Effect of warning on eyewitness memory protection at different time points / 中华行为医学与脑科学杂志

Objective:To investigate the protective effect of warning at different time points on eyewitness memory during repeated memory retrieval.Methods:A pilot test and artificial intelligence technology were used to develop a set of witness memory experiment procedures applicable to Chinese people. A total of 46 healthy participants were included in the pilot test and 101 healthy participants were included in the formal experiment. A mixed 3 (group of warning) ×4 (memory test time points) design was applied to this study and SPSS 23.0 software was used for data analysis.The memory of 101 healthy participants (33 in the pre-warning group, 30 in the no-warning group, and 38 in the post-warning group) using two-factor repeated measure ANOVA. The memory accuracy rate, memory misleading rate and confidence of the three groups in different memory test time points were taken as dependent variables, and the group of warning and the test time points were taken as independent variables to analyze the differences in memory among the groups in different test time points.Results:(1)In the early two repeated memory tests, the accuracy of memory in pre-warning group ((0.67±0.11), (0.67±0.12)) were significantly higher than those in no warning group ((0.58±0.15), (0.60±0.15)) (both P<0.05); at the third repeat memory test, the accuracy of post-warning group (0.63±0.12) and no warning group (0.60±0.13) were significantly lower than that of pre-warning group (0.69±0.12) (both P<0.05). (2)In the three repeated memory tests, the memory misleading rates of the pre-warning group (0.25(0.13, 0.38), 0.25(0.13, 0.38), 0.25(0.13, 0.38)) and the post-warning group (0.25(0.13, 0.38), 0.25(0.13, 0.38), 0.25(0.13, 0.38)) were significantly lower than those of the no warning group (0.63(0.34, 0.78), 0.63(0.34, 0.75), 0.63(0.25, 0.75)) (all P<0.05). (3)There were no significant difference in the answer confidence between any pair of groups at any corresponding memory test (both P>0.05). Conclusion:The protective effect of warning before misleading information is better than the warning after misleading information, and the protection of the two warnings are still working.

Stress and long-term memory retrieval: a systematic review

Abstract Introduction The experience of stressful events can alter brain structures involved in memory encoding, storage and retrieval. Here we review experimental research assessing the impact of the stress-related hormone cortisol on long-term memory retrieval. Method A comprehensive literature search was conducted on PubMed, Web of Science and PsycNet databases with the following terms: "stress," "long-term memory," and "retrieval." Studies were included in the review if they tested samples of healthy human participants, with at least one control group, and with the onset of the stress intervention occurring after the encoding phase and shortly (up to one hour) before the final memory test. Results Thirteen studies were included in the qualitative synthesis (N = 962) and were classified according to the time elapsed between stress induction and memory retrieval (stress-retrieval delay), the stress-inducing protocol (stressor), the time of day in which stress induction took place, sex, and age of participants. Most studies induced stress with the Trier Social Stress Test (TSST) between 15 and 25 minutes before the final memory (mostly recall) test and showed significant increases in cortisol levels and memory impairment. Discussion The reviewed studies indicate that stress does impair retrieval, particularly when induced with the TSST, in the afternoon, up to 45 minutes before the onset of the final memory test, in healthy young men. These results may inform future research on the impact of stress-induced cortisol surges on memory retrieval.

Memory retrieval-extinction paradigm and its application on drug addicts / 中华行为医学与脑科学杂志

Based on the traditional fear extinction training paradigm, the retrieval-extinction para-digm rewrites fear memory within the reconsolidation window,and reduces their fear response by decreasing the valence of fear stimulus. From the perspective of psychology,the main reason of addicts relapse is that the intensive memory of the painful experience inspired when protracted withdrawal symptoms of drug depend-ence. The reduction of the sensitivity of drug related memory, which is the key of drug detoxification is to change the memory caused by drug related cues. The retrieval-extinction paradigm provides no drug treatment and a new non-invasive model for addicts,and a new perspective to reduce the relapse rate,and to improve the quality of life of addicts. We can do empirical research which using memory retrieval-estinction paradigm on drug addicts in the future.The memory retrieval paradigm can be applied to empirical research in drug ad-dicts in future.

Effects of proteasome inhibitor MG132 on memory acquisition and retrieval in one-trial passive avoidance in mice / 中华行为医学与脑科学杂志

Objective To investigate the effects of proteasome inhibitor MG132 on memory acquisition and memory retrieval in one-trail passive avoidance for mice.Methods MG132 (25 mg/kg) was administrated at different time points to analyze the time-dependent effects of MG132 on hippocampus proteasome activity.MG132 (25 mg/kg) was administrated 3 hours before-training or 1.5 hours pre-test to investigate the effect on memory acquisition and retrieval.The interaction of low dose (12 mg/kg) of MG132 and novelty interference on memory retrieval to studied.Results Hippocampus proteasome activity was significantly blocked when MG132 (25 mg/kg) was administrated 0.5-1.5 hours before analysis.The inhibition recovered as time passing and backed to normal state 24 hours later.A significant difference was showed between vehicle and pre-training,pre-test group (pre-training vehicle (296.03 ± 3.97) s,pre-training (173.30 ± 47.51) s ; pre-test vehicle (199.23 ± 43.01) s,pre-test (44.10 ± 11.16) s).Proteasome inhibitor did not produce a significant effect on memory retrieval (vehicle (174.19 ± 30.54)s,lower dose (174.19± 30.54)s),then only together with a novelty task the retrieval was significantly altered(vehicle (164.02 ±35.26)s,MG132 +novelty group (84.70 ±23.92)s).Conclusion Proteasome inhibitor MG132 can inhibit memory acquisition and memory retrieval.Thereby the effect on memory retrieval is enhanced by novelty.Thus,a physiological proteasome activity is essential for learning abilities.

L-histidine provokes a state-dependent memory retrieval deficit in mice re-exposed to the elevated plus-maze

The effects of L-histidine (LH) on anxiety and memory retrieval were investigated in adult male Swiss Albino mice (weight 30-35 g) using the elevated plus-maze. The test was performed on two consecutive days: trial 1 (T1) and trial 2 (T2). In T1, mice received an intraperitoneal injection of saline (SAL) or LH before the test and were then injected again and retested 24 h later. LH had no effect on anxiety at the dose of 200 mg/kg since there was no difference between the SAL-SAL and LH-LH groups at T1 regarding open-arm entries (OAE) and open-arm time (OAT) (mean ± SEM; OAE: 4.0 ± 0.71, 4.80 ± 1.05; OAT: 40.55 ± 9.90, 51.55 ± 12.10, respectively; P > 0.05, Kruskal-Wallis test), or at the dose of 500 mg/kg (OAE: 5.27 ± 0.73, 4.87 ± 0.66; OAT: 63.93 ± 11.72, 63.58 ± 10.22; P > 0.05, Fisher LSD test). At T2, LH-LH animals did not reduce open-arm activity (OAE and OAT) at the dose of 200 mg/kg (T1: 4.87 ± 0.66, T2: 5.47 ± 1.05; T1: 63.58 ± 10.22; T2: 49.01 ± 8.43 for OAE and OAT, respectively; P > 0.05, Wilcoxon test) or at the dose of 500 mg/kg (T1: 4.80 ± 1.60, T2: 4.70 ± 1.04; T1: 51.55 ± 12.10, T2: 43.88 ± 10.64 for OAE and OAT, respectively; P > 0.05, Fisher LSD test), showing an inability to evoke memory 24 h later. These data suggest that LH does not act on anxiety but does induce a state-dependent memory retrieval deficit in mice.

Encoding and Retrieval of Words and Scenes Assessed by Functional MRI in Normal Right-Handed Volunteers / 대한간질학회지

PURPOSE: To find the activation patterns of frontal and medial temporal lobe during memory tasks (encoding and retrieval) with novel stimuli (words, scenes) in normal right-handed volunteers. Another aim is to examine which memory paradigms and processes are effective to activate medial temporal lobe. METHODS: We included 10 right-handed normal volunteers. Stimuli consisted of encoding and retrieval of novel word (15 items)/novel scenes (15 items). During scanning, each stimulus was presented for 2000 ms. Imaging was performed on 1.5 GE scanner. Group analysis was performed in volunteers with SPM 2 (uncorrected p10). RESULTS: Scenes encoding and retrieval activated both medial temporal lobes, more on the right side. Word encoding activated predominantly dominant frontal lobe, but failed to activate the medial temporal lobes. The word stimuli activated more the frontal lobe than the picture stimuli. Retrieval process activated more the medial temporal lobe than encoding process. CONCLUSION: Our results showed that the scenes encoding/retrieval and word retrieval are useful to activate the medial temporal lobe and word encoding is useful for activating dominant frontal lobe. Further studies will be necessary in patient groups with unilateral temporal lobe lesion to document the usefulness of this study.

Brain Activation Associated with Word Fluency Tasks: A Functional Magnetic Resonance Image Study

BACKGROUND: Two types of word fluency tasks, namely, word generation by semantic or phonemic cues, are part of the neuropsychological evaluation of neurological patients. Cognitive mechanisms, such as strategies of memory retrieval, may differ for these two tasks. We therefore used functional magnetic resonance image (fMRI) to examine whether brain areas activated by the phonemic word fluency task may differ from those activated by the semantic word fluency task. METHODS: Semantic and phonemic word fluency tasks were administered to 112 normal subjects with two categories for each (animal and fruit names for semantic word fluency, and 'ah' and 'd' sounds for phonemic word fluency). The number and the degree of scattering of generated words were examined for the analysis of cortical activation. With another seven normal subjects, fMRI experiments were conducted while they generated words with the two types of cues (five categories for each). RESULTS: Performance in terms of number of words generated was better with semantic cues than with phonemic cues (14.15 words for semantic cues and 10.36 words for phonemic cues on the average). The same words were more commonly generated across subjects in semantic fluency tasks than in phonemic fluency. In a fMRI experiment, higher signals were observed during phonemic than in semantic word fluency tasks at the bilateral posterior-inferior temporal gyri, left premotor area, right cerebellum, and bilateral superior parietal lobules. The opposite was observed at the bilateral posterior cingulate gyri. CONCLUSIONS: The fluency tasks showed differential performance and several cortical areas showed differential activation, depending on the type of cues given for word generation. This result is consistent with the hypothesis that an automated visual imagery is adopted as word-finding strategy for semantic fluency, whereas controlled articulatory evaluation is used as a strategy for phonemic fluency.