Research Topics
| Michael ValenzuelaSummaryAffiliation: University of New South Wales Country: Australia Publications
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Detail Information
Publications
Assessment of complex mental activity across the lifespan: development of the Lifetime of Experiences Questionnaire (LEQ)Michael J Valenzuela
School of Psychiatry, University of New South Wales, The Neuropsychiatric Institute, Prince of Wales Hospital, NSW, Australia
Psychol Med 37:1015-25. 2007..Since there is no instrument that comprehensively assesses complex mental activity through the lifespan, we developed and tested the Lifetime of Experiences Questionnaire (LEQ) in a prospective study of healthy ageing...
Can cognitive exercise prevent the onset of dementia? Systematic review of randomized clinical trials with longitudinal follow-upMichael Valenzuela
School of Psychiatry, University of New South Wales and Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, NSW, Australia
Am J Geriatr Psychiatry 17:179-87. 2009..The aim of this report was to therefore systematically review results from clinical trials, which have examined the effect of cognitive exercise on longitudinal cognitive performance in healthy elderly individuals...- Multiple biological pathways link cognitive lifestyle to protection from dementiaMichael J Valenzuela
Regenerative Neuroscience Group, School of Psychiatry, University of New South Wales, Sydney, Australia
Biol Psychiatry 71:783-91. 2012..Potential mechanisms include disease modification, neuroprotection, and compensation. Prospective, population-based brain series provide the rare opportunity to test the plausibility of these mechanisms in humans... - Magnetic resonance spectroscopy in ADM J Valenzuela
School of Psychiatry, University of New South Wales, and Neuropsychiatric Institute, The Prince Wales Hospital, Randwick, Sydney, Australia
Neurology 56:592-8. 2001..MRS has promise for predicting cognitive status and monitoring pharmacologic efficacy, and can assess cortical and subcortical neurochemical change... - Complex mental activity and the aging brain: molecular, cellular and cortical network mechanismsMichael J Valenzuela
School of Psychiatry, University of New South Wales, Sydney, Australia
Brain Res Rev 56:198-213. 2007..This paper will explore the neurobiological and clinical implications of this framework, in particular in the context of age-related brain disease... - Brain reserve and the prevention of dementiaMichael J Valenzuela
School of Psychiatry, University of New South Wales and Neuropsychiatric Institute, The Prince of Wales Hospital, Sydney, Australia
Curr Opin Psychiatry 21:296-302. 2008..To evaluate and synthesize recent evidence linking mental activity and dementia risk, which commonly invokes 'brain reserve' as the mediating construct... - Neural precursors from canine skin: a new direction for testing autologous cell replacement in the brainMichael J Valenzuela
School of Psychiatry, The University of New South Wales, Sydney, Australia
Stem Cells Dev 17:1087-94. 2008..This system may be an effective alternative for autologous neurorestorative cell replacement in canine models for further translational research... 
Lifespan mental activity predicts diminished rate of hippocampal atrophyMichael J Valenzuela
School of Psychiatry, University of New South Wales, Sydney, Australia
PLoS ONE 3:e2598. 2008..Our objective was to determine whether individual differences in lifespan complex mental activity are linked to altered rates of hippocampal atrophy independent of global measures of neurodegeneration...- Cognitive lifestyle and long-term risk of dementia and survival after diagnosis in a multicenter population-based cohortMichael Valenzuela
Brain and Ageing Research Program, University of New South Wales, Sydney, New South Wales, Australia
Am J Epidemiol 173:1004-12. 2011..are necessary for a protective link with dementia incidence. There was little evidence of an effect of cognitive lifestyle on survival after dementia diagnosis... - Memory training alters hippocampal neurochemistry in healthy elderlyMichael J Valenzuela
Neuropsychiatric Institute, The Prince of Wales Hospital, Euroa Centre, Randwick, NSW 2031, Australia
Neuroreport 14:1333-7. 2003..Biochemical changes related to cellular energy and cell-membrane turnover were found to increase after structured memory exercises and were limited to the medial temporal lobe... - Brain ageing in the new millenniumJ N Trollor
School of Psychiatry, University of New South Wales and Neuropsychiatric Institute, The Prince of Wales Hospital, Sydney, Australia
Aust N Z J Psychiatry 35:788-805. 2001..This paper examines the current literature pertaining to brain ageing. The objective of this review is to provide an overview of the effects of ageing on brain structure and function and to examine possible mediators of these changes... - Brain reserve and cognitive decline: a non-parametric systematic reviewMichael J Valenzuela
School of Psychiatry, University of New South Wales, AustraliaThe Black Dog Institute, Prince of Wales Hospital, Sydney, Australia
Psychol Med 36:1065-73. 2006..Our aim was to quantitatively review an independent set of longitudinal studies of cognitive change in order to clarify these factors... - Cortical responses to a graded working memory challenge predict functional decline in mild cognitive impairmentNicole A Kochan
Brain and Ageing Research Program, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
Biol Psychiatry 70:123-30. 2011..We observed greater deactivation of posteromedial cortex (PMC) under conditions of increased WM load in MCI compared with control subjects. Our objective here is to test whether this paradigm can predict ensuing functional decline... - Impact of load-related neural processes on feature binding in visuospatial working memoryNicole A Kochan
Brain and Ageing Research Program, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia
PLoS ONE 6:e23960. 2011..However the neural mechanisms underlying this process, and its modulation by task and load effects, are not well understood... - Cognitive and memory training in adults at risk of dementia: a systematic reviewNicola J Gates
School of Psychiatry, University of New South Wales, RandwickNSW 2031, Australia
BMC Geriatr 11:55. 2011.... - A novel method for the topographic analysis of neural activity reveals formation and dissolution of 'Dynamic Cell Assemblies'Michael Breakspear
Brain Dynamics Centre, Westmead Hospital, Westmead, NSW, 2145, Australia
J Comput Neurosci 16:49-68. 2004..In particular, the character of transitions between consecutive synchronous epochs may reflect important aspects of information processing and cognitive flexibility... - Study of Mental Activity and Regular Training (SMART) in at risk individuals: a randomised double blind, sham controlled, longitudinal trialNicola J Gates
School of Psychiatry, University of New South Wales, and Neuropsychiatric Institute, Prince of Wales Hospital, Randwick NSW 2031, Australia
BMC Geriatr 11:19. 2011.... - Magnetic resonance spectroscopy and its applications in psychiatryGin S Malhi
Mood Disorders Unit, The Villa, Prince of Wales Hospital, Randwick NSW 2031, Sydney, Australia
Aust N Z J Psychiatry 36:31-43. 2002..This paper briefly describes neuroimaging using magnetic resonance spectroscopy (MRS) and provides a systematic review of its application to psychiatric disorders... - Screening for bipolar disorder: the utility and comparative properties of the MSS and MDQ measuresGordon Parker
School of Psychiatry, University of New South Wales, Australia
J Affect Disord 109:83-9. 2008..Our objective was to further determine the diagnostic utility of the Mood Swings Survey (MSS) in distinguishing bipolar and unipolar disorders, and draw comparisons between this measure and the widely-used Mood Disorder Questionnaire (MDQ)... - Symbiotic relationship between brain structure and dynamicsMikail Rubinov
Black Dog Institute and School of Psychiatry, University of New South Wales, Sydney, Australia
BMC Neurosci 10:55. 2009..We provide further biophysical justification for this model and quantitatively characterize the relationship between structure, function and dynamics that accompanies the ensuing self-organization... - Synchronous gamma activity: a review and contribution to an integrative neuroscience model of schizophreniaKwang-Hyuk Lee
Cognitive Neuroscience Unit, Department of Psychology, University of Sydney, and The Brain Dynamics Centre, Westmead Hospital, 2145, Sydney, NSW, Australia
Brain Res Brain Res Rev 41:57-78. 2003..It is concluded that measures of Gamma synchrony offer a valuable window into the core integrative disturbance in schizophrenia cognition... - Simulation of neuronal death and network recovery in a computational model of distributed cortical activityMikail Rubinov
School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
Am J Geriatr Psychiatry 17:210-7. 2009..The authors utilize a model of activity-dependent neuronal plasticity to study the interplay between synaptogenesis, neuronal death, and neurogenesis on the resulting pattern of neuronal connectivity... - Modeling magnification and anisotropy in the primate foveal confluenceMark M Schira
School of Psychiatry and The Black Dog Institute, University of New South Wales, Sydney Australia
PLoS Comput Biol 6:e1000651. 2010..Our models demonstrate that the organization follows clear morphogenetic principles that are essential for our understanding of foveal vision in daily life... - The foveal confluence in human visual cortexMark M Schira
School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
J Neurosci 29:9050-8. 2009..75 degrees, the cortical representations for both V2 and V3 are larger than that of V1, indicating that more neuronal processing power is dedicated to second-level analysis in this small but important part of the visual field... - Spatiotemporal wavelet resampling for functional neuroimaging dataMichael Breakspear
Brain Dynamics Centre, Westmead Hospital and University of Sydney, Sydney, Australia
Hum Brain Mapp 23:1-25. 2004..The limitations and possible extensions of the proposed technique are discussed... - Small-world properties of nonlinear brain activity in schizophreniaMikail Rubinov
Black Dog Institute and School of Psychiatry, University of New South Wales, Sydney, Australia
Hum Brain Mapp 30:403-16. 2009..This randomization may underlie the cognitive disturbances characteristic of schizophrenia... - The nonlinear theory of schizophreniaMichael Breakspear
The School of Psychiatry, University of New South Wales and the Black Dog Institute, Australia
Aust N Z J Psychiatry 40:20-35. 2006..Only a few studies of brain activity in schizophrenia, however, have used nonlinear methods. This review paper evaluates the contribution of the nonlinear sciences towards understanding schizophrenia... - The multiscale character of evoked cortical activityMichael Breakspear
The Black Dog Institute, Hospital Rd, Prince of Wales Hospital and The School of Psychiatry, University of New South Wales, Randwick, NSW 2031, Australia
Neuroimage 30:1230-42. 2006..It also affords a quantitative means of testing hierarchical and multiscale models of cortical activity... - Multi-frequency phase locking in human somatosensory cortexAngela J Langdon
School of Psychiatry, University of New South Wales, Sydney, Australia
Prog Biophys Mol Biol 105:58-66. 2011..The existence of n:m phase synchronization demonstrates the contribution of intrinsic cortical dynamics to stimulus encoding and provides a novel phenomenological criteria for the validation of large-scale models of the brain... - Cognitive exercise and its role in cognitive function in older adultsNicola Gates
Neuropsychiatric Institute, Prince of Wales Hospital, Randwick, Sydney, NSW 2031, Australia
Curr Psychiatry Rep 12:20-7. 2010..Finally, practical issues, including the strengths and weaknesses of commercial products, are explored, and recommendations for further research and clinical implementation are made... - Meta-analysis of plasma amyloid-β levels in Alzheimer's diseaseFei Song
Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, Australia
J Alzheimers Dis 26:365-75. 2011..Baseline Aβ1-40 and Aβ1-42 levels in cognitively normal elderly individuals might be predictors of higher rates of progression to AD, and should be further explored as potential biomarkers... - Dynamics of a neural system with a multiscale architectureMichael Breakspear
The Black Dog Institute, Prince of Wales Hospital and School of Psychiatry, University of New South Wales, Randwick, NSW 2031, Australia
Philos Trans R Soc Lond B Biol Sci 360:1051-74. 2005..A framework for relating the dynamical behaviour of the system to measured observables is presented and further extensions to capture wave phenomena and mode coupling are suggested... - Harnessing brain and cognitive reserve for the prevention of dementiaMichael Valenzuela
School of Psychiatry, University of New South Wales, Sydney Neuropsychiatric Institute, Prince of Wales Hospital, Randwick, Australia
Indian J Psychiatry 51:S16-21. 2009..High quality randomized clinical trials are therefore the most urgent priority in this area so that the promise of brain and cognitive reserve can be harnessed for the purpose of the primary prevention of dementia... - Human induced rotation and reorganization of the brain of domestic dogsTaryn Roberts
Faculty of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
PLoS ONE 5:e11946. 2010.... - "Dynamic" connectivity in neural systems: theoretical and empirical considerationsMichael Breakspear
School of Physics, University of Sydney, NSW, Australia
Neuroinformatics 2:205-26. 2004..We conclude by suggesting that techniques based on dynamical interdependence--or "dynamical connectivity"--show significant potential for extracting meaningful information from functional neuroimaging data... - Nonlinear phase desynchronization in human electroencephalographic dataMichael Breakspear
Brain Dynamics Centre, Department of Psychological Medicine, Westmead Hospital, Darcy Road, Westmead, Sydney, NSW 2048, Australia
Hum Brain Mapp 15:175-98. 2002..Statistical analysis reveals that this null hypothesis can be robustly rejected in a small number (approximately 4%) of EEG epochs. These findings are discussed with reference to the adaptive function and complex dynamics of the brain... - Inching toward Bethlehem: mapping melancholiaGordon Parker
School of Psychiatry, University of New South Wales, Sydney, Australia
J Affect Disord 123:291-8. 2010..Analyses then examined the capacity of both the refined symptom and validator sets to discriminate the assigned melancholic and non-melancholic subjects... - Homocysteine as a risk factor for cognitive impairment in stroke patientsPerminder S Sachdev
School of Psychiatry, University of New South Wales, Prince of Wales Hospital, Sydney, Australia
Dement Geriatr Cogn Disord 15:155-62. 2003..Elevated total homocysteine (tHcy) levels are associated with an increased risk of cerebrovascular disease. It is uncertain whether tHcy is also an independent risk factor for cognitive impairment... - Cognitive correlates of 1H MRS measures in the healthy elderly brainAmy J Ross
School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
Brain Res Bull 66:9-16. 2005..This research highlights the importance of the relationship between regional brain changes and cognitive function in the ageing brain, and suggests that MRS may be a sensitive marker of subclinical change in cognition... - Frequency and clinical, neuropsychological and neuroimaging correlates of apathy following stroke - the Sydney Stroke StudyHenry Brodaty
School of Psychiatry, University of New South Wales, Randwick, Australia
Psychol Med 35:1707-16. 2005..The frequency and clinical, neuropsychological and neuroimaging correlates of apathy in patients who have had a stroke are inadequately defined... - Cognitive leisure activities, but not watching TV, for future brain benefitsMichael J Valenzuela
Neurology 67:729; author reply 729. 2006 - Brain reserve and dementia: a systematic reviewMichael J Valenzuela
The Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, Australia
Psychol Med 36:441-54. 2006..So far there have been several epidemiological reports but no systematic review to put conflicting results into context. Our aim was to quantitatively review evidence for the effect of brain reserve on incident dementia...