This thesis examines how individual differences in social traits relate to behavioural and physiological responses to affective touch. Over the last few decades the functionality of C-Tactile afferents (CTs) have been investigated, with researchers positing that CTs function to signal the rewarding value of social tactile interactions. Here, by exploring the relationship between trait sociability and affective touch perception this social touch hypothesis is explored. In the first three studies, the role of sociability on the vicarious experience of affective touch was investigated. In study one; the aim was to determine how trait sociability affected an individual's vicarious experience of affective and discriminative touch. Here, individuals with the lowest number of autistic traits and theoretically the highest sociability were found to show the greatest sensitivity in their affective ratings of different velocities of touch, resulting in a significant quadratic relationship between non-CT-optimal and CT- optimal stimuli at CT-innervated locations. In study two the aim was investigate the vicarious experience of touch in young children. Children both with a diagnosis of ASD (here theorised to be one extremity of trait sociability) and without ASD observed the same videos depicting social touch. It was found that young children (aged 7-12) did not show the typically observed vicarious preference for CT-optimal velocity touch. Furthermore, there was no difference between children with an autism spectrum disorder (ASD) and typically developing children in their affective ratings of the observed touch. Study three again took the same sample of videos and used facial EMG to see whether the explicitly rated vicarious preference for CT-optimal over non-CT-optimal touch could be detected implicitly. It was found that observation of CT-optimal social tactile interactions did not elicit the same affective responses that have previously been reported in response to directly felt touch. This finding is perhaps consistent with the rather weak affective response elicited by touch in comparison to pain, for example. The fact that self-reported levels of empathetic concern correlated negatively with corrugator muscle activity, indicative of negative affect, in response to touch on CT innervated sites suggests individual differences in implicit affective response to touch are present. In study four, the aim was to determine whether individual differences in trait sociability affected implicit affective responses to first-hand experience of touch. Consistently, participants will low levels of autistic traits (high trait sociability) showed greater zygomaticus activity, indicative of positive affect, during evaluation of the touch they received than those with high levels of autistic traits. Stroking touch elicited little activity in the Corrugator, indicative of negative affect, in either group. Finally, study 5 used EEG to determine how the cortical activity related to fast conducting A-beta stimulation compared to later activity in response to slow conducting CTs. Specifically an ultra-late potential (ULP) was measured for CT-optimal stimuli. Furthermore, 30cm/s, which generates greater A-beta stimulation than 3cm /s, elicited a significantly greater p300 orienting response. Furthermore, there was a significant difference in the ULP peak amplitude between individuals with high and low levels of autistic traits suggesting differential patterns of activity. Taken together, these studies suggest that touch, including touch targeted to optimally activate CTs is indeed processed differently, both physiologically and behaviourally, by individuals with different levels of autistic traits, whether directly felt or vicariously experienced. It is hypothesised that these differences s reflect variation in sensitivity to the rewarding value of social stimuli. These studies provide some of the first evidence that individual differences in stable personality traits are associated with differential responses to social / affective touch.

This thesis set out to explore oral sensory processing. Oral sensory processing extends beyond taste perception, the nerves that innervate the mouth and carry taste information to the brain also carry chemosensations, thermal sensations and somatosensations. While a great deal is understood about oral chemo and thermal perception, this thesis focuses on the not fully recognised oral somatosensory processes. A substantial amount of movement occurs within the mouth, from movement while speaking to chewing food. As food moves around the mouth, different oral receptors are activated and the consumption experience changes. Taste perception varies between individuals in a way that has led to the identification of the taster status genetic polymorphism of taster status where three taster groups (hyper-taster, taster, tolerant taster) with differing sensitivity to bitter tastes were identified. This sensitivity is further represented in anatomical differences with differing densities of fungiform papillae on the tongue. Using psychophysical methods and the taster status phenotype, this thesis examined if different regions of the tongue and mouth experienced different chemostimulant intensity and if dynamic touch changed the intensity perception of chemostimulants in chapter 4. This identified that different regions of the oral cavity experience chemostimulant intensity differently with the tip of the tongue being the most sensitive and the vermillion of the lower lip the least sensitive to sensation. Furthermore, whilst there was no main effect of touch on sensation intensity an interaction between touch type, taster status and oral locations was found when using 10-ppm capsaicin and Sichuan pepper. A dynamic touch on the lip with mint oil was also considered more intense than a static touch. Chapter 5 investigated the possibility that C tactile (CT) afferents were present in the lower lip, the structure of the lip skin widely suggests that CTs are not present but their regular use in the affective behaviour of lip-to-lip contact between individuals suggests otherwise. By applying the standardised psychophysical stroking approach to the lip, cheek and mucosa the classic psychophysical inverted U associated with CT like behavioural responses to touch was found on the cheek where CTs are known to be present as well as on the lower lip. This CT like response on the lip warrants further detailed investigation. Serotonin (5-HT) is widely associated with hedonic experiences and reduced 5-HT levels are a linked with depression and anhedonia. 5-HT is also a candidate neurotransmitter associated with taste transduction. Chapter 6 describes an acute tryptophan depletion (ATD) study that examined the peripheral and central effect of reduced 5-HT levels on taste perception. The primary findings highlight that tryptophan levels do not effect sweet, sour, salt and bitter taste detection ability. A significant difference in bitter taste intensity and pleasantness was identified with tryptophan depletion increasing the taste intensity and decreasing bitter pleasantness at suprathreshold concentration. An effect of taster status was identified in bitter intensity ratings with tolerant-tasters reporting a greater intensity of sensation in the tryptophan depletion session than in the control. During the course of the experimental phase of this thesis, it became clear that describing oral sensations was a difficult task. When asked to describe how sensations felt within their mouth in chapter 4, participants were unable to find words to describe sensations. Therefore, the final study in chapter 7 describes the development of a candidate oral lexicon to aid in describing mouth feel and oral sensations highlighting that the approach to lexicon development previously used to develop the McGill Pain Questionnaire and the Touch Perception Task can successfully be applied to the development of an Oral Lexicon.

Background: Chronic musculoskeletal pain (CMP) is a common pervasive issue among older adults and may affect mobility and falls risk. Aims: Investigate the relationship between CMP and physical activity/ sedentary behaviour, psychological concerns related to falls and falls in community dwelling older adults. Method: A mixed method sequential explanatory approach was adopted, informed by three systematic reviews. Five quantitative studies were devised and community dwelling older adults were recruited across 10 sites in London. CMP was assessed and standardised information regarding falls, psychological concerns related to falls, sedentary behaviour and confounding factors collected. A convenience sample of 20 participants with CMP were recruited exploring the three phenomenon using semi structured interviews. Results: Overall, 295 participants participated in the quantitative studies (77.5±8.1 years, 66.4% female) and 52% had CMP (154/295). The first results paper demonstrated that older adults with CMP were more sedentary than those without CMP (11.5 hours vs 7.9, p < .001). The second results study elucidated that older adults with multisite CMP are at greatest risk of recurrent falls (odds ratio 2.25, 95% confidence interval: 1.03-4.88) and that the brief pain inventory (BPI) demonstrates promising discriminative ability. The third and fourth results studies demonstrated that high pain interference, pain severity and multisite pain were associated with increased concerns regarding falling (particularly lower balance confidence). The final quantitative results chapter demonstrated that collectively these mobility limitations and falls risk factors are significantly associated with lower health related quality of life in those with CMP. The qualitative study suggests that these relationships may not be that straight forward with few participants directly attributing pain as a cause of falls or increased concerns about falling. Conclusion: Older adults with CMP are significantly more likely to experience falls, be more sedentary and have heightened psychological concerns related to falls compared to those without CMP.

Fluent reading entails multiple levels of analysis including orthography, syntax and semantics but is also characterised by fast speed and apparent ease in understanding the various linguistic input. This thesis therefore focuses on the earliness and automaticity of single word recognition, which is a fundamental component of reading process. Exactly when a visual stimulus is recognised as a word and comprehended, and to what extent this is an automatic and not a controlled process, are two of the most debated issues in psycholinguistic research. A series of six Event-Related Potential (ERP) studies were carried out in this study, with the first five of these investigating Chinese single character words and pseudowords and the sixth investigating Spanish words and word-like strings. The critical ERP component of interest is visual Mismatch Negativity (vMMN), a visual counterpart of the well-documented auditory MMN (Näätänen, Gaillard, & Mäntysalo, 1978). VMMN has recently been demonstrated to be a neural index of automatic processing of not only generic visual features but also written words. To overcome the compounding of physical differences between stimulus conditions, a “same-stimulus” identity oddball paradigm was adopted throughout the studies. The vMMN was computed by comparing the ERP responses to deviant and standard stimuli of the same lexical/semantic category. It was found that lexical and semantic vMMN effects could be obtained within the first 250 ms after the stimulus onset, even when the critical words were presented briefly and outside of the focus of attention (perifoveally) and participants were instructed to carry out a non-linguistic distraction task, indicating automaticity of processing. The similarity in the timing of these early vMMN responses lends support to parallel processing models of linguistic information processing. In addition, vMMN to changes in lexicality was subject to configurations in the cognitive system, with attention and the magnitude of deviance revealed as two important variables. Language vMMN effects in normal adults as revealed in this thesis may serve as a benchmark for assessing the reading abilities of first or second language readers, as well as of people with linguistic impairments, such as dyslexia.

Whole-body coordination such as in sit-to-stand (STS) movements is an important activity of independent daily living that is affected by decreased muscular strength and postural control due to ageing and also as a result of neurological diseases such as stroke. Recent research has taken an interest in using motor imagery for rehabilitation and training because it has many features in common with movement execution without some of the practical difficulties of repeated physical practice. Imagery tends to be more effective when it takes a first person perspective and focuses on kinesthetic aspects of movement. On the contrary, research in exercise science shows that movement execution is more fluent when attention is focused on body-external perceptual consequences of movement. How ageing affects this difference in the impact of attentional focus is not well understood. This thesis examines the effects of body-external (visual) and body-internal (muscular or somatosensory) attentional focus on STS movement execution and imagery in healthy young and older adults. The thesis reports four experiments comparing execution and imagery performance in young and older adults. Experiment 1 was designed to clarify the impact of attentional focus on motor performance and imagery in young and older adults. Experiment 2 examined the impact of changing the level of effort (by manipulating the starting seat height) on the effects of attentional focus. Experiment 3 measured the impact of unimanually balancing a load in the hand on the role of attentional focus in physical and imagined STS movements. Experiment 4 studied the role of attentional focus in a training protocol employing motor imagery practice. Postural transition duration and transition stability during physical trials, self-reported movement times during physical and imagined trials, and ground reaction force and vividness of imagery during imagined trials were recorded. The results show that focusing attention on muscular effort not only benefitted older people’s motor performance, but also increased both the level and task-linked modulation of inadvertent force production during imagery (Experiment 1). Increasing the level of effort (by lowering seat height) resulted in better modulation of movement time as a function of effort level when older adults focused attention internally (Experiment 2). When a secondary task of holding a fluid container upright was added, external attentional focus benefitted both age groups (Experiment 3), indicating that the effects of attentional focus are task-linked. There was also a numerical indication that focusing attention on muscular load during motor imagery-based practice may be more effective in older adults (Experiment 4). These results suggest that kinesthetic imagery may be particularly consonant with the more internally focused motor control that benefits older people. Thus, training or rehabilitation protocols using kinesthetic imagery may serve more effectively as a form of practice for this age group by activating neural pathways similarly to their motor execution. On the other hand, young people consistently performed better under external attentional focus, and even modulated their force production during imagery better when externally focused. The focus on musculoskeletal dynamics that kinesthetic imagery requires may therefore correspond less closely to motor planning and control processes in this age group. Thus, pathways by which kinesthetic imagery can serve as practice are likely to be more indirect than for older people. These findings provide fundamental knowledge for further clinical research on patients who suffer disability in STS movements.

Background: There is evidence suggesting a relationship between physical activity and movement skills in adolescents. Evidence, primarily from animal and older adult data, suggests that physical activity can improve cognitive function. Both motor and cognitive function are essential components of school readiness. If these relationships exist in young children, promotion of physical activity may have a significant impact on school readiness and academic achievement. Participants and Methods Study 1: 394 children (mean 4.2 SD 0.5 years; 209 boys/185 girls) were recruited from 36 Glasgow preschools. Physical activity (PA) was measured using the Actigraph accelerometer, movement skills (MS) were assessed using a test based on the Movement Assessment Battery. Studies 2-4: 64 children (mean age 6.2 yrs SD 0.3; 33 boys / 38 girls) were recruited from 6 Glasgow primary schools. Psychological outcome measures were the Cambridge Neuropsychological Test Battery (CANTAB) (working memory), the Attention Network Test (reaction time) the Cognitive Assessment System (CAS) (executive function), and the short form of Connor’s Parent Rating Scale (CPRS:S) (behaviour). Physical activity was measured using the Actigraph GT1M accelerometer. A specialist and trained teacher-led physical activity intervention (active games) was run in intervention schools 2 hours per week for 10 weeks. The control PE sessions were specialist and teacher led standard curriculum, increased to 2 hours per week. Results: Study 1: There was a statistically significant, but very weak (r 0.18, p <0.001), correlation between MS and PA. Boys and girls in the highest quartile for MS had significantly greater time spent in MVPA than girls and boys and girls in the lowest quartile, but this difference was small; median difference between girls in Q4 and Q1 0.9%: 95% CI 0.2-1.6% p 0.01), median difference between boys in Q4 and Q1 (median difference 0.9% 95% CI 0.0-0.2% p 0.04). Studies 2-4: Test and 3 week retest intraclass correlations (ICC) from the Cambridge Neuropsychological Test Battery (CANTAB) and Attention Network Test (ANT) suggest these measures are not sufficiently reliable in to be used an outcome in a future RCT in this age group (CANTAB spatial span r 0.51 p<0.001; spatial working memory r 0.49 p<0.00.1; strategy r 0.08, p<0.52) (ANT reaction time 0.32 p<0.05; accuracy 0.62, p<0.001). The CAS was accepted well by young children, has good previously established reliability, and would be a suitable outcome measure for a full scale RCT. There was no significant difference between the intervention and control group change in CAS scores (Full scale t=-0.74, p=0.48) or any of the subscales (p all >0.05). Physical activity was significantly higher during the intervention, than the control physical education (PE) sessions (median difference 628 cpm 95% CI 460, 786 p= <0.0001). During the standard curriculum PE sessions children in the control group spent 58% of their monitored time in sedentary behaviour. The existing data suggest that a 10 week intervention may improve spatial working memory (t=2.78, p 0.01) and aspects of behaviour (CPRS:S Cognitive Problems/ Inattention (t=2.00 p=0.04) in this age group, but further research in larger samples, with a more robust measure of SPW would be required to confirm these findings. The data allowed a power calculation for a future full scale RCT to be calculated (based on the CAS Planning scale), based on data from the current study a sample size of n=75 in each arm would be required, recruiting 100 in each arm to allow for drop-out. Conclusion The present data suggest only a weak relationship between MS and habitual activity, and questions the strong emphasis placed on movement skill development in the preschool curriculum. The present thesis provides data to adequately design and power a future full scale RCT to examine the effects of exercise and cognitive function.

This investigation explored the impact of acute cold exposure on postural control during static balance tasks. The aims were to establish the impact of short term cold exposure on human postural control, identify key processes that lead to performance changes, and to examine approaches to maintaining performance of postural control during acute cold exposure. In study 1 the reliability of Centre of Pressure (COP) measurements using the RS Scan International Footscan® Plate System during quiet standing was tested. Quiet standing balance tests were compared over 5 days using a repeated trials protocol and intraclass correlational analysis. It was concluded that 3 practice trials result in consistent performances in room temperature conditions (21°C). In study 2 the effects of 30 minutes of cold exposure at -20 °C were established. No change was found for core body temperature. Head and calf skin temperatures were reduced. Foot temperatures reduced from 26.1 °C to 10.1 °C. Heart Rate Variability (HRV) measures showed effect sizes indicative of a generalised stress response but no significant differences. Postural control measures showed increased COP paths (≅ 100%) and decreased sway rates (20 – 25%) for two footed balance tests compared to room temperature performances. Single footed balance tests showed no change in sway rate but a 40 – 50% increase in COP path. In study 3 an ice bath protocol was employed to replicate foot skin temperatures of 10 °C, as had occurred during whole body cooling. Postural control variables indicated reduced performance but these changes were less pronounced than during whole body cooling. COP paths increased by 22 – 29% but sway rates were not significantly different. It was concluded that part of the impairment in postural control during acute cold exposure is due to anesthetised mechanoreceptors in the feet. In study 4 active heated footbeds were employed as a protective measure during 15 minutes of cold exposure. Performance was compared during 3 conditions: room temperature, -20 °C, and -20 °C with footbeds. Foot temperatures dropped to 11.2 °C after 15 minutes during both cold conditions. HRV analysis showed decreases in RR and LF/HF ratio during both cold exposure conditions. Postural control variables responded in the same manner as study 2 with no difference between cold conditions. Heated footbeds did not provide thermoregulatory, comfort or postural control advantages in this study. In conclusion cold exposure results in reduced accuracy in postural control which may increase accident risk during cold climate activities. A reduction in somatosensory feedback is a key factor in reduced performance but changes during initial whole body exposure suggest that attention may also play a key role in the processing of postural responses in the cold.

Utilizing self-determination theory (SDT; Deci & Ryan, 1985; Ryan & Deci, 2002) as a framework, the current thesis aimed to explore the social conditions that satisfy versus thwart psychological needs and, in turn, impact upon psychological and physiological functioning and well/ill-being in the sport context. Although research guided by SDT has explored the conditions (i.e., autonomy support) and psychological processes (i.e., need satisfaction) that foster healthy development and effective functioning in athletes, very little research has considered the potential role of interpersonal control and psychological need thwarting in the development of athlete ill-being. To address these limitations, this thesis begins by outlining the development and initial validation of two new questionnaire measures: the Controlling Coach Behaviors Scale (Chapter 2) and the Psychological Need Thwarting Scale (Chapter 3). The new questionnaire measures were subsequently utilized in three studies, reported in Chapter 4. Across all three samples, need satisfaction was better predicted by autonomy-supportive behaviors, and need thwarting was better predicted by coach control. In turn, athletes’ perceptions of need satisfaction predicted positive outcomes (i.e., vitality and positive affect) whereas need thwarting consistently better predicted maladaptive outcomes (i.e., disordered eating, burnout, depression, negative affect, physical symptoms, and perturbed physiological functioning). Such novel findings indicate that controlling interpersonal behaviors and psychological need thwarting represent important aspects of the SDT framework which must be further researched (both in sport and in other life domains) if the development of diminished functioning and ill-being is to be properly understood.

Timing is a crucial aspect of dynamic tasks, and understanding of timing effects in balance control may contribute to refine balance retraining paradigms for hemiparetic stroke. This thesis opens with a review on predictive and reactive modes of balance control. The initial review concludes there is unexplored potential in predictive setting of timing in imposed balance and in reactive adjustment of timing in self-perturbed balance. This leads to introduction and development of two paradigms by group studies. The first paradigm increases timing certainty of imposed force perturbations by using a regular metronome. Experiments indicate the effect of predictive control on reducing prolonged response time of hemiparetic stroke. The second paradigm introduces temporal metronome error to self-produced postural perturbations that are made in synchrony with the metronome. Experiments show deteriorated reactive control of timing due to increased biomechanical constraint in maintaining balance, but the potential of hemiparetic patients to adjust movement timing is also noted. Effects of these two paradigms in retraining hemiparetic balance are tested by single case studies. The first evidences training potential of predictive control to speed up responses. The second demonstrates training effect of timing cues in re-adjusting the asymmetric pattern between motions of two sides of the body. In conclusion, the paradigms of this thesis provide new means for examining timing effects of predictive and reactive postural responses. Empirical results encourage further development of balance retraining paradigms for hemiparetic stroke with an emphasis on timing, and so potential RCT designs are outlined.

The combination of functional magnetic resonance imaging (fMRI) and multivariate pattern analysis (MVPA) is a powerful method for investigating brain function, with multiple MVPA methods being applied to the task including Logistic Regression, Support Vector Machines, Neural Networks, and Gaussian Naive Bayes classifiers. Careful review of application of these methods revealed a common process used in most studies; the majority of variations occurring in the implementation choices in key sections such as feature selection or classification algorithms being employed. Thus, it is possible to develop modularised tools for performing MVPA of fMRI data which can be applied in a variety of ways through selection of appropriate components. Development of such a toolbox for use by the University of Birmingham Cognitive Neuroimaging Laboratory is described. The modular design allows for flexible application and provides a basis for development of novel methods, which is explored through implementation of a novel cross-validation method and development of a method for investigating the effects of learning on tuning of neural populations. The development process has resulted in an efficient, robust and reliable toolbox, capable of performing a pre-implemented set of standard multi-variate pattern analyses and provides a basis for further development of novel methods.