Neuro-electronic technology in medicine and beyond

This dissertation looks at the technology and social issues involved with interfacing electronics directly to the human nervous system, in particular the methods for both reading and stimulating nerves. The development and use of cochlea implants is discussed, and is compared with recent developments in artificial vision. The final sections consider a future for non-medicinal applications of neuro-electronic technology. Social attitudes towards use for both medicinal and non-medicinal purposes are discussed, and the viability of use in the latter case assessed

The evolution of a visual-to-auditory sensory substitution device using interactive genetic algorithms

Sensory Substitution is a promising technique for mitigating the loss of a sensory modality. Sensory Substitution Devices (SSDs) work by converting information from the impaired sense (e.g. vision) into another, intact sense (e.g. audition). However, there are a potentially infinite number of ways of converting images into sounds and it is important that the conversion takes into account the limits of human perception and other user-related factors (e.g. whether the sounds are pleasant to listen to). The device explored here is termed “polyglot” because it generates a very large set of solutions. Specifically, we adapt a procedure that has been in widespread use in the design of technology but has rarely been used as a tool to explore perception – namely Interactive Genetic Algorithms. In this procedure, a very large range of potential sensory substitution devices can be explored by creating a set of ‘genes’ with different allelic variants (e.g. different ways of translating luminance into loudness). The most successful devices are then ‘bred’ together and we statistically explore the characteristics of the selected-for traits after multiple generations. The aim of the present study is to produce design guidelines for a better SSD. In three experiments we vary the way that the fitness of the device is computed: by asking the user to rate the auditory aesthetics of different devices (Experiment 1), by measuring the ability of participants to match sounds to images (Experiment 2) and the ability to perceptually discriminate between two sounds derived from similar images (Experiment 3). In each case the traits selected for by the genetic algorithm represent the ideal SSD for that task. Taken together, these traits can guide the design of a better SSD

A Preliminary Assessment of Tidal Flooding along the New Hampshire Coast: Past, Present and Future

This report presents the results of a preliminary study that examines several critical coastal issues for New Hampshire including sea level fluctuations (past, present and future), shoreline migrations, and tidal flooding. Included are: 1) an analysis of sea level changes over the Holocene and resulting shoreline migrations, 2) an assessment of low-lying areas with elevations below selected tidal flooding datums in coastal areas, and 3) an assessment of increases in low-lying areas that are potentially at risk to tidal flooding over the next century due to sea level rise

The co-occurrence of mirror-touch with other types of synaesthesia

People with mirror-touch synaesthesia report tactile experiences on their body when seeing other people touched. Although this has been referred to as a type of synaesthesia, it is unknown whether it co-occurs with more commonly accepted variants of synaesthesia (e.g. grapheme-colour). If it did, then this would imply a common or partly shared causal mechanism. To this end, a sample of verified grapheme-colour synaesthetes (N=80) were given a recently developed online diagnostic measure of mirror-touch. The prevalence in this group (~20%) was around 10 times higher than the general population. Moreover, performance on this measure was significantly related to the self-report of mirror-touch given, on average, three years earlier

Functional and structural brain differences associated with mirror-touch synaesthesia

Observing touch is known to activate regions of the somatosensory cortex but the interpretation of this finding is controversial (e.g. does it reflect the simulated action of touching or the simulated reception of touch?). For most people, observing touch is not linked to reported experiences of feeling touch but in some people it is (mirror-touch synaesthetes). We conducted an fMRI study in which participants (mirror-touch synaesthetes, controls) watched movies of stimuli (face, dummy, object) being touched or approached. In addition we examined whether mirror touch synaesthesia is associated with local changes of grey and white matter volume in the brain using VBM (voxel-based morphometry). Both synaesthetes and controls activated the somatosensory system (primary and secondary somatosensory cortices, SI and SII) when viewing touch, and the same regions were activated (by a separate localiser) when feeling touch — i.e. there is a mirror system for touch. However, when comparing the two groups, we found evidence that SII seems to play a particular important role in mirror-touch synaesthesia: in synaesthetes, but not in controls, posterior SII was active for watching touch to a face (in addition to SI and posterior temporal lobe); activity in SII correlated with subjective intensity measures of mirror-touch synaesthesia (taken outside the scanner), and we observed an increase in grey matter volume within the SII of the synaesthetes' brains. In addition, the synaesthetes showed hypo-activity when watching touch to a dummy in posterior SII. We conclude that the secondary somatosensory cortex has a key role in this form of synaesthesia

Individual differences in sensory sensitivity: a synthesising framework and evidence from normal variation and developmental conditions

For some people, simple sensory stimuli (e.g., noises, patterns) may reliably evoke intense and aversive reactions. This is common in certain clinical groups (e.g., autism) and varies greatly in the neurotypical population. This paper critically evaluates the concept of individual differences in sensory sensitivity, explores its possible underlying neurobiological basis, and presents a roadmap for future research in this area. A distinction is made between subjective sensory sensitivity (self-reported symptoms); neural sensory sensitivity (the degree of neural activity induced by sensory stimuli); and behavioral sensory sensitivity (detection and discrimination of sensory stimuli). Whereas increased subjective and neural sensory sensitivity are assumed to increase together, the status of behavioral sensory sensitivity depends on the extent to which the increased neural activity is linked to signal or noise. A signal detection framework is presented that offers a unifying framework for exploring sensory sensitivity across different conditions. The framework is discussed, in more concrete terms, by linking it to four existing theoretical accounts of atypical sensory sensitivity (not necessarily mutually exclusive): increased excitation-to-inhibition ratio; predictive coding; increased neural noise; and atypical brain connectivity

The Effects of Light-Absorbing Aerosols, Blocking, and Clouds on Greenland's Surface

The Greenland Ice Sheet covers over 80% of Greenland’s land area and is the largest reservoir of frozen water in the Northern Hemisphere. Over the past few decades, the Greenland Ice Sheet has experienced significant summertime ice and surface snow loss. Much of this mass loss can be attributed to short-term processes that initiate surface energy changes. In this dissertation, we examine the effects of 1) light-absorbing aerosols on the Greenland Ice Sheet and in the overlying atmosphere, 2) the impacts of atmospheric block location over the Greenland Ice Sheet on cloud formation and atmosphere-surface energy exchanges, and 3) how these block-induced surface energy responses will change in the future. Aerosols are microscopic solid or liquid particles that can be transported long distances through the atmosphere. Light-absorbing aerosols like black carbon and certain types of dust are unique in that they absorb sunlight and warm the local environment. In the Arctic, black carbon reduces surface reflectivity and increases surface energy to induce or enhance melt. Light- absorbing aerosols suspended in the atmosphere warm the local air and change vertical circulation patterns. We use an idealized version of the Community Earth System Model (CESM) to understand how Greenland-specific local atmospheric and in-snow light-absorbing aerosols can affect Greenland Ice Sheet surface energy input and snowmelt processes. Overall, we find that the largest snowmelt and net surface energy responses occur in simulations containing only in-snow light-absorbing aerosols while atmospheric absorbing aerosols decrease incident sunlight on the surface and produce insignificant melt and energy changes. Atmospheric and in-snow aerosols have offsetting effects on the surface energy budget. Atmospheric blocks are mostly stationary high pressure systems that last for days to weeks at a time. Blocking over Greenland has been shown to enhance net surface energy by reducing cloud cover and transporting warm, moist air over the surface. The variability of the Greenland Ice Sheet topography impacts regional block-induced surface changes based on block location. We use a variety of observational datasets to understand the impacts of block location on cloud formation and surface energy fluxes over the Greenland Ice Sheet. Blocking over northern Greenland produces larger cloud reductions that enhance sunlight and decrease net longwave energy at the surface than southern Greenland blocking activity. Net surface energy increases for all block locations, but more so for blocks over eastern Greenland because of greater warm air transport in combination with enhanced sunlight absorption by the Greenland Ice Sheet. Five different global climate simulations from the Coupled Model Intercomparison Project, phase 6 (CMIP6) are examined to understand how summer Greenland blocking activity will affect net surface energy fluxes in the middle (2040-2059) and at the end (2080-2099) of the 21st century for the largest warming scenario. Net surface energy input increases with blocking over all simulations. However, atmospheric warming over the Greenland Ice Sheet produced by block circulation plays a larger role in total energy enhancement than solar energy input changes. Future net surface energy fluxes may be larger because historical (1986-2005) CMIP6 simulations underestimate component and total energy fluxes found in Modern Era Retrospective Analysis, version 2 (MERRA-2) observational data. These results indicate that Greenland blocking will continue to contribute to increased total surface energy in the future.PHDAtmospheric, Oceanic & Space ScienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163203/1/jamiewa_1.pd

Synaesthesia is linked to more vivid and detailed content of autobiographical memories and less fading of childhood memories

People with synaesthesia have enhanced memory on a wide range of laboratory tests of episodic memory, but very little is known about their real-world memory. This study used a standard measure of autobiographical remembering (the Autobiographical Memory Questionnaire, AMQ) considering four constructs (Recollection, Belief, Impact and Rehearsal) and two time periods (recent memories from adulthood, remote memories from childhood). Synaesthetes reported more Recollection (e.g. sensory detail) and Belief (e.g. confidence) which interacted with time, such that remote memories are reported to be comparatively better preserved in synaesthetes. This cannot be explained by synaesthetes recalling more salient episodes (the groups did not differ in Impact). It suggests instead that childhood memories have a special status in synaesthesia that reflects the different neurodevelopmental trajectory of this group. With regards to Rehearsal, controls tended to report that more recent memories tend to resurface (i.e. adulthood > childhood), but the synaesthetes showed the opposite dissociation (i.e. childhood > adulthood)

Is synaesthesia an X-linked trait with lethality in males?

In previous research the inheritance patterns of synaesthesia (eg experiencing colours from graphemes) has been studied and it was concluded that synaesthesia is most likely to be the outcome of a single gene passed on the X chromosome in a dominant fashion. In addition, it has been reported that the female-male ratio of synaesthetes is as high as 6 : 1 and the families of synaesthetes contain more female than male members. This raises the possibility that the gene may be associated with lethality in males. In this study we replicate and extend previous research by investigating the female-male ratio and inheritance patterns in a large sample of synaesthetic families (N = 85). We were able to verify the authenticity of grapheme-colour associates in at least one proband from each family using internal consistency. As before, our results show a female-male bias and are broadly consistent with an X-linked dominant mode of inheritance. However, there was no evidence of male lethality (eg synaesthetes are just as likely to give birth to sons as to daughters). Moreover, our female-male ratio of synaesthetes within families was 2 : 1-considerably lower than previous estimates. We speculate that men may be more reluctant to disclose synaesthesia than women (indeed, our female -male ratio based on self-referral was 3.7 : 1). Finally, we discuss how the genotype may give rise to the phenotype in terms of changes in synaptogenesis or plasticity extending into childhood, to be subsequently shaped by the environment

Regional Population Projections for Labrador and the Northern Peninsula 2016-2036

In 2015, Newfoundland and Labrador had the most rapidly aging population in the country – which when combined with high rates of youth out-migration, declining birth rates, and an increasing number of people moving from rural parts of the province to more urban centres, means that the province is facing an unprecedented population challenge. Without intervention, this trend will have a drastic impact on the economy, governance, and the overall quality of life for the people of the province. Planning for this change and developing strategies to adjust and adapt to it is paramount