Professor Frini Karayanidis

Objective: Maternal asthma often complicates pregnancy and is linked with poorer quality of life. Additionally, individuals with asthma are at an increased risk of depression and anxiety. We examined whether asthma during pregnancy is related to parenting stress in the first year postpartum and if this relationship varies with level of asthma control. Methods: This cohort survey-based study included mothers with (n = 157) and without (n = 79) asthma. Mothers with asthma participated in this study following participation in a randomized controlled trial of a novel asthma management strategy during pregnancy. Mothers completed the Parenting Stress Index¿Short Form during the first 12 months postpartum. Mothers with asthma also completed the Asthma Control Questionnaire. Results: Parenting stress did not differ between mothers with and without asthma. Additionally, for mothers with asthma, there were no differences in levels of parenting stress based on asthma control. Conclusions: This study suggests that mothers with asthma are not at an increased risk for excessive parenting stress. However, due to response and sampling bias, levels of parenting stress in asthmatic mothers may be underreported in our sample.

Infants diagnosed with autism spectrum disorder (autism) have difficulty engaging in social communication and interactions with others and often experience language impairment. The use of infant-directed speech (IDS), which is the speech register used when interacting with infants, is associated with infant language and socio-communicative development. The aim of this study was twofold; the first aim was to scope the literature to determine if evidence exists for differences between the IDS caregivers use to infants at high-risk or those later diagnosed with autism, and the IDS typically spoken to neurotypical infants. The second aim was to investigate if any IDS characteristics used by caregivers of high-risk or diagnosed infant populations predicted language development. Twenty-six studies were included and provided evidence that high-risk and later diagnosed infants are exposed to similar amounts of IDS as their neurotypical peers. There is evidence, however, that the IDS used with high-risk and later diagnosed infants may comprise shorter utterances, more action-directing content, fewer questions, more attention bids, and more follow-in commenting. There is also evidence that more attention bids and follow-in commenting used to infants at high risk or those later diagnosed with autism were associated with better language abilities longitudinally.

During task-switching paradigms, both event-related potentials and time-frequency analyses show switch and mixing effects at frontal and parietal sites. Switch and mixing effects are associated with increased power in broad frontoparietal networks, typically stronger in the theta band (~4¿8¿Hz). However, it is not yet known whether mixing and switch costs rely upon common or distinct networks. In this study, we examine proactive and reactive control networks linked to task switching and mixing effects, and whether strength of connectivity in these networks is associated with behavioural outcomes. Participants (n¿= 197) completed a cued-trials task-switching paradigm with concurrent electroencephalography, after substantial task practice to establish strong cue-stimulus¿response representations. We used inter-site phase clustering, a measure of functional connectivity across electrode sites, to establish cross-site connectivity from a frontal and a parietal seed. Distinct theta networks were activated during proactive and reactive control periods. During the preparation interval, mixing effects were associated with connectivity from the frontal seed to parietal sites, and switch effects with connectivity from the parietal seed to occipital sites. Lateralised occipital connectivity was common to both switch and mixing effects. After target onset, frontal and parietal seeds showed a similar pattern of connectivity across trial types. These findings are consistent with distinct and common proactive control networks and common reactive networks in highly practised task-switching performers.

Objectives: Differences in the development of autistic children have been observed within the first year of life. Infant siblings of autistic children who are later diagnosed with autism themselves have differences in temperament, social communication, attention, and sensory and motor behaviors by 12¿months of age. However, less is known about the early development of other increased-likelihood groups. Some studies have identified that children born to mothers with asthma have a slightly elevated likelihood of autism. However, no studies have examined other aspects of their early development. Methods: Using a case series design, we profiled the temperament (Carey Temperament Scales), sensory (Sensory Profile 2), and global developmental features (Bayley-III) of seven Australian infants born to mothers with asthma who were screened to have an elevated likelihood of autism (First Year Inventory). Results: We found differences from the norms in temperament across the three timepoints (6¿weeks, 6¿months, and 12¿months), in the domains of rhythmicity, mood, persistence, and distractibility. Infants had typical sensory features at 6¿weeks and 6¿months; however, a sensory-sensitivity subtype was observed at 12¿months. Lastly, at 12¿months, cognitive skills were mostly typical, language skills were underdeveloped, and motor skills varied between infants. Conclusions: Results suggest that there may be a developmental profile indicative of an elevated likelihood of autism in infants born to mothers with asthma. However, due to the small sample size, these findings need to be considered with caution. Further research is needed to confirm diagnoses of autism in our sample.

Maternal asthma in pregnancy is associated with an increased risk of adverse perinatal outcomes. Adverse perinatal outcomes may result in poorer infant developmental outcomes, such as temperament and sensory difficulties. This study aimed to (1) assess differences in temperament and sensory features between infants born to mothers with and without asthma and (2) investigate differences in these infant behaviours as a function of maternal asthma severity and asthma control. Mothers completed the Carey Temperament Scales and the Sensory Profile 2 at either 6 weeks, 6 months, or 12 months postpartum. Overall, we observed no significant differences between infants born to mothers with and without asthma in their temperament or sensory features; scores in both domains fell within the normative range. More infants in the asthma group, however, were reported to be highly distractible. When compared with normative data, infants in both groups were reported to have poor predictability of biological functions and fewer infants engaged in low levels of sensory behaviours. Some infants were observed to experience difficulties with hyper-reactivity within several domains. Maternal asthma severity and control during pregnancy were not linked to significant differences between infant temperament and sensory features. The present findings indicate that infants born to mothers with asthma are not at an increased risk overall for temperament or sensory difficulties, compared to control infants. However, a subset of infants across both groups may be at risk for attention or sensory hyper-reactivity difficulties. Further research into the developmental outcomes of infants born to mothers with asthma is warranted.

Objective: We aimed to examine the prevalence and severity of psychological distress of women with asthma in both the prenatal and postnatal periods, and to determine whether asthmatic women with and without mental health problems differ in self-management, medications knowledge, and asthma symptoms. Methods: We assessed spirometry performance and asthma symptoms in 120 women (mean age 29.8 years) before 23 weeks gestation, as part of the Breathing for Life Trial (Trial ID: ACTRN12613000202763). Prenatal depression data was obtained from medical records. At 6 weeks postpartum, we assessed general health, self-reported asthma control, depression symptoms (with the Edinburgh Postnatal Depression Scale) and adaptive functioning (with the Achenbach System of Empirically Based Assessment scales). Results: Twenty percent of our sample reported having a current mental health diagnosis, 14% reported currently receiving mental health care, while 47% reported having received mental health care in the past (and may/may not have received a diagnosis). The sample scored high on the Aggressive Behavior, Avoidant Personality, and Attention Deficit/Hyperactivity scales. Poorer self-reported postnatal asthma control was strongly correlated with elevated somatic complaints, externalizing problems, antisocial personality problems, and greater withdrawal. Prenatal spirometry or asthma severity and control were largely not associated with measures of psychopathology. Conclusions: These findings indicate that pregnant women with asthma frequently report issues with psychopathology during the prenatal and postnatal periods, and that the subjective perception of asthma control may be more related to psychopathology than objective asthma measures. However, due to sample bias, these findings are likely to be understated.

An important feature of human cognition is the ability to flexibly and efficiently adapt behavior in response to continuously changing contextual demands. We leverage a large-scale dataset from Lumosity, an online cognitive-training platform, to investigate how cognitive processes involved in cued switching between tasks are affected by level of task practice across the adult lifespan. We develop a computational account of task switching that specifies the temporal dynamics of activating task-relevant representations and inhibiting task-irrelevant representations and how they vary with extended task practice across a number of age groups. Practice modulates the level of activation of the task-relevant representation and improves the rate at which this information becomes available, but has little effect on the task-irrelevant representation. While longterm practice improves performance across all age groups, it has a greater effect on older adults. Indeed, extensive task practice can make older individuals functionally similar to lesspracticed younger individuals, especially for cognitive measures that focus on the rate at which task-relevant information becomes available.

Investigations into the neurophysiological underpinnings of control suggest that frontal theta activity is increased with the need for control. However, these studies typically show this link by reporting associations between increased theta and RT slowing ¿ a process that is contemporaneous with cognitive control but does not strictly reflect the specific use of control. In this study, we assessed frontal theta responses that underpinned the switch cost in task switching ¿ a specific index of cognitive control that does not rely exclusively on RT slowing. Here, we utilised a single-trial regression approach to assess 1) how cognitive control demands beyond simple RT slowing were linked to midfrontal theta and 2) whether midfrontal theta effects remained stable over time. In a large cohort that included a longitudinal subsample, we found that midfrontal theta was modulated by switch costs, with enhanced theta power when preparing to switch vs. repeating a task. These effects were reliable after a two-year interval (Cronbach's a.39-0.74). In contrast, we found that trial-by-trial modulations of midfrontal theta power predicted the size of the switch cost ¿ so that switch trials with increased theta produced smaller switch costs. Interestingly, these relationships between theta and behaviour were less stable over time (Cronbach's a 0-0.61), with participants first using both delta and theta bands to influence behaviour whereas after two years only theta associations with behaviour remained. Together, these findings suggest midfrontal theta supports the need for control beyond simple RT slowing and reveal that midfrontal theta effects remain relatively stable over time.

The ability to control behaviour is thought to rely at least partly on adequately suppressing impulsive responses to external stimuli. However, the evidence for a relationship between response inhibition ability and impulse control is weak and inconsistent. This study investigates the relationship between response inhibition and both self-report and behavioural measures of impulsivity as well as engagement in risky behaviours in a large community sample (N = 174) of healthy adolescents and young adults (15¿35 years). Using a stop-signal paradigm with a number parity go task, we implemented a novel hierarchical Bayesian model of response inhibition that estimates stop-signal reaction time (SSRT) as a distribution and also accounts for failures to react to the stop-signal (i.e., ¿trigger failure¿), and failure to react to the choice stimulus (i.e., ¿go failure¿ or omission errors). In line with previous studies, the model reduced estimates of SSRT by approximately 100 ms compared with traditional non-parametric SSRT estimation techniques. We found significant relationships between behavioural and self-report measures of impulsivity and traditionally estimated SSRT, that did not hold for the model-based SSRT estimates. Instead, behavioural impulsivity measures were correlated with rate of trigger failure. The relationship between trigger failure and impulsivity suggests that the former may index a higher order inhibition process, whereas SSRT may index a more automatic inhibition process. We suggest that the existence of distinct response inhibition processes that may be associated with different levels of cognitive control.

Objective: Maternal asthma during pregnancy is associated with a higher risk of negative perinatal outcomes. However, little is known about the direct effects of maternal asthma on infant cognitive development. We examined the evidence for an impact of maternal asthma during pregnancy on cognitive and behavioral development of the child. Data sources: We conducted a MEDLINE, PsychINFO, and manual search of the databases for all available studies until January 9th, 2018. Study Selections: Studies were deemed relevant if they included child cognitive and behavioral development as the outcome, with maternal asthma as the determinant of interest. Results: Ten articles matched selection criteria. Some studies report that maternal asthma is associated with increased risk for autism and intellectual disability in children. However, these effects are small and are often eliminated when controlling for confounding variables. Other studies have found no association. The only prospective study found that well-managed asthma during pregnancy was not associated with negative developmental outcomes in children. Conclusions: The evidence suggests that the relationship between maternal asthma during pregnancy and poor developmental and behavioral outcomes of children is weak. Children of mothers with well-managed asthma during pregnancy have similar developmental trajectories to those born to healthy mothers. Prospective, longitudinal studies are needed to confirm these conclusions. Optimal asthma management is important in pregnancy as it may have longer term benefits for the health of the offspring. As the rate of asthma increases in the population, the implications of maternal asthma on child development will be of greater importance.

Transcranial direct current stimulation (tDCS) has been proposed as a tool to enhance stroke rehabilitation; however, evidence to support its use is lacking. The aim of this study was to investigate the effects of anodal and cathodal tDCS on upper limb function in chronic stroke patients. Twenty five participants were allocated to receive 20 min of 1 mA of anodal, cathodal or sham cortical stimulation in a random, counterbalanced order. Patients and assessors were blinded to the intervention at each time point. The primary outcome was upper limb performance as measured by the Jebsen Taylor Test of Hand Function (total score, fine motor subtest score and gross motor subtest score) as well as grip strength. Each outcome was assessed at baseline and at the conclusion of each intervention in both upper limbs. Neither anodal nor cathodal stimulation resulted in statistically significantly improved upper limb performance on any of the measured tasks compared with sham stimulation (P>0.05). When the data were analysed according to disability, participants with moderate/severe disability showed significantly improved gross motor function following cathodal stimulation compared with sham (P=0.014). However, this was accompanied by decreased key grip strength in the unaffected hand (P=0.003). We are unable to endorse the use of anodal and cathodal tDCS in the management of upper limb dysfunction in chronic stroke patients. Although there appears to be more potential for the use of cathodal stimulation in patients with severe disability, the effects were small and must be considered with caution as they were accompanied by unanticipated effects in the unaffected upper limb.

Low frequency oscillations in the theta range (4¿8 Hz) are increasingly recognized as having a crucial role in flexible cognition. Such evidence is typically derived from studies in the context of reactive (stimulus-driven) control processes. However, little research has explored the role of theta oscillations in preparatory control processes. In the current study, we explored the extent of theta oscillations during proactive cognitive control and determined if these oscillations were associated with behavior. Results supported a general role of theta oscillations during proactive cognitive control, with increased power and phase coherence during the preparatory cue interval. Further, theta oscillations across frontoparietal electrodes were also modulated by proactive control demands, with increased theta phase synchrony and power for cues signaling the need for goal updating. Finally, we present novel evidence of negative associations between behavioral variability and both power and phase synchrony across many of these frontoparietal electrodes that were associated with the need for goal updating. In particular, greater consistency in frontoparietal theta oscillations, indicated by increased theta phase and power during mixed-task blocks, resulted in more consistent task-switching performance. Together, these findings provide new insight into the temporal dynamics and functional relevance of theta oscillations during proactive cognitive control.

The relationship between metacognitive monitoring of working memory performance and academic achievement was examined in 73 Grade 4 children. Working memory was assessed using the Working Memory Power Test (WMPT) for children. Metacognitive monitoring was assessed by confidence ratings and two calibration measures, the Bias Index and the Absolute Accuracy Index, calculated from WMPT scores. Children also completed the Wechsler Individual Achievement Test - Australian Abbreviated (WIAT-II). Regression analyses showed the Bias Index was the best metacognitive monitoring calibration measure for predicting academic achievement. These findings extend previous research in two important ways. Firstly, we have shown that Grade 4 children have metacognitive monitoring abilities. Secondly, we have demonstrated that children are able to metacognitively monitor their working memory performance and that the calibration of this monitoring is related to their academic achievement.

Task-switching performance relies on a broadly distributed frontoparietal network and declines in older adults. In this study, they investigated whether this age-related decline in task switching performance was mediated by variability in global or regional white matter microstructural health. Seventy cognitively intact adults (43¿87 years) completed a cued-trials task switching paradigm. Microstructural white matter measures were derived using diffusion tensor imaging (DTI) analyses on the diffusion-weighted imaging (DWI) sequence. Task switching performance decreased with increasing age and radial diffusivity (RaD), a measure of white matter microstructure that is sensitive to myelin structure. RaD mediated the relationship between age and task switching performance. However, the relationship between RaD and task switching performance remained significant when controlling for age and was stronger in the presence of cardiovascular risk factors. Variability in error and RT mixing cost were associated with RaD in global white matter and in frontoparietal white matter tracts, respectively. These findings suggest that age-related increase in mixing cost may result from both global and tract-specific disruption of cerebral white matter linked to the increased incidence of cardiovascular risks in older adults. Hum Brain Mapp 38:1588¿1603, 2017. © 2016 Wiley Periodicals, Inc.

Although the relationship between aging and cognitive decline is well established, there is substantial individual variability in the degree of cognitive decline in older adults. The present study investigates whether variability in cognitive performance in community-dwelling older adults is related to the presence of whole brain or tract-specific changes in white matter microstructure. Specifically, we examine whether age-related decline in performance on the Montreal Cognitive Assessment (MoCA), a cognitive screening tool, is mediated by the white matter microstructural decline. We also examine if this relationship is driven by the presence of cardiovascular risk factors or variability in cerebral arterial pulsatility, an index of cardiovascular risk. Sixty-nine participants (aged 43-87) completed behavioral and MRI testing including T1 structural, T2-weighted FLAIR, and diffusion-weighted imaging (DWI) sequences. Measures of white matter microstructure were calculated using diffusion tensor imaging analyses on the DWI sequence. Multiple linear regression revealed that MoCA scores were predicted by radial diffusivity (RaD) of white matter beyond age or other cerebral measures. While increasing age and arterial pulsatility were associated with increasing RaD, these factors did not mediate the relationship between total white matter RaD and MoCA. Further, the relationship between MoCA and RaD was specific to participants who reported at least one cardiovascular risk factor. These findings highlight the importance of cardiovascular risk factors in the presentation of cognitive decline in old age. Further work is needed to establish whether medical or lifestyle management of these risk factors can prevent or reverse cognitive decline in old age.

Flexible control of cognition bestows a remarkable adaptability to a broad range of contexts. While cognitive control is known to rely on frontoparietal neural architecture to achieve this flexibility, the neural mechanisms that allow such adaptability to context are poorly understood. In the current study, we quantified contextual demands on the cognitive control system via a priori estimation of information across three tasks varying in difficulty (oddball, go/nogo, and switch tasks) and compared neural responses across these different contexts. We report evidence of the involvement of multiple frequency bands during preparation and implementation of cognitive control. Specifically, a common frontoparietal delta and a central alpha process corresponded to rule implementation and motor response respectively. Interestingly, we found evidence of a frontal theta signature that was sensitive to increasing amounts of information and a posterior parietal alpha process only seen during anticipatory rule updating. Importantly, these neural signatures of context processing match proposed frontal hierarchies of control and together provide novel evidence of a complex interplay of multiple frequency bands underpinning flexible, contextually sensitive cognition.

Our understanding of the complex interplay between structural and functional organisation of brain networks is being advanced by the development of novel multi-modal analyses approaches. The Age-ility Project (Phase 1) data repository offers open access to structural MRI, diffusion MRI, and resting-state fMRI scans, as well as resting-state EEG recorded from the same community participants (n = 131, 15-35 y, 66 male). Raw imaging and electrophysiological data as well as essential demographics are made available via the NITRC website. All data have been reviewed for artifacts using a rigorous quality control protocol and detailed case notes are provided.

Anodal transcranial direct current stimulation (tDCS) over the motor cortex is considered a potential treatment for motor rehabilitation following stroke and other neurological pathologies. However, both the context under which this stimulation is effective and the underlying mechanisms remain to be determined. In this study, we examined the mechanisms by which anodal tDCS may affect motor performance by recording event-related potentials (ERPs) during a cued go/nogo task after anodal tDCS over dominant primary motor cortex (M1) in young adults (Experiment 1) and both dominant and non-dominant M1 in older adults (Experiment 2). In both experiments, anodal tDCS had no effect on either response time (RT) or response-related ERPs, including the cue-locked contingent negative variation (CNV) and both target-locked and response-locked lateralized readiness potentials (LRP). Bayesian model selection analyses showed that, for all measures, the null effects model was stronger than a model including anodal tDCS vs. sham. We conclude that anodal tDCS has no effect on RT or response-related ERPs during a cued go/nogo task in either young or older adults.

Cognitive control involves both proactive and reactive processes. Paradigms that rely on reactive control have shown that frontoparietal oscillatory synchronization in the theta frequency band is associated with interference control. This study examines whether proactive control is also associated with connectivity in the same frontoparietal theta network or involves a distinct neural signature. A task-switching paradigm was used to differentiate between proactive and reactive control processes, involved in preparing to switch or repeat a task and resolving post-target interference, respectively. We confirm that reactive control is associated with frontoparietal theta connectivity. Importantly, we show that proactive control is also associated with theta band oscillatory synchronization but in a different frontoparietal network. These findings support the existence of distinct proactive and reactive cognitive control processes that activate different theta frontoparietal oscillatory networks.

Purpose: Research popularity and scope for the application of transcranial direct current stimulation have been steadily increasing yet many fundamental questions remain unanswered. We sought to determine if anodal stimulation of either hemisphere leads to improved performance of the contralateral hand and/or altered function of the ipsilateral hand, or affects movement preparation, in older subjects. Method: In this cross-over, double blind, sham controlled study, 34 healthy aged participants (age range 40-86) were randomised to receive 20 minutes of stimulation to either the dominant or non-dominant motor cortex. The primary outcome was functional performance of both upper limbs measured by the Jebsen Taylor Test and hand grip strength. Additionally, we measured motor preparation using electrophysiological (EEG) recordings. Results: Anodal stimulation resulted in statistically significantly improved performance of the non-dominant hand (p < 0.01) but did not produce significant changes in the dominant hand on any measure (p > 0.05). This effect occurred irrespective of the hemisphere stimulated. Stimulation did not produce significant effects on measures of gross function, grip strength, reaction times, or electrophysiological measures on the EEG data. Conclusion: This study demonstrated that the hemispheres respond differently to anodal stimulation and the response appears to be task specific but not mediated by age.

Anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been proposed as a possible therapeutic rehabilitation technique for motor impairment. However, despite extensive investigation into the effects of anodal tDCS on motor output, there is little information on how anodal tDCS affects response processes. In this study, we used a cued go/nogo task with both directional and non-directional cues to assess the effects of anodal tDCS over the dominant (left) primary motor cortex on prepared and unprepared motor responses. Three experiments explored whether the effectiveness of tDCS varied with timing between stimulation and test. Healthy, right-handed young adults participated in a double-blind randomised controlled design with crossover of anodal tDCS and sham stimulation. In Experiment 1, twenty-four healthy young adults received anodal tDCS over dominant M1 at least 40 mins before task performance. In Experiment 2, eight participants received anodal tDCS directly before task performance. In Experiment 3, twenty participants received anodal tDCS during task performance. In all three experiments, participants responded faster to directional compared to non-directional cues and with their right hand. However, anodal tDCS had no effect on go/nogo task performance at any stimulation - test interval. Bayesian analysis confirmed that anodal stimulation had no effect on response speed. We conclude that anodal tDCS over M1 does not improve response speed of prepared or unprepared responses of young adults in a go/nogo task.