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PubMed1998

Differential effects of amitriptyline on perception of somatic and visceral stimulation in healthy humans.

Tricyclic antidepressants treat chronic pain both in patients with somatic illness and with functional bowel disorders. We compared the effects of amitriptyline on perception of cutaneous and gastrointestinal stimulation to assess differential analgesic effects of tricyclics on somatic and visceral pain. Cutaneous electrical stimulation and rectal and esophageal distension were performed before and after 21 days of double-blind 50 mg amitriptyline vs. placebo in healthy volunteers. Amitriptyline increased currents that elicited cutaneous threshold, moderate discomfort, and moderate pain compared with basal (P < 0.05), whereas placebo had no effect. Amitriptyline had no effect on perception of rectal and esophageal distension and did not alter luminal compliance; thus the lack of effect on perception is not due to altered visceral elastic wall properties. In conclusion, amitriptyline reduces perception of cutaneous stimulation but does not alter visceral perception or compliance. This investigation demonstrates differential effects of tricyclics on somatic and visceral afferent function in healthy humans and provides insight into mechanisms of action in chronic pain both from somatic disease and from functional bowel disorders.

Adult↗

PubMed1999

Physiological changes in blood glucose do not affect gastric compliance and perception in normal subjects.

Marked hyperglycemia (blood glucose approximately 14 mmol/l) slows gastric emptying and affects the perception of sensations arising from the gut. Elevation of blood glucose within the physiological range also slows gastric emptying. This study aimed to determine whether physiological changes in blood glucose affect proximal gastric compliance and/or the perception of gastric distension in the fasting state. Paired studies were conducted in 10 fasting healthy volunteers. On a single day, isovolumetric and isobaric distensions of the proximal stomach were performed using an electronic barostat while the blood glucose concentration was maintained at 4 and 9 mmol/l in random order. Sensations were quantified using visual analog scales. The blood glucose concentration had no effect on the pressure-volume relationship during either isovolumetric or isobaric distensions or the perception of gastric distension. At both blood glucose concentrations, the perceptions of fullness, nausea, bloating, and abdominal discomfort, but not hunger or desire to eat, were related to intrabag volume (P </= 0.002) and pressure (P </= 0.01). We conclude that, in the fasted state, elevations of blood glucose within the physiological range do not affect proximal gastric compliance or the perception of gastric distension.

Adult↗

PubMed2006

Internalizing agency of self-action: perception of one's own hand movements depends on an adaptable prediction about the sensory action outcome.

Extensive work on learning in reaching and pointing tasks has demonstrated high degrees of plasticity in our ability to optimize goal-directed motor behavior. However, studies focusing on the perceptual awareness of our own actions during motor adaptation are still rare. Here we present the first simultaneous investigation of sensorimotor adaptation on both levels, i.e., action and action perception. We hypothesized that self-action perception relies on internal predictions about the sensory action outcome that are updated in a way similar to that of motor control. Twenty human subjects performed out-and-back pointing movements that were fed back visually. Feedback was initially presented in spatiotemporal correspondence with respect to the actual finger position, but later rotated by a constant angle. When distorted feedback was applied repetitively, subjects' perceived pointing direction shifted in the direction of the trajectory rotation. A comparable perceptual reinterpretation was observed in control trials without visual feedback, indicating that subjects learned to predict the new visual outcome of their actions based on nonvisual, internal information. The perception of the world, however, remained unchanged. The changes in perception of one's own movements were accompanied by adaptive changes in motor performance of the same amount, i.e., a secondary motor compensation opposite to the direction of the imposed visual rotation. Our results show that the perception of one's own actions depends on adaptable internal predictions about the sensory action outcome, allowing us to attribute new sensory consequences of our actions to our own agency. Furthermore, they indicate that the updated sensory prediction can be used to optimize motor control.

Adult↗

PubMed2005

Vestibular perception and action employ qualitatively different mechanisms. I. Frequency response of VOR and perceptual responses during Translation and Tilt.

To investigate the neural mechanisms that humans use to process the ambiguous force measured by the otolith organs, we measured vestibuloocular reflexes (VORs) and perceptions of tilt and translation. One primary goal was to determine if the same, or different, mechanisms contribute to vestibular perception and action. We used motion paradigms that provided identical sinusoidal inter-aural otolith cues across a broad frequency range. We accomplished this by sinusoidally tilting (20 degrees, 0.005-0.7 Hz) subjects in roll about an earth-horizontal, head-centered, rotation axis ("Tilt") or sinusoidally accelerating (3.3 m/s2, 0.005-0.7 Hz) subjects along their inter-aural axis ("Translation"). While identical inter-aural otolith cues were provided by these motion paradigms, the canal cues were substantially different because roll rotations were present during Tilt but not during Translation. We found that perception was dependent on canal cues because the reported perceptions of both roll tilt and inter-aural translation were substantially different during Translation and Tilt. These findings match internal model predictions that rotational cues from the canals influence the neural processing of otolith cues. We also found horizontal translational VORs at frequencies >0.2 Hz during both Translation and Tilt. These responses were dependent on otolith cues and match simple filtering predictions that translational VORs include contributions via simple high-pass filtering of otolith cues. More generally, these findings demonstrate that internal models govern human vestibular "perception" across a broad range of frequencies and that simple high-pass filters contribute to human horizontal translational VORs ("action") at frequencies above approximately 0.2 Hz.

Adult↗

PubMed2006

Roll rotation cues influence roll tilt perception assayed using a somatosensory technique.

We investigated how the nervous system processes ambiguous cues from the otolith organs by measuring roll tilt perception elicited by two motion paradigms. In one paradigm (tilt), eight subjects were sinusoidally tilted in roll with the axis of rotation near ear level. Stimulus frequencies ranged from 0.005 to 0.7 Hz, and the peak amplitude of tilt was 20 degrees . During this paradigm, subjects experienced a sinusoidal variation of interaural gravitational force with a peak of 0.34 g. The second motion paradigm (translation) was designed to yield the same sinusoidal variation in interaural force but did not include a roll canal cue. This was achieved by sinusoidally translating the subjects along their interaural axis. For the 0.7-Hz translation trial, the subjects were simply translated from side to side. A centrifuge was used for the 0.005- to 0.5-Hz translation trials; the subjects were rotated in yaw at 250 degrees /s for 5 min before initiating sinusoidal translations yielding an interaural otolith stimulus composed of both centrifugal and radial acceleration. Using a somatosensory task to measure roll tilt perception, we found substantial differences in tilt perception during the two motion paradigms. Because the primary difference between the two motion paradigms was the presence of roll canal cues during roll tilt trials, these perceptual differences suggest that canal cues influence tilt perception. Specifically, rotational cues provided by the semicircular canals help the CNS resolve ambiguous otolith cues during head tilt, yielding more accurate tilt perception.

Adult↗

PubMed2006

Measuring perceptions of breast cancer risk.

BACKGROUND: Accurate measurement of people's risk perceptions is important for numerous bodies of research and in clinical practice, but there is no consensus about the best measure. OBJECTIVE: This study evaluated three measures of women's breast cancer risk perception by assessing their psychometric and test characteristics. DESIGN: A cross-sectional mailed survey to women from a primary care population asked participants to rate their chance of developing breast cancer in their lifetime on a 0% to 100% numerical scale and a verbal scale with five descriptive categories, and to compare their risk to others (seven categories). Six hundred three of 956 women returned the survey (63.1%), and we analyzed surveys from the 566 women without a self-reported personal history of breast or ovarian cancer. RESULTS: Scores on the numeric, verbal, and comparative measures were correlated with each other (r > 0.50), worry (r > 0.51), the Gail estimate (r > 0.26), and family history (r > 0.25). The numerical scale had the strongest correlation with annual mammogram (r = 0.19), and its correlation with the Gail estimate was unassociated with participants' sociodemographics. The numerical and comparative measures had the highest sensitivity (0.89-0.90) and specificity (0.99) for identifying women with very high risk perception. The numerical and comparative scale also did well in identifying women with very low risk perception, although the numerical scale had the highest specificity (0.96), whereas the comparative scale had the highest sensitivity (0.89). CONCLUSION: Different measures of women's perceptions about breast cancer risk have different strengths and weaknesses. Although the numerical measure did best overall, the optimal measure depends on the goals of the measure (i.e., avoidance of false positives or false negatives).

Adult↗

PubMed1995

Phonetics of intervocalic consonant perception: retrospect and prospect.

This article reviews the production characteristics and perceptual cues of intervocalic consonants as a background for acoustic studies of consonant perception in fluent speech. Data show that in conversation intervocalic consonants occur much more commonly than consonants in initial or final position; all phonetic features are strongly represented. Production characteristics of intervocalic consonants are seen to depend on the tempo and rhythmic conditions of the syllables of which they are components. At a moderate tempo, consonants in syllable-final position combine with the onset consonant of the following syllable. This affects durational characteristics and may be explained by higher energy efficiency of CV units in production. Phonological phenomena are related to the shifts in syllable position and the temporal compensations of intervocalic consonant production. Studies of consonant perception in fluent context have dealt with tempo of utterance, position in word, and rhythmic pattern, as well as phonemic context. Major phenomena are effects of coarticulation, invariance in consonant perception, and cue interaction and masking. Much evidence suggests a dominance of the perceptual cues in the CV portion of VCCV and VCV sequences. We suggest that exploration of perception variables that affect consonants in fluent context would be expedited by reorienting experimental procedures to employ listener adjustment of stimuli, instead of the traditional phoneme identification and discrimination procedures with large sets of constant stimuli. Most of the relevant literature deals with stop consonants. Lateral, rhotic, and nasal consonants also deserve intensive study because of their very frequent occurrence. Theoretical issues of phoneme perceptual invariance and motor vs. auditory theory of perception are discussed in relation to proposed experiments which vary syllable tempo and stress pattern.

Humans↗

PubMedDate not supplied

Modulation of motor excitability during speech perception: the role of Broca's area.

Studies in both human and nonhuman primates indicate that motor and premotor cortical regions participate in auditory and visual perception of actions. Previous studies, using transcranial magnetic stimulation (TMS), showed that perceiving visual and auditory speech increased the excitability of the orofacial motor system during speech perception. Such studies, however, cannot tell us which brain regions mediate this effect. In this study, we used the technique of combining positron emission tomography with TMS to identify the brain regions that modulate the excitability of the motor system during speech perception. Our results show that during auditory speech perception, there is increased excitability of motor system underlying speech production and that this increase is significantly correlated with activity in the posterior part of the left inferior frontal gyrus (Broca's area). We propose that this area "primes" the motor system in response to heard speech even when no speech output is required and, as such, operates at the interface of perception and action.

Adult↗

PubMed2003

The reentry hypothesis: linking eye movements to visual perception.

Cortical organization of vision appears to be divided into perception and action. Models of vision have generally assumed that eye movements serve to select a scene for perception, so action and perception are sequential processes. We suggest a less distinct separation. According to our model, occulomotor areas responsible for planning an eye movement, such as the frontal eye field, influence perception prior to the eye movement. The activity reflecting the planning of an eye movement reenters the ventral pathway and sensitizes all cells within the movement field so the planned action determines perception. We demonstrate the performance of the computational model in a visual search task that demands an eye movement toward a target.

Attention↗

PubMed1995

Perception of bronchial obstruction in asthmatic patients. Relationship with bronchial eosinophilic inflammation and epithelial damage and effect of corticosteroid treatment.

We studied the perception of bronchoconstriction in asthmatic subjects who were randomly treated with inhaled beta 2 agonist given either alone (n = 9) or associated with inhaled corticosteroids (n = 9). Methacholine and bradykinin challenges, bronchoalveolar lavage, and bronchial biopsies were performed in all subjects. After each dose of agonist, breathlessness was assessed using a visual analog scale (VAS) and the forced expiratory volume in 1 s (FEV1) was measured. The relationship between VAS scores and FEV1 and the slope of the regression line of VAS scores on the corresponding FEV1 (VAS/FEV1 slope) were analyzed for each agonist. Subjects without corticosteroids had good perception of methacholine but poor perception of bradykinin-induced bronchoconstriction. In subjects with corticosteroids, bronchoconstriction was well perceived whatever the agonist. VAS/FEV1 slopes for bradykinin but not for methacholine correlated negatively with the magnitude of eosinophilic inflammation in airway mucosa. VAS/FEV1 slopes for each agonist correlated positively with the percentage of basement membrane covered by airway epithelium. We conclude that in asthmatic patients perception of bronchoconstriction is related to eosinophilic inflammation and to epithelial damage in airways and that corticosteroid treatment is associated with improved perception of bronchoconstriction induced by bradykinin, a mediator endogenously produced in asthma.

Adrenal Cortex Hormones↗

PubMed2004

Impairment of social perception associated with lesions of the prefrontal cortex.

OBJECTIVE: Behavioral and social impairments have been frequently reported after damage to the prefrontal cortex in humans. This study evaluated social perception in patients with prefrontal cortex lesions and compared their performance on a social perception task with that of healthy volunteers. METHOD: Thirty-three patients with prefrontal cortex lesions and 31 healthy volunteers were tested with the Interpersonal Perception Task. In this task, subjects viewed videotaped social interactions and relied primarily on nonverbal cues to make interpersonal judgments, such as determining the degree of intimacy between two persons depicted in the videotaped scene. Patients with prefrontal cortex lesions were classified according to lesion involvement of specific regions, including the orbitofrontal cortex, dorsolateral prefrontal cortex, and anterior cingulate cortex. RESULTS: Relative to the comparison subjects, patients whose lesions involved the orbitofrontal cortex demonstrated impaired social perception. Contrary to predictions, patients with lesions in the dorsolateral prefrontal cortex also showed deficits in using social cues to make interpersonal judgments. All patients, particularly those with lesions in the dorsolateral prefrontal cortex, showed poorer insight into their deficits, relative to healthy volunteers. CONCLUSIONS: These findings of deficits in social perception after damage to the orbitofrontal cortex extend previous clinical and experimental evidence of damage-related impairment in other aspects of social cognition, such as the ability to accurately evaluate emotional facial expressions. In addition, the results suggest that the dorsolateral prefrontal cortex is recruited when inferences about social interactions are made on the basis of nonverbal information.

Brain Injuries↗

PubMed2005

Effects of antipsychotic treatment on emotion perception deficits in first-episode schizophrenia.

OBJECTIVE: The authors evaluated emotion perception in acutely ill patients experiencing a first episode of schizophrenia. They also investigated the effects of antipsychotic medication on emotion perception. METHOD: Tests of the ability to perceive and discriminate emotional expressions from the Penn Computerized Neuropsychological Battery were given to 13 patients experiencing their first episode of schizophrenia. Patients were also assessed with the Positive and Negative Syndrome Scale. The patients were tested while they were unmedicated and again following clinical stabilization. Healthy individuals were evaluated over a similar time interval. RESULTS: Patients with first-episode schizophrenia demonstrated impairments in emotion perception before treatment and no significant improvement after treatment. Emotion perception deficits were correlated with negative symptoms after clinical stabilization. CONCLUSIONS: Deficits in emotion perception are present at illness onset in schizophrenia and show minimal response to effective antipsychotic treatment.

Antipsychotic Agents↗

PubMed1989

Relationship between social perception and peer status in children with learning disabilities.

This study was undertaken to examine the social perceptual skill deficit theory in explaining the low peer acceptance of children with learning disabilities. The quality of tests measuring social perception was also examined. Thirty 9- to 12-year-old children with learning disabilities and a matched control group were given two measures of social perception: a laboratory task and a behavior rating scale. The behavior rating scale was completed by the children's teachers. In addition, the Peer Acceptance Scale (Bruininks, Rynders, & Gross, 1974) was administered to assess peer status. Results showed that the children with learning disabilities differed significantly from their nondisabled peers on each of the three measures-the children with learning disabilities obtained lower social perception and peer acceptance scores. However, the relationships between sociometric status and social perception varied as a function of task. A small but significant correlation wa found between the behavior rating scale and peer status. The laboratory task was not correlated with either the behavior rating scale or peer status. Results are discussed in terms of the psychometric properties of laboratory versus naturalistic measures of social perception and the importance of establishing the external validity of social skill measures by correlating them with outcome measures such as peer status.

Child↗

PubMed2002

Tone perception ability of Cantonese-speaking children.

Studies have shown that while children acquire all Cantonese tones by age two, they are not able to label them reliably until approximately age 10. One possible explanation for the large age discrepancy may be the different methodologies used. This study aimed to (1) investigate a new research design for the collection of reliable tone perception data from young children; (2) compare lexical and nonlexical items for testing tone perception ability; and (3) identify the relative ease of perceiving the three basic tone contrasts in Cantonese, that is, high level/high rising (T1/T2), high level/low falling (T1/T4), and, high rising/low falling tones (T2/T4). The three tone pairs were presented to 31 children in the form of word and nonword stimuli. It was found that the research design could be used to assess the tone perception knowledge of children as young as 2;09. Significant differences were found between word and nonword stimuli and also in the identification of the T2/T4 contrast in comparison with the other two pairs. Children's overall tone perception abilities are discussed in detail with reference to the role of lexical knowledge and the potential for tone perception confusions arising from differences in fundamental frequencies for tone onset and offset.

Child↗

PubMed2004

Visual memory and visual perception recruit common neural substrates.

This human neuroimaging review aims to determine the degree to which visual memory evokes activity in neural regions that have been associated with visual perception. A visual perception framework is proposed to identify cortical regions associated with modality-specific processing (i.e., visual, auditory, motor, or olfactory), visual domain-specific processing (i.e., "what" versus "where," or face versus visual context), and visual feature-specific processing (i.e., color, motion, or spatial location). Independent assessments of visual item memory studies and visual working memory studies revealed activity in the appropriate cortical regions associated with each of the three levels of visual perception processing. These results provide compelling evidence that visual memory and visual perception are associated with common neural substrates. Furthermore, as with visual perception, they support the view that visual memory is a constructive process, in which features or components from disparate cortical regions bind together to form a coherent whole.

Cerebral Cortex↗

PubMed1999

Perception of bronchoconstriction in asthma patients measured during histamine challenge test.

This study investigated two aspects of the perception of bronchoconstriction ("sensitivity" and "absolute perceptual magnitude") in asthmatic patients and identified which clinical characteristics are related to these two aspects of perception of bronchoconstriction. The perception of histamine induced bronchoconstriction was measured in 128 asthmatic patients. Subjects quantified their breathlessness on a Visual Analogue Scale (VAS) before forced expiratory volume in one second (FEV1 was measured after each inhalation of histamine. The perceptive "sensitivity" for changes in FEV1 was analysed by the "VAS percentage fall in FEV1" slope. The "absolute perceptual magnitude" was determined by the VAS value at a 20% fall in FEV1. Spearman correlations were used for analysis between the two aspects of perception and asthma symptoms, peak flow variability, bronchial responsiveness and FEV1 % predicted. Patients with a low "sensitivity" for changes in FEV1 were more likely to show a frequent peak flow variability (Rs=-0.21; p<0.05), a high bronchial responsiveness (Rs= 0.37; p<0.001) and a low baseline FEV1 % pred (Rs=0.22; p<0.05). Patient's "absolute perceptual magnitude" correlated positively with symptoms during daily life (significant correlations varied 0.21-0.32) but not with the lung function parameters. The severity of asthma reflected by a low lung function and a high bronchial responsiveness, is associated with a low "sensitivity" for changes in forced expiratory volume in one second. A patient's "absolute perceptual magnitude" is positively related with asthma symptoms during daily life.

Adult↗

PubMedDate not supplied

The influence of age on pressure perception of static and moving two-point discrimination in normal subjects.

The purpose of the present study was to determine the effect of age on digital pressure perception as measured by two-point discrimination (2PD) testing. The subjects were 177 normal volunteers ranging in age from 20 to 79 years. Perceptible pressure of static and moving 2PD was measured on the index finger and little finger, using the Pressure-specifying Sensory Device. The threshold of pressure perception increased significantly with advancing age in both static and moving 2PD tests. There was a marked increase in subjects older than 60 years. Pressure perception was significantly higher for static 2PD than for moving 2PD in subjects 70-79 years of age. The threshold of pressure perception for static and moving 2PD gradually increased with advancing age, and was markedly elevated in subjects older than 60 years.

Adult↗

PubMed2006

Componential analysis of interpersonal perception data.

We examine the advantages and disadvantages of 2 types of analyses used in interpersonal perception studies: componential and noncomponential. Componential analysis of interpersonal perception data (Kenny, 1994) partitions a judgment into components and then estimates the variances of and the correlations between these components. A noncomponential analysis uses raw scores to analyze interpersonal perception data. Three different research areas are investigated: consensus of perceptions across social contexts, reciprocity of attraction, and individual differences in self-enhancement. Finally, we consider criticisms of componential analysis. We conclude that interpersonal perception data necessarily have components (e.g., perceiver, target, measure, and their interactions), and that the researcher needs to develop a model that best captures the researcher's questions.

Humans↗