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Results for “Learning Curve”

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PubMed2005

Purkinje cell loss affects differentially the execution, acquisition and prepulse inhibition of skeletal and facial motor responses in Lurcher mice.

Adult heterozygous Lurcher mice show a degeneration of almost all Purkinje cells and 90% of the granular cells of the cerebellum, resulting in ataxia or general deficits in motor coordination. These mice are therefore an excellent model for studying the role of the cerebellar cortex in motor performance, including the acquisition of new motor abilities. The performance of 3-month-old Lurcher mice was studied in various behavioural (fall, horizontal bar, rotating cylinder, and ladder), spatial orientation (water maze) and associative learning (eyelid classical conditioning) tasks and compared with that of wild-type mice. Behavioural tasks indicated a deficit for motor abilities in Lurcher mice but with some adaptation to the tests and improvement in performance. Wild-type and Lurcher mice performed swimming equally, but the latter learned the task significantly more slowly than the former. The late component of reflex blinks was smaller in amplitude and had a longer latency in Lurcher mice than in controls. Learning curves for Lurcher mice during classical conditioning of eyelid responses were similar to controls, but the amplitude of the learned response in Lurcher mice was significantly lower. The startle response to a severe tone was similar in both control and Lurcher mice but the latter were unable to produce prepulse inhibition. These results suggest that the cerebellar cortex is not indispensable for the performance of this complete set of skeletal and facial tasks, or for the acquisition of new motor abilities, but it is for the appropriate execution and adjustment of any of these motor activities.

Acoustic Stimulation↗

PubMed1989

Intra-operative and postoperative biliary endoscopy (choledochoscopy). The role of the surgeons.

Intra-operative and postoperative choledochoscopy is an important adjunct to biliary surgery. In the last two decades, the necessity of this examination became obvious but two surveys clearly indicated that despite the availability of instruments surgeons do not use it routinely. One of the reasons is the long learning curve and the limited experience. The introduction of the video choledochoscope opened a new chapter because the surgeon could learn it faster and the technique is easier to use. Choledochoscopy is a "two man" job, requiring four hands. Using video choledochoscopy, the assistant and the operator can observe the situation together, therefore coordination of movement is easier. The actual endoscopic procedure is faster and the location of the stone, its removal, and the sphincter function are recorded on tape. This is a great step forward in analyzing sphincter function. It became the method of choice in teaching. It is assumed that, with the introduction of video choledochoscopy, the incidence of missed stones will be decreased significantly.

Animals↗

PubMed1994

Learning phacoemulsification: the surgeon-in-training.

With the increasing trend towards phacoemulsification a perceived increased complication rate during the learning curve gives rise to a dilemma as to the best stage at which a surgeon-in-training can safely learn the technique. We prospectively analysed the complications and visual outcome of the first 160 phacoemulsification procedures performed by three surgeons-in-training. The main outcome measures included posterior capsule tear, vitreous and nuclear loss, surgical re-intervention rate and visual outcome. Posterior capsule tear occurred in 7 eyes (4.4%) and vitreous loss in 6 (3.8%). No nucleus was lost in the vitreous. Surgical re-intervention was required in 1 eye. Best corrected visual acuity was 6/12 or better in 88% of eyes. These results compare favourably with reports of surgeons-in-training learning extracapsular surgery and also with recently reported phacoemulsification series. This study indicates that with careful case selection and supervision phacoemulsification can be a safe procedure.

Aged↗

PubMed2026

DeepGeSeq: deep learning library for genomic sequence modeling and analysis.

MOTIVATION: Deep learning methods have demonstrated significant potential in genomics, enabling broad applications such as sequence activity prediction, regulatory rule identification, and variant effect quantification. However, their widespread adoption is often hindered by the steep computational learning curve required for model construction, training, and downstream biological interpretation. Here, we introduce DeepGeSeq, a user-friendly Deep-learning library tailored for Genomic Sequence modeling and analysis. RESULTS: By integrating state-of-the-art architectural modules, DeepGeSeq streamlines the entire deep learning workflow, requiring minimal user input via a simple configuration file and an intuitive agentic skill. We comprehensively validate the efficacy of DeepGeSeq through diverse case studies, encompassing pipeline verification using synthetic datasets, the reproduction and application of established models, and model fine-tuning coupled with biological interpretation on user-defined data. Furthermore, we demonstrate DeepGeSeq's versatility in domain-specific applications, including single-cell ATAC-seq modeling for cell-type clustering, and MPRA data modeling coupled with in silico saturation mutagenesis to dissect cis-regulatory elements. Ultimately, DeepGeSeq bridges the gap between computational complexity and biological discovery, providing an accessible resource that facilitates the development and broad application of deep learning methods in genomics research. AVAILABILITY AND IMPLEMENTATION: https://github.com/JiaqiLi1024/DeepGeSeq.

Deep Learning↗

PubMed1995

Oriental double eyelid: a simplified nonincisional technique using the twin-needle suturer.

An alternative nonincisional method for creating Oriental double eyelid using the twin-needle suturer was presented. The benefits of the new technique include (1) no eversion of the eyelid is necessary, (2) guided by the needle tip indicator, the possibility of crease distortion due to incorrect placement of the sutures is reduced, and (3) a decreased learning curve for creating cosmetically pleasing supratarsal crease is expected. With the aid of this suturer, it is much easier to learn and master the Oriental double eyelid procedure, especially for inexperienced operators, such as those with only occasional request for such procedures.

Asian People↗

PubMed2004

EUS Meets Voxel-Man: three-dimensional anatomic animation of linear-array endoscopic ultrasound images.

Endoscopic ultrasonography (EUS) is a widely used imaging modality in gastroenterology. The development of linear-array endoscopic ultrasound transducers, with facilities for EUS-guided diagnostic and therapeutic procedures, led to increasingly widespread use in different areas of the body. Examiners need to have excellent knowledge of anatomy. Orientation in linear EUS is more difficult and the learning curve is long. In an effort to shorten the training, reducing the risk to the patient and to allow a faster learning of the basic anatomic structures EUS meets VOXEL-MAN, an interactive three-dimensional anatomic simulation program has been developed for linear EUS for the purposes of private and independent study.

Anatomy, Artistic↗

PubMed1997

[Role of the multimedia technology in the evolution of learning of endonasal surgery of the sinuses].

The functional endonasal sinus surgery makes great strides. In the meantime learning the surgical techniques can be difficult. A learning curve describes the evolution in mastering the surgical steps by the analysis of the number of complications. This means that each learning step presents specific risks. An interactive training system with multimedia technology has been developed to diminish the complication rate. This system is presented briefly. In our view it allows an improvement of the training of ENT surgeons. It permits the visualized reproduction of difficult surgical steps as a base to master then. We propose a plan for progressive learning including this technology.

CD-ROM↗

PubMed2006

Selective enhancement of associative learning by microstimulation of the anterior caudate.

Primates have the remarkable ability to rapidly adjust or modify associations between visual cues and specific motor responses. Whereas little is known as to how such adjustments in behavioral policy are implemented, recent learning models suggest that the anterior striatum is optimally positioned to have a role in this process. We recorded from single units and delivered microstimulation in the striatum of rhesus monkeys performing an associative learning task. Caudate activity during reinforcement was closely correlated with the rate of learning and peaked during the steepest portion of the learning curve when new associations were being acquired. Moreover, delivering microstimulation in the caudate during the reinforcement period significantly increased the rate of learning without altering the monkeys' ultimate performance. These findings suggest that the caudate is responsible for implementing selective adjustments to the 'associative weights' between sensory cues and motor responses during learning, thus enhancing the likelihood of selecting profitable actions.

Animals↗

PubMed1997

New surgical procedures: can our patients benefit while we learn?

Several forces have combined to encourage gynecologic surgeons to acquire the skills they need to perform new endoscopic procedures. Pressures from health care institutions, industry, and, most important, from patients lead to increased demand for less invasive approaches to the treatment of gynecologic conditions. This demand may outstrip the profession's ability to demonstrate the safety and effectiveness of new procedures through rigorous clinical trials. Early on, the benefits expected from laparoscopic surgery may be limited by harms resulting from surgical inexperience. Physicians will struggle to achieve a balance between their ethical obligation to benefit patients while avoiding harm to them and their professional expectation of continued learning. Acquisition of new techniques involves a learning curve, across which complications and operating time decrease while the potential for benefit rises. To minimize harm to patients during the surgeon's learning process, peer review should play an expanded role. Surgeons should discuss their own surgical experience and level of skill openly with their patients as part of the process of informed consent. A relationship of trust is vital when one engages patients in a cooperative educational venture.

Clinical Trials as Topic↗

PubMed2002

Three dimensional spatial memory and learning in real and virtual environments.

Human orientation and spatial cognition partly depends on our ability to remember sets of visual landmarks and imagine their relationship to us from a different viewpoint. We normally make large body rotations only about a single axis which is aligned with gravity. However, astronauts who try to recognize environments rotated in 3 dimensions report that their terrestrial ability to imagine the relative orientation of remembered landmarks does not easily generalize. The ability of human subjects to learn to mentally rotate a simple array of six objects around them was studied in 1-G laboratory experiments. Subjects were tested in a cubic chamber (n = 73) and a equivalent virtual environment (n = 24), analogous to the interior of a space station node module. A picture of an object was presented at the center of each wall. Subjects had to memorize the spatial relationships among the six objects and learn to predict the direction to a specific object if their body were in a specified 3D orientation. Percent correct learning curves and response times were measured. Most subjects achieved high accuracy from a given viewpoint within 20 trials, regardless of roll orientation, and learned a second view direction with equal or greater ease. Performance of the subject group that used a head mounted display/head tracker was qualitatively similar to that of the second group tested in a physical node simulator. Body position with respect to gravity had a significant but minor effect on performance of each group, suggesting that results may also apply to weightless situations. A correlation was found between task performance measures and conventional paper-and-pencil tests of field independence and 2&3 dimensional figure rotation ability.

Adolescent↗

PubMedDate not supplied

[The learning characteristics of rats under free-choice conditions].

The ability to organize a four-link operant food-procuring habit in a multiple alternative maze using the free-choice method was studied in albino rats. Three types of animals were observed which were different in the character of learning. The learning curve of 20% of rats had of exponential character (type I). Some animals (37%) acquired the skill through "insight" and the process of learning in these cases could be described by a logistic regression function (type II). The remaining rats (43%) refused from solving the intricate task and were able to acquire only the simplest form of a response, i.e., running to feeders. It is suggested that learning differences between the I and II types of animals may be associated with different strategies of problem solving: "procedural" (algorithmic) and "conceptual" (semantic).

Animals↗

PubMed1986

Preserved motor learning in Alzheimer's disease: implications for anatomy and behavior.

Learning and retention of 3 types of information were examined in patients with Alzheimer's disease (AD) and in normal controls. While patients were unable to learn series of frequent words and unfamiliar faces, they improved significantly in a motor skill, showing a learning curve similar to controls. Furthermore, no significant loss of the motor skill was evident in a 20 min delay trial. Such dissociation in learning has not been noted previously in AD, although it has been noted in amnesias caused by other disease processes. The results support the existence of two, relatively independent, learning systems related to "declarative" knowledge and "procedural" knowledge. Judging from the pathologic correlates of these amnesias, the declarative knowledge system appears to be associated with corticotemporo/limbic structures, while the procedural system is likely to depend on corticocerebellar/striatal structures. The data also offer additional cognitive correlates for the selective damage to neural systems recently identified in AD.

Alzheimer Disease↗

PubMed2002

Self-selected modular recurrent neural networks with postural and inertial subnetworks applied to complex movements.

It has been shown that dynamic recurrent neural networks are successful in identifying the complex mapping relationship between full-wave-rectified electromyographic (EMG) signals and limb trajectories during complex movements. These connectionist models include two types of adaptive parameters: the interconnection weights between the units and the time constants associated to each neuron-like unit; they are governed by continuous-time equations. Due to their internal structure, these models are particularly appropriate to solve dynamical tasks (with time-varying input and output signals). We show in this paper that the introduction of a modular organization dedicated to different aspects of the dynamical mapping including privileged communication channels can refine the architecture of these recurrent networks. We first divide the initial individual network into two communicating subnetworks. These two modules receive the same EMG signals as input but are involved in different identification tasks related to position and acceleration. We then show that the introduction of an artificial distance in the model (using a Gaussian modulation factor of weights) induces a reduced modular architecture based on a self-elimination of null synaptic weights. Moreover, this self-selected reduced model based on two subnetworks performs the identification task better than the original single network while using fewer free parameters (better learning curve and better identification quality). We also show that this modular network exhibits several features that can be considered as biologically plausible after the learning process: self-selection of a specific inhibitory communicating path between both subnetworks after the learning process, appearance of tonic and phasic neurons, and coherent distribution of the values of the time constants within each subnetwork.

Adult↗

PubMed2006

Transfer of skills from the experimental model to the patients.

Laparoscopy is a major part of urologists' daily practice. It is becoming more and more popular and interest in it is increasing, as is the number of urologists attracted by it. Patients also frequently demand a treatment through a laparoscopic approach. Nevertheless, laparoscopy is a physically and technically demanding surgery. It has been proven that it has a long learning curve with a high complication rate at the beginning. Thus, there is need for a training program that can effectively reduce its time of apprenticeship. The learning path is a multistep process that involves several phases. The pelvic trainer is the first step of this path that is made with increasing difficulty. Gradually and gently the trainee faces up to different levels under the guidance of a mentor. At the end of training, trainees should be able to perform every procedure, both easy and difficult ones, by themselves.

Cadaver↗

PubMed2001

Harmaline induces different motor effects on facial vs. skeletal-motor systems in alert cats.

Harmaline's effects on reflex and classically conditioned eyelid responses and on tremor picked up by a coil attached to the back were measured in alert cats. Harmaline at a dose of 10 mg/kg produced skeletal muscle tremogenic effects that lasted 4h. Back movements presented a tremor-like displacement with a frequency peak at 10 Hz, but lid responses oscillated as in controls, at 20 Hz during both reflex and conditioned eyelid movements, with no increase in oscillation amplitude or frequency. The learning curves of harmaline-injected animals remained as in controls, but eyelid conditioned responses showed longer latencies, and smaller amplitude and peak velocity. Reflex and already-learned eyelid responses were not modified by harmaline. These results imply that neuronal control systems for skeletal-motor and facial responses are differentially affected by harmaline.

Journal Article↗

PubMedDate not supplied

Training, transfer, and retention of three-dimensional spatial memory in virtual environments.

Human orientation requires one to remember and visualize spatial arrangements of landmarks from different perspectives. Astronauts have reported difficulties remembering relationships between environmental landmarks when imagined in arbitrary 3D orientations. The present study investigated the effects of strategy training on humans' 1) ability to infer their orientation from landmarks presented ahead and below, 2) performance when subsequently learning a different array, and 3) retention of configurational knowledge over time. On the first experiment day, 24 subjects were tested in a virtual cubic chamber in which a picture of an animal was drawn on each wall. Through trial-by-trial exposures, they had to memorize the spatial relationships among the six pictures around them and learn to predict the direction to a specific picture when facing any view direction, and in any roll orientation. Half of the subjects ("strategy group") were taught methods for remembering picture groupings, while the remainder received no such training ("control group"). After learning one picture array, the procedure was repeated in a second. Accuracy (% correct) and response time learning curves were measured. Performance for the second array and configurational memory of both arrays were also retested 1, 7, and 30 days later. Results showed that subjects "learned how to learn" this generic 3D spatial memory task regardless of their relative orientation to the environment, that ability and configurational knowledge was retained for at least a month, that figure rotation ability and field independence correlate with performance, and that teaching subjects specific strategies in advance significantly improves performance. Training astronauts to perform a similar generic 3D spatial memory task, and suggesting strategies in advance, may help them orient in three dimensions.

Adolescent↗

PubMed1981

Operant conditioning and discrimination of alpha: some methodological limitations inherent in response-discrimination experiments.

Studies on the operant conditioning of central nervous system activity have produced results interpreted as demonstrating that responses, certain properties of responses, or response-produced stimuli can function as discriminative stimuli. It is assumed that the feedback stimulus in biofeedback makes the subject aware of the internal response and that by becoming aware of the response, the subject can acquire voluntary control over it. In this context, awareness is operationally defined as the ability to use the response as a discriminative stimulus. Since direct evidence for the assumed relationship between control and discrimination is lacking, an attempt was made to test the hypothesis that discrimination of a response automatically leads to control over that response. The discriminative stimuli were the presence and absence of occipital alpha electroencephalograph (EEG) activity. Data from two experiments are reported. The first study, employing naive subjects, was designed to answer the following questions: (a) Since pilot data indicated that subjects seemed to match their responses to the more probable type of trial, would increases in the probability of a correct response result when the probabilities of alpha and nonalpha trials were held near .50? (b) If correct responding does increase, would performance of these subjects in an alpha feedback task be enhanced relative to that of subjects not previously given discrimination training? and (c) If subjects could not learn the discrimination task, would feedback training enhance their performance in a subsequent discrimination task? Results from this study indicate that holding the probabilities of alpha and nonalpha discrimination trials near .50 results in an absence of learning curves, but leaves open the possibility that sophisticated subjects are capable of discriminating alpha and nonalpha activity. The second study deals with two questions: (a) Can sophisticated subjects learn to discriminate occipital alpha activity from nonalpha activity? and (b) Does the procedure of providing subjects with salient stimuli, contingent on the presence and absence of alpha activity, establish stimulus control of the presence and absence of alpha activity? Results indicate that it is not possible to conclude that subjects can learn to discriminate alpha and nonalpha activity. However, learning to increase percent-time nonalpha or decrease percent-time alpha with respect to baseline levels by means of EEG-contingent stimulation provides subjects with the ability to suppress percent-time alpha in the absence of feedback. Information gained in both studies through subject interviews indicates that subjects most often acquired their control of alpha activity during feedback by a specific strategy and then used the strategy during the stimulus-control tests.

Alpha Rhythm↗

PubMed1973

An analysis of the learning deficit following hyoscine administration to man.

1. Twelve volunteer subjects completed a free-recall word learning test, a number-colour association test, and a scanning task after the following treatments: saline 1 ml, hyoscine 0.4 mg, or atropine 0.6 mg, administered by intravenous injection.2. Performance on all three tests was not significantly impaired after atropine.3. Performance on the two learning tests but not on the scanning task, was significantly impaired after hyoscine.4. Analysis of the results of the free-recall word learning test indicates that impairment of learning following hyoscine does not affect recall over intervals of a few seconds, but affects that portion of the learning curve which has been attributed to long-term (or secondary) rather than short-term (or primary) memory.5. The results suggest that hyoscine 0.4 mg may impair learning processes, without significantly depressing other psychological functions, and that the impairment of learning following hyposcine does not affect recall over intervals memory.

Adult↗