Assessing the role of pair familiarity in the associative deficit of older adults

Title from PDF of title page (University of Missouri--Columbia, viewed on September 28, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Moshe Naveh-Benjamin.Vita.Ph. D. University of Missouri--Columbia 2009.While aging causes relatively minor impairment in recognition memory for components, older adults' ability to remember associations between components is typically significantly compromised, relative to that of younger adults (see Naveh-Benjamin, 2000). Moreover, using dual process models of memory, Jennings & Jacoby (1997) have demonstrated that age differences are much larger for measures of recollection than for familiarity. Because older adults have intact use of familiarity, one possibility is that they rely too heavily on their familiarity of the components when making judgments about associations, causing them to mistakenly recognize novel pairings of familiar items. The purpose of the current study is to explore possible methods that allow older adults to capitalize on their intact familiarity in order to accurately remember pairings of information. Experiments 1 and 2 investigated this by unitizing two components of a pair such that the color information enables certain pairings to appear as one unit. In Experiments 3 and 4, participants were repeatedly presented with pairings prior to a study list so that the pairs were already familiar during the study phase. Remember/know judgments were collected in order to determine if any advantages in associative tests were related to reliance on familiarity or recollection. Evidence shows that both unitization and repetition increase associative memory in both younger and older adults. While recollection seems to mediate this effect in unitization, findings suggest that both familiarity and recollection are involved in enhancing associative memory via repetition.Includes bibliographical reference

Paying attention to binding: is the associative deficit of older adults mediated by reduced attentional resources?

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (July 10, 2006)Includes bibliographical references.Thesis (M.A.) University of Missouri-Columbia 2005.Dissertations, Academic -- University of Missouri--Columbia -- Psychology.One notion put forth to explain age-related, episodic memory problems is the associative-deficit hypothesis, stating that they are due to older adults' decreased binding ability (i.e., their ability to encode separate components into a cohesive unit). The present experiments investigated whether such a binding deficit is mediated by a reduction of attentional resources by using a dual task procedure where participants were asked to study lists of words while completing an auditory reaction time task. Results show that when younger adults' resources were manipulated using divided attention, they did not simulate the deficit of older adults. Furthermore, older adults who underwent the same divided attention procedure did not show a larger associative deficit than that seen under full attention. A follow-up experiment (in which participants separately learned the components or their associations) showed similar results in terms of memory accuracy, replicating the associative deficit seen in older adults. This second experiment also investigated the separate attentional costs for learning the components or their associations. These results reveal that older adults had a larger attentional cost during encoding than younger adults overall; however, the costs to the older adults were not larger for tasks involving the binding of components than for tasks involving the learning of components alone when compared to younger adults. These data do not support the suggestion that the associative deficit is mediated by a reduction of attentional resources

The superior function of the subplate in early neocortical development

During early development the structure and function of the cerebral cortex is critically organized by subplate neurons (SPNs), a mostly transient population of glutamatergic and GABAergic neurons located below the cortical plate. At the molecular and morphological level SPNs represent a rather diverse population of cells expressing a variety of genetic markers and revealing different axonal-dendritic morphologies. Electrophysiologically SPNs are characterized by their rather mature intrinsic membrane properties and firing patterns. They are connected via electrical and chemical synapses to local and remote neurons, e.g., thalamic relay neurons forming the first thalamocortical input to the cerebral cortex. Therefore SPNs are robustly activated at pre- and perinatal stages by the sensory periphery. Although SPNs play pivotal roles in early neocortical activity, development and plasticity, they mostly disappear by programmed cell death during further maturation. On the one hand, SPNs may be selectively vulnerable to hypoxia-ischemia contributing to brain damage, on the other hand there is some evidence that enhanced survival rates or alterations in SPN distribution may contribute to the etiology of neurological or psychiatric disorders. This review aims to give a comprehensive and up-to-date overview on the many functions of SPNs during early physiological and pathophysiological development of the cerebral cortex

Axonal connections between S1 barrel, M1, and S2 cortex in the newborn mouse

The development of functionally interconnected networks between primary (S1), secondary somatosensory (S2), and motor (M1) cortical areas requires coherent neuronal activity via corticocortical projections. However, the anatomical substrate of functional connections between S1 and M1 or S2 during early development remains elusive. In the present study, we used ex vivo carbocyanine dye (DiI) tracing in paraformaldehyde-fixed newborn mouse brain to investigate axonal projections of neurons in different layers of S1 barrel field (S1Bf), M1, and S2 toward the subplate (SP), a hub layer for sensory information transfer in the immature cortex. In addition, we performed extracellular recordings in neocortical slices to unravel the functional connectivity between these areas. Our experiments demonstrate that already at P0 neurons from the cortical plate (CP), layer 5/6 (L5/6), and the SP of both M1 and S2 send projections through the SP of S1Bf. Reciprocally, neurons from CP to SP of S1Bf send projections through the SP of M1 and S2. Electrophysiological recordings with multi-electrode arrays in cortical slices revealed weak, but functional synaptic connections between SP and L5/6 within and between S1 and M1. An even lower functional connectivity was observed between S1 and S2. In summary, our findings demonstrate that functional connections between SP and upper cortical layers are not confined to the same cortical area, but corticocortical connection between adjacent cortical areas exist already at the day of birth. Hereby, SP can integrate early cortical activity of M1, S1, and S2 and shape the development of sensorimotor integration at an early stage

How social media use influences health behaviors – A social-cognitive perspective

Social media represents an important and omnipresent social environment that impacts human health. However, little is known about when and how health-related social media use influences health behaviors. Based on three manuscripts, including a theoretical framework and four empirical studies, this dissertation comprehensively examined how specific types of health-related social media use might influence health behaviors, emphasizing effects on eating behavior. The research conducted in this dissertation is theoretically embedded in the reasoned action approach and self-determination theory. In the first manuscript, I outlined a conceptual framework to better understand mechanisms of action underlying health-related social media effects. According to this framework, social media use can be characterized by four essential factors: (1) communication features used, (2) directionality of interaction, (3) communicated contents, and (4) engagement level. These factors are essential for identifying the active ingredients of health-related social media use and communication that might cause health behavior change (i.e., the behavior change techniques that might be contained or whose enactment might be triggered). Behavior change techniques are, in turn, assumed to cause health behavior change through changes in psychosocial determinants of health behaviors. I also pointed out that social media contributes to increased social influences on health behaviors due to its omnipresence and high accessibility. It might also intensify these influences due to the unique characteristics of the social media environment (e.g., omnipresence, curation algorithms, network homophily). In the second manuscript, I experimentally examined the effects of posting about fruit and vegetable consumption on the intake of senders (posters) and receivers of these postings (Study 1, N = 81) and the senders’ intake in the context of a behavior change goal (Study 2, N = 128). I explored the effects’ underlying mechanisms of action (i.e., active behavior change techniques and their effect on psychosocial determinants of health behaviors) and the temporal dynamics of effects using intensive longitudinal data. Results show that public intake-related social media postings lead to higher fruit and vegetable intake of senders and receivers (Study 1). It further supported eating behavior change goals but not more strongly than private self-monitoring of intake (Study 2), suggesting that self-monitoring might be the most active behavior change technique. The examined psychosocial determinants of eating behavior did not mediate potential effects on eating behavior change. There were positive dose-response relationships within-person on a daily level. On days on which senders used social media more than usual related to their postings, they reported higher fruit and vegetable intake, perceived social support, and goal commitment (but lower self-efficacy). Furthermore, on days on which they posted more intake-related postings than usual, they reported higher fruit and vegetable intake (only in Study 2), intentions, self-efficacy, goal commitment, and more favorable attitudes. The results suggest that eating-related social media effects might be more transient and in timely proximity to actual social media use and need more time to unfold. The effects are complex (especially regarding the effects on psychosocial determinants) and likely dependent on the intensity of social media use and the social responses in reaction to postings. In the third manuscript, I investigated need-support provision in health-related social media communication as potential mechanisms of action for supporting health behavior change. I developed a short educational video about need-supportive communication strategies. The effects of watching the video on the use of these strategies in written responses to fictive social media postings were experimentally tested (Study 1, N = 76). I found that these strategies can be learned and applied in written communication immediately after watching the intervention video and one week later. The effects did not translate to a real- world setting, a forum-based health behavior intervention supported by an online support community (Study 2, N = 537). Participants who watched the intervention video did not show higher use of need-supportive communication strategies compared to participants who watched a control video. Due to this missing effect on strategy use, they did also not report higher perceived need-support, goal attainment (regarding fruit and vegetable intake and physical activity-related behavior change goals), and more favorable values in psychosocial determinants. There were positive effects on participant engagement (i.e., higher number of postings and subjective forum visit frequency in participants who watched the intervention video). Possible reasons for the missing effect on the use of the strategies might be the high goal attainment in both experimental groups, a misfit of the communication strategies and posting content, and low overall participant engagement. The solid theoretical foundation suggests the usefulness of need-supportive communication for supporting health behavior change. Thus, future research should identify populations that might benefit from the video intervention and increasing need-support (e.g., individuals with behavior change barriers) and foster the application of need-supportive communication strategies (e.g., through incentivizing role models or training of content moderators). This dissertation emphasizes the relevance of social media in influencing health behaviors and supporting health behavior change, highlighting the positive role of social media. When and how social media influences health behaviors is dependent on the actual enactment of effective motivation and behavior change strategies. Future research should take the complexity of social media effects into account and examine both, within- and between- person effects, and the interactivity between senders and receivers of social media communication. Therefore, researchers should make greater use of experimental methods with high ecological validity, intensive longitudinal data with longer time periods, big data approaches and combining different data sources, and advanced analysis methods such as social network analysis. Social media environments need to be considered to better understand influence factors for health behaviors and for effective health promotion and prevention

Integration, cooperation or competition. The role of Aid to Youths within a model of allday schooling

Ob und wie Schule und Jugendhilfe zusammenarbeiten sollten, wird schon lange diskutiert. Die aktuellen Debatten über eine Haushaltskonsolidierung, über Ganztagsschulkonzepte und die Qualität der Schule können ein Aufeinanderzugehen der beiden Institutionen anregen. Von den möglichen Formen wird eine partielle Integration von schulischen und Jugendhilfeangeboten favorisiert. (DIPF/Orig.)The discussion about whether and in which form school and youth welfare services should cooperate is not new. At present, however, the two traditionally rather separate institutions seem to approach each other due to a public discourse focusing on three major issues: the question of budgetary consolidation, concepts for the day-long opening of schools and last not least the quality of German schools in the light of the PISA-study. (DIPF/Orig.

Giant depolarizing potentials trigger transient changes in the intracellular Cl(-) concentration in CA3 pyramidal neurons of the immature mouse hippocampus

Giant depolarizing potentials (GDPs) represent a typical spontaneous activity pattern in the immature hippocampus. GDPs are mediated by GABAergic and glutamatergic synaptic inputs and their initiation requires an excitatory GABAergic action, which is typical for immature neurons due to their elevated intracellular Cl(-) concentration ([Cl(-)](i)). Because GABA(A) receptors are ligand gated Cl(-) channels, activation of these receptors can potentially influence [Cl(-)](i). However, whether the GABAergic activity during GDPs influences [Cl(-)](i) is unclear. To address this question we performed whole-cell and gramicidin-perforated patch-clamp recordings from visually identified CA3 pyramidal neurons in immature hippocampal slices of mice at postnatal days 4-7. These experiments revealed that the [Cl(-)](i) of CA3 neurons displays a considerable heterogeneity, ranging from 13 to 70 mM (average 38.1 ± 3.2 mM, n = 36). In accordance with this diverse [Cl(-)] (i), GDPs induced either Cl(-)-effluxes or Cl(-)-influxes. In high [Cl(-)](i) neurons with a negative Cl(-)-driving force (DF(Cl)) the [Cl(-)](i) decreased after a GDP by 12.4 ± 3.4 mM (n = 10), while in low [Cl(-)](i) neurons with a positive DF(Cl) [Cl(-)](i) increased by 4.4 ± 0.9 mM (n = 6). Inhibition of GDP activity by application of the AMPA receptor antagonist CNQX led to a [Cl(-)](i) decrease to 24.7 ± 2.9 mM (n = 8). We conclude from these results, that Cl(-)-fluxes via GABA(A) receptors during GDPs induced substantial [Cl(-)](i) changes and that this activity dependent ionic plasticity in neuronal [Cl(-)](i) contributes to the functional consequences o

The role of the human glycine receptor transmembrane domains for the function, assembly and allosteric modulation by the general anesthetic propofol and closely related derivates

Glycine receptors (GlyRs) are pentameric ligand-gated ion channels (pLGICs) that mediate fast synaptic transmission. A GlyR subunit comprised of a large N-terminal extracellular domain (ECD), four transmembranedomains (TMD1–4), a long intracellular loop (IL) connecting M3 and M4, and a short extracellular C-terminus. At the first glance, one would suppose that the primary task of the TMDs is to anchor the protein in the cell membrane. However, TMDs are more than just anchors: They build in their entirety the central located ion conducting channel and mutations of TMD amino acids can result in massive functional disorders. Moreover, previously published data indicate that structural rearrangements between the TMDs exist, which are key processes for the opening and closing of the channel. Therefore, it is of great interest to increase the knowledge about the TMDs functions because a decreased GlyR activity is evident in chronic inflammatory and neuropathic pain as well as in the hyperekplexia disease. In this study we characterized the role of the GlyR TMDs for the assembly, function and allosteric modulation by the general anesthetic propofol (pro) and derivates. We found that the TMDs are important determinants for the assembly and function of both the α1 Gly- and the 5-HT3A receptor. We also characterized the role of the TMDs for the allosteric modulation of the GlyR function by the general anesthetic propofol (pro) and derivates

Time to Take New Measures: Developing a Cost-Per-Cited-Reference Metric for the Assessment of E-Journal Collections

The current primary quantitative measure of e-journal subscription return-on-investment (ROI) is cost-per-use (CPU). While CPU is widely used, it also widely criticized and should not be relied on to the exclusion of other factors when assessing ROI. Because CPU is an imperfect measure, the authors developed a new, complementary metric for evaluating e-journal subscription ROI: Cost-per-cited reference (CPCR). CPCR assigns a dollar value to each citation of a particular journal by authors affiliated with the subscribing institution during a specified time period. By focusing on the content that researchers cite in their scholarly output, a CPCR metric assists in measuring the value of journal subscriptions to researchers and the institutions that support them. This article gives a very high-level overview of a collaborative project, conducted by librarians in the Triangle Research Libraries Network (TRLN), to develop a local CPCR metric and apply that metric to the evaluation of a consortial Big Deal. The authors explain CPCR, how they calculated and applied it to a particular shared Big Deal, and where they would like to take it in future. A more in-depth description of this project may be found in Serials Review’s final issue for 2016 (Martin, Gray, Kilb, & Minchew, n.d.)

Subplate Cells: Amplifiers of Neuronal Activity in the Developing Cerebral Cortex

Due to their unique structural and functional properties, subplate cells are ideally suited to function as important amplifying units within the developing neocortical circuit. Subplate neurons have extensive dendritic and axonal ramifications and relatively mature functional properties, i.e. their action potential firing can exceed frequencies of 40 Hz. At earliest stages of corticogenesis subplate cells receive functional synaptic inputs from the thalamus and from other cortical and non-cortical sources. Glutamatergic and depolarizing GABAergic inputs arise from cortical neurons and neuromodulatory inputs arise from the basal forebrain and other sources. Activation of postsynaptic metabotropic receptors, i.e. muscarinic receptors, elicits in subplate neurons oscillatory burst discharges which are transmitted via electrical and chemical synapses to neighbouring subplate cells and to immature neurons in the cortical plate. The tonic non-synaptic release of GABA from GABAergic subplate cells facilitates the generation of burst discharges. These cellular bursts are amplified by prominent gap junction coupling in the subplate and cortical plate, thereby eliciting 10–20 Hz oscillations in a local columnar network. Thus, we propose that neuronal networks are organized at earliest stages in a gap junction coupled columnar syncytium. We postulate that the subplate does not only serve as a transient relay station for afferent inputs, but rather as an active element amplifying the afferent and intracortical activity