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Open Access Publications from the University of California

Scholarly Works (77 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2017)
    Cover page: Introduction to the JINS Special Issue: Motor Cognition
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (1989)
    The purpose of these experiments was to determine if the two hemispheres play different roles in controlling closed loop movements. Subjects were asked to move to a narrow or wide target in the left or right hemispace. Reaction time (RT) was faster for the left arm of normals, only in the right hemispace, but there were no differences between arms in movement execution. Right but not left hemisphere stroke (CVA) patients showed longer RTs for the contralateral but not ipsilateral arm. The right CVA group's ipsilateral movement, especially to narrow targets was less accurate. The left CVA group's RT did not benefit from advanced information, but ipsilateral movement execution was normal. These results were discussed in terms of inter- as well as intrahemispheric control of programming and execution of closed loop movements.
      Cover page: The role of the hemispheres in closed loop movements
      • Thesis
      • Peer Reviewed
      UCLA Electronic Theses and Dissertations (2014)

      Increasing the ability of underprepared and underserved students to acquire the skills necessary for college success is a critical component of the mission of California community colleges, yet faculty, staff, and administrators have historically received little training in how to effectively do so. For one statewide professional development effort underway, the Reading Apprenticeship Project (RAP), a study was conducted to examine the impact of a teaching innovation, Reading Apprenticeship, on classroom practice and on faculty understanding of student engagement and progress as a result of incorporating the innovation. RAP, a community of practice initiative funded by the state system through its California Community Colleges' Success Network (3CSN), seeks to address a significant gap in faculty pedagogical training: how to support adult students' academic literacy acquisition in discipline-specific contexts.

      Because 3CSN's RAP has structured its professional development delivery around social learning modalities, a conceptual framework designed to analyze the value of interventions enacted through communities and networks was employed to examine the largely self-reported perceptions provided by the study's key informants, seven experienced Reading Apprenticeship practitioners. Qualitative data collected through individual and group interviews and practitioner observations were systematically described and analyzed using the five categories or "cycles" of the conceptual framework. Additionally, the data, where applicable, were examined within the context of the Reading Apprenticeship Framework itself.

      Evidence pointing to perceived value was discovered across all cycles, patterns connecting the cycles of community and network learning to the RA dimensions were described, and seven findings corresponding to the research questions were outlined. Through its findings, the study ultimately sought to clarify the core features necessary for the implementation of professional learning that makes a transformative difference in classrooms and across institutions and can be reproduced at scale.

        Cover page: "You Can't Just Jump Into the Icy Pool of Metacognition": The Value of Networking and Community Building in California Community Colleges' Reading Apprenticeship Project
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2016)
        The medial cortico-striatal-thalamo-cortical (CSTC) motor circuit is a core system that exerts control over interval timing and action. A common network generates these behaviors possibly owing to cellular coding of temporal and non-temporal information, which in turn promotes reconfiguration of functional connectivity in accord with behavioral goals. At the neuroanatomical level, support for flexible CSTC reconfiguration comes from studies of temporal illusions demonstrating that this system calibrates the experience of time through functional interactions with various context-sensitive brain regions. Revelations that CSTC effective connectivity is pivotal for context-dependent facets of voluntary actions, namely action planning, complement its role in predictive processes such as timing. These observations suggest that the CSTC is positioned to represent high-level information about 'what to do' and 'when to do it' by dynamically reconfiguring effective connectivity as circumstances arise.
          Cover page: Reconfiguration of striatal connectivity for timing and action
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (1987)
          The extent to which complex skills are programmed before movement is a concern for research in motor control. This study investigates a model which maintains that after a motor program is constructed, only the first response in a sequence is programmed prior to movement (Sternberg, Monsell, Knoll, & Wright, 1978). In a simple reaction time paradigm, subjects executed sequences of hand postures that varied in length, the number of different hand postures, and the location of a hand posture transition. For sequences containing repetitions of the same hand posture, sequence length had a small effect on RT when the number of responses ranged between two and five (Experiment 1) and no effect when the number of responses ranged between three and five (Experiment 2). For sequences containing clearly different hand postures, Experiment 2 showed that RT was influenced by the type of hand posture beyond the first response. The analysis of interresponse times suggested that the first two responses were completely preprogrammed before movement. These results were consistent with a model in which responses are hierarchically organized and some but not all information about each response in the sequence is preprogrammed before movement execution.
            Cover page: Programming Sequences of Hand Postures
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (1996)
            Studies in brain-damaged patients indicate that the left hemisphere in right-handers is specialized for controlling cognitive-motor tasks in both arms. Recent functional imaging data support this conclusion, with the finding that ipsilateral, as well as contralateral, movements activate the left, but not the right, motor cortex or association areas of either hemisphere. Future studies must aspire to identify the mechanisms for this asymmetry.
              Cover page: Hemispheric asymmetry of movement
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (1989)
              This study examined whether the left and right hemispheres play differential roles in controlling the initial and corrective components of aiming movements. A simple aiming task was administered to 31 normal control subjects and 29 unilateral stroke patients (14 with right hemisphere damage and 15 with left hemisphere damage). Movement amplitude was varied (25, 64 and 100 mm) and reaction time, movement time and accuracy were measured. Through a trajectory analysis, initial and corrective movements were separated. The stroke patients performed the task with their ipsilateral arm which was compared to the normal controls' right or left are performance. Regardless of the movement amplitude the left hemisphere group's reaction time was slower, and the execution of the initial movement component was less accurate than controls. No performance deficits were found on corrective movements. Performance was not impaired for the right hemisphere group on any measures. These results are discussed in terms of the hemispheres' possible roles in controlling movements which are largely open or closed loop.
                Cover page: Hemispheric control of the initial and corrective components of aiming movements
                • Article
                • Peer Reviewed
                UC San Diego Previously Published Works (1991)
                Left and right hemisphere stroke patients and control subjects performed sequences of hand postures which varied in complexity (repetitive and heterogeneous) and length (one to five). Performance in the hand ipsilateral to the stroke was compared to a control group using the same hand. Neither stroke group had problems preprogramming sequences prior to movement. The only deficit seen for the right hemisphere group was a greater difference in movement time (MT) between heterogeneous and repetitive sequences relative to controls, regardless of sequence length. This suggested right hemisphere damage results in subtle timing but not error deficits on more complex movements, perhaps due to increased external spatial demands. The left hemisphere group was slower to execute single postures, and had difficulty scheduling motor programs for repetitive and heterogeneous movements such that inter-response times (IRTs) were more affected by sequence length than for controls. Left hemisphere patients also made more errors on heterogeneous sequences as they increased in length, and the difference in MTs between repetitive and heterogeneous sequences increased more with increasing length relative to their control group. These results suggested the left hemisphere plays a role in controlling single postures, in scheduling motor programs during repetitive and heterogeneous movements, and in processes related to sequential ordering.
                  Cover page: Hemispheric specialization for motor sequencing: Abnormalities in levels of programming
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2009)
                  Sounds provide important information about the spatial environment, including the location of approaching objects. Attention to sounds can be directed through automatic or more controlled processes, which have been well studied in the visual modality. However, little is known about the neural underpinnings of attentional control mechanisms for auditory signals. We studied healthy adults who underwent event-related FMRI while performing a task that manipulated automatic and more controlled auditory orienting by varying the probability that cues correctly predicted target location. Specifically, we examined the effects of uninformative (50% validity ratio) and informative (75% validity ratio) auditory cues on reaction time (RT) and neuronal functioning. The stimulus-onset asynchrony (SOA) between the cue and the target was either 100 or 800 ms. At the 100 ms SOA, RT was faster for valid than invalid trials for both cue types, and frontoparietal activation was greater for invalid than valid trials. At the 800 ms SOA, RT and functional activation depended on whether cues were informative or uninformative, and whether cues correctly or incorrectly predicted the target location. Contrary to our prediction, activation in a frontoparietal network was greater for uninformative than informative cues across several different comparisons and at both SOAs. This finding contrasts with similar research of visual orienting, and suggests that the auditory modality may be more biased toward automatic shifts of attention following uninformative cues.
                    Cover page: Neuronal modulation of auditory attention by informative and uninformative spatial cues
                    • Article
                    • Peer Reviewed
                    UC San Diego Previously Published Works (1993)
                    In Experiments 1 and 2, aiming movements were performed with and without visual feedback in young and elderly adults. The initial (acceleration and deceleration phases) and secondary movement components were analyzed. Although deceleration phase accuracy decreased without visual feedback in both age groups, accuracy diminished as movement amplitude increased only in the elderly. This suggested that the elderly were more dependent on visual feedback to modify motor programs for longer duration movements. Velocity also increased less with increasing amplitude and target size in the elderly, which was related to impaired preprogramming (acceleration phase) and implementation (deceleration phase) of higher forces. This conclusion was confirmed directly in Experiment 2 because only the deceleration phase was affected by the removal of visual feedback of arm position when availability of visual information could not be predicted before movement.
                      Cover page: Effects of Aging on Planning and Implementing Arm Movements
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