The contributions of the hippocampal formation, perirhinal cortex and areas TH/TF to object, spatial and contextual recognition memory in primates

Adult monkeys (Macaca mulatta) with lesions of the hippocampal formation, perirhinal cortex, areas TH/TF, as well as controls were tested on tasks of object, spatial and contextual recognition memory. ^ Using a visual paired-comparison (VPC) task, all experimental groups showed a lack of object recognition relative to controls, although this impairment emerged at 10 sec with perirhinal lesions, 30 sec with areas TH/TF lesions and 60 sec with hippocampal lesions. In contrast, only perirhinal lesions impaired performance on delayed nonmatching-to-sample (DNMS), another task of object recognition memory. All groups were tested on DNMS with distraction (dDNMS) to examine whether the use of active cognitive strategies during the delay period could enable good performance on DNMS in spite of impaired recognition memory (revealed by the VPC task). Distractors affected performance of animals with perirhinal lesions at the 10-sec delay (the only delay in which their DNMS performance was above chance). They did not affect performance of animals with areas TH/TF lesions. Hippocampectomized animals were impaired at the 600-sec delay (the only delay at which prevention of active strategies would likely affect their behavior). ^ While lesions of areas TH/TF impaired spatial location memory and object-in-place memory, hippocampal lesions impaired only object-in-place memory. The pattern of results for perirhinal cortex lesions on the different task conditions indicated that this cortical area is not critical for spatial memory. ^ Finally, all three lesions impaired contextual recognition memory processes. The pattern of impairment appeared to result from the formation of only a global representation of the object and background, and suggests that all three areas are recruited for associating information across sources. ^ These results support the view that (1) the perirhinal cortex maintains storage of information about object and the context in which it is learned for a brief period of time, (2) areas TH/TF maintain information about spatial location and form associations between objects and their spatial relationship (a process that likely requires additional time) and (3) the hippocampal formation mediates associations between objects, their spatial relationship and the general context in which these associations are formed (an integrative function that requires additional time). ^

STUDIES ON CHOLINERGIC FUNCTION AND MEMORY IN MICE (CHOLINOTOXINS, WORKING, REFERENCE MEMORY, RADIAL ARM MAZE)

Considerable evidence suggests that central cholinergic neurons participate in either acquisition, storage or retrieval of information. Experiments were designed to evaluate information processing in mice following either reversible or irreversible impairment in central cholinergic activity. The cholinergic receptor antagonists, atropine and methylatropine were used to reversibly inhibit cholinergic transmission. Irreversible impairment in central cholinergic function was achieved by central administration of the cholinergic-specific neurotoxins, N-ethyl-choline aziridinium (ECA) and N-ethyl-acetylcholine aziridinium (EACA).^ ECA and EACA appear to act by irreversible inhibition of high affinity choline uptake (proposed rate-limiting step in acetylcholine synthesis). Intraventricular administration of ECA or EACA produced persistent reduction in hippocampal choline acetyltransferase activity. Other neuronal systems and brain regions showed no evidence of toxicity.^ Mice treated with either ECA or EACA showed behavioral deficits associated with cholinergic dysfunction. Passive avoidance behavior was significantly impaired by cholinotoxin treatment. Radial arm maze performance was also significantly impaired in cholinotoxin-treated animals. Deficits in radial arm maze performance were transient, however, such that rapid and apparent complete behavioral recovery was seen during retention testing. The centrally active cholinergic receptor antagonist atropine also caused significant impairment in radial arm maze behavior, while equivalent doses of methylatropine were without effect.^ The relative effects of cholinotoxin and receptor antagonist treatment on short-term (working) memory and long-term (reference) memory in radial arm maze behavior were examined. Maze rotation studies indicated that there were at least two different response strategies which could result in accurate maze performance. One strategy involved the use of response algorithms and was considered to be a function of reference memory. Another strategy appeared to be primarily dependent on spatial working memory. However, all behavioral paradigms with multiple trails have reference memory requirements (i.e. information useful over all trials). Performance was similarly affected following either cholinotoxin or anticholinergic treatment, regardless of the response strategy utilized. In addition, rates of behavioral recovery following cholinotoxin treatment were similar between response groups. It was concluded that both cholinotoxin and anticholinergic treatment primarily resulted in impaired reference memory processes. ^

Efficiency at Rest: Magnetoencephalographic Resting-State Connectivity and Individual Differences in Verbal Working Memory

Inter-individual differences in cognitive performance are based on an efficient use of task-related brain resources. However, little is known yet on how these differences might be reflected on resting-state brain networks. Here we used Magnetoencephalography resting-state recordings to assess the relationship between a behavioral measurement of verbal working memory and functional connectivity as measured through Mutual Information. We studied theta (4?8 Hz), low alpha (8?10 Hz), high alpha (10?13 Hz), low beta (13?18 Hz) and high beta (18?30 Hz) frequency bands. A higher verbal working memory capacity was associated with a lower mutual information in the low alpha band, prominently among right-anterior and left-lateral sensors. The results suggest that an efficient brain organization in the domain of verbal working memory might be related to a lower resting-state functional connectivity across large-scale brain networks possibly involving right prefrontal and left perisylvian areas.

Models of immune memory: On the role of cross-reactive stimulation, competition, and homeostasis in maintaining immune memory

There has been much debate on the contribution of processes such as the persistence of antigens, cross-reactive stimulation, homeostasis, competition between different lineages of lymphocytes, and the rate of cell turnover on the duration of immune memory and the maintenance of the immune repertoire. We use simple mathematical models to investigate the contributions of these various processes to the longevity of immune memory (defined as the rate of decline of the population of antigen-specific memory cells). The models we develop incorporate a large repertoire of immune cells, each lineage having distinct antigenic specificities, and describe the dynamics of the individual lineages and total population of cells. Our results suggest that, if homeostatic control regulates the total population of memory cells, then, for a wide range of parameters, immune memory will be long-lived in the absence of persistent antigen (T1/2 > 1 year). We also show that the longevity of memory in this situation will be insensitive to the relative rates of cross-reactive stimulation, the rate of turnover of immune cells, and the functional form of the term for the maintenance of homeostasis.

Structure and function of declarative and nondeclarative memory systems

This article reviews recent studies of memory systems in humans and nonhuman primates. Three major conclusions from recent work are that (i) the capacity for nondeclarative (nonconscious) learning can now be studied in a broad array of tasks that assess classification learning, perceptuomotor skill learning, artificial grammar learning, and prototype abstraction; (ii) cortical areas adjacent to the hippocampal formation, including entorhinal, perirhinal, and parahippocampal cortices, are an essential part of the medial temporal lobe memory system that supports declarative (conscious) memory; and (iii) in humans, bilateral damage limited to the hippocampal formation is nevertheless sufficient to produce severe anterograde amnesia and temporally graded retrograde amnesia covering as much as 25 years.

Functional neuroimaging studies of encoding, priming, and explicit memory retrieval

Human functional neuroimaging techniques provide a powerful means of linking neural level descriptions of brain function and cognition. The exploration of the functional anatomy underlying human memory comprises a prime example. Three highly reliable findings linking memory-related cognitive processes to brain activity are discussed. First, priming is accompanied by reductions in the amount of neural activation relative to naive or unprimed task performance. These reductions can be shown to be both anatomically and functionally specific and are found for both perceptual and conceptual task components. Second, verbal encoding, allowing subsequent conscious retrieval, is associated with activation of higher order brain regions including areas within the left inferior and dorsal prefrontal cortex. These areas also are activated by working memory and effortful word generation tasks, suggesting that these tasks, often discussed as separable, might rely on interdependent processes. Finally, explicit (intentional) retrieval shares much of the same functional anatomy as the encoding and word generation tasks but is associated with the recruitment of additional brain areas, including the anterior prefrontal cortex (right > left). These findings illustrate how neuroimaging techniques can be used to study memory processes and can both complement and extend data derived through other means. More recently developed methods, such as event-related functional MRI, will continue this progress and may provide additional new directions for research.

Migration and War Memory in a European Perspective A Case-Study on Displaced Persons in Belgium. Natolin Research Paper 05/2011

In the aftermath of World War II, about 20,000 people who had experienced displacement entered Belgium.1 Among those there were about 350 soldiers serving in the Polish armed forces in the West, and about 4,000 ostarbeiterinnen - young female Soviet citizens who were deported to Nazi Germany to do forced labour. All the soldiers and Soviet women married Belgian citizens, and most settled in the home town or city of their spouses. This paper focuses on the war memories of these migrants in post-war life, memories that were arguably shaped not only by the characteristics of their war experiences themselves, but also by the changing positions which they held within their home and host societies. Following the migrants from their moment of settlement until today, the article highlights the changing dynamics of their war memories over time, starting during the Cold War era and ending up in present day Europe. As such, the study finds itself on the crossroads of memory and migration studies, two academic disciplines that only recently started to dialogue with each other.2 Before analysing the arrival, settlement and war memories of the Displaced Persons at study, I give an interpretation of academic literature on memory of World War II from the perspective of migration studies.

HRT and everyday memory at menopause: A comparison of two samples of mid-aged women

Research on the effect of hormone replacement therapy (HRT) on memory in mid-aged women is equivocal although findings indicate that oestrogen may enhance verbal memory. Mood may mediate the relationship between HRT and memory. This study examined the effect of HRT on mood and everyday memory in two samples of women between ages 40 and 60 years. In the cross-sectional comparison (N = 124), HRT users performed significantly better on tests of everyday and verbal memory. A within-woman comparison of 17 women showed that everyday memory, working memory, and delayed verbal memory improved after 3 months of HRT use. The improvement in memory was not mediated by mood. These results suggest that any effect of HRT on mood may be short-term but that some aspects of everyday memory are enhanced, particularly verbal memory. The development of the everyday memory construct and future investigation are discussed.

The effect of hormone replacement therapy on mood and everyday memory in younger mid-life women

Research on the effect of hormone replacement therapy (HRT) on both mood and memory indicates that oestrogen may enhance verbal memory in younger mid-aged women. This study examined the effect of HRT on everyday memory, while accounting for mood changes, in women between ages 40 and 60. A within-subjects comparison of 17 women, showed that mood, everyday memory, working memory, and delayed verbal memory improved after 3 months of HRT use. The improvement in memory was not mediated by mood, but changes in mood were moderated by exercise habits. The results suggest that verbal memory in particular may be enhanced by HRT in this age group, and everyday memory is an important construct to consider in future research.

False recognition of objects in visual scenes:findings from a combined direct and indirect memory test

We report an extension of the procedure devised by Weinstein and Shanks (Memory & Cognition 36:1415-1428, 2008) to study false recognition and priming of pictures. Participants viewed scenes with multiple embedded objects (seen items), then studied the names of these objects and the names of other objects (read items). Finally, participants completed a combined direct (recognition) and indirect (identification) memory test that included seen items, read items, and new items. In the direct test, participants recognized pictures of seen and read items more often than new pictures. In the indirect test, participants' speed at identifying those same pictures was improved for pictures that they had actually studied, and also for falsely recognized pictures whose names they had read. These data provide new evidence that a false-memory induction procedure can elicit memory-like representations that are difficult to distinguish from "true" memories of studied pictures. © 2012 Psychonomic Society, Inc.

Digitally manipulating memory:effects of doctored videos and imagination in distorting beliefs and memories

In prior research on false autobiographical beliefs and memories, subjects have been asked to imagine fictional events and have been exposed to false evidence that indicates that the fictional events occurred. But what are the relative contributions of imagination and false evidence toward false belief and memory construction? In the present study, subjects observed and copied various simple actions; then they viewed doctored videos that suggested that they had performed extra actions and they imagined performing some of those and some other actions. Subjects returned 2 weeks later for a memory test. False evidence or imagination alone was often sufficient to cause belief and memory distortions; in combination, they appeared to have additive or even superadditive effects. The results bear on the mechanisms underlying false beliefs and memories, and we propose legal and clinical applications of these findings. © 2009 The Psychonomic Society, Inc.

Allusion and Cultural Memory in Late Antiquity: Ausonius, Prudentius, and Claudian

Thesis (Ph.D.)--University of Washington, 2016-08

The Scots in Ireland: culture, colonialism and memory, 1315-1826

This thesis examines three key moments in the intersecting histories of Scotland, Ireland and England, and their impact on literature. Chapter one Robert Bruce and the Last King of Ireland: Writing the Irish Invasion, 1315- 1826‘, is split into two parts. Part one, Barbour‘s (other) Bruce‘ focuses on John Barbour‘s The Bruce (1375) and its depiction of the Bruce‘s Irish campaign (1315-1318). It first examines the invasion material from the perspective of the existing Irish and Scottish relationship and their opposition to English authority. It highlights possible political and ideological motivations behind Barbour‘s negative portrait of Edward Bruce - whom Barbour presents as the catalyst for the invasion and the source of its carnage and ultimate failure - and his partisan comparison between Edward and his brother Robert I. It also probes the socio-polticial and ideological background to the Bruce and its depiction of the Irish campaign, in addition to Edward and Robert. It peers behind some of the Bruce‘s most lauded themes such as chivalry, heroism, loyalty, and patriotism, and exposes its militaristic feudal ideology, its propaganda rich rhetoric, and its illusions of freedom‘. Part one concludes with an examination of two of the Irish section‘s most marginalised figures, the Irish and a laundry woman. Part two, Cultural Memories of the Bruce Invasion of Ireland, 1375-1826‘, examines the cultural memory of the Bruce invasion in three literary works from the Medieval, Early Modern and Romantic periods. The first, and by far the most significant memorialisation of the invasion is Barbour‘s Bruce, which is positioned for the first time within the tradition of ars memoriae (art of memory) and present-day cultural memory theories. The Bruce is evaluated as a site of memory and Barbour‘s methods are compared with Icelandic literature of the same period. The recall of the invasion in late sixteenth century Anglo-Irish literature is then considered, specifically Edmund Spenser‘s A View of the State of Ireland, which is viewed in the context of contemporary Ulster politics. The final text to be considered is William Hamilton Drummond‘s Bruce’s Invasion of Ireland (1826). It is argued that Drummond‘s poem offers an alternative Irish version of the invasion; a counter-memory that responds to nineteenth-century British politics, in addition to the controversy surrounding the publication of the Ossian fragments. Chapter two, The Scots in Ulster: Policies, Proposals and Projects, 1551-1575‘, examines the struggle between Irish and Scottish Gaels and the English for dominance in north Ulster, and its impact on England‘s wider colonial ideology, strategy, literature and life writing. Part one entitled Noisy neighbours, 1551-1567‘ covers the deputyships of Sir James Croft, Sir Thomas Radcliffe, and Sir Henry Sidney, and examines English colonial writing during a crucial period when the Scots provoked an increase in militarisation in the region. Part two Devices, Advices, and Descriptions, 1567-1575‘, deals with the relationship between the Scots and Turlough O‘Neill, the influence of the 5th Earl of Argyll, and the rise of Sorley Boy MacDonnell. It proposes that a renewed Gaelic alliance hindered England‘s conquest of Ireland and generated numerous plantation proposals and projects for Ulster. Many of which exhibit a blurring‘ between the documentary and the literary; while all attest to the considerable impact of the Gaelic Scots in both motivating and frustrating various projects for that province, the most prominent of which were undertaken by Sir Thomas Smith in 1571 and Walter Devereux, 1st Earl of Essex in 1573.

PATHWAY IN MEMORY: RELATIONS BETWEEN THE VERBAL AND VISUAL IN INFOGRAPHIC

The relationship between verbal and visual materiality in printed infographics is provided. The manner the verbal significant updates certain discursive memories may be understood when related to the visual significant is thus investigated. Whereas the object under investigation is an infographic of the magazine Saúde titled The virus that combats viruses; the analysis, which is based on a materialist theoretical stance, triggers the notions of memory and materiality. Content effect reiterates the functioning of the linguistic sign through the language’s literality within the word-thing relationship and it establishes itself within the visual stance while producing faithful effects with the real. When one investigates the manner discursive memory performs the relationship between the verbal and the visual in infographics, one understands that this relationship is established within the context of incompleteness of the above-mentioned types of materiality. It also occurs within the equivocation that verbal materiality may be complemented by the visual or that the image may faithfully represent the real. The formulation of infographics demands-updates-reaffirms a verbal faithfulness with the visual within a content relationship. Verbal interweaving (in explicatory graphics) with images (the visual) produces meaning effects that project language as an instrument, ideal in its transparency, and literally reveals the thing to which it refers.

Primary students’ spatial visualization and spatial orientation : an evidence base for instruction

This paper reports on the performance of 58 11 to 12-year-olds on a spatial visualization task and a spatial orientation task. The students completed these tasks and explained their thinking during individual interviews. The qualitative data were analysed to inform pedagogical content knowledge for spatial activities. The study revealed that “matching” or “matching and eliminating” were the typical strategies that students employed on these spatial tasks. However, errors in making associations between parts of the same or different shapes were noted. Students also experienced general difficulties with visual memory and language use to explain their thinking. The students’ specific difficulties in spatial visualization related to obscured items, the perspective used, and the placement and orientation of shapes.