Disputes over memory ownership: What memories are disputed?

The ownership of memories is sometimes disputed, particularly by twins. Examination of 77 disputed memories, 71 provided by twins, showed that most of the remembered events are negative and that the disputants appear to be self-serving. They claim for themselves memories for achievements and suffered misfortunes but are more likely to give away memories of personal wrongdoing. The research suggests that some of the memories in which we play a leading role might in fact have been the experiences of others.

Resistance exercise decreases skeletal muscle tumor necrosis factor alpha in frail elderly humans.

Skeletal muscle protein and function decline with advancing age but the underlying pathophysiology is poorly understood. To test the hypothesis that the catabolic cytokine tumor necrosis factor alpha (TNF-alpha) contributes to this process, we studied the effects of aging and resistance exercise on TNF-alpha expression in human muscle. Using in situ hybridization, TNF-alpha message was localized to myocytes in sections of skeletal muscle from elderly humans. Both TNF-alpha mRNA and protein levels were elevated in skeletal muscle from frail elderly (81+/-1 year) as compared to healthy young (23+/-1 year) men and women. To determine whether resistance exercise affects TNF-alpha expression, frail elderly men and women were randomly assigned to a training group or to a nonexercising control group. Muscle biopsies were performed before and after 3 months. Muscle TNF-alpha mRNA and protein levels decreased in the exercise group but did not change in the control group. Muscle protein synthesis rate in the exercise group was inversely related to levels of TNF-alpha protein. These data suggest that TNF-alpha contributes to age-associated muscle wasting and that resistance exercise may attenuate this process by suppressing skeletal muscle TNF-alpha expression.

Olfactory conditioning facilitates diet transition in human infants.

We evaluated whether Pavlovian conditioning methods could be used to increase the ingestion of non-preferred solutions by formula-fed human infants. In baseline measures, 5-7 month old infants sucked less frequently and consumed less water than regular formula. During a 3-day olfactory conditioning period, parents placed a small scented disk, the conditioned stimulus, on the rim of their infants' formula bottle at every feeding. Following this training, infants' responses to water were tested when their water bottles had a disk scented with the training odor, a novel odor, or no odor. Infants tested with the training odor sucked more frequently and consumed significantly more water than they had at baseline. Infants tested with no odor or a novel odor consumed water at or below baseline levels. These data demonstrate that olfactory conditioning can be used to enhance ingestion in infants and suggest that such methods may be useful for infants experiencing difficulty when making transitions from one diet to another.

Novel goblet cell gene related to IgGFcgammaBP is regulated in adapting gut after small bowel resection.

The loss of functional small bowel surface area leads to a well-described adaptive response in the remnant intestine. To elucidate its molecular regulation, a cohort of cDNAs were cloned using a rat gut resection model and subtractive/differential hybridization cloning techniques. This study reports a novel cDNA termed "ileal remnant repressed" (IRR)-219, which shares 80% nucleotide identity with the 3'end of a human intestinal IgG Fc binding protein (IgGFcgammaBP) and is homologous to human and rat mucins. IRR-219 mRNA is expressed in intestine and colon only. At 48 h after 70% intestinal resection, mRNA levels decreased two- to fivefold in the adaptive small bowel but increased two- to threefold in the colon. Expression of IRR-219 was suppressed in adaptive small bowel as late as 1 wk after resection. IRR-219 expression is also regulated during gut ontogeny. In situ hybridization revealed IRR-219 expression in small intestinal and colonic goblet cells only. Its unique patterns of expression during ontogeny and after small bowel resection suggest distinctive roles in small bowel and colonic adaptation.

Altered enteroendocrine cell expression in T cell receptor alpha chain knock-out mice.

Mice lacking T cell receptor alpha chain (TCRalpha(-/-)) develop inflammation of the colon. We have examined the effect of this inflammation on the colonic epithelium by studying markers of epithelial cuff, enteroendocrine, and immune cell differentiation. Using immunohistochemical techniques, colons were compared in normal C57/BL6 and murine TCR alpha(-/-) mice aged 2 and 3 weeks and 3-11 months. TCR alpha(-/-) mice aged 3-11 months had histologic evidence of inflammation with increased expression of CD45, CD4+, CD8+, and B220+ cells and a decrease in expression of IgA+ cells. There was a decrease in the number of cholecystokinin, serotonin, and neurotensin enteroendocrine expressing cells in the colon of TCR alpha(-/-) mice. These changes were not present in 2-3-week-old suckling/weaning mice. In contrast, peptide tyrosine tyrosine (PYY), glucagon-like peptide-1, and gastrin expression did not change and small intestinal enteroendocrine cells remained unaltered. The change in colonic enteroendocrine cell expression appears to be a specific response, since only a subset of these cells was altered, and the epithelium was intact by histologic analysis. The absence of functional T cells in TCR alpha(-/-) colon has a marked effect on differentiation of a specific subpopulation of enteroendocrine cells, prior to loss of integrity of the epithelium.

Internal languages of retrieval: the bilingual encoding of memories for the personal past.

In contrast to most research on bilingual memory that focuses on how words in either lexicon are mapped onto memory for objects and concepts, we focus on memory for events in the personal past. Using a word-cue technique in sessions devoted exclusively to one language, we found that older Hispanic immigrants who had come to the United States as adults internally retrieved autobiographical memories in Spanish for events in the country of origin and in English for events in the U.S. These participants were consistently capable of discerning whether a memory had come to them "in words" or not, reflecting the distinction between purely imagistic or conceptual memories and specifically linguistic memories. Via examination of other phenomenological features of these memories (sense of re-living, sensory detail, emotionality, and rehearsal), we conclude that the linguistic/nonlinguistic distinction is fundamental and independent of these other characteristics. Bilinguals encode and retrieve certain autobiographical memories in one or the other language according to the context of encoding, and these linguistic characteristics are stable properties of those memories over time.

The distribution of early childhood memories.

The quantitative distribution of autobiographical memories for the first decade of life is described. The distribution, based on over 11,000 autobiographical memories from age 10 and younger from published studies, is nearly identical for males and females, for participants of different ages, and for different methods of collecting data, including using words to cue memories from anywhere in the lifespan or from just the childhood years, exhaustive listing of all early memories, and interviews.

Vitamin A status modulates intestinal adaptation after partial small bowel resection.

BACKGROUND: Intestinal adaptation after loss of functional small bowel surface area is characterized by cellular hyperplasia and increased absorptive function. Interventions to enhance the adaptive response are needed to decrease the morbidity and mortality associated with short bowel syndrome. Retinoic acid was shown to stimulate crypt cell proliferation in the adapting remnant rat ileum by 6 hours after resection. Thus, vitamin A, which is required for normal epithelial cell proliferation and differentiation and which can modulate programmed cell death, may play an important role in the adapting intestine. On the basis of these observations, the effects of vitamin A deficiency on intestinal morphology, epithelial cell proliferation, and apoptosis in the adapting intestine after resection were investigated. METHODS: Weanling male Sprague-Dawley rats fed either a vitamin A-deficient or -sufficient diet for 58 days underwent 70% proximal small bowel resection. The deficient rats were divided into cohorts that were either maintained on the experimental diet after surgery or replenished with vitamin A 20 hours before surgery and switched to the control diet after surgery. RESULTS: Ten days after resection, vitamin A-deficient rats exhibited a markedly blunted adaptive response. The adaptive increase in villus height and crypt depth was absent in the deficient rats. However, adaptive increases in crypt cell proliferation were not attenuated by vitamin A deficiency, and there were no differences in apoptotic indices. CONCLUSIONS: Vitamin A deficiency inhibits the adaptive response to partial small bowel resection, supporting a role for vitamin A in the adaptive process. Changes in cellular proliferation or programmed cell death are not sufficient to account for this inhibition. This model system will be useful for examining the role of other mechanisms, such as changes in cell-cell and cell-extracellular matrix interactions, and rates of epithelial cell migration and cell extrusion.

Music, emotion, and autobiographical memory: they're playing your song.

Very long-term memory for popular music was investigated. Older and younger adults listened to 20-sec excerpts of popular songs drawn from across the 20th century. The subjects gave emotionality and preference ratings and tried to name the title, artist, and year of popularity for each excerpt. They also performed a cued memory test for the lyrics. The older adults' emotionality ratings were highest for songs from their youth; they remembered more about these songs, as well. However, the stimuli failed to cue many autobiographical memories of specific events. Further analyses revealed that the older adults were less likely than the younger adults to retrieve multiple attributes of a song together (i.e., title and artist) and that there was a significant positive correlation between emotion and memory, especially for the older adults. These results have implications for research on long-term memory, as well as on the relationship between emotion and memory.

The neural basis of naming impairments in Alzheimer's disease revealed through positron emission tomography.

The naming impairments in Alzheimer's disease (AD) have been attributed to a variety of cognitive processing deficits, including impairments in semantic memory, visual perception, and lexical access. To further understand the underlying biological basis of the naming failures in AD, the present investigation examined the relationship of various classes of naming errors to regional brain measures of cerebral glucose metabolism as measured with 18 F-Fluoro-2-deoxyglucose (FDG) and positron emission tomography (PET). Errors committed on a visual naming test were categorized according to a cognitive processing schema and then examined in relationship to metabolism within specific brain regions. The results revealed an association of semantic errors with glucose metabolism in the frontal and temporal regions. Language access errors, such as circumlocutions, and word blocking nonresponses were associated with decreased metabolism in areas within the left hemisphere. Visuoperceptive errors were related to right inferior parietal metabolic function. The findings suggest that specific brain areas mediate the perceptual, semantic, and lexical processing demands of visual naming and that visual naming problems in dementia are related to dysfunction in specific neural circuits.

Regulation of PC4/TIS7 expression in adapting remnant intestine after resection.

The adaptive response of the small intestine to loss of functional surface area includes enhanced crypt cell proliferation and enterocyte differentiation. To better define the underlying molecular and cellular mechanisms, we have cloned rat genes that are specifically regulated in the adaptive gut after 70% small intestinal resection. One of these is the immediate early gene PC4/TIS7. Compared with sham-resected control ileum, PC4/TIS7 mRNA levels in the adaptive remnant ileum were markedly increased at 16 and 48 h but not 1 wk after resection. Greater augmentation of PC4/TIS7 mRNA levels occurred in the ileum compared with the duodenum and proximal jejunum. After resection, the changes in intestinal PC4/TIS7 mRNA levels also exceeded changes in extraintestinal levels. The demonstration by in situ hybridization that villus-associated, but not crypt, cells express PC4/TIS7 mRNA is consistent with a role in regulating cytodifferentiation. The pattern of expression in the Caco-2 cell line is also consistent with such a role. Although the precise function of PC4/TIS7 in adaptation remains unclear, the early and intestine-specific changes in mRNA levels after 70% resection suggest that it might augment the adaptive response by stimulating the production of differentiated enterocytes.

Memory and learning for a novel written style.

Subjects read and recalled a series of five short stories in one of four plot and style combinations. The stories were written in one of two styles that consisted of opposing clause orders (i.e., independent-dependent vs. dependent-independent), tense forms (i.e., past vs. present), and descriptor forms (modifier modifier vs. modifier as a noun). The subjects incorporated both plot and style characteristics into their recalls. Other subjects, who, after five recalls, either generated a new story or listed the rules that had been followed by the stories read, included the marked forms of the characteristics they learned more often, except for tense. The subjects read and recalled four stories of the same plot and style and then read and recalled a fifth story of the same plot and style or of one of the other three plot/style combinations. Ability to switch style depended on both the characteristic and the markedness.

Characterization of rat epimorphin/syntaxin 2 expression suggests a role in crypt-villus morphogenesis.

The rodent intestinal mucosa undergoes a remarkable morphogenesis as the crypt-villus axis is formed. Endoderm-mesenchymal interactions play a critical role in this process. Epimorphin is a mesenchymal protein postulated to play a role in lung and skin morphogenesis. The rat homologue, syntaxin 2, belongs to a family of integral membrane proteins that function in vesicle docking and fusion. To clarify its role in fetal gut morphogenesis, epimorphin expression was examined during ontogeny, in an isograft model of ischemic injury and mucosal repair, and during intestinal adaptation after small bowel resection. Epimorphin/syntaxin 2 mRNA levels were increased in fetal gut during lumen formation and villus morphogenesis. mRNA levels remained elevated in the first 2 wk after birth and then declined at weaning. In situ hybridization showed epimorphin/syntaxin 2 mRNA in gestational day 14 (G14) and G15 intestinal mesenchymal cells and in the mucosal lamina propria during villus formation. Epimorphin/syntaxin 2 mRNA expression increased during villus repair in the isograft. In contrast, in the early stages of intestinal adaptation after small bowel resection, epimorphin/syntaxin 2 mRNA expression was suppressed in the adapting gut. We conclude the cell-specific and temporal patterns of epimorphin expression in the models used in this study suggest a role in the morphogenesis of the crypt-villus axis.

Subepithelial fibroblast cell lines from different levels of gut axis display regional characteristics.

The intestine is characterized by morphofunctional differences along the proximodistal axis. The aim of this study was to derive mesenchymal cell lines representative of the gut axis. We isolated and cloned rat intestinal subepithelial myofibroblasts raised from 8-day proximal jejunum, distal ileum, and proximal colon lamina propria. Two clonal cell lines from each level of the gut were characterized. They 1) express the specific markers vimentin, smooth muscle alpha-actin, and smooth muscle myosin heavy chain, revealed by immunofluorescence microscopy and 2) distinctly support endodermal cell growth in a coculture model, depending on their regional origin, and 3) the clones raised from the various proximodistal regions maintain the same pattern of morphogenetic and growth and/or differentiation factor gene expression as in vivo: hepatocyte growth and/or scatter factor and transforming growth factor-beta 1 mRNAs analyzed by RT-PCR were more abundant, in the colon and ileal clones and mucosal connective tissue, respectively. In addition, epimorphin mRNA studied by Northern blot was also the highest in one ileal clone, in which it was selectively upregulated by all-trans retinoic acid (RA) treatment. Epimorphin expression in isolated 8-day intestinal lamina propria was higher in the distal small intestine and proximal colon than in the proximal small intestine. In conclusion, we isolated and characterized homogeneous cell subtypes that can now be used to approach the molecular regulation of the epithelium-mesenchyme-dependent regional specificity along the gut.

Visual memory-deficit amnesia: a distinct amnesic presentation and etiology.

We describe a form of amnesia, which we have called visual memory-deficit amnesia, that is caused by damage to areas of the visual system that store visual information. Because it is caused by a deficit in access to stored visual material and not by an impaired ability to encode or retrieve new material, it has the otherwise infrequent properties of a more severe retrograde than anterograde amnesia with no temporal gradient in the retrograde amnesia. Of the 11 cases of long-term visual memory loss found in the literature, all had amnesia extending beyond a loss of visual memory, often including a near total loss of pretraumatic episodic memory. Of the 6 cases in which both the severity of retrograde and anterograde amnesia and the temporal gradient of the retrograde amnesia were noted, 4 had a more severe retrograde amnesia with no temporal gradient and 2 had a less severe retrograde amnesia with a temporal gradient.

The spacing effect depends on an encoding deficit, retrieval, and time in working memory: evidence from once-presented words.

The spacing effect in list learning occurs because identical massed items suffer encoding deficits and because spaced items benefit from retrieval and increased time in working memory. Requiring the retrieval of identical items produced a spacing effect for recall and recognition, both for intentional and incidental learning. Not requiring retrieval produced spacing only for intentional learning because intentional learning encourages retrieval. Once-presented words provided baselines for these effects. Next, massed and spaced word pairs were judged for matches on their first three letters, forcing retrieval. The words were not identical, so there was no encoding deficit. Retrieval could and did cause spacing only for the first word of each pair; time in working memory, only for the second.

Structure of murine enterokinase (enteropeptidase) and expression in small intestine during development.

Enterokinase (enteropeptidase) is expressed only in proximal small intestine, where it initiates digestive enzyme activation by converting trypsinogen into trypsin. To investigate this restricted expression pattern, mouse enterokinase cDNA was cloned, and the distribution of enterokinase mRNA and enzymatic activity were determined in adult mice and during gestation. Analysis of enterokinase sequences showed that a mucinlike domain near the NH2 terminus is composed of repeated approximately 15-amino acid Ser/Thr-rich motifs. By Northern blotting and trypsinogen activation assays, enterokinase mRNA and enzymatic activity were undetectable in stomach, abundant in duodenum, and decreased distally until they were undetectable in midjejunum, ileum, and colon. By in situ mRNA hybridization, enterokinase mRNA was localized to the enterocytes throughout the villus. Expression was not observed in goblet cells, Paneth cells, or Brunner's glands. Enterokinase mRNA and enzymatic activity were not detected in the duodenum of fetal mice but were easily detected in the duodenum on postnatal days 2-6. Both enterokinase mRNA and enzymatic activity decreased to very low levels after day 7 but increased after weaning and reached a high level characteristic of adult life by day 60. Therefore, in mice, duodenal enterocytes are the major type of cells expressing enterokinase, which appears to be regulated at the level of mRNA abundance.