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PubMed2004

Consolidation of human motor cortical neuroplasticity by D-cycloserine.

D-Cycloserine (CYC), a partial N-methyl-D-aspartate (NMDA) agonist, has been shown to improve cognitive functions in humans. However, the neurophysiological basis of this effect is unclear so far. We studied the impact of this drug on long-lasting after-effects of transcranial direct current (tDCS)-generated motor cortical excitability shifts, as revealed by transcranial magnetic stimulation-elicited motor-evoked potentials. While anodal tDCS enhances motor cortical excitability, cathodal tDCS diminishes it. Both effects seem to be NMDA receptor dependent. D-CYC selectively potentiated the duration of motor cortical excitability enhancements induced by anodal tDCS. D-CYC alone did not modulate excitability. The potency of this drug to consolidate neuronal excitability enhancements, most probably by stabilizing the strengthening of NMDA receptors, which is a probable neurophysiological derivate of learning processes, makes it an interesting substance to improve cognitive functions.

Adult↗
PubMed2002

Neural correlates of instrumental learning in primary auditory cortex.

In instrumental learning, Thorndike's law of effect states that stimulus-response relations are strengthened if they occur prior to positive reinforcement and weakened if they occur prior to negative reinforcement. In this study, we demonstrate that neural correlates of Thorndike's law may be observed in the primary auditory cortex, A1. Adult owl monkeys learned to discriminate tones higher than a standard frequency. Responses recorded from implanted microelectrodes initially exhibited broad spectral selectivity over a four-to-five octave range. With training, frequency discrimination thresholds changed from close to one octave to about 1/12 octave. Physiological recordings during the week in which the monkey came under behavioral control signaled by a drop in measured threshold had stronger responses to all frequencies. During the same week, A1 neural responses to target stimuli increased relative to standard and nontarget stimuli. This emergent difference in responsiveness persisted throughout the subsequent weeks of behavioral training. These data suggest that behavioral responses to stimuli modulate responsiveness in primary cortical areas.

Animals↗
PubMed1984

Perceived time: its relationship with locus of control, filled versus unfilled time intervals, and perceiver's sex.

The present study examined the role of locus of control and the perceiver 's sex in the estimation of filled and unfilled time intervals. One hundred male and 100 female undergraduates, ranging in age between 16 and 21 years, were administered Collins' I-E Scale followed by a time-estimation task. The latter involved judging 10 time intervals which were either "filled" with a tapping sound presented by the E, or were "unfilled." Results indicate that (a) high internals, compared to low internals, were less likely to overestimate filled intervals, but were more likely to overestimate unfilled intervals, possibly because high internals are more time-conscious; (b) the extent of absolute error in estimation is jointly affected by internality, filled/unfilled intervals, and the perceiver 's sex, but the last-mentioned variable had the most prominent independent effect. In general, males made less error in time estimation than females. It is suggested that the observed sex differences in the present study was probably due to socially learned differences in time consciousness.

Adolescent↗
PubMed2002

Learning from demonstrations: the role of visual search during observational learning from video and point-light models.

In this study, we examined the visual search strategies used during observation of video and point-light display models. We also assessed the relative effectiveness of video and point-light models in facilitating the learning of task outcomes and movement patterns. Twenty-one female novice soccer players were divided equally into video, point-light display and no-model (control) groups. Participants chipped a soccer ball onto a target area from which radial and variable error scores were taken. Kinematic data were also recorded using an opto-electrical system. Both a pre- and post-test were performed, interspersed with three periods of acquisition and observation of the model. A retention test was completed 2 days after the post-test. There was a significant main effect for test period for outcome accuracy and variability, but observation of a model did not facilitate outcome-based learning. Participants observing the models acquired a global movement pattern that was closer to that of the model than the controls, although they did not acquire the local relations in the movement pattern, evidenced by joint range of motion and angle-angle plots. There were no significant differences in learning between the point-light display and video groups. The point-light display model group used a more selective visual search pattern than the video model group, while both groups became more selective with successive trials and observation periods. The results are discussed in the context of Newell's hierarchy of coordination and control and Scully and Newell's visual perception perspective.

Adult↗
PubMed2006

The role of response selection in sequence learning.

We investigated the role of response selection in sequence learning in the serial reaction time (SRT) task, by manipulating stimulus-response compatibility. Under conditions in which other types of learning, like perceptual, response-based, and response-effect learning, were unaffected, sequence learning was better with an incompatible than with a compatible stimulus-response mapping. Stimulus discriminability, on the other hand, had no influence on the amount of sequence learning. This indicates that the compatibility effects cannot be accounted for by a different level of task difficulty. Relating our results to the dimensional overlap model (Kornblum, Hasbroucq, & Osman, 1990), which assumes that incompatible stimulus-response mappings require more controlled response selection than do compatible stimulus-response mapping, we suggest that sequence learning in the SRT task is particularly effective when response selection occurs in a controlled way.

Adult↗
PubMed2004

Learning in a clinical education programme in primary care: the Maastricht Adoption Programme.

INTRODUCTION: At Maastricht University, the integration of knowledge, skills and attitudes in preclinical medical education is promoted by an 'Adoption Programme', where students carry out assignments in a general practice setting. The assignments are explained and discussed in practical medical coaching groups. The aim of this study was to examine the relationships between the elements that affect learning in the programme. METHOD: Data from the evaluation questionnaires of 188 medical students were used to test a causal model of learning in the programme. A distinction was made between 'action' and 'reflection on action'. We examined the relationships between perceived instructiveness (the programme's value as a learning experience) and the following variables: comprehensibility; feasibility and execution of the assignments; time spent on the assignments, and the direct and indirect influences of the hosting general practitioner (GP) and the practical medical coaching group. RESULTS: Performing the assignments had little effect on perceived instructiveness. Coaching by the hosting GP influenced the execution of assignments mainly by its effect on feasibility. Coaching by the GP and in the practical medical coaching groups barely affected perceived instructiveness. DISCUSSION AND CONCLUSION: The model gives insight into the contribution of aspects of the Adoption Programme to student learning. The results are probably negatively influenced by the insufficient priority given to the Adoption Programme in the practical medical coaching groups and by inadequate instruction given to the GPs for the purposes of their coaching role. More careful planning of patient-related assignments is recommended. Reflection on assignments and feedback on procedures are needed to lift practical experience onto a higher educational level.

Attitude of Health Personnel↗
PubMed1999

Cytoplasmic polyadenylation in development and beyond.

Maternal mRNA translation is regulated in large part by cytoplasmic polyadenylation. This process, which occurs in both vertebrates and invertebrates, is essential for meiosis and body patterning. In spite of the evolutionary conservation of cytoplasmic polyadenylation, many of the cis elements and trans-acting factors appear to have some species specificity. With the recent isolation and cloning of factors involved in both poly(A) elongation and deadenylation, the underlying biochemistry of these reactions is beginning to be elucidated. In addition to early development, cytoplasmic polyadenylation is now known to occur in the adult brain, and there is circumstantial evidence that this process occurs at synapses, where it could mediate the long-lasting phase of long-term potentiation, which is probably the basis of learning and memory. Finally, there may be multiple mechanisms by which polyadenylation promotes translation. Important questions yet to be answered in the field of cytoplasmic polyadenylation are addressed.

Animals↗
PubMed1997

Quantal organization of reflex and conditioned eyelid responses.

Quantal organization of reflex and conditioned eyelid responses. J. Neurophysiol. 78: 2518-2530, 1997. Upper lid movements and the electromyographic activity of the orbicularis oculi muscle were recorded in behaving cats during spontaneous and experimentally evoked reflex blinks, and conditioned eyelid responses. Reflex blinks evoked by the presentation of air puffs, flashes, or tones consisted of a fast downward lid movement followed by late, small downward waves, recurring at approximately 50-ms intervals. The latency, maximum amplitude, peak velocity, and number of late waves depended on the modality, intensity, and duration of the evoking stimulus. The power spectra of acceleration records indicated a dominant frequency of approximately 20 Hz for air puff-evoked blinks. Flashes and tones usually evoked small and easily fatigable reflex responses of lower dominant frequencies (14-17 and 9-11 Hz, respectively). A basic approximately 20-Hz oscillation was also noticed during lid fixation, and ramplike lid displacements evoked by optokinetic stimuli. Five classical conditioning paradigms were used to analyze the frequency-domain properties of conditioned eyelid responses. These learned lid movements differed in latency, maximum amplitude, and profile smoothness depending on the modality (air puff, tone), intensity (weak, strong), and presentation site (ipsi-, contralateral to the unconditioned stimulus) of the conditioned stimulus. It was found that the characteristic ramplike profile of a conditioned response was not smooth, but appeared to be formed by a succession of small waves at a dominant frequency of approximately 20 Hz. The amplitude (and number) of the constituting waves depended on the characteristics of the conditioned stimulus and on the time interval until unconditioned stimulus presentation. Thus conditioned responses seemed to be formed from lid displacements of 2-6 degrees in amplitude and approximately 50 ms in duration, which increased in number throughout conditioning sessions, until a complete (i.e., lid closing) conditioned response was reached. It is suggested that a approximately 20-Hz oscillator underlies the generation of reflex and conditioned eyelid responses. The oscillator is susceptible to being neurally modulated to modify the velocity of a given quantum of movement, and the total duration of the lid response. Learned eyelid movements are probably the result of a successively longer release of the oscillator as a function of the temporal-spatial needs of the motor response.

Acoustic Stimulation↗
PubMed2000

The Southampton Needs Assessment Questionnaire (SNAQ): a valid tool for assessing the rehabilitation needs of disabled people.

OBJECTIVE: To validate the Southampton Needs Assessment Questionnaire (SNAQ) for use with disabled people during face-to-face interviews. DESIGN: The SNAQ was designed to be used in a cross-sectional survey of disabled people with a physical disability with a follow-up study one year later. Content and criterion validity was examined using 32 disabled people who took part in the pilot study. Construct validity and internal reliability was examined using data from 93 disabled people who took part in the main survey. Responsiveness of the questionnaire was evaluated using the data gathered during a follow-up study of 77 people had taken part in the original study. OUTCOME MEASURES: The OPCS Disability Severity Scales (OPCS) and the Functional Independence Measure (FIM) were used to measure level of disability of participants, the Nottingham Health Profile (NHP) and the UK version of the SF-36 to examine perceived health status. PARTICIPANTS: People with a primary physical disability, aged 16-65, randomly selected from two disability registers in southern England. MAIN RESULTS: Content and criterion validity were established. Construct validity and internal reliability of the SNAQ was good. Inter-rater reliability was not tested since only one researcher conducted the interviews. Test-retest reliability was not formally tested because of the probability that participants would learn from the first needs assessment questionnaire and that different results on a retest occasion could arise from this. The SNAQ was sensitive in picking up changes over time. CONCLUSION: The SNAQ has shown good validity (content, coverage and construct), internal reliability, sensitivity and responsiveness. Further studies are needed to define the consequences of meeting or not meeting the rehabilitation needs of disabled people. Inter-rater reliability remains to be established.

Adolescent↗