Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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The Development of Spatial Orientation in Children After Perinatal Stroke

To enable investigation of spatial orientation abilities across a range of ages and developmental abilities, we developed a navigation task comprised of a video game in a virtual museum in which subjects were required to find different rooms with distinct themes. We then validated the task by studying a large number of healthy young adults and confirming a strong correlation with self-reported orientation abilities in everyday life (Chapter 2). We also analysed performance on the navigation task as it related to demographics and video game use, verifying previously observed gender differences and demonstrating that individuals with a longer history of video game play, as well as participants who played video games that required navigation, performed better than individuals without experience navigating in video games. Our evidence, therefore, supports the hypothesis that better navigation and orientation skills in individuals playing video games are likely due to the consistent practice of those skills while playing for entertainment (Chapter 2). Children who have experienced a stroke around the time of birth have been shown to have IQ in the normal or near normal range as a group; however a portion of children has consistently demonstrated cognitive delays. Utilizing both concurrent neuropsychological testing and pre-existing clinical data, we found that the factors that were predictive of initial performance on the spatial orientation task were age, gender, motor dexterity, the presence of Arterial Ischemic Stroke (AIS), and loss of grey matter volume (Chapter 3). Furthermore, the modest deficits in topographical orientation, seen in AIS patients, were ameliorated by further practice and were no longer seen after the second time playing the video game. In contrast, AIS, parental education and involvement of the dorsolateral prefrontal (DLPF) cortex were predictive factors for full-scale intelligence quotient (FSIQ). Loss of tissue volume predicted reduced verbal comprehension index (VCI) scores (Chapter 3). The relative preservation of spatial orientation, a multifaceted behaviour with a prolonged developmental course, would lend support to the hypothesis that injury within a network allows for better resiliency of that skill and may be an illustration that there is better recovery of an ability if injury occurs before that proficiency has fully matured

The effect of induced stress on long-term memory in lymnaea stagnalis

Bibliography: p. 139-157Some pages are in colour.Lymnaea stagnalis is a pond snail that has proven useful for studies of learning and memory of aerial respiration. Aerial respiration is an easily quantified behaviour that is controlled by a central pattern generator whose necessity and sufficiency has been directly demonstrated. If snails are exposed to an aversive chemical stimulus ( causes a defensive behaviour without causing permanent harm) before or after conditioning, a training schedule that normally only results in intermediate-term memory, causes long­term memory persisting at least 24 hours. A single application of an aversive chemical stressor is also capable of forming long-term memory if the application is contingent with pneumostome opening. Therefore training related to stress or a particularly aversive stimulus is enhanced and, therefore, results in long-term memory. This memory has many of the same characteristics as memory from more extensive training but is, in general, more resistant to manipulation after consolidation

Memory from one-trial training is resistant to extinction in Lymnaea Stagnaliss

Background: Memories that follow a traumatic event or extreme stress have been shown in some cases, to be particularly resistant to therapies meant to reduce their impact on patients. Two methods shown to decrease memories in laboratory tests are disruption after reactivation and extinction training. Newly formed memories undergo a period of stabilization, during which they are susceptible to amnesia treatments. Over a period of time memories become stabilized and can no longer be disrupted. However memories that are retrieved are returned to a labile state that must undergo a process of ‘reconsolidation’. Also, many memories can be occluded by ‘extinction training’, which consists of withholding the training stimulus in the training environment resulting in a new memory that overshadows the original training. Methods and Results: Using the Lymnaea stagnalis model system we show that memories following an extreme aversive stimulus demonstrate resistance to manipulation by these methods. Lymnaea stagnalis are fresh-water pond snails that can breathe either cutaneously or aerially through an orifice (pneumostome). Snails can form a long-term memory (LTM) to suppress pneumostome opening after operant conditioning consisting of either multiple sessions of repeated tactile stimulation to the orifice area each time the snail attempts to open its pneumostome or a single applications of 25mM KCl stimulus contingent with pneumostome opening (one-trial training; 1TT). The LTM formed following one-trial training has many of the same characteristics as memory formed following repetitive tactile training. Specifically, both are dependent on new mRNA synthesis in the circuit that controls aerial respiration and both can be blocked by cooling immediately after training. However, we show that memories in Lymnaea that form after a single, highly aversive stimulus, unlike LTM after repetitive training, aren’t disrupted after reactivation. We also attempted to extinguish the 1TT memory by placing the snails in the training beaker and not applying the KCl stimulus when they opened their pneumostome. When repetitive training was employed, extinction sessions such as these resulted in naïve levels of aerial respiration i.e. occlusion of the operantly trained memory. Conclusions: Therefore, memory after 1TT is more resistant to suppression by extinction training than memories formed after less aversive stimuli. Further research will attempt to determine the cellular mechanism that causes the memory to be particularly resilient

The Emergence of Cognitive Maps for Spatial Navigation in 7- to 10-Year-Old Children

Although much is known about adults' ability to orient by means of cognitive maps (mental representations of the environment), it is less clear when this important ability emerges in development. In the present study, 97 seven- to 10-year-olds and 26 adults played a video game designed to investigate the ability to orient using cognitive maps. The game required participants to reach target locations as quickly as possible, necessitating the identification and use of novel shortcuts. Seven- and 8-year-olds were less effective than older children and adults in using shortcuts. These findings provide clear evidence of a distinct developmental change around 9 years of age when children begin to proficiently orient and navigate using cognitive maps

Tactile cortical responses and association with tactile reactivity in young children on the autism spectrum

Abstract Background Unusual behavioral reactions to sensory stimuli are frequently reported in individuals on the autism spectrum (AS). Despite the early emergence of sensory features (< age 3) and their potential impact on development and quality of life, little is known about the neural mechanisms underlying sensory reactivity in early childhood autism. Methods Here, we used electroencephalography (EEG) to investigate tactile cortical processing in young children aged 3–6 years with autism and in neurotypical (NT) children. Scalp EEG was recorded from 33 children with autism, including those with low cognitive and/or verbal abilities, and 45 age- and sex-matched NT children during passive tactile fingertip stimulation. We compared properties of early and later somatosensory-evoked potentials (SEPs) and their adaptation with repetitive stimulation between autistic and NT children and assessed whether these neural measures are linked to “real-world” parent-reported tactile reactivity. Results As expected, we found elevated tactile reactivity in children on the autism spectrum. Our findings indicated no differences in amplitude or latency of early and mid-latency somatosensory-evoked potentials (P50, N80, P100), nor adaptation between autistic and NT children. However, latency of later processing of tactile information (N140) was shorter in young children with autism compared to NT children, suggesting faster processing speed in young autistic children. Further, correlational analyses and exploratory analyses using tactile reactivity as a grouping variable found that enhanced early neural responses were associated with greater tactile reactivity in autism. Limitations The relatively small sample size and the inclusion of a broad range of autistic children (e.g., with low cognitive and/or verbal abilities) may have limited our power to detect subtle group differences and associations. Hence, replications are needed to verify these results. Conclusions Our findings suggest that electrophysiological somatosensory cortex processing measures may be indices of “real-world” tactile reactivity in early childhood autism. Together, these findings advance our understanding of the neurophysiological mechanisms underlying tactile reactivity in early childhood autism and, in the clinical context, may have therapeutic implications