Intraoperative Guidance for Pediatric Brain Surgery based on Optical Techniques

For most of the patients with brain tumors and/or epilepsy, surgical resection of brain lesions, when applicable, remains one of the optimal treatment options. The success of the surgery hinges on accurate demarcation of neoplastic and epileptogenic brain tissue. The primary goal of this PhD dissertation is to demonstrate the feasibility of using various optical techniques in conjunction with sophisticated signal processing algorithms to differentiate brain tumor and epileptogenic cortex from normal brain tissue intraoperatively. In this dissertation, a new tissue differentiation algorithm was developed to detect brain tumors in vivo using a probe-based diffuse reflectance spectroscopy system. The system as well as the algorithm were validated experimentally on 20 pediatric patients undergoing brain tumor surgery at Nicklaus Children’s Hospital. Based on the three indicative parameters, which reflect hemodynamic and structural characteristics, the new algorithm was able to differentiate brain tumors from the normal brain with a very high accuracy. The main drawbacks of the probe-based system were its high susceptibility to artifacts induced by hand motion and its interference to the surgical procedure. Therefore, a new optical measurement scheme and its companion spectral interpretation algorithm were devised. The new measurement scheme was evaluated both theoretically with Monte Carlo simulation and experimentally using optical phantoms, which confirms the system is capable of consistently acquiring total diffuse reflectance spectra and accurately converting them to the ratio of reduced scattering coefficient to absorption coefficient (µs’(λ)/µa(λ)). The spectral interpretation algorithm for µs’(λ)/µa(λ) was also validated based on Monte Carlo simulation. In addition, it has been demonstrated that the new measurement scheme and the spectral interpretation algorithm together are capable of detecting significant hemodynamic and scattering variations from the Wistar rats’ somatosensory cortex under forepaw stimulation. Finally, the feasibility of using dynamic intrinsic optical imaging to distinguish epileptogenic and normal cortex was validated in an in vivo study involving 11 pediatric patients with intractable epilepsy. Novel data analysis methods were devised and applied to the data from the study; identification of the epileptogenic cortex was achieved with a high accuracy

Dynamics of brain states and cortical excitability in paroxysmal neurological conditions

Epilepsy and migraine are neurological conditions that are characterised by periods of disruption of normal neuronal functioning. Aside from this paroxysmal feature, both conditions share genetic mutations and altered cortical excitability. People with epilepsy appear to be diagnosed with migraine more often than people without epilepsy and, likewise, people with migraine seem to be diagnosed with epilepsy more often than people without migraine. Changes in cortical excitability may help explain the pathophysiological link between both conditions, and could be a biomarker to monitor disease activity. In this thesis, the association between migraine and epilepsy and their relation to cortical excitability is further explored. A meta-analysis of previous population based studies provides epidemiological evidence for the co-occurrence of migraine and epilepsy. The combination of computer modelling with human electroencephalographic recordings offers insight into multi-stability of brain states in epilepsy. Results described in this thesis show that Transcranial Magnetic Stimulation can be used to measure cortical excitability, but that its use as a biomarker of disease activity in epilepsy is limited due to large interindividual variability. By combining Transcranial Magnetic Stimulation with electroencephalography, two novel variables that may contribute to cortical excitability are investigated: phase clustering, which possibly reflecting functional neuronal connectivity, and the non-linear residual of a stimulus-response curve, which may reflect brain state multi-stability. The results presented in this thesis suggest that the higher propensity to global synchronisation is not shared between epilepsy and migraine. These new variables have potential value to differentiate people with epilepsy, but not people with migraine, from normal controls

Aspects of automation in the shoe industry

The shoe manufacturing industry has undergone a revolution during the last 50 years, due to the introduction of task specific machinery. Great technological strides have been made in the areas of shoe manufacture prior to actual component assembly. Computer systems are now becoming the norm for the design of shoes for today's market place. Technological innovations have also started to be applied in the assembly and construction processes of modern shoes. Computer controlled cutting machines calculate the optimum usage of leather from any given hide, new machines allow decorative stitch patterns to be associated with a given shape and size of component and automatically stitched on to the presented workpiece. However the majority of assembly operations have remained predominantly manual with technology playing a secondary role to the human operator due to complexities either in manipulation, control or sensing. In these machines electronic and mechanical innovations have been used to add new features to often simple machines and in some cases to simplify some of the more complex operations, thus increasing productivity but reducing the required dexterity and knowledge of an operator. Modern preferences in industry are to utilise fully automated machines, that are as operator independent as possible, thus improving quality, consistency and production speed whilst at the same time reducing production costs.Due to the nature of the shoe manufacturing industry and the complex operations that have to be performed in order to construct a shoe, machinery manufacturers who have ventured into this field of automation have generally struggled to gain acceptance from the shoe makers as the machinery is generally complex and slow in operation. This together with the fact that a large proportion of the world's main footwear production is centred in the far east, with their correspondingly low labour costs, has held back the automation of the shoe  manufacturing industry.This thesis examines a selection of operations encountered in the construction of a typical shoe. These include operations for processing single flat component parts as well as more complex three-dimensional operations encountered when lasting and soling a shoe. The aim of the research was to develop an understanding of processes encountered in specific areas within the shoe manufacturing industry in order to identify areas where further advances in automation could be achieved. This understanding has been applied to produce proposals and in some cases hardware, to allow for the development of working systems

Women in Science 2016

Women in Science 2016 summarizes research done by Smith College’s Summer Research Fellowship (SURF) Program participants. Ever since its 1967 start, SURF has been a cornerstone of Smith’s science education. In 2016, 150 students participated in SURF (144 hosted on campus and nearby eld sites), supervised by 56 faculty mentor-advisors drawn from the Clark Science Center and connected to its eighteen science, mathematics, and engineering departments and programs and associated centers and units. At summer’s end, SURF participants were asked to summarize their research experiences for this publication.https://scholarworks.smith.edu/clark_womeninscience/1005/thumbnail.jp

The neuroscience of musical creativity using complexity tools

This project is heavily experimental and draws on a wide variety of disciplines from musicology and music psychology to cognitive neuroscience and (neuro)philosophy. The objective is to explore and characterise brain activity during the process of creativity and corroborating this with self-assessments from participants and external assessments from professional “judges”. This three-way experimental design bypasses the semantically difficult task of defining and assessing creativity by asking both participants and judges to rate ‘How creative did you think that was?’. Characterising creativity is pertinent to complexity as it is an opportunity to comprehensively investigate a neural and cognitive system from multiple experimental and analytical facets. This thesis explores the anatomical and functional system underlying the creative cognitive state by analysing the concurrent time series recorded from the brain and furthermore, investigates a model in the stages of creativity using a behavioural experiment, in more detail than hitherto done in this domain. Experimentally, the investigation is done in the domain of music and the time series is the recorded Electroencephalogram (EEG) of a pianist’s whilst performing the two creative musical tasks of ‘Interpretation’ and ‘Improvisation’ manipulations of musical extracts. An initial pilot study consisted of 5 participants being shown 30 musical extracts spanning the Classical soundworld across different rhythms, keys and tonalities. The study was then refined to only 20 extracts and modified to include 10 Jazz extracts and 8 participants from a roughly equal spread of Classical and Jazz backgrounds and gender. 5 external assessors had a roughly even spread of expertise in Jazz and Classical music. Source localisation was performed on the experimental EEG data collected using a software called sLORETA that allows a linear inverse mapping of the electrical activity recorded at the scalp surface onto deeper cortical structures as the source of the recorded activity. Broadman Area (BA) 37 which has previously been linked to semantic processing, was robustly related to participants from a Classical background and BA 7 which has previously been linked to altered states of consciousness such as hypnagogia and sleep, was robustly related to participants from a Jazz background whilst Improvising. Analyses exploring the spread, agreement and biases of ratings across the different judges and self-ratings revealed a judge and participant inter-rater reliability at participant level. There was also an equal agreement between judges when rating the different genres Jazz or Classical, across the different tasks of ‘Improvisation’ and ‘Interpretation’, increasing confidence in inter-genre rating reliability for further analyses on the EEG of the extracts themselves. Furthermore, based on the ratings alone, it was possible to partition participants into either Jazz or Classical, which agreed with phenomenological interview information taken from the participants themselves. With the added conditions of extracts that were deemed creative by objective judge assessment, source localisation analyses pinpointed BA 32 as a robust indicator of Creativity within the participants’ brain. It is an area that is particularly well connected and allows an integration of motoric and emotional communication with a maintenance of executive control. Network analysis was performed using the PLV index (Phase Locking Value) between the 64 electrodes, as the strength of the links in an adjacency matrix of a complex network. This revealed the brain network is significantly more efficient and more strongly synchronised and clustered when participants’ are playing Classical extracts compared to Jazz extracts, in the fronto-central region with a clear right hemispheric lateralization. A behavioural study explored the role of distraction in the ‘Incubation’ period for both interpretation and improvisation using a 2-back number exercise occupying working memory, as the distractor. Analysis shows that a distractor has no significant effect on ‘Improvisation’ but significantly impairs ‘Interpretation’ based on the self-assessments by the participants.Open Acces

A health-oriented emotion-centred origami-based PSS concept. A product-service system concept aimed to help users manage and reduce their stress more tangibly to improve their health and well-being.

Emotions have a fundamental role in the experience, perception, cognition, and development of people (Barrett et al., 2016; Plutchik, 2001). Negative emotions such as stress, if not managed appropriately, may be a risk factor in developing diseases such as dementia, cardiovascular problems, and depression, amongst others (Dum et al., 2016; Sandi et al., 2001). This interdisciplinary research presents OrigamEase, a health-oriented emotion-centred origami-based PSS concept to help adults manage their stress more tangibly, in response to its main research question: How can engineering design research contribute to improving people’s emotional health and wellbeing? OrigamEase was designed throughout this research, and its design and testing served to develop a health & well-being oriented, emotion-centred engineering design methodology (HWOEED). Therefore, the design of this methodology is the result of the structuring and ordering of the developmental process of exploring, conducting and streamlining the research, design and testing of OrigamEase. The design of OrigamEase (both the product and the service part) is based on the cognitive research stream of emotions and stress. Therefore, this research also aims to broaden the knowledge about the implications and management of the emotional experience of stress from an engineering and design point of view, complementing the available solutions for stress management through a structured, measurable, and tangible tool. The HWOEED methodology is influenced by Kansei Engineering and Design Thinking methodologies and integrates various engineering design research methods. However, this methodology proposes a different application of the integration of emotional considerations into engineering design processes., it seeks to improve the emotional experience of users to preserve and promote their health and well-being through specifically designed products, services or PSS. Therefore, these designs become the means and not the end of the engineering design efforts. Also, this methodology can be transferrable to other engineering design solutions. OrigamEase was tested with 114 adults between 18 and 70 years old through three pilot tests (n=43) and six trial tests (n=71) using a concurrent triangulation mixed methods design. Then the results from these tests were contrasted with two control tests (n=22). The results show that using OrigamEase reduced the measured stress levels of participants (self-reported, heart rate and electrodermal activity) significantly, supporting the experiment hypothesis. Stress levels were recorded before and after using OrigamEase; then, a repeated-measures t-test was applied to find if these differences were significant or not. After using OrigamEase, 73.2% of participants reported feeling less stressed (mean reduction=13.94%), 85.5% experienced a reduction in their heart rate (mean reduction=9.8 bpm), and 78.9% had a lower electrodermal activity (mean reduction= 10.8 points). The testing of OrigamEase served as an initial application validation of the HWOEED methodology. This research demonstrates that engineering and design fields not only can but need to contribute to research on emotions through interdisciplinary research. Emotions are a fundamental part of all human experiences, impacting a person’s health and well-being profoundly

Affective Computing

This book provides an overview of state of the art research in Affective Computing. It presents new ideas, original results and practical experiences in this increasingly important research field. The book consists of 23 chapters categorized into four sections. Since one of the most important means of human communication is facial expression, the first section of this book (Chapters 1 to 7) presents a research on synthesis and recognition of facial expressions. Given that we not only use the face but also body movements to express ourselves, in the second section (Chapters 8 to 11) we present a research on perception and generation of emotional expressions by using full-body motions. The third section of the book (Chapters 12 to 16) presents computational models on emotion, as well as findings from neuroscience research. In the last section of the book (Chapters 17 to 22) we present applications related to affective computing

Neural mechanisms of visual awareness and their modulation by social threat

The human brain can extract an enormous wealth of visual information from our surroundings. However, only a fraction of this immense data set ever becomes available to the observer’s awareness. How and why certain information is selected for awareness are questions under active investigation. Following two introductory chapters, this thesis contains six inter-related experimental chapters, through which I will explore two key outstanding questions in this field, using bistable perceptual paradigms to study conscious and non-conscious visual processing in healthy human volunteers. The first major theme focuses on adding new insight into the brain regions and networks that facilitate transfer between non-conscious and conscious modes of visual processing. In Chapters 3 and 4 I will use fMRI, both in task-related and resting-state conditions, to delineate areas, and their interactions (in terms of effective connectivity), which are relevant for transition between different conscious perceptual experiences. In Chapter 5 I will focus on one specific region in the proposed perceptual transition-related network (the frontal eye field) and explore its causal role in access to awareness using repetitive TMS. The second key question explored in this thesis is how social cues in the visual environment influence non-conscious visual processing as well as transition to conscious vision. In Chapter 6 I will study behavioural effects of non-conscious social cues from faces, and the relationship of these effects to focal brain anatomy. Based on finding slower perceptuomotor performance when non-conscious faces contain threatening cues in Chapter 6, I hypothesise that a defensive freezing response is engaged in such situations. The final two experimental chapters will explore the correlates of putative human freezing in the context of non-conscious social threat: using fMRI and psychophysiological measurements to study effects on perceptual transition in Chapter 7, and relating TMS-induced motor-evoked potentials and concurrent psychophysiological measurements to non-conscious perceptuomotor performance in Chapter 8. Taken together, the presented findings shed new light on the network of brain regions involved in transition between non-conscious and conscious modes of visual processing. In addition, they uncover novel mechanisms through which socially relevant visual cues shape our awareness of the visual world, with particular emphasis on the engagement of defensive responses by socially threatening stimuli. The concluding chapter discusses the implications of these findings and explores relevant avenues for future work