Neurosteroids in the Hippocampus: Neuronal Plasticity and Memory

The hippocampus, which is critically involved in learning and memory processes, is known to be a target for the neuromodulatory actions of steroid hormones produced by the adrenal glands and gonads. Much of the work of B.S. McEwen and collaborators has focused on the role of glucocorticosteroids and estrogen in modulating hippocampal plasticity and functions. In addition to hormones derived from the endocrine glands, cells in the hippocampus may be exposed to locally synthesized neurosteroids, including pregnenolone, dehydroepiandrosterone and their sulfated esters as well as progesterone and its reduced metabolites. In contrast to hormones derived from the circulation, neurosteroids have paracrine and/or autocrine activities. In the hippocampus, they have been shown to have trophic effects on neurons and glial cells and to modulate the activity of a variety of neurotransmitter receptors and ion channels, including type A gamma-aminobutyric acid, N-methyl-D-aspartate and sigma receptors and N- and L-type Ca2+ channels. There is accumulating evidence that some neurosteroids, in particular pregnenolone sulfate, have strong influences on learning and memory processes, most likely by regulating neurotransmission in the hippocampus. However, the hippocampus is not the only target for the mnesic effects of neurosteroids. Associated brain regions, the basal nuclei of the forebrain and the amygdaloid complex, are also involved. Some neurosteroids may thus be beneficial for treating age- or disease-related cognitive impairments.     

Out of the depths

A fundamental approach of theology as practiced within the palliative setting is care for the whole human being, with particular focus on spirituality and the spiritual dimension. Theology and medicine come together in palliative care in which the spiritual aspect is an important component together with the physical, psychological, and social. This article is based on a mixed methods study of spirituality among persons receiving palliative care. Findings revealed the importance of spirituality and its multidimensional elements by which spirituality was perceived as a complex phenomenon relating to religious and non-religious aspects of human life. Theological reflection based on the present findings indicates that a sharp distinction between the concepts of religion and spirituality is not beneficial. It also reveals the significance of the spiritual dimension and that theology has an important role in creating a deeper understanding of this complex part of human existence. Spiritual needs, expressed in various ways, were evident among the participants receiving palliative care. The findings confirm that the theological approach in palliative care, with its focus on the whole human being and emphasis on spirituality and the spiritual dimension, continues to be the hallmark of practicing theology within palliative care.     

Can men talk about problems with weight? The therapeutic implications of a discourse analytic study

This paper discusses the implications for counsellors of a discourse analytic study examining men's talk about body weight. It is argued that research in the area of problems with body has neglected the growing pressures on men to manage body as a feature of self. This research perpetuates the dominant discursive construction of men's relationship to body as unproblematic — a construction that may present many barriers to men in seeking help for any distress encountered. An analysis of men's talk is discussed in terms of the expectation that body is not problematic and the observable downplaying of any concerns acknowledged. The accountability of body as a site of regulation also emerges within the extracts presented. It is argued that this property within the accounts resonates with work highlighting the growing pressures on men to exercise control over body. The contradictions between the two discourses identified are discussed in terms of their therapeutic implications. It is postulated that male distress emerging from the growing pressures to maintain body weight may be neglected within primary care and therapeutic domains if discourses formulating such difficulties as not relevant to men remain dominant.     

Hippocampal memory processes are modulated by insulin and high-fat-induced insulin resistance

Insulin regulates glucose uptake and storage in peripheral tissues, and has been shown to act within the hypothalamus to acutely regulate food intake and metabolism. The machinery for transduction of insulin signaling is also present in other brain areas, particularly in the hippocampus, but a physiological role for brain insulin outside the hypothalamus has not been established. Recent studies suggest that insulin may be able to modulate cognitive functions including memory. Here we report that local delivery of insulin to the rat hippocampus enhances spatial memory, in a PI-3-kinase dependent manner, and that intrahippocampal insulin also increases local glycolytic metabolism. Selective blockade of endogenous intrahippocampal insulin signaling impairs memory performance. Further, a rodent model of type 2 diabetes mellitus produced by a high-fat diet impairs basal cognitive function and attenuates both cognitive and metabolic responses to hippocampal insulin administration. Our data demonstrate that insulin is required for optimal hippocampal memory processing. Insulin resistance within the telencephalon may underlie the cognitive deficits commonly reported to accompany type 2 diabetes.     

Coherency in children's discourse

We provide evidence that the capacity of young children to engage in social interaction exceeds that suggested by Piaget (1926). Rather than being collective monologues, the conversations between the subjects of this study (twin boys) were dialogues: the children attended to one another's utterances and provided relevant responses. This was observed for conversations which were referentially based as well as for sound play exchanges. This is not to say that the children experienced no difficulty in sustaining cooperative discourse. It could take a speaker several turns to secure the attention of the coconversationalist and establish a discourse topic.     

What’s Wrong with Joyguzzling?

Our thesis is that there is no moral requirement to refrain from emitting reasonable amounts of greenhouse gases (GHGs) solely in order to enjoy oneself. Joyriding in a gas guzzler (joyguzzling) provides our paradigm example. We first distinguish this claim that there is no moral requirement to refrain from joyguzzling from other more radical claims. We then review several different proposed objections to our view. These include: the claim that joyguzzling exemplifies a vice, causes or contributes to harm, has negative expected value, exceeds our fair share of global emissions, and undermines political duties. We show why none of these objections succeeds and conclude that no good reason has yet been proposed that shows why joyguzzling violates a moral requirement.     

I Could Never Quite Get It Together: Lessons for End-of –Life Care in Harold Pinter’s The Caretaker

Pinter's play The Caretaker explores interpersonal tensions relating to terminal illness. This paper interrogates notions of care, suffering, ownership, dignity and the consequences of active intervention and inaction in two key sections of the play: Aston's monologue concerning his own brutal treatment (active intervention) and Davies's final rejection by the brothers who fail to provide accommodation and care (inaction). This interprofessional analysis combines theatrical and clinical perspectives to create insights which can enhance empathy improve decision-making in end of life care and can inform the education of healthcare professionals.     

A Single‐Stage Approach to Learning Phonological Categories: Insights From Inuktitut

To acquire one’s native phonological system, language‐specific phonological categories and relationships must be extracted from the input. The acquisition of the categories and relationships has each in its own right been the focus of intense research. However, it is remarkable that research on the acquisition of categories and the relations between them has proceeded, for the most part, independently of one another. We argue that this has led to the implicit view that phonological acquisition is a “two‐stage” process: Phonetic categories are first acquired and then subsequently mapped onto abstract phoneme categories. We present simulations that suggest two problems with this view: First, the learner might mistake the phoneme‐level categories for phonetic‐level categories and thus be unable to learn the relationships between phonetic‐level categories; on the other hand, the learner might construct inaccurate phonetic‐level representations that prevent it from finding regular relations among them. We suggest an alternative conception of the phonological acquisition problem that sidesteps this apparent inevitability and acquires phonemic categories in a single stage. Using acoustic data from Inuktitut, we show that this model reliably converges on a set of phoneme‐level categories and phonetic‐level relations among subcategories, without making use of a lexicon.     

Reprint of: 'Brain insulin signaling: A key component of cognitive processes and a potential basis for cognitive impairment in type 2 diabetes'

Understanding of the role of insulin in the brain has gradually expanded, from initial conceptions of the brain as insulin-insensitive through identification of a role in regulation of feeding, to recent demonstration of insulin as a key component of hippocampal memory processes. Conversely, systemic insulin resistance such as that seen in type 2 diabetes is associated with a range of cognitive and neural deficits. Here we review the evidence for insulin as a cognitive and neural modulator, including potential effector mechanisms, and examine the impact that type 2 diabetes has on these mechanisms in order to identify likely bases for the cognitive impairments seen in type 2 diabetic patients.     

Positive mood and executive function: evidence from stroop and fluency tasks

Contrasting predictions have been made about the effects of positive mood states on the performance of frontal lobe tests that tap executive functions such as inhibition, switching, and strategy use. It has been argued that positive mood is likely to improve some cognitive processes, particularly those dependent on the frontal cortex and anterior cingulate of the brain. However, there is some evidence that happy mood may impair executive functioning. The current experiments investigated the effects of positive mood on Stoop and fluency tests, which are frequently used to assess executive function. Positive mood impaired performance on a switching condition of the Stroop test, but improved performance on a creative uses test of fluency. The effect of positive mood on an executive task may therefore depend on whether a task is inherently motivating or is impaired by diffuse semantic activation.