William M. Jenkins

Bio: William M. Jenkins is an academic researcher from University of California, San Francisco. The author has contributed to research in topics: Phonemic awareness & Vocabulary. The author has an hindex of 20, co-authored 34 publications receiving 3752 citations. Previous affiliations of William M. Jenkins include Pontifical Catholic University of Chile.

Temporal processing deficits of language-learning impaired children ameliorated by training

Abstract: Children with language-based learning impairments (LLIs) have major deficits in their recognition of some rapidly successive phonetic elements and nonspeech sound stimuli. In the current study, LLI children were engaged in adaptive training exercises mounted as computer "games" designed to drive improvements in their "temporal processing" skills. With 8 to 16 hours of training during a 20-day period, LLI children improved markedly in their abilities to recognize brief and fast sequences of nonspeech and speech stimuli.

A primate genesis model of focal dystonia and repetitive strain injury I. Learning-induced dedifferentiation of the representation of the hand in the primary somatosensory cortex in adult monkeys

Abstract: In this study we tested a neuroplasticity/learning origins hypothesis for repetitive strain injuries (RSIs), including occupationally induced focal dystonia.Repetitive movements produced in a specific form and in an appropriate behavioral context cause a degradation of the sensory feedback information controlling fine motor movements, resulting in the ``learned99 genesis of RSIs. Two adult New World owl monkeys were trained at a behavioral task that required them to maintain an attended grasp on a hand grip that repetitively and rapidly (20 msec) opened and closed over short distances. The monkeys completed 300 behavioral trials per day (1,100 to 3,000 movement events) with an accuracy of 80 to 90%. A movement control disorder was recorded in both monkeys. Training was continued until the performance accuracy dropped to below 50%. We subsequently conducted an electrophysiologic mapping study of the representations of the hand within the primary somatosensory (SI) cortical zone. The hand representation in the true primary somatosensory cortical field, SI area 3b, was found to be markedly degraded in these monkeys, as characterized by (1) a dedifferentiation of cortical representations of the skin of the hand manifested by receptive fields that were 10 to 20 times larger than normal, (2) the emergence of many receptive fields that covered the entire glabrous surface of individual digits or that extended across the surfaces of two or more digits, (3) a breakdown of the normally sharply segregated area 3b representations of volar glabrous and dorsal hairy skin of the hand, and (4) a breakdown of the local shifted-overlap receptive field topography of area 3b, with many digital receptive fields overlapping the fields of neurons sampled in cortical penetrations up to more than four times farther apart than normal. Thus, rapid, repetitive, highly stereotypic movements applied in a learning context can actively degrade cortical representations of sensory information guiding fine motor hand movements. This cortical plasticity/learning-based dedifferentiation of sensory feedback information from the hand contributes to the genesis of occupationally derived repetitive strain injuries, including focal dystonia of the hand. Successful treatment of patients with RSI will plausibly require learning-based restoration of differentiated representations of sensory feedback information from the hand. NEUROLOGY 1996;47: 508-520

Receptive fields in the body-surface map in adult cortex defined by temporally correlated inputs.

Abstract: Receptive fields (RFs) obtained at specific cortical sites can be used to define a topographic map of the body surface in adult mammalian somatosensory cortex. This map is not static, and RFs at particular cortical sites can change in size and location throughout adult life. Conversely, the cortical loci at which a given skin surface is represented can shift hundreds of micrometres across the cortex in the koniocortical field, area 3b (refs 1-12). This plasticity suggests that RFs derive not from rigid anatomical connections, but by the selection of a subset of a large number of inputs. We have proposed that inputs are selected on the basis of temporal correlation 11-15. Here we test this idea by altering the correlation of inputs from two adjacent digits on the adult owl monkey hand by surgically connecting the skin surfaces of the two fingers (the formation of syndactyly). This manipulation increases the correlation of inputs from skin surfaces of adjacent fingers. The striking discontinuity between the zones of representation of adjacent digits on the somatosensory cortex disappeared. These results support the hypothesis that the topography of the body-surface map in the adult cortex is influenced by the temporal correlations of afferent inputs.

Method and apparatus for automated training of language learning skills

Abstract: A computer program for execution on a computing device is provided to cross-train students in language development skills such as letter-word correspondence, word recognition, vocabulary, and sentence and paragraph comprehension. A set of programs provide an adaptive methodology for training a student in decoding (semantic, syntactic, phonological, and morphological relationships), knowledge of rhymes, synonyms, antonyms, and homophones, spelling, letter-word correspondences, sentence comprehension, grammatical comprehension, working memory, vocabulary, paragraph comprehension, and improved reading comprehension. In each program, students are presented with an animated scene that poses a question, and a set of answers. The set of answers contain a correct response, and a number of incorrect responses or foils. The student advances to more complex levels by satisfying predetermined correct thresholds. Through repetition and intensity, the student's language skills are developed.

From Neurons to Neighborhoods: The Science of Early Childhood Development

Abstract: 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.

CORTICAL PLASTICITY: From Synapses to Maps

Abstract: It has been clear for almost two decades that cortical representations in adult animals are not fixed entities, but rather, are dynamic and are continuously modified by experience. The cortex can preferentially allocate area to represent the particular peripheral input sources that are proportionally most used. Alterations in cortical representations appear to underlie learning tasks dependent on the use of the behaviorally important peripheral inputs that they represent. The rules governing this cortical representational plasticity following manipulations of inputs, including learning, are increasingly well understood. In parallel with developments in the field of cortical map plasticity, studies of synaptic plasticity have characterized specific elementary forms of plasticity, including associative long-term potentiation and long-term depression of excitatory postsynaptic potentials. Investigators have made many important strides toward understanding the molecular underpinnings of these fundamental plasticity processes and toward defining the learning rules that govern their induction. The fields of cortical synaptic plasticity and cortical map plasticity have been implicitly linked by the hypothesis that synaptic plasticity underlies cortical map reorganization. Recent experimental and theoretical work has provided increasingly stronger support for this hypothesis. The goal of the current paper is to review the fields of both synaptic and cortical map plasticity with an emphasis on the work that attempts to unite both fields. A second objective is to highlight the gaps in our understanding of synaptic and cellular mechanisms underlying cortical representational plasticity.

Knowing What Students Know: The Science and Design of Educational Assessment

Abstract: Education is a hot topic. From the stage of presidential debates to tonight's dinner table, it is an issue that most Americans are deeply concerned about. While there are many strategies for improving the educational process, we need a way to find out what works and what doesn't work as well. Educational assessment seeks to determine just how well students are learning and is an integral part of our quest for improved education. The nation is pinning greater expectations on educational assessment than ever before. We look to these assessment tools when documenting whether students and institutions are truly meeting education goals. But we must stop and ask a crucial question: What kind of assessment is most effective? At a time when traditional testing is subject to increasing criticism, research suggests that new, exciting approaches to assessment may be on the horizon. Advances in the sciences of how people learn and how to measure such learning offer the hope of developing new kinds of assessments-assessments that help students succeed in school by making as clear as possible the nature of their accomplishments and the progress of their learning. Knowing What Students Know essentially explains how expanding knowledge in the scientific fields of human learning and educational measurement can form the foundations of an improved approach to assessment. These advances suggest ways that the targets of assessment-what students know and how well they know it-as well as the methods used to make inferences about student learning can be made more valid and instructionally useful. Principles for designing and using these new kinds of assessments are presented, and examples are used to illustrate the principles. Implications for policy, practice, and research are also explored. With the promise of a productive research-based approach to assessment of student learning, Knowing What Students Know will be important to education administrators, assessment designers, teachers and teacher educators, and education advocates.

Increased Cortical Representation of the Fingers of the Left Hand in String Players

Abstract: Magnetic source imaging revealed that the cortical representation of the digits of the left hand of string players was larger than that in controls. The effect was smallest for the left thumb, and no such differences were observed for the representations of the right hand digits. The amount of cortical reorganization in the representation of the fingering digits was correlated with the age at which the person had begun to play. These results suggest that the representation of different parts of the body in the primary somatosensory cortex of humans depends on use and changes to conform to the current needs and experiences of the individual.