Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Touch”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed2003

The spatial distribution of attentional selectivity in touch: evidence from somatosensory ERP components.

OBJECTIVE: Somatosensory event-related brain potentials (ERPs) were measured to investigate the spatial distribution of selective attention in touch, and whether the focus of tactile attention can be split between non-contiguous areas of the body surface. METHODS: On each trial, vibratory tactile stimuli were delivered to one of 4 possible locations of the right hand. Participants had to attend to either one or two locations in order to detect infrequently presented target stimuli there. ERPs were recorded to tactile non-targets at attended and unattended locations. RESULTS: Attention directed to one finger versus another was reflected by amplitude modulations of the sensory-specific P100 component and a subsequent attentional negativity (Nd). These effects were smaller for within-finger as compared to between-finger selection. When attention was directed simultaneously to non-adjacent fingers, ERPs in response to stimuli delivered to spatially and anatomically intervening fingers showed no attentional modulations whatsoever. CONCLUSIONS: Allocating tactile-spatial attention to one finger versus another affects early modality-specific somatosensory processing stages, and these effects of within-hand attentional selectivity decrease gradually with increasing distance from the current attentional focus. Unlike vision, the focus of tactile attention can be split, and directed simultaneously to non-adjacent areas, thus excluding spatially and anatomically intermediate regions from attentional processing.

Adult↗
PubMed1997

The role of touch in facilitated communication.

Imagine that one day a nonverbal autistic child suddenly starts to type messages, such as "I am not retarded," using a computer keyboard while being touched by an assistant. Facilitated communication (FC) appears to create this miracle around the world. To understand how this works, experiments were conducted involving a "telepathy game" using a rod with an attached strain gauge. A force from the assistant, which controlled what was spelled through physical support, was measured. It was thus completely possible for any message to appear to be typed with FC regardless of the autistic child's actual knowledge or language ability.

Adolescent↗
PubMed1996

Dynamic touch.

People can perceive a number of spatial and other properties of objects, without the benefit of vision, simply by wielding and hefting the objects. A variety of recent experiments are reported, showing that in this kind of touching, which is closely connected with the states of muscles, the nervous system cleverly exploits the physics of rotations.

Discrimination Learning↗
PubMed1986

Perception of texture by vision and touch: multidimensionality and intersensory integration.

A series of six experiments offers converging evidence that there is no fixed dominance hierarchy for the perception of textured patterns, and in doing so, highlights the importance of recognizing the multidimensionality of texture perception. The relative bias between vision and touch was reversed or considerably altered using both discrepancy and nondiscrepancy paradigms. This shift was achieved merely by directing observers to judge different dimensions of the same textured surface. Experiments 1, 4, and 5 showed relatively strong emphasis on visual as opposed to tactual cues regarding the spatial density of raised dot patterns. In contrast, Experiments 2, 3, and 6 demonstrated considerably greater emphasis on the tactual as opposed to visual cues when observers were instructed to judge the roughness of the same surfaces. The results of the experiments were discussed in terms of a modality appropriateness interpretation of intersensory bias. A weighted averaging model appeared to describe the nature of the intersensory integration process for both spatial density and roughness perception.

Adolescent↗
PubMed2000

Crossmodal links between vision and touch in covert endogenous spatial attention.

The authors report a series of 6 experiments investigating crossmodal links between vision and touch in covert endogenous spatial attention. When participants were informed that visual and tactile targets were more likely on 1 side than the other, speeded discrimination responses (continuous vs. pulsed, Experiments 1 and 2; or up vs. down, Experiment 3) for targets in both modalities were significantly faster on the expected side, even though target modality was entirely unpredictable. When participants expected a target on a particular side in just one modality, corresponding shifts of covert attention also took place in the other modality, as evidenced by faster elevation judgments on that side (Experiment 4). Larger attentional effects were found when directing visual and tactile attention to the same position rather than to different positions (Experiment 5). A final study with crossed hands revealed that these visuotactile links in spatial attention apply to common positions in external space.

Adult↗
PubMed1985

Spatial and movement-based heuristics for encoding pattern information through touch.

Seven experiments investigated the heuristics people use to encode spatial pattern information through touch. Observers traced a tangible pathway with one hand and then answered questions about either the euclidean line between the pathway endpoints or the pathway itself. Parameters of the euclidean line were held constant, while characteristics of the felt pathway were manipulated. Experiments 1-4 showed that blindfolded sighted and blind observers increasingly overestimated the length of the euclidean line as the length of the explored pathway increased. This indicates a movement-based heuristic for encoding distance. Experiments 5-7 indicated that judgments of the position of the euclidean line did not vary with the position of the felt pathway or the extent to which it deviated from that line. Instead, the results indicated that observers relied on implicit spatial axes, which are movement independent, to judge position. These and other results have implications for theories of haptic encoding of spatial pattern and for the construction of tangible graphics displays.

Adult↗
PubMed1996

Learning the configuration of a landmark array: I. Touch-screen studies with pigeons and humans.

Pigeons and humans searched on a touch-screen monitor for an unmarked goal located relative to an array of landmarks presented in varied screen locations. After training with the goal centered in various square arrays of 4 landmarks, humans, but not pigeons, transferred accurately to arrays with novel elements. Humans searched in the middle of expanded arrays, whereas pigeons preserved the distance and direction to a single landmark. When trained with the goal centered below 2 identical horizontally aligned landmarks, humans responded to horizontal expansions or contractions of the array by shifting their search vertically, preserving angles from landmarks to goal. Pigeons did not adjust their search vertically. Humans trained with a single landmark adjusted search distance when landmark size was changed. Both pigeons and humans use the configuration of a landmark array, but the underlying processes seem to differ.

Adult↗
PubMed2000

Touch can change visual slant perception.

The visual system uses several signals to deduce the three-dimensional structure of the environment, including binocular disparity, texture gradients, shading and motion parallax. Although each of these sources of information is independently insufficient to yield reliable three-dimensional structure from everyday scenes, the visual system combines them by weighting the available information; altering the weights would therefore change the perceived structure. We report that haptic feedback (active touch) increases the weight of a consistent surface-slant signal relative to inconsistent signals. Thus, appearance of a subsequently viewed surface is changed: the surface appears slanted in the direction specified by the haptically reinforced signal.

Biofeedback, Psychology↗
PubMed2004

Keeping the world a constant size: object constancy in human touch.

The perceived size of objects touching different regions of skin varies across the body surface by much less than is predicted from variations in tactile receptor density. Here we show that altering the visual experience of the body alters perceived tactile distances. We propose that the brain attempts to preserve tactile size constancy by rescaling the primary, distorted body-surface representation into object-centered space according to visual experience of the body.

Adult↗
PubMed2003

PKC alpha mediates maternal touch regulation of growth-related gene expression in infant rats.

During short-term periods of separation of rat pups from their mothers, the loss of certain sensory signals suppresses the increase in ornithine decarboxylase (ODC) gene expression induced by the growth-promoting hormones prolactin (PRL) and growth hormone (GH). Here, we identify a molecular mechanism through which maternal separation (MS) curtails ODC expression. Our results demonstrate that the absence of specific tactile stimuli provided by the mother limits PRL-evoked stimulation of ODC biosynthesis by interfering with sn-1,2-diacylglycerol's (DAG) ability to activate protein kinase Calpha (PKCalpha) and consequently c-myc mRNA and max mRNA expression. The proteins encoded by these proto-oncogenes function as direct transactivators of the ODC gene. As ODC activity is obligatory for normal cell replication and differentiation, PKCalpha activation by DAG represents an important control point at which 'nurturing touch' regulates growth and development of the neonate. Such a mechanism can explain the maladaptive consequences of disrupting mother-infant tactile interactions as occurs in isolated premature babies. Also, it could provide a basis for developing therapeutic interventions to maximize growth potential in children failing-to-thrive despite normal maternal care.

Animals↗
PubMed1998

Therapeutic touch as a nursing intervention.

Therapeutic Touch (TT) is being proposed as a nursing intervention. Its proponents claim that it is integral to the art of nursing practice and can facilitate comfort and healing in a wide range of patients. However, the practice of TT is also controversial, primarily because it does not usually involve physical contact and is based on energy field theoretical frameworks. The development of TT and its conceptualization as an energy field interaction are reviewed, and points of controversy discussed. The method of practice is described. Review of controlled efficacy studies indicates limited and inconclusive scientific support for its proposed effects. The intrinsic relationship between TT and the placebo phenomenon is discussed. The potential of TT to enhance the placebo effect requires further exploration but should not be discounted in seeking to relieve discomfort and distress and facilitate healing. For some patients, TT may serve as a beneficial adjuvant nursing intervention.

Humans↗
PubMed1999

Involvement of primary afferent C-fibres in touch-evoked pain (allodynia) induced by prostaglandin E2.

Nociceptive primary afferents have the capacity to induce a state of increased excitability in dorsal horn neurons of the spinal cord or central sensitization causing thermal hyperalgesia and touch-evoked pain (allodynia). It is believed that primary afferent C-fibres become hypersensitive and induce hyperalgesia and that low-threshold Abeta-fibres are responsible for induction of allodynia, the mechanisms of which remain elusive. We previously showed that intrathecal administration of prostaglandin E2 (PGE2) and prostaglandin F2alpha (PGF2alpha) induce allodynia in conscious mice. Here we demonstrated that selective elimination of C-fibres by neonatal capsaicin treatment resulted in the disappearance of allodynia induced by PGE2, but not that by PGF2alpha. PGE2-induced allodynia was not observed in N-methyl-D-aspartate (NMDA) receptor epsilon1 subunit knockout mice and was sensitive to morphine. In contrast, PGF2alpha-induced allodynia was not observed in NMDA epsilon4 subunit knockout mice and was insensitive to morphine. Furthermore, while PGF2alpha showed a capsaicin-insensitive feeble facilitatory action on evoked excitatory postsynaptic currents in dorsal horn neurons, PGE2 induced a long-lasting facilitation of evoked excitatory postsynaptic currents in a capsaicin-sensitive manner. Taken together, the present study demonstrates that there are two pathways for induction of allodynia and that capsaicin-sensitive C-fibres may participate in PGE2-induced allodynia.

Afferent Pathways↗
PubMed2001

Health information: an evaluation of the use of touch screen kiosks in two hospitals.

An exit questionnaire survey of 150 hospital users of a touch screen health information kiosk was undertaken. It was compiled by Royal Cornwall Hospitals NHS to evaluate kiosk use and was reanalysed by researchers at City University to determine whether the information obtained went anyway to meeting patients' information needs. The study established two effective outcome variables on kiosk use: whether the information found answered the users' questions and if users intended, after using the kiosk, to find more information elsewhere. Two-thirds of respondents said that the information found had answered their question, whilst 16% said that after using the kiosk they still had further questions and intended to talk to a health professional to obtain this information. The variables found to have an impact on the information outcome included: gender, navigational ease, object of search, and ease of reading and understanding the information.

Adolescent↗
PubMed2002

Positive Touch and massage in the neonatal unit: a British approach.

There is now a general trend towards a more baby friendly, family centred approach in the Neonatal Unit. Aspects of that approach-including positive touch and massage- are gaining in popularity. This has caused much debate due to the ambiguity surrounding the implementation and validity of the interventions. Here the impact of these complementary practices (not to be confused with complementary therapies) is discussed. A review of the author's approach and potential guidelines for implementation is provided.

Health Education↗
PubMed1980

The dominance of touch by vision: sometimes incomplete.

It is generally agreed that, when the two senses are in conflict, vision dominates touch. In the series of experiments reported here the discrepancy between the visual and the haptic images was progressively increased. In each experiment half of the observes were adults and half children, and half of each group wore a glove which concealed the distortion produced by the lens. In experiment 1 the visual image of a haptic square was transformed by a week or strong cylindrical lens so that the sides were in the ratio 1:1.5 or 1:1.8. Gloved observers selected a comparison image close to the visual image. Bare-handed observers gave compromise judgements with the strong lens, but judgements similar to those of the gloved observers with the weak lens. In experiment 2 the square had a visual image which was either a diamond or a parallelogram, the parallelogram having angles of 70 degrees and 110 degrees. Observers described and drew their percepts, which were generally in accord with the visual image. There were no significant differences due to age, a finding contrary to that of Page and Locke, nor were there differences in experiment 2 due to the gloved-hand-bare-hand dimension. It is concluded (i) that repeated observations do not destroy the effect, (ii) tht considerable discrepancies between the visual and haptic images do not destroy the effect, but (iii) that feedback from a bare hand can reduce the effect when it is of considerable magnitude.

Adult↗
PubMed1981

The dominance of touch by vision: occurs with familiar objects.

In a study of visual dominance based on Rock and Victor's experiments, observers examined well-known objects while receiving conflicting tactual and visual information. In experiment 1 observers simultaneously felt a circular 20 cent coin and looked at it through a lens which transformed the visual image to an oval with axes in the ratio 1 : 1.8. In experiment 2 another sample of observers felt well known cubic objects-dice-and looked at them through lens systems made the visual images: (i) rectangular with sides in the ratio 1 : 1.3; (2) diamond-shaped with 72 degrees smaller angles; (iii) rectangular with side in the ratio 1 : 1.8; and (iv) a parallelogram with side lengths in the ratio 1 : 1.8 and with 60 degrees smaller angles. Although there was some conflict between the observers' cognitions and their percepts, effectively all reported that the target objects were like or felt like their visual images, demonstrating that the dominance of vision over touch is far stronger than has been recognised.

Adolescent↗
PubMed1998

The influence of stimulus tilt on haptic curvature matching and discrimination by dynamic touch.

We investigated whether haptic comparison of the curvature of strips is influenced by the tilt (the average slope relative to the horizontal) of the curved strips. This particular stimulus manipulation was chosen to decide between two broad ways in which dynamic curvature comparison might be done: on the basis of the attitude (slope) differences over the surfaces or on the basis of the attitude (slope) differences between successively presented surfaces. For this purpose we conducted matching and discrimination experiments in which strips of constant curvature 9 cm long were touched dynamically and the tilts of the strips were varied. The results of the matching experiment showed some influence of tilt: the strips were judged to be slightly more curved if the tilt was nonzero than if it was zero. The results of the discrimination experiment did not show an effect of tilt. Because the attitude (slope) differences over the surfaces were independent of the tilt it is concluded that curvature comparison is based primarily on attitude differences over the curved surfaces.

Humans↗
PubMed2001

Amplitude and spatial-period discrimination in sinusoidal gratings by dynamic touch.

We measured discrimination thresholds for sinusoidal gratings using active dynamic touch. In the first experiment we measured the thresholds for amplitude discrimination as a function of amplitude and spatial period. Thresholds ranged between 10.8%, and 15.8% of the standard amplitude. We showed that amplitude differences as small as 2 microm can be detected. We found that Weber fractions for amplitude discrimination are constant over a range of amplitudes, but are influenced by the spatial period of the grating; discrimination improved with increasing spatial period. In the second experiment we determined the thresholds for spatial-period discrimination. We used the same design as in the first experiment. Weber fractions ranged from 6.4% to 11.8%. Amplitude was found to have no effect on the Weber fractions for spatial-period discrimination. However, the spatial period had an effect on the Weber fractions: larger spatial periods yielded lower Weber fractions.

Adult↗