The Genetics Of Cognitive Deficits In Attention Deficit Hyperactivity Disorder (ADHD)
Funder
National Health and Medical Research Council
Funding Amount
$675,512.00
Summary
Attention deficit hyperactivity disorder (ADHD) is a common psychiatric disorder of childhood that is marked by age-inappropriate levels of inattention and-or hyperactivity-impulsivity. The disorder appears genetic with a number of different genes likely contributing risk for ADHD. This project takes an innovative approach by asking whether there are different genetic profiles associated with children with ADHD who do or do not have neurocognitive deficits.
Auditory Attentional Processes In Stroke Patients With Unilateral Neglect And In Normal Listeners
Funder
National Health and Medical Research Council
Funding Amount
$281,900.00
Summary
A common consequence of a stroke affecting the parietal lobe of the right hemisphere of the brain is a failure to attend to stimuli presented to the left side of the patient. This disorder, called unilateral spatial neglect, affects up to 50% of all stroke sufferers, and poses a significant problem for recovery of function. Neglect has been most widely studied in the modality of vision. Although neglect of auditory stimuli and of stimuli in other modalities has been reported, it has been studied ....A common consequence of a stroke affecting the parietal lobe of the right hemisphere of the brain is a failure to attend to stimuli presented to the left side of the patient. This disorder, called unilateral spatial neglect, affects up to 50% of all stroke sufferers, and poses a significant problem for recovery of function. Neglect has been most widely studied in the modality of vision. Although neglect of auditory stimuli and of stimuli in other modalities has been reported, it has been studied in much less detail, and the relationship between visual and auditory neglect has not been investigated using tasks of similar complexity. One aim of this project is to examine the relationship between auditory and visual neglect using tasks that are carefully matched for complexity and cognitive demands. A second aim relates to the important recent discovery that substantial changes in a visual scene can go unnoticed unless the observer's attention is drawn to them, a phenomenon termed change blindness. The project will examine the ability of normal listeners and of stroke patients to detect changes in complex auditory environments in which sounds arise from multiple sources located in different regions of space. We aim to establish whether there is a change deafness phenomenon analogous to change blindness, and if this is exacerbated in stroke patients with neglect. The results of this project will increase our understanding of the nature of normal auditory attentional processes and of their disruption as a consequence of stroke. The importance of these studies derives from the fact that hearing and attention to auditory stimuli serve a critical role in human communication and as an early warning system for events in the environment that are not within a person's visual field. Increased understanding of disturbances in auditory attention in neglect patients could lead to better rehabilitation of neglect, for which there is currently no effective treatment.Read moreRead less
Neuroanatomical Dynamics Of Attention In Stroke Patients And Healthy Individuals: A Magnetic Stimulation Investigation
Funder
National Health and Medical Research Council
Funding Amount
$360,363.00
Summary
Mechanisms of selective attention are of central importance in guiding human behaviour. The brain uses attention to enhance the processing of information that is behaviourally relevant, and to suppress irrelevant information. The operation of attention within sensory modalities (vision, touch, hearing) has been studied for many decades; however, little is known about how attention combines information between different senses. An understanding of 'crossmodal' attention is important for many reas ....Mechanisms of selective attention are of central importance in guiding human behaviour. The brain uses attention to enhance the processing of information that is behaviourally relevant, and to suppress irrelevant information. The operation of attention within sensory modalities (vision, touch, hearing) has been studied for many decades; however, little is known about how attention combines information between different senses. An understanding of 'crossmodal' attention is important for many reasons. First, real events in the environment provide inputs simultaneously from different locations to multiple senses, and these inputs must be integrated to yield coherent perception. Second, the most basic aspects of human perception depend upon attention; the brain implements selective mechanisms in order to filter the immense quantities of information that constantly bombard our sensory receptors. Finally, many neurological disorders are characterised by impairments of attention; these syndromes are debilitating for the patients themselves, and also place a heavy burden on caregivers and the healthcare system. This project will examine mechanisms of attention in healthy individuals and in stroke patients with attentional deficits. In all experiments, we will employ a new technique in neuroscience called 'transcranial magnetic stimulation' (TMS). TMS enables the safe and reversible stimulation of brain activity in humans. In the current project, we will use TMS with two broad objectives: (i) to determine the key brain areas involved in crossmodal attention in healthy individuals, and (ii) to treat attentional deficits that occur within and between the senses in stroke patients ('magnetic stimulation rehabilitation'). This research will provide important insights into the brain mechanisms that govern selective attention in the healthy brain, and will help guide future methods for managing and treating neurological disorders in which deficits of attention are prominent.Read moreRead less
Crossmodal Interactions In Selective Attention: A Combined Human Lesion/transcranial Magnetic Stimulation Study
Funder
National Health and Medical Research Council
Funding Amount
$188,182.00
Summary
Aspects of attention are of central importance in guiding human behaviour. The brain uses these mechanisms to enhance the processing of sensory information that is currently relevant for behaviour, and to suppress irrelevant sensory information. Although there is a considerable body of knowledge, from both animal and human research, on how attention operates within individual sensory modalities (vision, touch, hearing, etc.), very little is known about how attention integrates information across ....Aspects of attention are of central importance in guiding human behaviour. The brain uses these mechanisms to enhance the processing of sensory information that is currently relevant for behaviour, and to suppress irrelevant sensory information. Although there is a considerable body of knowledge, from both animal and human research, on how attention operates within individual sensory modalities (vision, touch, hearing, etc.), very little is known about how attention integrates information across these different modalities. An understanding of these 'crossmodal' attentional mechanisms is important for several reasons. First, much brain activity in primary sensory areas is modulated by the attentive state of the individual, so discovering how crossmodal attention works will facilitate our understanding of the neural mechanisms of sensory processing generally. Second, the most basic aspects of human perception are fundamentally dependent upon attention; without attention we would perceive inputs from the different senses as fragmentary, rather than as bound together into coherent multimodal representations. Finally, many acquired and developmental neurological disorders are characterised by debilitating impairments of attention. This project will examine crossmodal spatial attention in stroke patients with damage to an exclusively visual brain area (occipital cortex), or to a multisensory brain area (parietal cortex). It will also measure the extent of crossmodal interactions in healthy participants, using cortical transcranial magnetic stimulation (TMS) to induce reversible, 'virtual' lesions that mimic those of the stroke patients. The specific goals of the research are to explain how inputs from the senses of vision and touch interact to give rise to coherent perception; and to provide an empirical foundation for the development of more effective rehabilitative techniques for stroke patients, by exploiting any preserved crossmodal attentional mechanisms.Read moreRead less
A Study Addressing Motor, Cognitive And Attentional Deficits In Presymptomatic Gene Carriers For Huntington's Disease
Funder
National Health and Medical Research Council
Funding Amount
$180,330.00
Summary
Since the discovery of the Huntington's disease (HD) gene mutation there has been much controversy in the literature relating to whether there are any preclinical deficits in individuals who are gene positive for HD but who have not yet been clinically diagnosed with the disease. Our aim is to examine, over a three year period, the cognitive, attentional and motor performance of presymptomatic gene-positive, and negative, individuals on a wide variety of computerized experimental procedures, whi ....Since the discovery of the Huntington's disease (HD) gene mutation there has been much controversy in the literature relating to whether there are any preclinical deficits in individuals who are gene positive for HD but who have not yet been clinically diagnosed with the disease. Our aim is to examine, over a three year period, the cognitive, attentional and motor performance of presymptomatic gene-positive, and negative, individuals on a wide variety of computerized experimental procedures, which we have previously shown to be sensitive to deficits in individuals who have already been diagnosed with HD. If progressive behavioural changes in gene-positive individuals can be reliably documented to occur before the clinical symptoms of HD are evident, this would be of profound significance as it would allow a set of criteria to be established to assist in early detection of clinical onset of symptoms, and possibly permit use of newly-emerging therapies.Read moreRead less
Selective Attention And The Processing Of Observed Actions.
Funder
National Health and Medical Research Council
Funding Amount
$343,812.00
Summary
Our ability to understand the hand and face gestures of others is a crucial part of social interaction. Deficits in the ability to perceive others' actions are associated with clinical disorders such as autism and apraxia. We will examine how specific regions of the brain operate to process and recognise actions that we observe. This is a crucial first-step toward understanding and redefining clinical disorders such as apraxia that involve deficits in the perception of actions and gestures.
An Event Related Functional Magnetic Resonance Imaging (fMRI) Study Of Cognitive Deficits In Huntington's Disease
Funder
National Health and Medical Research Council
Funding Amount
$257,550.00
Summary
Huntington's disease (HD) is a progressive disorder clinically characterized by the onset of involuntary jerky movements, impaired voluntary movements, cognitive-attentional deterioration, and psychiatric symptoms. It is a consequence of progressive and selective brain degeneration. Over the last decade our research unit has made significant progress in describing the cognitive deficits in HD; however, we still don't know much about the parts of the brain that underlie these deficits. The aim of ....Huntington's disease (HD) is a progressive disorder clinically characterized by the onset of involuntary jerky movements, impaired voluntary movements, cognitive-attentional deterioration, and psychiatric symptoms. It is a consequence of progressive and selective brain degeneration. Over the last decade our research unit has made significant progress in describing the cognitive deficits in HD; however, we still don't know much about the parts of the brain that underlie these deficits. The aim of this project is to use event related functional magnetic resonance imaging (fMRI) to correlate structural and functional changes in the brain via the use of various cognitive behavioural measures. In this way we can elucidate what brain areas are responsible for various cognitive functions. In addition, we intend to ascertain how different brain areas decrement in function over time and to determine whether there is a relationship between rate of disease progression, age at onset and certain genetic characteristics. Understanding how the brain functions and how the disease progresses over time will be essential, from the point of view of patient management, when new drug treatments eventually permit prevention of the development, or slows further progress, of the disorder.Read moreRead less