Physiological interpersonal synchrony, the spontaneous alignment of indicators of physiological activity, is highly associated with the level of empathy between people in emotionally meaningful relationships. However, synchrony has not been studied with nonverbal, severely-disabled individuals, many of whom have a limited means to communicate. In this study, dyadic physiological synchrony in client-parent-therapist triads was quantified through simultaneously recording electrodermal activity, heart rate, cortical brain activity (client-parent only), and cortisol level. For the majority of the trials, a greater level of synchrony was observed in the client-parent dyads compared to the client-therapist dyads; however, the client-therapist dyads demonstrated an increased level of synchrony in the later trials. Electroencephalography analysis revealed widespread interbrain synchrony involving empathy-related regions. Our results suggest that even in the presence of disabilities, synchrony due to empathy exists and that the measurement of this synchrony may serve as a clinical adjunct to the self-report of interpersonal relationships.

Physiological interpersonal synchrony, the spontaneous alignment of indicators of physiological activity, is highly associated with the level of empathy between people in emotionally meaningful relationships. However, synchrony has not been studied with nonverbal, severely-disabled individuals, many of whom have a limited means to communicate. In this study, dyadic physiological synchrony in client-parent-therapist triads was quantified through simultaneously recording electrodermal activity, heart rate, cortical brain activity (client-parent only), and cortisol level. For the majority of the trials, a greater level of synchrony was observed in the client-parent dyads compared to the client-therapist dyads; however, the client-therapist dyads demonstrated an increased level of synchrony in the later trials. Electroencephalography analysis revealed widespread interbrain synchrony involving empathy-related regions. Our results suggest that even in the presence of disabilities, synchrony due to empathy exists and that the measurement of this synchrony may serve as a clinical adjunct to the self-report of interpersonal relationships.

Musical behaviours, such as singing, dancing and musical production, encourage high levels of interpersonal synchrony. In adults, interpersonal synchrony (i.e. moving in time with others) has been shown to encourage affiliative behaviours among those involved. People are more cooperative, helpful, and trusting toward people with whom they have moved synchronously compared to asynchronously. Until the present thesis, it was unknown if these affiliative effects of interpersonal synchrony influenced social behaviour from an early age. In Chapter 2, I provided the first evidence that 14-month-old infants are more helpful toward synchronously- compared to asynchronously-moving partners. In Chapter 3, I showed that interpersonal synchrony only boosts infant helping directed toward their synchronously-moving partner, but not a neutral stranger. However, in Chapter 4, I showed that infants are more likely to help the positive affiliate (“friend”) of their synchronously-moving partner over the “friend” of their asynchronously-moving partner. Chapter 5 explores how background music in Chapters 2-4 contributed to the overall experience. Here, I found that even in a non-musical context, infants still helped synchronously-moving partners more than asynchronously-moving partners. However, infants were more distressed and took more time to help than in Chapters 2-4, suggesting that music may provide an emotionally regulating context within which interpersonal synchrony can be experienced. Together, these findings suggest that behaviours encouraging high levels of synchronous movement, such as musical behaviours, have important consequences for early social development. / Dissertation / Doctor of Philosophy (PhD)

Phase Synchrony (PS) and coherence analyses of stochastic time series - tools to discover brain tissue pathways traveled by electrical signals - are considered for the specific purpose of processing of the electroencephalogram (EEG). We propose the Phase Synchrony Processor (PSP), as a tool for implementing phase synchrony analysis, and examine its properties on the basis of known signals. Long observation times and wide filter bandwidths can decrease bias in PS estimates. The value of PS is affected by the difference in frequency of the sequences being analyzed and can be related to that frequency difference by the periodic sinc function. PS analysis of the EEG shows that the average PS is higher - for a number of electrode pairs - for non-ADHD than for ADHD participants. The difference is more pronounced in the δ rhythm (0-3 Hz) and in the γ rhythm (30-50 Hz) PS. The Euclidean classifier with electrode masking yields 66 % correct classification on average for ADHD and non-ADHD subjects using the δ and γ1 rhythms. We observed that the average γ1 rhythm PS is higher for the eyes closed condition than for the eyes open condition. The latter may potentially be used for vigilance monitoring. The Euclidean discriminator with electrode masking shows an average percentage of correct classification of 78 % between the eyes open and eyes closed subject conditions. We develop a model for a pair of EEG electrodes and a model-based MS coherence estimator aimed at processing short (i.e. 20 samples) EEG frames. We verify that EEG sequences can be modeled as AR(3) processes degraded by additive white noise with an average SNR of approximately 11-12 dB. Application of the MS coherence estimator to the EEG suggests that MS coherence is generally higher for non-ADHD individuals than for ADHD participants when evaluated for the θ rhythm of EEG. Also, MS coherence is consistently higher for ADHD subjects than for the majority of non-ADHD individuals when computed for the low end of the δ rhythm (i.e. below 1 Hz). ADHD produces more measurable effects in the frontal lobe EEG and for participants performing attention intensive tasks. / Ph. D.

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In this thesis, I discuss the grammatical constructionalization involving BA in some depth. I aim to present how a constructional approach can be used to rethink diachronic change in Chinese Expressions involving BA. In previous research of relevance (e.g. Sun 1996; Xing 2006), BA is considered to be a single item that has undergone grammaticalization. From a constructional perspective (e.g. Goldberg 1995, 2006; Traugott 2003a; Trousdale 2008a, 2010; Traugott and Trousdale forthcoming), this view requires some revision. I attempt to provide a constructional account in which an Expression involving BA is understood as a “construction” at the micro-level. As constructions change over time, the form-meaning pairings involving BA are associated with more schematic higher-level constructions. I show the constructionalization process in which an Expression involving BA is reanalyzed and incorporated into different constructions with increased schematicity at higher-levels. Therefore, I assume that a network of correlated constructions is implicated. The diachronic research is conducted mainly based on data collected from the BA corpus, which is a subcorpus I compiled based on the Peking (CCL PKU) Corpus. Using the constructional framework, I also analyze Expressions involving BA in Contemporary Chinese. The aim of the synchronic research is to explore how an Expression involving BA is used currently, and to associate the synchrony with diachrony in some respects.

Past research suggested that greater rhythmic complexity in musical behavior increases affiliation in small groups. The current research tested the hypothesis that musical behavior including melody would promote affiliation. In the current experiment, a video showed models either singing nonsense syllables in unison or speaking identical syllables in synchrony. Participants were assigned to either imitate, or merely listen to, the videos. Participants perceived both the synchronous speaking condition and singing conditions as musical behavior. In the imitate conditions, synchronous speaking produced more affiliation and ingroup favoritism and less embarrassment than singing, whereas in the listen-only conditions, affiliation, ingroup favoritism, and embarrassment did not differ between singing and speaking. Reported happiness and fun were greater in the imitate conditions. The successfulness of imitation, coded by judges, was less, and self-reported difficulty was greater, in the singing condition compared to the synchronous speaking condition. Ratings of success at imitation were positively related to affiliation, positive affect, and ingroup favoritism. Ratings of success were also related to the average trait approach motivation, agreeableness, and emotional stability of the groups. The results partially supported the hypothesis that musical behavior promotes affiliation. However, performance of the sound-making task was much worse in the singing condition than in the synchronous speaking condition. Because melody was confounded with failure at the sound-making activity, the effect of melody on affiliation is difficult to interpret. Future research should examine the effect of melody on affiliation when melody is not confounded with failure.

Joint attention is an early emerging skill that plays a critical role in early child development (Moore & Dunham, 1995). This shared engagement facilitates language acquisition (e.g., Morales et al., 1998) and predicts social cognition in early childhood (Van Hecke et al., 2007). Thus, it is important to understand factors contributing to individual differences in joint attention development. One potential predictor is mother-infant synchrony, the extent to which mothers’ verbal and nonverbal input is contingent upon their infants’ focus (Siller & Sigman, 2002). Researchers found synchrony to be positively associated with the rate of language development (Akhtar et al., 1991). However, few studies have examined mother-infant synchrony longitudinally and whether synchrony influences individual differences in joint attention. The present study is one of the first to examine these relationships in depth prospectively. Twenty typically-developing infants (11 male) and their mothers participated at approximately 9, 12, and 15 months of age as part of a larger longitudinal study of infants at risk for Autism Spectrum Disorders. Each dyad engaged in a 15-minute unstructured play session, which was coded for synchrony (Siller & Sigman, 2002). In addition, researchers administered the Early Social Communication Scales (ESCS; Mundy et al., 2003) with the infant, which was coded for Initiating Joint Attention (IJA) and Responding to Joint Attention (RJA). The results suggest that synchrony was stable within dyads across 9, 12, and 15 months. Surprisingly, higher 9-month synchrony was correlated with lower 12-month RJA. Growth curve modeling revealed significant growth in RJA, but not IJA, over time. However, synchrony scores did not significantly predict growth in IJA or RJA over time as predicted. These preliminary results suggest that synchrony is a relatively stable construct that likely reflects true differences between mother-infant dyads. Mothers following their child’s lead more often at 9 months had infants exhibiting less RJA at 12 months. Contrary to our predictions, there were no other significant associations between synchrony and joint attention. These findings will be reexamined upon collection of additional data. Nonetheless, the current study helps to elucidate the nature of synchrony and joint attention over time in infancy. / text

A CA1 pyramidal neuron in the rodent hippocampus integrates inputs from as many as 30,000 synapses distributed over hundreds of microns, making synaptic integration an intricate spatio-temporal computation. Crucial to this computation, is the timing of synaptic inputs at the axo-somatic integration site. Consequently, it would be beneficial if co-incident proximal and distal inputs arrive simultaneously at the axo-somatic integration site. This, however, is a challenge considering that spatially dispersed inputs have to propagate varying distances, leading to location-dependent temporal differences at the soma. Here we show that CA1 pyramidal neurons have an intrinsic biophysical mechanism in the form of a gradient of HCN channels that actively counteracts location-dependent temporal differences of dendritic inputs at the soma. HCN channels, due to their slow kinetics and unusual gating properties, impart an inductive reactance to the neuronal membrane properties. Using multi-site whole cell recordings, we show that this gradient of inductive reactance actively compensates for the location-dependent capacitive delay of dendritic inputs. This leads to a response synchrony of spatially dispersed inputs at the soma. This response synchrony is optimum for oscillatory signals in the theta frequency range (4-12 Hz). Using computational modeling we show that the characteristic sigmoidal distribution of HCN channels in CA1 neurons is crucial for the efficient and exclusive transfer of these synchronous theta frequencies from dendrite to the soma. To understand the significance of this oscillatory synchrony during synaptic integration, we used the dynamic clamp technique to simulate different temporal patterns of synaptic input in the dendrites of CA1 neurons. Our results reveal that this oscillatory synchrony is best harnessed by theta and gamma (40-140 Hz) frequency synaptic input patterns in CA1 neurons. Gamma and theta oscillations are associated with synchronizing activity across space in the hippocampal network. Our results thus identify a novel mechanism by which this synchrony extends to activity within single pyramidal neurons with complex dendritic arbors. / text

The brain is a complex dynamic and self-organizing system. Normal brain function emerges from synchronized neuronal firing between local neurons which are integrated into large scale networks via white matter tracts. Normal brain function and consciousness arise from the continual integration and dissolution of neuronal networks, and this fluctuation in synchronization is termed variability. Brain electrical activity is recorded as local field potentials using electroencephalography (EEG). The phase synchrony and variability of EEG waveforms can be quantified. The healthy brain exhibits a relatively low degree of phase synchrony and a high degree of variability. Clinicians are interested in using a complex system approach to brain function to provide dynamic information on neuronal physiology and pathology not available by other evaluation methods. A common challenge in paediatric critical care is evaluation of the comatose child post brain injury. Coma and medical interventions confound the clinical examination making monitoring and prognostication of outcome difficult. Brain cells and white matter tracts are disrupted post injury altering the phase synchrony between neuronal networks. It is proposed in this thesis that the estimation of the variability in EEG phase synchrony can evaluate paediatric brain function. The EEG recordings of normal children and patients in coma post brain injury are used, in a series of studies, to test the main hypothesis that slow EEG wave brain states associated with brain injury have higher magnitudes of EEG phase synchrony and lower variability values than those of EEG waves associated with consciousness. Further, the effects of age, brain development brain and the effect of a conscious slow wave EEG state (hyperventilation) on phase synchrony and variability are evaluated. Results of the studies showed that EEG phase synchrony is increased in all slow wave states and is highest in comatose children with poor neurological outcome. Younger children’s brains have higher phase synchrony than older children. The variability of the EEG phase synchrony differentiates between the awake (higher values) and unconscious states (lower values). Physiologic models underlying EEG phase synchrony are discussed. The EEG phase synchrony and variability measures provide new insight into paediatric brain function.