Sleep Deprivation by Exposure to Novel Objects Increases Synapse Density and Axon-Spine Interface in the Hippocampal CA1 Region of Adolescent Mice

Sleep has been hypothesized to rebalance overall synaptic strength after ongoing learning during waking leads to net synaptic potentiation. If so, because synaptic strength and size are correlated, synapses on average should be larger after wake and smaller after sleep. This prediction was recently confirmed in mouse cerebral cortex using serial block-face electron microscopy (SBEM). However, whether these findings extend to other brain regions is unknown. Moreover, sleep deprivation by gentle handling was reported to produce hippocampal spine loss, raising the question of whether synapse size and number are differentially affected by sleep and waking. Here we applied SBEM to measure axon-spine interface (ASI), the contact area between pre-synapse and post-synapse, and synapse density in CA1 stratum radiatum. Adolescent YFP-H mice were studied after 6-8 h of sleep (S = 6), spontaneous wake at night (W = 4) or wake enforced during the day by novelty exposure (EW = 4; males/females balanced). In each animal ≥425 ASIs were measured and synaptic vesicles were counted in ~100 synapses/mouse. Reconstructed dendrites included many small, nonperforated synapses and fewer large, perforated synapses. Relative to S, ASI sizes in perforated synapses shifted toward higher values after W and more so after EW. ASI sizes in nonperforated synapses grew after EW relative to S and W, and so did their density. ASI size correlated with presynaptic vesicle number but the proportion of readily available vesicles decreased after EW, suggesting presynaptic fatigue. Thus, CA1 synapses undergo changes consistent with sleep-dependent synaptic renormalization and their number increases after extended wake.SIGNIFICANCE STATEMENT Sleep benefits learning, memory consolidation, and the integration of new with old memories, but the underlying mechanisms remain highly debated. One hypothesis suggests that sleep's cognitive benefits stem from its ability to renormalize total synaptic strength, after ongoing learning during wake leads to net synaptic potentiation. Supporting evidence for this hypothesis mainly comes from the cerebral cortex, including the observation that cortical synapses are larger after wake and smaller after sleep. Using serial electron microscopy, we find here that sleep/wake synaptic changes consistent with sleep-dependent synaptic renormalization also occur in the CA1 region. Thus, the role of sleep in maintaining synaptic homeostasis may extend to the hippocampus, a key area for learning and synaptic plasticity

Psychosocial Factors That Shape Patient and Carer Experiences of Dementia Diagnosis and Treatment : A Systematic Review of Qualitative Studies

Funding: This article presents independent research commissioned by the UK National Institute for Health Research (NIHR) under Research for Patient Benefit (Grant Reference Number PB-PG-0808-16024). The views expressed in this paper are those of the authors and not necessarily those of the NHS, the NIHR, nor the Department of Health. The sponsor of the study had no role in study design, data analysis, data interpretation or writing of the reportEarly diagnosis and intervention for people with dementia is increasingly considered a priority, but practitioners are concerned with the effects of earlier diagnosis and interventions on patients and caregivers. This systematic review evaluates the qualitative evidence about how people accommodate and adapt to the diagnosis of dementia and its immediate consequences, to guide practice. Methods and Findings: We systematically reviewed qualitative studies exploring experiences of community-dwelling individuals with dementia, and their carers, around diagnosis and the transition to becoming a person with dementia. We searched PubMed, PsychINFO, Embase, CINAHL, and the British Nursing Index (all searched in May 2010 with no date restrictions; PubMed search updated in February 2012), checked reference lists, and undertook citation searches in PubMed and Google Scholar (ongoing to September 2011). We used thematic synthesis to identify key themes, commonalities, barriers to earlier diagnosis, and support identified as helpful. We identified 126 papers reporting 102 studies including a total of 3,095 participants. Three overarching themes emerged from our analysis: (1) pathways through diagnosis, including its impact on identity, roles, and relationships; (2) resolving conflicts to accommodate a diagnosis, including the acceptability of support, focusing on the present or the future, and the use or avoidance of knowledge; and (3) strategies and support to minimise the impact of dementia. Consistent barriers to diagnosis include stigma, normalisation of symptoms, and lack of knowledge. Studies report a lack of specialist support particularly post-diagnosis. Conclusions: There is an extensive body of qualitative literature on the experiences of community-dwelling individuals with dementia on receiving and adapting to a diagnosis of dementia. We present a thematic analysis that could be useful to professionals working with people with dementia. We suggest that research emphasis should shift towards the development and evaluation of interventions, particularly those providing support after diagnosis.Peer reviewedFinal Published versio

Conceptualisation of self-management intervention for people with early stage dementia

Dementia is a major challenge for health and social care services. People living with dementia in the earlier stages experience a "care-gap". Although they may address this gap in care, self-management interventions have not been provided to people with dementia. It is unclear how to conceptualise self-management for this group and few published papers address intervention design. Initial focusing work used a logic mapping approach, interviews with key stakeholders, including people with dementia and their family members. An initial set of self-management targets were identified for potential intervention. Self-management for people living with dementia was conceptualised as covering five targets: (1) relationship with family, (2) maintaining an active lifestyle, (3) psychological wellbeing, (4) techniques to cope with memory changes, and (5) information about dementia. These targets were used to focus literature reviewing to explore an evidence base for the conceptualisation. We discuss the utility of the Corbin and Strauss (Unending work and care: managing chronic illness at home. Jossey-Bass, Oxford, 1988) model of self-management, specifically that self-management for people living with dementia should be conceptualised as emphasising the importance of "everyday life work" (targets 1 and 2) and "biographical work" (target 3), with inclusion of but less emphasis on specific "illness work" (targets 4, 5). We argue that self-management is possible for people with dementia, with a strengths focus and emphasis on quality of life, which can be achieved despite cognitive impairments. Further development and testing of such interventions is required to provide much needed support for people in early stages of dementia

Mild Cognitive Impairment

Mild cognitive impairment (MCI), a heterogeneous disorder, is frequently diagnosed by geriatricians and neurologists and is a hot topic in research. MCI refers to cognitive impairment that is worse than would be expected on the basis of age but which does not meet the criteria for dementia. The diagnosis is based on the patient history and an interview with an informant, preferably supplemented with objective tests to establish the cognitive status of the patient. MCI is an important risk factor for the development of dementia: annually 5-15% of patients with MCI develop dementia. There is currently no treatment for MCI, but it is important to treat possible organic factors. For now, it is important for the general practitioner to know the background of diagnosed MCI or reported mild cognitive problems, and to support and guide patients and their relatives. There is no added benefit to the general practitioner making the diagnosis.</p