Patricia L. Davies - US grants

The maturation of the frontal lobe of the brain may play an important role in the development of information processing abilities. Recordings of EEG and event-related potentials (ERPs) permit the examination of regional brain activity during the performance of specific information processing tasks. The goals of this research plan are: 1) to establish electrophysiological markers of development through adolescence; and 2) to relate the electrophysiological data to cognitive performance changes that occur in adolescence. This process will allow us to relate regional brain development as reflected in electrophysiological data to behavioral changes across ages. Three hypotheses are to be examined: 1) ERP patterns that are reflective of specific cognitive functioning will vary for participants of different ages; 2) ERPs associated with posterior regions of the brain will manifest adult properties at a younger age than ERPs associated with frontal regions of the brain; and 3) the ERP data will correlate with performance on behavioral tasks. These hypothesis will be tested by examining ERP components recorded while children and young adults perform specific information processing tasks. The educational objectives of this mentored research scientist award are: 1) The PI will expand research skills and extend research network. Dr. Sid Segalowitz will serve as mentor for this experience in the laboratory. The PI will attend courses that reinforce the laboratory experience. 2) Advance research wills of PI and develop new research projects addressing clinical intervention in rehabilitation. This will be accomplished through the completion of the research plan and the initiation of pilot studies that will examine ERP patterns in children with disabilities. 3) Promote skills in the dissemination of research results and laboratory management. The PI will prepare manuscripts for peer reviewed journals reporting the results of these studies and supervise graduate students in related research projects.

[unreadable] DESCRIPTION (provided by applicant): The long-term goals of this program of research are to contribute to the increasing amount of evidence for continued development of the brain into early adulthood. Electroencephalographic (EEC) measures and neuropsychological assessments are being employed to investigate the interrelationships of maturation of specific brain regions and the development of cognitive and emotional processes in children and adolescents. The results obtained from this study will be applied to the development of a model that will elucidate interrelationships of variables representing stimulus-response mechanisms, trait, and state characteristics of an individual and their associated changes in various ERP measurements observed during periodic assessments in typically developing children using a longitudinal design. The goals of the proposed research are to: 1) Determine if developmental trends exist in the reliability of ERPs, and 2) Clarify the relationship of executive functions, specifically attention, to ERPs components and ERP reliability. The research design entails obtaining multiple channel EEC recordings from 30 participants in each of 3 age groups (8-yr olds, 12-yr olds and young adults) while performing 3 ERP paradigms: the novelty auditory oddball (an auditory discrimination task), contingent negative variation (a sustained attention task), and the error-related negativity (error-monitoring in simple visual discrimination task). Each participant will complete these EEG/ERP tasks in each of two visits separated by a 1-2 week period. Split-half and test-retest reliability coefficients will then be determined for the principle components of these ERP paradigms. Split-half and test-retest will then be recomputed using the standardized residuals instead of the original ERP measures. These new reliability coefficients are expected to be higher than those not accounting for variance due to waveform processing. Relationships of attentional measures and ERP reliability and the ERP components (i.e, CNV, P3a, P3b and ERN) will be evaluated. Health related impacts include understanding changes in the brain in relation to attention in childhood and adolescence. In addition, results have the potential of providing a wealth of information regarding individual differences in cognitive ERPs and ERP reliability. This information will be helpful, especially when clinical populations (e.g., attention deficit disorders and learning disabilities) are included in developmental ERP studies. [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): The long-term goals of this program of research on sensory gating in children is based on building a multivariate model that will help elucidate which factors contribute to measuring stable sensory gating in children and testing the model to determine if it functions similarly for children and adults. The model states that measures of sensory gating may vary from individual to individual because the outcome represents an interaction of stimulus presentation protocols, such as stimulus intensity, number of trials, and task instructions, with several trait and state variables of the participant including but not limited to maturation of prefrontal cortex and executive function (attention), alpha/ nicotinic acetylcholine receptor gene (gene abnormalities), and stress level at electroencephalography (EEC) testing (noradrenergic tone). The proposed project will contribute to understanding the role of attention in this model of sensory gating. The three specific aims of the project are: 1) To determine if the manipulation of attention will differentially effect sensory gating in adults and children; 2) To demonstrate that the developmental nature of attention coincides with changes in levels of sensory gating in children; and 3) To determine the split-half and test-retest reliability measures of sensory gating in children and adults. The research design entails assessing 40 young adults and 40 children, ages 6 to 12 years, during two visits. EEC data will be collected using 3 variations of the Sensory Gating event-related potential (ERP) paradigm which manipulate the focus of attention. One version will be used twice, once on each visit, in order to obtain test-retest reliability measures. To investigate maturation of attention in children and its relationship to changes in sensory gating performance, several behavioral measures of attention will be obtained. The health related impact of the project is a better understanding of the variability in sensory gating measures observed in children. Such knowledge will lead to more reliable and objective measures of the brain's ability and inability to gate sensory information which will allow valid early identification of neurodevelopmental disorders such as in schizophrenia and autism. Improved measures of sensory gating may lead to productive and cost efficient studies assessing treatment effectiveness. [unreadable] [unreadable] [unreadable]

Brain-computer interfaces (BCIs) are hardware and software systems that allow users to interact with computer applications by changing their mental activity, which causes variations in weak electrical voltages produced by the brain. BCIs measure these voltages in one of two ways: invasive methods use electrodes implanted in the brain, while noninvasive methods use electrodes resting on the scalp that are part of a cap worn by the user. A long-term goal of BCI research is a new mode of communication for subjects with diseases and injuries resulting in the loss of voluntary muscle control, such as amyotrophic lateral sclerosis (ALS), multiple sclerosis, high-level spinal cord injuries or severe cerebral palsy. If all voluntary muscle control is lost, a locked-in syndrome results in which a person is unable to communicate with the outside world. BCIs can provide a new way for users to communicate with their caregivers and to control devices such as televisions, wheelchairs, speech synthesizers and computers. While BCI technology holds great promise, most BCI systems remain in research labs. The goal of this project is to remove barriers to practical, noninvasive, BCI technology that exist in current approaches, and to field test the resulting BCI systems in the homes of users who suffer from motor impairments. Limitations of current BCI systems that will be addressed include the difficulty of applying an electrode cap, signal artifacts due to other assistive technology in the user's environment, and long computer and user training times required to calibrate current EEG classification algorithms.

A key barrier to practical BCI systems is the lack of methods for reliable, fast classification of EEG signals. In this project, this limitation will be addressed by conducting experiments in three areas. One set of experiments will investigate the quality of EEG signals recorded in subjects' homes and the performance of BCI applications in real-time in the homes. The second set of experiments will involve new algorithms for EEG artifact removal and signal classification that are tailored for EEG recorded in subjects' homes and for real-time use. For the second set of experiments, new user interfaces will be studied and compared to currently available interfaces. For the third set of experiments, several different user interface designs for BCI applications will be developed and studied. The effectiveness of visual and auditory feedback provided to the user in real-time will be investigated.

This interdisciplinary project involves a team of investigators and students from diverse backgrounds. Faculty and students in computer science will design and implement algorithms and the BCI user interface. Faculty and students in occupational therapy will guide the field testing of BCI systems and will guide the evaluation of these experiments. Progress will be evaluated in a number of ways, including experiments comparing EEG signal representations and classifiers by accuracy, reliability, and training time, and field tests of BCI systems. Ultimately, the project's success will be measured by new or improved means of individuals interacting with computers in their homes for purposes of communication with others and control of assistive devices like wheelchairs.

Broader Impacts: This project will develop a new technology for sensing and analyzing electroencephalogram signals (EEG) from human subjects. The resulting technology will help advance brain imaging and its application. The long term goal of this research is a new brain-computer interface based on EEG signals with which persons can use a computer to communicate with others in their vicinity or remotely over the net, to surf the net, and to control environmental entertainment, and assistive devices. The new technology will be simple enough for any person with minimal training to use. The project will also play a strong role in the education of future researchers and health professionals in this interdisciplinary field by involving graduate and undergraduate students from multiple departments as research assistants, by teaching a new course in BCI for students from a variety of backgrounds, and by providing fieldwork experiences.