jan Bures, December 22, 1995 ABSTRACT Head trauma leading to concussion and elec- preceding the accident, and 10% report no amnesia at all. In troconvulsive shock (ECS) in humans causes amnesia for a more naturalistic study, retrograde amnesia was assessed by events that occurred shortly before the injury (retrograde interviewing football players within 30 sec after a concussion. amnesia). The present experiment investigated the amnesic They were able to remember details of the game, and what they effect of lidocaine and ECS in 25 rats trained on a working were doing shortly before they got injured, but 5 min later the memory version ofthe Morris water task. Each day, the escape injured players could no longer recall such details (3). This platform was moved to a new location; learning was evidenced confirmed the clinical observations and was interpreted as a by a decrease in the latency to find the platform from the first failure of short-term memories getting stored or strengthened to the second trial. "Consolidation" of this newly encoded into long-term memory. spatial engram was disrupted by bilateral inactivation of the Electroconvulsive shock (ECS) has been used to simulate dorsal hippocampus with 1 ,ll of 4% lidocaine applied as soon the amnesic effects of concussion. In animal studies [for as possible after the first trial. When trial 2 was given after example, using one trial inhibitory avoidance in the rat (6)] recovery from the lidocaine (30 min after the injection), a ECS has a graded amnesic effect: more severe for short delays normal decrease in latency indicated that the new engram was between the first learning trial and the ECS. Delays up to 1 min not disrupted. When trial 2 was given under the influence of show amnesic effects, and this time can be increased with lidocaine (5 min after injection), absence of latency decrease higher levels of ECS current. In the present experiment we demonstrated both the success of the inactivation and the tested whether the rapid consolidation of newly acquired importance of hippocampus for the task. To examine the role spatial memories could be disrupted by direct interference of events immediately after learning, ECS (30 or 100 mA, 50 with the hippocampus, which is known to be essential for Hz, 1.2 sec) was applied 0 sec to 45 sec after a single escape spatial learning (7, 8). In order to do so, we trained rats on a to the new platform location. A 2-h delay between ECS and working memory version of the Morris water task (9), which trial 2 allowed the effects of ECS to dissipate. ECS applied 45 can be acquired in only one trial. The rats must search for a sec or 30 sec after trial 1 caused no retrograde amnesia: escape submerged platform, the location of which varies from day to latencies on trial 2 were the same as in control rats. However, day. Even with delays of up to several hours between trials rats ECS applied 0 sec or 15 sec after trial 1 induced clear still show savings from the previous trial (9). By introducing a retrograde amnesia: escape latencies on trial 2 were no shorter disruptive procedure after trial 1, and then waiting until the than on trial 1. It is concluded that the consolidation of a anterograde effects ofthe procedure dissipate before perform- newly formed memory for spatial location can only be dis- ing the second trial, we could test whether the engram formed rupted by ECS within 30 sec after learning. during the first trial was consolidated or not. A consolidated engram would result in decreased latencies on the second trial, A period of amnesia for new events (anterograde amnesia) whereas a disrupted consolidation process would result in often follows severe head trauma, suggesting that at least some latencies on the second trial that were no shorter than those forms of information cannot be encoded until the brain observed on the first. recovers from injury. Loss ofmemory for events which precede In the first study we directly blocked the hippocampus with a trauma (retrograde amnesia) has also been reported (1). The lidocaine, which is known to produce a retrieval deficit in fact that memory for recent events appears to be more another version of this task (10), as soon as possible after the vulnerable than older memories (2-4) suggests that "consol- first learning trial in the new location. In the second study we idation" processes occurring after learning are essential to the used ECS, a disruptingprocedure which could be administered stabilization of memory. While earlier work focused on a more quickly. Delays of 0-45 sec between the first trial and the short-term "memory consolidation" process, typically lasting ECS were used, and the strength of the engram was always seconds, minutes, or hours, more recent work (5) has empha- tested 2 h after the administration of the ECS when the rats sized a longer-term process involving interactions between were found to be completely recovered from any retrieval memory traces stored in several brain regions. In patients with impairments or anterograde deficits (11). damage to the medial temporal lobe, retrograde amnesia can be observed for periods lasting up to 15 years. These two MATERIALS AND METHODS aspects of consolidation-a short-term process and a much longer-term process-must be carefully separated and ana- Subjects. Twenty-five male Long-Evans rats, weighing 250- lyzed. The present report focuses on short-term consolidation 270 g at the start of the experiment, were used. The rats were processes; a report on long-term mechanisms is under prep- obtained from the Institute's breeding facility. Rats were aration. grouped by five in large cages and had free access to food and In the clinic (2), 20% of concussion cases suffer a memory water throughout the experiment. Each rat was handled for 3 loss for up to several days, 70% lose memories for <30 min days before pretraining. Eight rats were assigned to the group receiving lidocaine, eight rats were assigned to the group The publication costs of this article were defrayed in part by page charge payment.