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At least 199 records · Page 11Linked to original sources
PubMed1999

Unique salience of maternal breast odors for newborn infants.

Human infants are particularly responsive to olfactory cues emanating from their mother's nipple/areola region. Beginning within minutes after birth, maternal breast odors elicit preferential head orientation by neonates and help guide them to the nipple. Such odors also influence babies' general motor activity and arousal, which may contribute further to successful nipple localization and sucking. The role of maternal olfactory signals in the mediation of early breast-feeding is functionally analogous to that of nipple-search pheromone as described in nonhuman mammals. To some extent, the chemical profile of breast secretions overlaps with that of amniotic fluid. Therefore, early postnatal attraction to odors associated with the nipple/areola may reflect prenatal exposure and familiarization. Although newborns are generally attracted to breast odors produced by lactating women, breast-fed infants rapidly learn their mother's characteristic olfactory signature while sucking at her breasts and can subsequently recognize her by that unique scent alone. Early odor-based recognition may be an important factor in the development of the infant-mother bond.

Animals↗
PubMed1995

Computer-simulated eye surgery. A novel teaching method for residents and practitioners.

PURPOSE: To describe an eye surgery simulator that uses a computerized graphic display to allow ophthalmic surgeons of all experience levels to enhance their surgical skills. METHODS: The eye surgery simulation environment consists of a high-speed computer graphics workstation, a stereo operating system, a wrist rest, and a position tracking stylus connected to force feedback motors. The surgeon views computer-generated images of the eye and surgical instruments through the stereo operating system and controls the position and orientation of the chosen surgical instrument by moving the stylus. During the simulated instrument-tissue interactions, three feedback motors generate component force feedback along three orthogonal axes connected by thin rigid bars to the tip of the stylus. RESULTS: The current proof-of-concept system provides a method for rapid learning experiences in a living eye simulation. Procedures can be recorded for playback and analysis, as well as for examination of techniques from different viewpoints (e.g., from inside the eye). Four simulated surgical instruments are available for use (scalpel, forceps, scissors, and phacoemulsifier). CONCLUSION: Eye surgery simulation offers both beginning and experienced ophthalmic surgeons an opportunity to learn new techniques and skills and achieve a satisfactory level of proficiency before use of that procedure in the operating room. When fully developed, this system should shorten the learning curve for new surgeons (i.e., residents) and offer an opportunity for practice before doing a difficult case or development of new techniques by experienced surgeons. The goal of replacement of current standard training methods for surgeons awaits further refinement and adjustment of the model.

Computer Simulation↗
PubMed2000

Lesions of the medial shell of the nucleus accumbens impair rats in finding larger rewards, but spare reward-seeking behavior.

The goal of this study was to help better understand the importance of the nucleus accumbens (Nacc) in the processing of position and reward value information for goal-directed orientation behaviors. Sixteen male Long-Evans rats, under partial water deprivation, were trained in a plus-maze to find water rewards in the respective arms which were lit in pseudo-random sequence (training trials). Each day one reward arm was selected to deliver six drops of water (at 1 s intervals) the others provided only one drop per visit. After 32 visits, probe trials were intermittently presented among training trials. Here, all four arms were lit and offered the previously assigned reward. The rats rapidly learned to go to the highly rewarded arm. Six trained rats were given bilateral electrolytic lesions in the Nacc shell, two others had unilateral lesions and eight had sham operations (with approved protocols). Field potentials evoked by fornix stimulation were recorded in lesion electrodes to guide placements. Only the lesioned rats showed significant impairments (P<0.05) in selecting the greater reward on probe trials. However on training trials, lesioned (and sham-operated) rats made only rare errors. While the motivation to drink and the capacity for cue-guided goal-directed orientation behavior was spared, lesioned rats were impaired in learning the location of the larger reward. The accumbens lesions apparently impaired integration of position and reward value information, consistent with anatomical and electrophysiological data showing the convergence of hippocampal, amygdalar, ventral tegmental area (VTA) and prefrontal cortical inputs there.

Amygdala↗
PubMed2002

5-HT3 receptor ligands lack discriminative stimulus properties.

The putative discriminative stimulus of the 5-HT3 receptor antagonists ondansetron and (DL)-11-[(2-methyl-1H-imidazol-1-yl)methyl]-4,5,6,7,10,11,12-octahydroazepinol[3,2,1-jk]-carbazol-12-one hydrochloride (DU122932), and of the 5-HT3 receptor agonists 2-methyl-5-HT and 3,4-dichlorophenylbiguanide (3,4DCPB) were investigated in a standard two-lever, food-reinforced drug-saline discrimination procedure with groups of rats (N= 10 per group). In three groups of rats after 80 sessions with training doses ranging from 0.1 to 4.0 mg/kg po, stimulus control by ondansetron, DU122932 and 2-methyl-5-HT was still absent. The same 30 animals thereafter rapidly learned to discriminate chlordiazepoxide (CDP) from vehicle. In three other groups of rats, stimulus control by CDP was first established. Then, the vehicle was gradually (from 0.1 to 2.0 mg/kg po) replaced by either ondansetron, DU122932 or 2-methyl-5-HT. Finally, the dose of CDP was gradually decreased. In all three groups, stimulus control disappeared. A seventh group was trained to discriminate 3,4DCPB (5.0 mg/kg po) from saline. When training was not successful, dose and route were changed but discrimination was not attained. It is concluded that in the rat, using the classical two lever discrimination procedure, the 5-HT3 receptor ligands ondansetron, DU122932, 2-methyl-5-HT and 3,4DCPB are incapable of producing an internal state that can act as a stimulus to control responding.

Animals↗
PubMed1997

Invariant face and object recognition in the visual system.

Neurophysiological evidence is described, showing that some neurons in the macaque temporal cortical visual areas have responses that are invariant with respect to the position, size and view of faces and objects, and that these neurons show rapid processing and rapid learning. A theory is then described of how such invariant representations may be produced in a hierarchically organized set of visual cortical areas with convergent connectivity. The theory proposes that neurons in these visual areas use a modified Hebb synaptic modification rule with a short-term memory trace to capture whatever can be captured at each stage that is invariant about objects as the object changes in retinal position, size, rotation and view. Simulations are then described which explore the operation of the architecture. The simulations show that such a processing system can build invariant representations of objects.

Animals↗
PubMed1998

Differential effects of CRH infusion into the central nucleus of the amygdala in the Roman high-avoidance and low-avoidance rats.

Roman-high (RHA/Verh) and low (RLA/Verh) avoidance rats are selected and bred for rapid learning versus non-acquisition of two-way, active avoidance behavior in a shuttle box. RHA/Verh rats generally show a more active coping style than do their RLA/Verh counterparts when exposed to various environmental challenges. The central nucleus of the amygdala (CeA) is known to be involved in the regulation of autonomic, neuroendocrine and behavioural responses to stress and stress-free conditions, and it is considered in relation to coping strategies. Corticotropin-releasing hormone (CRH) seems to be a key factor in the control of the CeA output. Neuroanatomical studies have revealed that the majority of CRH fibers from the CeA have direct connections with autonomic regulatory nuclei in the brainstem, e.g. lateral parabrachial nucleus (lPB), ventrolateral periaquaductal gray (vlPAG). The modulating effects of CRH (30 ng) on CeA activity were studied by infusion of CRH into the CeA in freely moving male RHA/Verh and RLA/Verh rats under stress-free conditions. Heart-rate and behavioural activities were repeatedly measured before, during and after local administration of CRH or vehicle, after which early gene product FOS immunocytochemistry and CRH-mRNA in situ hybridisation were carried out in selected brain areas. CRH infusion into the CeA caused a long lasting increase in heart-rate and behavioural activation in the RHA/Verh rats, leaving the RLA/Verh rats unaffected. As a result of CRH infusion, the number of FOS positive cells in the CeA and lPB of RLA/Verh rats was increased whereas an opposite response was found in the RHA/Verh rats. However, CRH into the CeA of the Roman rat lines induced no pronounced effects on FOS staining in the vlPAG and CRH mRNA levels in the CeA. These results indicate that the CRH system of the CeA, connected with the output brainstem areas, is differentially involved in cardiovascular and behavioural responses.

Adaptation, Psychological↗
PubMed1985

Pharyngeal reconstruction after total laryngectomy with preservation of phonation.

The goal of pharyngeal reconstruction after laryngectomy is to prevent fistulization and to permit rapid resumption of satisfactory deglutition. Alaryngeal speech acquisition by the traditional method of esophageal speech is effective if insufflation is rapidly learned and tolerated by the pharyngoesophageal segment. Experience with tracheoesophageal phonation revealed an incidence of pharyngoesophageal spasm in 40% of an esophageal speech failure population which prevented useful air flow for speech production. This is related to esophageal distention and reflexive upper esophageal sphincter hypertension. It is suggested that pharyngeal reconstruction after total laryngectomy may permit higher wall tension than is desirable for speech acquisition. The problem of post laryngectomy pharyngoesophageal spasm may be reduced by myotomy of the pharyngeal constrictors with resultant higher air flows in the residual vocal tract for speech. Alterations in the pharyngeal wall tonicity will affect the pitch of the speech and listener acceptability. Recently identification and division of the pharyngeal plexus has produced a similar result in improved phonatory air flows with subjective vocal pitch approximating more normal voices. The above mentioned techniques are readily applied to the laryngectomy procedure and enhance the likelihood of alaryngeal speech acquisition.

Humans↗
PubMedDate not supplied

A preliminary comparison of guided compliance and high-probability instructional sequences as treatment for noncompliance in children with developmental disabilities.

The efficacy of guided compliance and high-probability instructional sequences was compared with two children referred to an outpatient clinic for treatment of noncompliance. Parents were taught to implement the procedures in their homes, and parent-training outcomes for the two interventions were compared in terms of treatment effectiveness, procedural integrity, and parent satisfaction. Levels of compliance were higher under guided compliance than under high-probability instructional sequences. Nevertheless, parents rapidly learned to implement both treatments with a high degree of accuracy and reported equal satisfaction with the procedures.

Adult↗
PubMed1999

Curriculum for building medical resources on the Internet--experience in Taiwan.

This paper describes our experience with a one-semester course on how to build a medically-related homepage on the Internet, designed for fourth-year medical students. Based on the assumption of limited technical knowledge of the Internet, this class taught students Internet-exploring skills, multimedia authoring and HTML (Hypertext Markup Language) in the first eight-week period. Students were then divided into four-person teams and asked to select a topic for a homepage. These teams were then asked to collect the necessary resources for the development of the homepage both through individual work and, consultation with an advisor. Each group project for building medically-related homepage was accomplished and presented in the remaining four-week period. The resultant projects of these fourth-year medical students were of surprisingly good content and high quality. Medical students rapidly learned to use the software tools, and through proper instruction and provision of equipment, they were able to build significant medical resources on the Internet that can potentially be useful in education, clinical applications and research.

Curriculum↗
PubMed1998

Cue control and head direction cells.

Previous research has shown that head direction (HD) cells in both the anterior dorsal thalamus (ADN) and the postsubiculum (PoS) in rats discharge in relation to familiar, visual landmarks in the environment. This study assessed whether PoS and ADN HD cells would be similarly responsive to nonvisual or unfamiliar environmental cues. After visual input was eliminated by blindfolding the rats, HD cells maintained direction-specific discharge, but their preferred firing directions became less stable. In addition, rotations of the behavioral apparatus indicated that some nonvisual cues (presumably tactile, olfactory, or both) exerted above chance stimulus control over a cell's preferred firing direction. However, a prominent auditory cue was not effective in exerting stimulus control over a cell's preferred direction. HD cell activity also was assessed after rotation of a novel visual cue exposed to the rat for 1, 3, or 8 min. An 8-min exposure was enough time for a novel visual cue to gain control over a cell's preferred direction, whereas an exposure of 1 or 3 min led to control in only about half the sessions. These latter results indicate that HD cells rely on a rapid learning mechanism to develop associations with landmark cues.

Animals↗
PubMed2005

Ordinal judgments and summation of nonvisible sets of food items by two chimpanzees and a rhesus macaque.

Two chimpanzees and a rhesus macaque rapidly learned the ordinal relations between 5 colors of containers (plastic eggs) when all containers of a given color contained a specific number of identical food items. All 3 animals also performed at high levels when comparing sets of containers with sets of visible food items. This indicates that the animals learned the approximate quantity of food items in containers of a given color. However, all animals failed in a summation task, in which a single container was compared with a set of 2 containers of a lesser individual quantity but a greater combined quantity. This difficulty was not overcome by sequential presentation of containers into opaque receptacles, but performance improved if the quantitative difference between sizes was very large.

Animals↗
PubMed1999

Scrub jays (Aphelocoma coerulescens) remember the relative time of caching as well as the location and content of their caches.

Two experiments examined whether food-storing scrub jays (Aphelocoma coerulescens) could remember when they cached particular food items as well as what they cached and where. In Experiment 1, scrub jays cached and recovered perishable "wax worms" (wax moth larvae) and nonperishable peanuts in 2 visuospatially distinct and trial-unique trays. The birds searched preferentially for fresh wax worms if they had cached them 4 hr earlier but rapidly learned to search for peanuts and avoid decayed wax worms that had been cached 124 hr previously. This pattern also was observed when the food items were removed before recovery on test trials. These results were replicated in Experiment 2 using a procedure in which both types of food were cached in different sides of the same caching tray: On the basis of a single, trial-unique experience, scrub jays could remember the relative time of caching as well as what type of food was cached in each cache site.

Animals↗
PubMed2003

Using idiothetic cues to swim a path with a fixed trajectory and distance: necessary involvement of the hippocampus, but not the retrosplenial cortex.

Rats rapidly learned to find a submerged platform in a water maze at a constant distance and angle from the start point, which changed on every trial. The rats performed accurately in the light and dark, but prior rotation disrupted the latter condition. The rats were then retested after receiving cytotoxic hippocampal or retrosplenial cortex lesions. Retrosplenial lesions had no apparent effect in either the light or dark. Hippocampal lesions impaired performance in both conditions but spared the ability to locate a platform placed in the center of the pool. A hippocampal deficit emerged when this pool-center task was run in the dark. The spatial effects of hippocampal damage extend beyond allocentric tasks to include aspects of idiothetic guidance.

Animals↗
PubMed1978

Novel taste facilitation of the association of visual cues with toxicosis in rats.

The present experiments examined the conditions under which rats rapidly learn to avoid ingesting visually distinctive food objects associated with toxicosis. It was found that the presence of a novel taste associated with a visually distinctive food object faciliated acquisition of visual-cue-toxicosis associations. Further experiments failed to support either higher order conditioning or sensory preconditioning models of this phenomenon. The results are discussed in terms of species' differences in the conditions under which attention is directed to visual cues associated with ingesta. The implications of these findings for the existence of visual aposomatisms (warning colors) in naturally occurring toxic species are also examined.

Animals↗
PubMed1998

Episodic-like memory during cache recovery by scrub jays.

The recollection of past experiences allows us to recall what a particular event was, and where and when it occurred, a form of memory that is thought to be unique to humans. It is known, however, that food-storing birds remember the spatial location and contents of their caches. Furthermore, food-storing animals adapt their caching and recovery strategies to the perishability of food stores, which suggests that they are sensitive to temporal factors. Here we show that scrub jays (Aphelocoma coerulescens) remember 'when' food items are stored by allowing them to recover perishable 'wax worms' (wax-moth larvae) and non-perishable peanuts which they had previously cached in visuospatially distinct sites. Jays searched preferentially for fresh wax worms, their favoured food, when allowed to recover them shortly after caching. However, they rapidly learned to avoid searching for worms after a longer interval during which the worms had decayed. The recovery preference of jays demonstrates memory of where and when particular food items were cached, thereby fulfilling the behavioural criteria for episodic-like memory in non-human animals.

Animals↗
PubMed2005

The anxiogenic drug yohimbine reinstates palatable food seeking in a rat relapse model: a role of CRF1 receptors.

The major problem in treating excessive eating is high rates of relapse to maladaptive eating habits during diet treatments; this relapse is often induced by stress or anxiety states. Preclinical studies have not explored this clinical problem. Here, we adapted a reinstatement model (commonly used to study relapse to abused drugs) to examine the role of stress and anxiety in relapse to palatable food seeking during dieting. Rats were placed on restricted diet (75-80% of daily standard food) and for 12 intermittent training days (9 h/day, every other day) lever-pressed for palatable food pellets (25% fat, 48% carbohydrate) under a fixed ratio 1 (20-s timeout) reinforcement schedule. Subsequently, the rats were given 10 daily extinction sessions during which lever presses were not reinforced, and were then injected with yohimbine (an alpha-2 adrenoceptor antagonist that induces stress and anxiety in humans and non-humans) or given a single food pellet to assess reinstatement of food seeking. The rats rapidly learned to lever press for the palatable pellets and across the training days the ratio of timeout nonreinforced lever presses to reinforced lever presses progressively increased more than three-fold, suggesting the development of compulsive eating behavior. After extinction, yohimbine injections and pellet priming reliably reinstated food seeking. The corticotropin-releasing factor1 (CRF1) receptor antagonist antalarmin attenuated the reinstatement induced by yohimbine, but not pellet priming. Antalarmin also reversed yohimbine's anxiogenic effects in the social interaction test. These data suggest that CRF is involved in stress-induced relapse to palatable food seeking, and that CRF1 antagonists should be considered for the treatment of maladaptive eating habits.

Adrenergic alpha-Antagonists↗
PubMed1983

Speech modification by a deaf child through dynamic orometric modeling and feedback.

Baseline physiologic, acoustic, and phonetic data are presented to characterize speech production of a 3 1/2-year-old deaf girl prior to a visual articulatory modeling and feedback program. These observations suggest that she used an articulatory strategy based on visual information about lip and jaw movements rather than tongue positions as a primary means of differentiating speech sounds. The training program which followed used instrumentally generated displays of tongue position and movements to teach production of the (i) and (a) vowels in single and bisyllable word contexts. Linguapalatal contact patterns for the consonant (t) were then introduced and taught in combinations with the vowels. Goal articulatory gestures were learned rapidly with respect to both positional and timing features of speech.

Articulation Disorders↗
PubMed2005

New arrivals: speech and language assessment for internationally adopted infants and toddlers within the first months home.

Speech-language pathologists are increasingly requested to assess development in newly arrived internationally adopted children. These infants and toddlers typically arrive home with developmental delays and a lack of proficiency in any language, making it difficult to make objective service delivery decisions. This article reports the results of speech and language assessments for a group of 28 children aged 12 to 24 months who were newly adopted from Eastern Europe. Most of the children did well, with average English language standard scores within normal limits on the Communication and Symbolic Behavior Scale-Developmental Profile. The majority of children were also rapidly learning to understand and produce English words as measured on the MacArthur-Bates Communicative Development Inventory. These findings were used to develop peer-based infant-toddler guidelines for early speech and language intervention. Using these guidelines, 65% of the internationally adopted children did not require early intervention, 7% were borderline and recommended for follow-up assessments within 2 to 3 months, and 28% were recommended for speech and language early intervention.

Adoption↗