Download or read book The Neural Basis of the Effects of Aging on Temporal Processing in the Rat Primary Auditory Cortex written by Charlene Michelle Ricketts and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One complaint among the elderly is a difficulty in understanding speech. One factor that may contribute to this, is an age-related deterioration in temporal processing speed, manifested as a decreased ability to process dynamic aspects of speech such as formant transitions. The goal of this study was to explore the neural basis of the effects of aging on auditory temporal processing. A useful stimulus for this investigation is the frequency-modulated (FM) sweep which resembles formant transitions. Extracellular single unit responses were recorded in the auditory cortex (AI) of young and old male Long Evans hooded rats. Tone bursts were presented followed by linear FM sweeps (from low to high and from high to low) at different rates of modulation. Results show that the majority of cells recorded from young rats responded best to fast FM sweeps while those from old rats preferred slower speeds. This suggests a neurophysiological basis for the difference in cortical temporal processing speed between young and old rats for dynamic stimuli.
Download or read book The Neural Basis of the Effects of Aging on Temporal Processing in the Rat Primary Auditory Cortex written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Neurophysiological Effect of Aging on AM Processing in the Rat Auditory Cortex written by Tasneem Wallani and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Difficulty in speech discrimination is a common complaint among the elderly population. In recent years, it has been proposed that part of this difficulty in speech perception may be the result of age-related changes in the central auditory system, specifically a decline in temporal processing speed. The goal of the present study was to investigate the neurophysiological effects of aging on temporal processing speed within the auditory cortex. Sinusoidal amplitude modulations (SAM) was the stimulus of choice as it is a complex sound found in animal vocalizations including human speech. Extracellular single unit recordings were made from cells of young and old male Long Evans Hooded rats in the auditory cortex. Tone bursts were presented to assess characteristic frequency followed by SAM stimuli to assess best modulation frequency (BMF) of the cells. Results indicate no significant differences between age groups for BMFs. Thus no neural basis for aging was found using SAM stimuli.
Download or read book Age related Changes in Auditory Temporal Processing written by Jacqueline Alexandra Overton and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Age-related hearing loss (ARHL) is the third most prevalent cause of disability in adults over age 65. However, we still do not have an adequate understanding of the mechanisms underlying ARHL. The primary complaint of those with ARHL is a difficulty comprehending speech, particularly in challenging listening environments. This can lead to social isolation, depression and contribute to cognitive decline. Importantly, impairments in speech processing and comprehension occur even in the absence of measurable changes in hearing thresholds. Similarly, speech comprehension difficulties are often not corrected with hearing aids. Understanding age-related changes in temporal processing in the central auditory system is critical to understanding the neural mechanisms of speech processing deficits associated with ARHL. This is the central question of my thesis.There are five chapters in this dissertation. In Chapter 1, I introduce the thesis with an overview of ARHL, and a review of the literature covering age related changes in speech and temporal processing, and age-related changes in the central auditory pathway. In Chapter 2, I present single-unit electrophysiology data recorded from primary auditory cortex (A1) in older rhesus macaque monkeys in response to amplitude modulated (AM) broadband noise presented across a range of modulation frequencies, and compare those data with the results from younger monkeys reported previously in Yin and colleagues (2011). This was the first study of age-related changes in cortical auditory temporal processing in the macaque. I found that neurons from older monkeys show dramatic changes in their responses to AM noise as measured by their ability to phase-lock to the envelope and by their overall firing rate. Several measures of tuning were correlated in young monkeys, but these relationships were either reversed, or lost in units from older monkeys. Underlying these changes was a decrease in the ability of older neurons to phase-lock to the envelope of an AM stimulus, and dramatically increased spontaneous and evoked firing rates (replicated from previous studies). These data, however, were collected under passive stimulus presentation conditions, so it is unclear how these changes affect the ability to accurately represent the stimulus. The logical follow-up to the study presented in Chapter 2, is to record from single units in macaque A1 while they are performing a task that requires them to attend to and make decisions regarding a specific attribute of the AM stimulus (in this case modulation frequency). I, therefore, designed a two-alternative forced choice (2AFC) AM frequency discrimination task for this purpose. How modulation frequency discrimination ability may change with age had not been tested previously. Hence, in Chapter 3, I present psychophysical data from a cross-sectional sample of 33 human participants ranging in age from 25 to 80 years, and compare those data to results from one 16-year old macaque. I found an age-related decline in AM frequency discrimination at the highest AM frequencies measured, but no age-related difference in performance at lower frequencies. Importantly, age-related changes in discrimination ability were not related to hearing thresholds, further supporting that age-related temporal processing deficits are due to changes in the central auditory system independent of peripheral changes. Comparison to monkey data showed that human subjects’ discrimination ability was more acute overall, and extended to temporal frequencies beyond the monkey’s upper limit of AM frequency discrimination. This result suggests a perceptual specialization in humans for fine changes in temporal frequency that is likely to be relevant to speech processing. This section of the thesis is concluded in Chapter 4, where I discuss the implications of results presented in the previous two chapters in the context of the introductory chapter, and offer directions for future research. Cranial implants are a necessary component of neurophysiological investigation of nonhuman primates. In Chapter 5, I present a methodology for implanting nonhuman primates with custom-fitted acrylic-free headposts and recording cylinders using biocompatible materials. Each titanium headpost was hand-form to fit a 3D-printed replica of the animal’s skull, which was created from CT data. I provide a timeline and detail each step of the process, including information for converting DICOM data to a 3D-printable format. Furthermore, I discuss issues of biocompatibility of materials, and suggest procedures for promoting osseointegration of titanium implants. Overall, these methods have proven to reduce implant surgery times up to 70%. All implanted headposts remained intact and free of infection for the experimental life of each animal (four years and counting).
Download or read book The Neurophysiological Effect of Aging on AM Processing in the Rat Auditory Cortex written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Aging on Temporal Processing in the Rat Inferior Colliculus Responses to Frequency modulated Sweeps written by Hyo Jin Lee and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Difficulty in understanding speech is a common problem afflicting the elderly. One potential factor is an age-related deterioration in temporal processing speed, expressed as a decreased ability to process dynamic aspects of speech such as the formant transitions. The study used frequency-modulated (FM) sweep stimuli to examine the effects of aging on auditory temporal processing at a subcortical level, specifically in the inferior colliculus (IC). Extracellular single-unit recordings were made from the IC of young and old Long-Evans Hooded rats in response to linear FM sweeps that changed both in speed and direction. There was no significant difference in the preferred speed of FM sweep between the two age groups. In addition, for direction selectivity of FM sweep, most of the cells in both groups were non-direction selective. The results show temporal processing speed is not affected by aging at the level of the IC.
Download or read book The Effects of Aging on Temporal Processing in the Rat Inferior Colliculus Responses to Frequency modulated Sweeps written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distinct Temporal and Special Components of Developmental Plasticity in Rat Auditory Cortex written by Theodore M. Moallem and published by . This book was released on 2003 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The effect of hearing loss on neural processing written by Jonathan E. Peelle and published by Frontiers Media SA. This book was released on 2015-06-03 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient auditory processing requires the rapid integration of transient sensory inputs. This is exemplified in human speech perception, in which long stretches of a complex acoustic signal are typically processed accurately and essentially in real-time. Spoken language thus presents listeners’ auditory systems with a considerable challenge even when acoustic input is clear. However, auditory processing ability is frequently compromised due to congenital or acquired hearing loss, or altered through background noise or assistive devices such as cochlear implants. How does loss of sensory fidelity impact neural processing, efficiency, and health? How does this ultimately influence behavior? This Research Topic explores the neural consequences of hearing loss, including basic processing carried out in the auditory periphery, computations in subcortical nuclei and primary auditory cortex, and higher-level cognitive processes such as those involved in human speech perception. By pulling together data from a variety of disciplines and perspectives, we gain a more complete picture of the acute and chronic consequences of hearing loss for neural functioning.
Download or read book The Auditory Cortex written by Jeffery A. Winer and published by Springer Science & Business Media. This book was released on 2010-12-02 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been substantial progress in understanding the contributions of the auditory forebrain to hearing, sound localization, communication, emotive behavior, and cognition. The Auditory Cortex covers the latest knowledge about the auditory forebrain, including the auditory cortex as well as the medial geniculate body in the thalamus. This book will cover all important aspects of the auditory forebrain organization and function, integrating the auditory thalamus and cortex into a smooth, coherent whole. Volume One covers basic auditory neuroscience. It complements The Auditory Cortex, Volume 2: Integrative Neuroscience, which takes a more applied/clinical perspective.
Download or read book The Neurophysiological Effects of Aging on Temporal Processing in the Visual Cortex written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Brain Aging written by David R. Riddle and published by CRC Press. This book was released on 2007-04-19 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recognition that aging is not the accumulation of disease, but rather comprises fundamental biological processes that are amenable to experimental study, is the basis for the recent growth of experimental biogerontology. As increasingly sophisticated studies provide greater understanding of what occurs in the aging brain and how these changes occur
Download or read book From Neurons to Neighborhoods written by National Research Council and published by National Academies Press. This book was released on 2000-11-13 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: How we raise young children is one of today's most highly personalized and sharply politicized issues, in part because each of us can claim some level of "expertise." The debate has intensified as discoveries about our development-in the womb and in the first months and years-have reached the popular media. How can we use our burgeoning knowledge to assure the well-being of all young children, for their own sake as well as for the sake of our nation? Drawing from new findings, this book presents important conclusions about nature-versus-nurture, the impact of being born into a working family, the effect of politics on programs for children, the costs and benefits of intervention, and other issues. The committee issues a series of challenges to decision makers regarding the quality of child care, issues of racial and ethnic diversity, the integration of children's cognitive and emotional development, and more. Authoritative yet accessible, From Neurons to Neighborhoods presents the evidence about "brain wiring" and how kids learn to speak, think, and regulate their behavior. It examines the effect of the climate-family, child care, community-within which the child grows.
Download or read book Journal of Experimental Biology written by and published by . This book was released on 2008 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Awards Index written by and published by . This book was released on 1989 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Elementary Signal Detection Theory written by Thomas D. Wickens and published by Oxford University Press. This book was released on 2001-10-11 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Signal detection theory, as developed in electrical engineering and based on statistical decision theory, was first applied to human sensory discrimination about 40 years ago. The theory's intent was to explain how humans discriminate and how we might use reliable measures to quantify this ability. An interesting finding of this work is that decisions are involved even in the simplest of discrimination tasks--say, determining whether or not a sound has been heard (a yes-no decision). Detection theory has been applied to a host of varied problems (for example, measuring the accuracy of diagnostic systems, survey research, reliability of lie detection tests) and extends far beyond the detection of signals. This book is a primer on signal detection theory, useful for both undergraduates and graduate students.
Download or read book The Auditory Brainstem Response written by John T. Jacobson and published by Taylor & Francis Group. This book was released on 1985 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
