New Zealand Brain Research Institute

Napier, New Zealand

New Zealand Brain Research Institute

Napier, New Zealand
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Poudel G.R.,New Zealand Brain Research Institute | Poudel G.R.,Christchurch Hospital | Poudel G.R.,Monash University | Innes C.R.H.,New Zealand Brain Research Institute | And 5 more authors.
NeuroImage | Year: 2013

Sleep loss leads to both time-on-task slowing of responsiveness and increased frequency of transient response errors. The consequences of such errors during real-world visuomotor tasks, such as driving, are serious and life threatening. To investigate the neuronal underpinning of time-on-task and transient errors during a visuomotor tracking task following sleep restriction, we performed fMRI on 20 healthy individuals when well-rested and when sleep-restricted while they performed a 2-D pursuit-tracking task. Sleep restriction to 4-h time-in-bed was associated with significant time-on-task decline in tracking performance and an increased number of transient tracking errors. Sleep restriction was associated with time-on-task decreases in BOLD activity in task-related areas, including the lateral occipital cortex, intraparietal cortex, and primary motor cortex. In contrast, thalamic, anterior cingulate, and medial frontal cortex areas showed overall increases irrespective of time-on-task after sleep-restriction. Furthermore, transient errors after sleep-restriction were associated with distinct transient BOLD activations in areas not involved in tracking task per se, in the right superior parietal cortex, bilateral temporal cortex, and thalamus. These results highlight the distinct cerebral underpinnings of sustained and transient modulations in alertness during increased homeostatic drive to sleep. Ability to detect neuronal changes associated with both sustained and transient changes in performance in a single task allowed us to disentangle neuronal mechanisms underlying two important aspects of sustained task performance following sleep loss. © 2013 Elsevier Inc.

Toppi J.,University of Rome La Sapienza | Toppi J.,Neuroelectrical Imaging and BCI Laboratory | Astolfi L.,University of Rome La Sapienza | Astolfi L.,Neuroelectrical Imaging and BCI Laboratory | And 8 more authors.
NeuroImage | Year: 2016

An episode of complete failure to respond during an attentive task accompanied by behavioural signs of sleep is called a behavioural microsleep. We proposed a combination of high-resolution EEG and an advanced method for time-varying effective connectivity estimation for reconstructing the temporal evolution of the causal relations between cortical regions when microsleeps occur during a continuous visuomotor task. We found connectivity patterns involving left-right frontal, left-right parietal, and left-frontal/right-parietal connections commencing in the interval [- 500; - 250] ms prior to the onset of microsleeps and disappearing at the end of the microsleeps. Our results from global graph indices derived from effective connectivity analysis have revealed EEG-based biomarkers of all stages of microsleeps (preceding, onset, pre-recovery, recovery). In particular, this raises the possibility of being able to predict microsleeps in real-world tasks and initiate a 'wake-up' intervention to avert the microsleeps and, hence, prevent injurious and even multi-fatality accidents. © 2015 Elsevier Inc.

Van Stockum S.,New Zealand Brain Research Institute | Van Stockum S.,University of Otago | Macaskill M.R.,New Zealand Brain Research Institute | Macaskill M.R.,University of Otago | And 4 more authors.
European Journal of Neuroscience | Year: 2013

Many studies have shown that Parkinson's disease (PD) affects not only the ability to generate voluntary saccades but also the ability to suppress reflexive saccades (hyper-reflexivity). To further investigate these apparently contradictory effects of PD on the saccade system we adapted a well-known dual-task paradigm (Deubel, 2008) to measure saccades with and without a peripheral discrimination task. Previously we reported that the concurrent performance of a perceptual discrimination task abnormally reduced the latencies of reflexive saccades in PD. Here we report the effects of the concurrent discrimination task on the generation of voluntary saccades in a PD and a control group. As expected, when saccades were performed without the discrimination task the PD group made voluntary saccades with longer latencies and smaller gain than the control group. The concurrent performance of the perceptual discrimination task facilitated the initiation of voluntary saccades in both groups, but, surprisingly, this facilitatory effect was stronger in the PD group than in the control group. In addition, in the PD group voluntary saccades were abnormally facilitated by the peripheral symbol-changes that occur during saccade planning in this paradigm. The results of this study may help to clarify apparently contradictory oculomotor abnormalities observed in PD. © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Woodward L.J.,University of Canterbury | Woodward L.J.,New Zealand Brain Research Institute | Clark C.A.C.,University of Oregon | Bora S.,University of Canterbury | Inder T.E.,University of Washington
PLoS ONE | Year: 2012

Background: Cerebral white matter abnormalities on term MRI are a strong predictor of motor disability in children born very preterm. However, their contribution to cognitive impairment is less certain. Objective: Examine relationships between the presence and severity of cerebral white matter abnormalities on neonatal MRI and a range of neurocognitive outcomes assessed at ages 4 and 6 years. Design/Methods: The study sample consisted of a regionally representative cohort of 104 very preterm (≤32 weeks gestation) infants born from 1998-2000 and a comparison group of 107 full-term infants. At term equivalent, all preterm infants underwent a structural MRI scan that was analyzed qualitatively for the presence and severity of cerebral white matter abnormalities, including cysts, signal abnormalities, loss of white matter volume, ventriculomegaly, and corpus callosal thinning/myelination. At corrected ages 4 and 6 years, all children underwent a comprehensive neurodevelopmental assessment that included measures of general intellectual ability, language development, and executive functioning. Results: At 4 and 6 years, very preterm children without cerebral white matter abnormalities showed no apparent neurocognitive impairments relative to their full-term peers on any of the domain specific measures of intelligence, language, and executive functioning. In contrast, children born very preterm with mild and moderate-to-severe white matter abnormalities were characterized by performance impairments across all measures and time points, with more severe cerebral abnormalities being associated with increased risks of cognitive impairment. These associations persisted after adjustment for gender, neonatal medical risk factors, and family social risk. Conclusions: Findings highlight the importance of cerebral white matter connectivity for later intact cognitive functioning amongst children born very preterm. Preterm born children without cerebral white matter abnormalities on their term MRI appear to be spared many of the cognitive impairments commonly associated with preterm birth. Further follow-up will be important to assess whether this finding persists into the school years. © 2012 Woodward et al.

Alamri Y.,New Zealand Brain Research Institute
New Zealand Medical Journal | Year: 2017

AIM: Children who are admitted with acute orthopaedic problems are often fit and healthy. The house officer (ie, intern) is required to carry out the formal clerking/admission of inpatients. However, they are often also busy with sick ward patients, which leads to delays in formal clerking of these children until after they have been to the operating theatre (OT). The aim of this study was to assess what information, if any, is missed in children who were seen by a house officer prior to going to OT, compared to those who were not. METHODS: All patients admitted to the paediatric surgical ward, under the orthopaedics service care, between 1 September 2015 and 30 November 2015 were included in this study. Information on age, sex, medical background, details of the admission and post-operative complications were collected. RESULTS: A total of 139 children were admitted during the study period. The median age was 7.4 years (range, 0.2–17.5) and a male:female ratio of 1.3:1. In this study, there was no statistically significant difference in patient characteristics, post-operative complications or length of hospital stay. However, patients clerked by house officers had better documentation of their regular medications and non-orthopaedic examination findings. CONCLUSION: To the author’s knowledge, this is the first study to examine the effect of house officer admission on paediatric orthopaedic patient outcomes. A suggested solution would be to encourage documentation of medication history and examination findings by the anaesthetic registrar, since all patients must be reviewed pre-operatively. © NZMA.

Poudel G.R.,New Zealand Brain Research Institute | Poudel G.R.,Christchurch Hospital | Innes C.R.H.,New Zealand Brain Research Institute | Innes C.R.H.,Christchurch Hospital | And 3 more authors.
Sleep | Year: 2012

Objectives: To investigate changes in resting cerebral blood flow (CBF) after acute sleep restriction. To investigate the extent to which changes in CBF after sleep restriction are related to drowsiness as manifested in eye-video. Design: Participants were scanned for 5 min using arterial spin labeling (ASL) perfusion imaging after both sleep-restricted and rested nights. Participants were rated for visual signs of drowsiness in the eye-video recorded during the scan. Setting: Lying supine in a 3-Tesla magnetic resonance imaging scanner. Participants: Twenty healthy adults (age 20-37 yr) with no history of neurologic, psychiatric, or sleep disorder, and with usual time in bed of 7.0-8.5 h. Interventions: In the night before the sleep-restricted session, participants were restricted to 4 h time in bed. Results: There was an overall reduction in CBF in the right-lateralized fronto-parietal attentional network after acute sleep restriction, although this was largely driven by participants who showed strong signs of drowsiness in the eye-video after sleep restriction. Change in CBF correlated with change in drowsiness in the basal forebrain-cingulate regions. In particular, there was a pronounced increase in CBF in the basal forebrain and anterior and posterior cingulate cortex of participants who remained alert after sleep restriction. Conclusions: The pattern of cerebral activity after acute sleep restriction is highly dependent on level of drowsiness. Nondrowsy individuals are able to increase activity in the arousal-promoting brain regions and maintain activity in attentional regions. In contrast, drowsy individuals are unable to maintain arousal and show decreased activity in both arousal-promoting and attentional regions.

Alamri Y.A.S.,New Zealand Brain Research Institute
Journal of Medical Ethics | Year: 2016

It is human nature, perhaps more so for doctors and nurses, to comfort children in distress. Unfortunately, however, necessary medical procedures carried out by healthcare providers (eg, venipuncture) can often result in pain and discomfort, which may in turn cause the provider a degree of guilt and distress. Is it ever acceptable to comfort a paediatric patient with a kiss? This essay examines the literature published on this subject reflecting on a recent encounter with a patient. © 2016 by the BMJ Publishing Group Ltd & Institute of Medical Ethics.

Harland B.C.,University of Canterbury | Collings D.A.,University of Canterbury | Mcnaughton N.,University of Otago | Abraham W.C.,University of Otago | And 3 more authors.
Hippocampus | Year: 2014

Injury to the anterior thalamic nuclei (ATN) may affect both hippocampus and retrosplenial cortex thus explaining some parallels between diencephalic and medial temporal lobe amnesias. We found that standard-housed rats with ATN lesions, compared with standard-housed controls, showed reduced spine density in hippocampal CA1 neurons (basal dendrites, -11.2%; apical dendrites, -9.6%) and in retrospenial granular b cortex (Rgb) neurons (apical dendrites, -20.1%) together with spatial memory deficits on cross maze and radial-arm maze tasks. Additional rats with ATN lesions were also shown to display a severe deficit on spatial working memory in the cross-maze, but subsequent enriched housing ameliorated their performance on both this task and the radial-arm maze. These enriched rats with ATN lesions also showed recovery of both basal and apical CA1 spine density to levels comparable to that of the standard-housed controls, but no recovery of Rgb spine density. Inspection of spine types in the CA1 neurons showed that ATN lesions reduced the density of thin spines and mushroom spines, but not stubby spines; while enrichment promoted recovery of thin spines. Comparison with enriched rats that received pseudo-training, which provided comparable task-related experience, but no explicit spatial memory training, suggested that basal CA1 spine density in particular was associated with spatial learning and memory performance. Distal pathology in terms of reduced integrity of hippocampal and retrosplenial microstructure provides clear support for the influence of the ATN lesions on the extended hippocampal system. The reversal by postoperative enrichment of this deficit in the hippocampus but not the retrosplenial cortex may indicate region-specific mechanisms of recovery after ATN injury. © 2014 Wiley Periodicals, Inc.

Anderson T.J.,University of Otago | MacAskill M.R.,New Zealand Brain Research Institute
Nature Reviews Neurology | Year: 2013

The neural pathways and brain regions involved in eye movements during ocular fixation and gaze control include the cerebrum, brainstem and cerebellum, and abnormal eye movements can indicate the presence of neurodegeneration. In some patients, oculomotor signs are key to making a diagnosis. Careful clinical examination of eye movements in patients with neurodegenerative disorders is, therefore, an invaluable adjunct to neurological and cognitive assessments. Eye movement recordings in the laboratory are generally not necessary for diagnostic purposes, but can be a useful addition to the clinical examination. Laboratory recordings of eye movements can provide valuable information about disease severity, progression or regression in neurodegenerative disease, and hold particular promise for objective evaluation of the efficacy of putative neuroprotective and neurorestorative therapies. For example, aspects of saccade performance can be tested to probe both motor and cognitive aspects of oculomotor behaviour. This Review describes the oculomotor features of the major age-related movement disorders, including Parkinson disease, Huntington disease, dementia and other neurodegenerative disorders. Findings in presymptomatic individuals and changes associated with disease progression are discussed. © 2013 Macmillan Publishers Limited. All rights reserved.

Miles A.,University of Canterbury | Miles A.,University of Auckland | Huckabee M.-L.,University of Canterbury | Huckabee M.-L.,New Zealand Brain Research Institute
International Journal of Speech-Language Pathology | Year: 2013

This study investigated the inter-rater and intra-rater reliability of subjective judgements of cough in patients following inhalation of citric acid. Eleven speech-language pathologists (SLPs) currently using cough reflex testing in their clinical practice (experienced raters) and 34 SLPs with no experience using cough reflex testing (inexperienced raters) were recruited to the study. Participants provided a rating of strong, weak, or absent to 10 video segments of cough responses elicited by inhalation of nebulized citric acid. The same video segments presented in a different sequence were re-evaluated by the same clinicians following a 15-minute break. Inter-rater reliability for experienced raters was calculated with a Fleiss' generalized kappa of .487; intra-rater reliability was higher with a kappa of .700. Inexperienced raters showed similar reliability, with kappa values for inter-rater and intra-rater reliability of .363 and .618, respectively. In conclusion, SLPs demonstrate only fair-to-moderate reliability in subjectively judging a patient's cough response to citric acid. Experience in making cough judgements does not improve inter-rater reliability significantly. Further validity and reliability research, including an evaluation of the effect of training on judgement reliability, would be beneficial for guiding clinical policies. © 2013 The Speech Pathology Association of Australia Limited.

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