In this experiment it was investigated how scent affect the memory. Encoding information in the same context as retrieving it has been suggested to be beneficial for memory, earlier research has mostly explored how environmental contextual cues affects the memory. In this research the contextual cue was created by a presentation of a scent. The participants were presented with two lists of words, during the encoding of the first list all the participants were presented with a scent, half of the group was directed to forget the first list straight after encoding and the other half to keep remembering the list. For the second list no one was presented with a scent. In the retrieval of both lists half of each group was reinstated with the scent they were presented with at encoding and the other half without the scent (control group). The data were analysed with univariate ANOVAs and significant effects were followed up with independent-samples t-test. The results were that participants that were reinstated with the scent were thought to remember more than the others, however there was only a significant difference in the forget condition with reinstatement, where they remembered less than in the other conditions.

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Children with ADHD exhibit impairments in memory retrieval processes that are required for successful performance in a wide range of activities including social/interpersonal interactions, as well as academic success. There have been few attempts of explaining the relationship between these memory retrieval deficits in children with ADHD and specific executive functions such as working memory. The current study addresses the possible mediating effects of the subsystems of working memory (phonological short-term memory, visual-spatial short-term memory, and the central executive) on memory retrieval. Children ages 8-12 with ADHD and typically developing children completed a counterbalanced series of working memory tasks that were specific to the subsystems (phonological and visual-spatial). The Central Executive portion of working memory was obtained using a regression approach of these measures. The children also completed the Kaufman Test of Educational Achievement (KTEA-II), as the associational fluency task was used as the memory retrieval measure for this investigation.

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Yes / This study examined the effects of providing cues to facilitate autobiographical memory retrieval in Parkinson's disease. Previous findings have shown that individuals with Parkinson's disease retrieve fewer specific autobiographical memories than older adult controls. These findings are clinically significant since the quality of autobiographical memory is linked to identity and sense of self. In the current study, 16 older adults with Parkinson's disease without dementia and 16 matched older adult controls were given 3 min in which to recall autobiographical memories associated with five different time periods and to give each memory a short title. Participants were later asked to retrieve the memories in three phases: firstly in a free recall phase; secondly in response to general cues (time periods) and finally in response to specific cues (the short titles previously given). The number of memories and the quality of the memory (general or specific) was recorded in each condition. Compared with matched older adult controls, the Parkinson's disease group was impaired in retrieving the memories that they had previously given in the free recall phase and in response to general cues. The performance of the group with Parkinson's disease was only equivalent to the older adults when they retrieved memories in response to self-generated cues. The findings are discussed in relation to theories of autobiographical memory and the neuropsychology of Parkinson's disease.

The conversion of a memory from an initially fragile state to an enduring representation requires cellular, molecular, and systems-level brain network changes. This reorganization is hypothesized to involve time-dependent neuroanatomical changes that may differentially support some types of remote versus recent memory, and may also influence the latency to decide and complete responses during retrieval. To quantify the timecourse of learning and retrieval after different retention durations, a paradigm is developed to measure in humans and monkeys the retrieval speed of visuomotor associations, which require an intact hippocampus for initial acquisition but not for retrieval after days or weeks. Two components of retrieval speed, a decision time to initiate movement and a velocity-dependent movement completion time to complete a motor response, are shown to change differently relative to a pre-retention baseline. Movement completion times decrease across repetitions within single learning session, and continue to decrease from the level reached at the end of learning following retention. Decision times also decrease within the learning session, but increase on the first post-retention retrieval attempt as a function of retention interval duration. Extensive practice is required for decision times to reach a level below that obtained at the end of learning, and the transition from a long- to short-latency decision depends on the number and spacing of practice trials. The findings are discussed in a framework in which post-retention processing time is influenced by the speed of visual identification, the time to retrieve the associative relationship from long-term memory, and the time to plan and execute a motor response. The creation of sparser, long-lasting visual form representations and strengthened cortico-striatal connections predict behavioral efficiency gains in visual identification and motor responses after learning. Decision times could be fast and automatic following extensive practice when the neural representation may become stored permanently in cortico-cortical and cortico-striatal linkages, or could increase after retention because of several cognitive and neural factors, including interference and frontal inhibition of the hippocampal system to prevent new learning before choice feedback. The experimental results are discussed in the context of the existing literature on memory consolidation.

Activation in the hippocampus (HC) and prefrontal cortex (PFC) is critical to accurately retrieve overlapping sequences. Experiments 1 and 2 tested the hypotheses that activation in and interaction between HC and PFC increases as overlap between sequences increases in a non-spatial task. Experiment 3 tested the hypothesis that theta oscillations are involved in orchestrating interactions between HC and PFC in a spatial task with overlapping elements. In the first two studies, 17 participants (aged 18-34; 11 female) learned sequences consisting of a picture frame, face, and scene. Conditions varied by degree of overlap. Using fMRI, Experiment 1 tested how degree of overlap affected HC and PFC activation. In overlapping sequences, middle and posterior HC were active when predictability of the correct response increased, dorsolateral PFC was active when participants were able to ascertain the correct set of sequences, and ventrolateral PFC was active when inhibition of interfering associations was required. Experiment 2 examined functional connectivity of HC and PFC during disambiguation. Low- and high-overlap conditions were associated with increased connectivity in separate regions at different times indicating that retrieval under the two conditions used different neural networks and strategies. Low-overlap trials were associated with increased connectivity between HC and prefrontal and parietal regions. High-overlap trials showed increased connectivity between lateral PFC and visual areas, indicating that imagery may be necessary for accurate performance. Using EEG recording, Experiment 3 examined theta activity during retrieval of well-learned, overlapping and non-overlapping mazes in 17 participants (aged 18-34, 11 female). Theta activity increased in overlapping mazes during the first of four hallways, suggesting participants were looking ahead to upcoming turns in the maze. Theta activity increased at the beginning and choice point of the third overlapping hallway, possibly in response to interference from the paired, overlapping maze. These studies provide evidence that (1) overlapping associations in non-spatial sequences elicit interactions between hippocampus and lateral prefrontal cortex, (2) increasing the degree of overlap changes the neural processes required to perform the task, and (3) theta power increases in response to increased cognitive demand and maintenance of sequence information needed to differentiate between overlapping spatial routes.

Nous avons évalué les conséquences sur un plan endocrinien et cognitif de l’administration d’un stress aigu chez la souris BalbC jeune (6 mois) ou d’âge moyen (16 mois). Le stress aigu a été appliqué 5, 60 ou 120 minutes avant la phase de rappel dans une épreuve de mémoire contextuelle. La concentration en corticostérone hippocampique a été mesurée avant et après le stress. Suite à l'administration du stress, elle augmente rapidement (dès 15 minutes post-stress) et est inversement liée au rappel mnésique. En effet, plus la concentration de corticostérone hippocampique est élevée, plus faible est la réponse hippocampe-dépendante. Les effets cognitif et endocrinien du stress ont été reproduits par l'administration de corticostérone dans l'hippocampe et ont été bloqués par la métyrapone. Le vieillissement accroit l’anxiété et induit des conséquences sur le plan mnésique comparable à celles du stress chez la souris jeune. De plus, la concentration de corticostérone hippocampique, basale ou en réponse au stress, est plus élevée et durable chez les animaux âgés, par rapport aux jeunes. Par ailleurs, l’administration de diazépam 30 minutes avant le rappel chez la souris d’âge-moyen atténue les effets délétères du stress sur la mémoire et la concentration hippocampique de corticostérone. Ces données suggèrent que la perturbation de l'axe HPA chez la souris âgée joue un rôle clef dans les troubles de mémoire hippocampe-dépendants induits par le vieillissement. / The cognitive and endocrinal consequences of an acute stress were studied in young (6 months) and middle-aged (16 months) BalbC mice. Acute stress was delivered 5, 60 or 120 minutes before the retrieval phase of a contextual memory task. Hippocampal corticosterone concentration was measured before and after stress delivery by microdialysis. The acute stress induces a rapid hippocampal corticosterone rise in relation with a cognitive impairment. Indeed, when the level of hippocampal corticosterone is high, the cognitive performance of hippocampal-dependent memory is impaired. Moreover, the cognitive and endocrinal effects of stress were mimicked using corticosterone microinjection in the hippocampus, whereas metyrapone (an inhibitor of corticosterone synthesis) blocked it. The consequences of aging on memory retrieval are similar to stress effects in young mice. Furthermore, pre and post-stress hippocampal corticosterone concentration is higher in middle-aged as compared to young mice. In addition, the increase in hippocampal corticosterone is longer in middle-aged in contrast to young mice. Finally, the administration of diazepam in middle-aged mice (30 minutes before the retrieval test phase) attenuates the deleterious effects of an acute stress on memory retrieval and the increase in hippocampal corticosterone concentration. In conclusion, our data suggest that HPA axis dysregulation, observed in middle-aged subjects, plays a key role in episodic-like memory impairments induced by aging.

Consideration set formation has been suggested as an important decision-making stage prior to choice. The current research focuses on consideration sets in the memory-based choice context and addresses the gaps in the existing literature by investigating the effects of mindset abstraction on memory retrieval and the number of considered choice alternatives retrieved from memory. I propose that individuals in a concrete (vs. abstract) mindset think more contextual and specific details (vs. fewer essences) about a certain decision situation; therefore concrete and fine-grained mental representations, compared to abstract and rough representations, will activate more associated cues in memory and lead to larger memory-based consideration sets. Through a word association task, studies 1a and 1b show that concrete mindsets leads to more proliferative associations and a greater number of conceptual cues than abstract mindsets. In the domain of product consideration (i.e., snack and dinner), studies 2a and 2b directly demonstrate that individuals in concrete mindsets form a larger memory-based consideration set than ones in abstract mindsets. I further propose the Hypothesis of Top-down versus Bottom-up Approach of Memory Retrieval to explain the mechanism that underlies the mindset abstraction effect on size of memory-based consideration sets. Studies 3 and 4, using an episodic memory paradigm, support this hypothesis and reveal that the type of retrieval cues (superordinate vs. subordinate cues) used by individuals in an abstract versus a concrete mindset determines the likelihood that a brand is considered, and that the richer associations located at the subordinate level contribute to a greater number of choice alternatives that people consider in a concrete mindset. The theoretical contributions, practical implications, and future research directions of this research are finally discussed.

The diploma thesis "Autobiographical Memory in Suicide Attempters" deals with recall of specific autobiographical memories in suicide attempters. The theoretical part of the thesis defines basic concepts associated with autobiographical memory, presents its structure, role throughout the life-span, and describes relation of autobiographical memory to emotions, depression and self. The second part of the thesis presents basic concepts of suicidal behaviour, describes selected theoretical approaches and models of development of suicidal behaviour, methods and consequences, assessment and prevention of suicidal behaviour, and presents most common myths about suicide. The empirical part verifies ability to recall specific autobiographical memory, latency in recall of autobiographical memories, and tendency for overgeneral autobiographical memories. The empirical part employs Autobiographical Memory Test (AMT), Beck Depression Inventory (BDI - II), Suicide Behavior Questionnaire - Revised (SBQ-R) and The Stress Coping Style Questionnaire (SVF 78). The research sample consists of 40 participants (20 suicide attempters, 20 non-suicidal persons). The results indicate that suicide attempters show higher latency in producing specific autobiographical memories, produce fewer specific memories, and show lower...