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PubMed2006

Geoacoustic inversion of short range source data using a plane wave reflection coefficient approach.

Acoustic time series data were collected in a shallow, hard bottom lake environment located in central Texas using both short range (2 m) implosive data, obtained with the source and a single hydrophone located near mid-depth in the waveguide, along with longer range implosive and explosive data from a near surface source to a bottom mounted hydrophone. Matched field inversions using simulated annealing were performed with a ray trace plus complex plane wave reflection coefficient forward propagation model that was validated in previous work. Isolating bottom interacting paths to perform the inversions is shown to be essential to reduce parameter uncertainties in the hard bottom environment and enables a systematic approach to the inversions which establishes the number of layers needed to represent the lake environment. Measured transmission loss data from a towed source were compared through a RMS error analysis to modeled transmission loss, constructed with the parameters from inversions of data from several source types, to further establish the validity of the inversion approach for this environment. Geoacoustic parameters obtained by inversions of short range, low frequency impulsive data are used to predict transmission loss at longer ranges and higher frequencies. The range dependence of the global minimum is discussed.

Acoustics↗
PubMed2000

A matched-peak inversion approach for ocean acoustic travel-time tomography

A new approach for the inversion of travel-time data is proposed, based on the matching between model arrivals and observed peaks. Using the linearized model relations between sound-speed and arrival-time perturbations about a set of background states, arrival times and associated errors are calculated on a fine grid of model states discretizing the sound-speed parameter space. Each model state can explain (identify) a number of observed peaks in a particular reception lying within the uncertainty intervals of the corresponding predicted arrival times. The model states that explain the maximum number of observed peaks are considered as the more likely parametric descriptions of the reception; these model states can be described in terms of mean values and variances providing a statistical answer (matched-peak solution) to the inversion problem. A basic feature of the matched-peak inversion approach is that each reception can be treated independently, i.e., no constraints are posed from previous-reception identification or inversion results. Accordingly, there is no need for initialization of the inversion procedure and, furthermore, discontinuous travel-time data can be treated. The matched-peak inversion method is demonstrated by application to 9-month-long travel-time data from the Thetis-2 tomography experiment in the western Mediterranean sea.

Journal Article↗
PubMed2000

Machinery to support genome segment inversion exists in a herpesvirus which does not naturally contain invertible elements.

In many herpesviruses, genome segments flanked by inverted repeats invert during DNA replication. It is not known whether this inversion is a consequence of an inherently recombinagenic replicative mechanism common to all herpesviruses or whether the replication enzymes of viruses with invertible segments have specifically evolved additional enzymatic activities to drive inversion. By artificially inserting a fusion of terminal sequences into the genome of a virus which normally lacks invertible elements (murine cytomegalovirus), we created a genome composed of long and short segments flanked by 1,359- and 543-bp inverted repeats. Analysis of genomic DNA from this virus revealed that inversion of both segments generates equimolar amounts of four isomers during the viral propagation necessary to produce DNA for analysis from a single viral particle. We conclude that a herpesvirus which naturally lacks invertible elements is able to support efficient segment inversion. Thus, the potential to invert is probably inherent in the replication machinery of all herpesviruses, irrespective of genome structure, and therefore genomes with invertible elements could have evolved simply by acquisition of inverted repeats and without concomitant evolution of enzymatic activities to mediate inversion. Furthermore, the recombinagenicity of herpesvirus DNA replication must have some importance independent of genome segment inversion.

Animals↗
PubMed2006

Estimation of the voice source from speech pressure signals: evaluation of an inverse filtering technique using physical modelling of voice production.

OBJECTIVE: The goal of the study is to use physical modelling of voice production to assess the performance of an inverse filtering method in estimating the glottal flow from acoustic speech pressure signals. METHODS: An automatic inverse filtering method is presented, and speech pressure signals are generated using physical modelling of voice production so as to obtain test vowels with a known shape of the glottal excitation waveform. The speech sounds produced consist of 4 different vowels, each with 10 different values of the fundamental frequency. Both the original glottal flows given by physical modelling and their estimates computed by inverse filtering were parametrised with two robust voice source parameters: the normalized amplitude quotient and the difference (in decibels) between the levels of the first and second harmonics. RESULTS: The results show that for both extracted parameters the error introduced by inverse filtering was, in general, small. The effect of the distortion caused by inverse filtering on the parameter values was clearly smaller than the change in the corresponding parameters when the phonation type was altered. The distortion was largest for high-pitched vowels with the lowest value of the first formant. CONCLUSIONS: The study shows that the proposed inverse filtering technique combined with the extracted parameters constitutes a voice source analysis tool that is able to measure the voice source dynamics automatically with satisfactory accuracy.

Glottis↗
PubMed2005

Birth weight is inversely associated with incident coronary heart disease and stroke among individuals born in the 1950s: findings from the Aberdeen Children of the 1950s prospective cohort study.

BACKGROUND: Birth weight is inversely associated with cardiovascular disease risk factors, but few studies have examined the association with disease end points, in particular with stroke risk. Furthermore, previous studies demonstrating an inverse association between birth weight and coronary heart disease (CHD) risk have been conducted on populations born in the early part of the 20th century, when infant mortality rates were high. If the environmental factors associated with improvements in infant mortality rates over the last century explain the inverse association between birth weight and CHD risk, one would expect weaker associations in more contemporary birth cohorts. METHODS AND RESULTS: We have examined the association in a large birth cohort of 10,803 (with an average of 239,000 person-years of follow-up) singleton births that occurred between 1950 and 1956. Our outcomes were hospital admissions for, and fatalities from, CHD (n=296) and stroke (n=107). Birth weight was inversely associated with CHD and stroke. The age-adjusted hazards ratio for a 1-kg increase in birth weight was 0.62 (95% CI 0.50 to 0.78) for CHD and 0.38 (95% CI 0.24 to 0.60) for stroke. Adjustment for gestational age, social class at birth, height and body mass index at school entry, gravidity, maternal age at birth, pregnancy-induced hypertension, antepartum hemorrhage, and maternal height did not alter the association with CHD but attenuated the association with stroke to 0.48 (95% CI 0.30 to 0.76). This attenuation resulted largely from adjustment for gestational age, which was linearly inversely related to stroke risk. Adjusted hazard ratios per sex and gestational age standardized z score of birth weight were 0.85 (95% CI 0.73 to 0.97) for CHD and 0.74 (95% CI 0.71 to 0.88) for stroke. CONCLUSIONS: Birth weight is inversely associated with CHD and stroke in a population born at a time when environmental circumstances, as indexed by low infant mortality rates, were relatively advantageous for infants.

Adult↗
PubMedDate not supplied

The effect of exercise, prewrap, and athletic tape on the maximal active and passive ankle resistance of ankle inversion.

This investigation explored alternatives to the null hypotheses that maximal active and passive resistance to inversion developed by a near-maximally inverted and weightbearing ankle is not altered by 1) the use of prophylactic adhesive athletic tape, 2) the use of non-adhesive prewrap (underwrap), or 3) 40 minutes of vigorous exercise. Ten healthy men and 10 healthy women (mean age, 25 +/- 3 years) with no recent ankle injuries underwent testing to determine maximal ankle resistance to inversion under unipedal, weightbearing conditions. Tests were performed with and without the support of athletic tape, and before and after 40 minutes of exercise. Half the testing sessions were performed with prewrap under the tape. At 15 degrees of inversion, without any external ankle support, healthy young men and women could maximally resist a mean (SD) inversion moment of 52.9 (6.4) N-m and 28.3 (5.8) N-m, respectively. Although use of ankle tape provided a 10% increase in maximal resistance to inversion moments, this increase diminished to insignificant levels after 40 minutes of vigorous exercise. Use of prewrap improved maximal resistance to inversion by more than 10%.

Adult↗
PubMed1998

Elongation behavior of calcaneofibular and cervical ligaments during inversion loads applied in an open kinetic chain.

The cervical ligament plays a significant role in lateral stability of the subtalar joint but has received little attention compared with other ankle and subtalar joint ligaments. The purpose of this research was twofold. First, the elongation behavior of the cervical ligament was assessed with the calcaneofibular ligament intact and cut during two different types of inversion loads (manual and mechanical). Second, inversion range of motion was determined concomitantly with inversion loading and the difference in inversion range of motion between the calcaneofibular ligament intact to cut state was compared. The mean elongation of the cervical ligament with the calcaneofibular intact was 0.58 mm (+/- 0.33 mm) and 0.46 mm (+/- 0.23 mm) for manual and mechanical methods, respectively, and 0.88 mm (+/- 0.37 mm) and 0.78 mm (+/- 0.37 mm), respectively, for the same methods in the absence of the calcaneofibular ligament. This difference was statistically significant (P < 0.05 manually and P < 0.02 mechanically). An average increase in the inversion range of motion was noted with both methods [7.5 degrees manually (+/- 2.75 degrees) and 7.7 degrees mechanically (+/- 2.95 degrees)] after lesioning of the calcaneofibular ligament. This difference was statistically significant (P < 0.001) for both manual and mechanical range of motion testing. The results of this study indicate that there is a significant increase in elongation of the cervical ligament in the absence of the calcaneofibular ligament during manual and mechanically applied inversion loads in a open kinetic chain. Clinical and theoretical implications of this data are discussed.

Aged↗
PubMed2006

Reliability of two goniometric methods of measuring active inversion and eversion range of motion at the ankle.

BACKGROUND: Active inversion and eversion ankle range of motion (ROM) is widely used to evaluate treatment effect, however the error associated with the available measurement protocols is unknown. This study aimed to establish the reliability of goniometry as used in clinical practice. METHODS: 30 subjects (60 ankles) with a wide variety of ankle conditions participated in this study. Three observers, with different skill levels, measured active inversion and eversion ankle ROM three times on each of two days. Measurements were performed with subjects positioned (a) sitting and (b) prone. Intra-class correlation coefficients (ICC[2,1]) were calculated to determine intra- and inter-observer reliability. RESULTS: Within session intra-observer reliability ranged from ICC[2,1] 0.82 to 0.96 and between session intra-observer reliability ranged from ICC[2,1] 0.42 to 0.80. Reliability was similar for the sitting and the prone positions, however, between sessions, inversion measurements were more reliable than eversion measurements. Within session inter-observer measurements in sitting were more reliable than in prone and inversion measurements were more reliable than eversion measurements. CONCLUSION: Our findings show that ankle inversion and eversion ROM can be measured with high to very high reliability by the same observer within sessions and with low to moderate reliability by different observers within a session. The reliability of measures made by the same observer between sessions varies depending on the direction, being low to moderate for eversion measurements and moderate to high for inversion measurements in both positions.

Adult↗
PubMed1999

Effect of dosage form on stereoisomeric inversion of ibuprofen in volunteers.

Twelve healthy volunteers were given ibuprofen racemate in two different dosage forms, a suspension and a tablet. The plasma concentration-time profiles of S- and R-ibuprofen were determined and the R-ibuprofen inversion clearance was calculated. Although the area under the curve was almost the same in both the suspension and tablet studies, the inversion clearance was larger in the suspension study than in the tablet study (1.18+/-0.65 and 0.72+/-0.63 l/h, shown as the mean+/-S.D.). The Michaelis-Menten parameters for this inversion process were then determined in vitro with human liver microsomes (1.3+/-0.2 mM for Km and 3.1+/-0.3 nmol/min/mg protein for Vmax, shown as the mean+/-S.D.). These parameters indicated that the stereoisomeric inversion of R-ibuprofen in the liver was not likely to be saturated at the plasma concentrations measured in the volunteer study. The profile of the plasma concentration ratio between S-ibuprofen and R-ibuprofen revealed a difference in the early phase of these two studies. Therefore the inversion difference between those two studies probably resulted from the difference in the absorption phase of each dosage form. Our study demonstrated that R-ibuprofen inversion could be affected by alteration of dosage form.

Adult↗
PubMed2005

Uncertainties of inherent optical properties obtained from semianalytical inversions of ocean color.

We present a method to quantify the uncertainties in the in-water constituent absorption and backscattering coefficients obtained from an inversion of remotely sensed reflectance (rrs). We first find a set of positive inversion solutions within a given uncertainty range around the values of the inverted rrs. The uncertainties of the solutions are then computed based on the statistics of these solutions. We demonstrate the uncertainty calculation algorithm using a specific semianalytic inversion model applied to both a field and a simulated data set. When the associated uncertainties are taken into account, the inverted parameters are generally within the uncertainties of the measured (or simulated) parameters, highlighting the success of the inversion and the method to obtain uncertainties. The specific inversion we use, however, fails to retrieve two spectral parameters within a usable range. The method presented is general and can be applied to all existing semianalytical inversion algorithms.

Journal Article↗
PubMed2006

Correction of instrument line shape in Fourier transform spectrometry using matrix inversion.

A novel matrix inversion approach is proposed to correct several contributions to the instrument line shape (ILS) of a Fourier transform spectrometer. The matrix formalism for the ILS is first quickly reviewed. Formal inversion of the ILS matrix is next discussed, along with its limitations. The stability of the inversion process for large field-of view- (FOV-) limited and highly off-axis line shapes is investigated. The effect of inversion on the noise that is present in the spectrum is also presented. Use of classical iterative inversion methods, coupled with efficient synthesis algorithms, is proposed as a way to drastically speed up the inversion process. The method is applied to correct HBr spectra obtained from a laboratory spectrometer that has an adjustable field of view. ILSS from six FOVs are brought to the same spectral axis and to the same ideal sinc shape.

Algorithms↗
PubMed1998

Mammography in the evaluation of nipple inversion.

OBJECTIVE: The purpose of this study was to correlate the clinical and mammographic appearances of the nipple, determine the effects of breast compression on nipple position, and describe the mammographic findings in women with nipple inversion. SUBJECTS AND METHODS: We examined 312 consecutive women who were referred for mammography using routine craniocaudal and mediolateral oblique views, which resulted in 595 breasts imaged Nipple position (normal or inverted) was assessed visually, both with and without breast compression, and correlated with the findings at mammography. RESULTS: Of the 312 women, 29 (9%) had visually inverted nipples without breast compression; similarly, of the 595 breasts, 36 (6%) had visually inverted nipples without breast compression. Clinical nipple inversion was chronic in 33 (92%) of 36 breasts and acute in the remaining three breasts (8%) Nipple inversion occurred at birth in one (3%) of 36 breasts, during puberty in 21 (58%), and during adulthood in 14 (39%). Reported causative factors were pregnancy in one (3%) of 36 breasts, nursing in one (3%), prior benign biopsy in one (3%), and prior cancer in one (3%). In the other 32 breasts (89%), causative factors were not known. Both visually and mammographically, 29 (81%) of 36 clinically inverted nipples remained inverted with breast compression, but seven (19%) became normal in position. Of the 312 women, 23 (7%) had inverted nipples on mammography; likewise, of the 595 breasts, 29 nipples (5%) were inverted on mammography. Mammographic findings in the 33 breasts with chronically inverted nipples were normal in 29 (88%), probably benign masses in two (6%), multiple cysts in one (3%), and axillary lymphadenopathy in one (3%). Mammographic findings in the three breasts with acutely inverted nipples were normal in two (67%) and revealed a suspicious mass in one (33%). CONCLUSION: Mammography often failed to reveal nipple inversion; nearly one in five clinically inverted nipples became normal in position as a result of breast compression. In the vast majority of women with nipple inversion, the process was long-standing and without causative factors. Also, these women typically lacked mammographic findings suggestive of malignancy. Of the 14 patients with nipple inversion that had occurred during adulthood, two women (14%) had an underlying malignancy.

Aged↗
PubMed2003

Transcatheter arterial chemoembolization of hepatocellular carcinoma: usefulness of coded phase-inversion harmonic sonography.

OBJECTIVE: The purpose of our study was to assess the value of coded phase-inversion harmonic sonography performed approximately 1 week after the patients had undergone transcatheter arterial chemoembolization with iodized oil for hepatocellular carcinoma. SUBJECTS AND METHODS: We studied 40 patients with 44 nodules measuring 1.5-11.0 cm in diameter (mean +/- SD, 3.9 +/- 2.0 cm) who underwent transcatheter arterial chemoembolization. Coded phase-inversion harmonic sonography, a technique based on a combination of phase-inversion harmonics and coded technology, was performed with a contrast agent approximately 1 week after chemoembolization. The results were compared with those obtained using dynamic CT (n = 44 lesions) and dynamic MR imaging (n = 20 lesions). We also evaluated the recurrence of hepatocellular carcinoma during clinical follow-up in 17 patients who did not undergo additional local therapy. RESULTS: The detection rates of intratumoral vascularity of coded phase-inversion harmonic sonography, dynamic CT, and dynamic MR imaging were, respectively, 38 (86%) of 44 lesions, 19 (43%) of 44 lesions, and 10 (50%) of 20 lesions. Of 19 nodules of hepatocellular carcinoma treated only by transcatheter arterial chemoembolization, 17 nodules showed enhancement on coded phase-inversion harmonic sonography, suggesting incomplete responses. In all 17 nodules, apparent recurrence was noted on dynamic CT during clinical follow-up, even in nodules that had been observed to be completely filled with iodized oil 1 week after the chemoembolization. CONCLUSION: We found coded phase-inversion harmonic sonography to be highly sensitive and accurate for evaluating the treatment response in patients with hepatocellular carcinoma even shortly after treatment. Consequently, it allows early recognition of the need for additional local ablation therapy and estimation of the risk of hepatocellular carcinoma recurrence.

Aged↗
PubMedDate not supplied

Sonographic evaluation of breast nodules: comparison of conventional, real-time compound, and pulse-inversion harmonic images.

OBJECTIVE: To compare the use of conventional, real-time compound, and pulse-inversion harmonic imaging in the evaluation of breast nodules. MATERIALS AND METHODS: Fifty-two breast nodules were included in this study, conducted between May and December 2000, in which conventional, real-time compound, and pulse-inversion harmonic images were obtained in the same plane. Three radiologists, each blinded to the interpretations of the other two, evaluated the findings, characterizing the lesions and ranking the three techniques from grade 1, the worst, to grade 3, the best. Lesion conspicuity was assessed, and lesions were also characterized in terms of their margin, clarity of internal echotexture, and clarity of posterior echo pattern. The three techniques were compared using Friedman's test, and interobserver agreement in image interpretation was assessed by means of the intraclass correlation coefficient. RESULTS: With regard to lesion conspicuity, margin, and internal echotexture of the nodules, real-time compound imaging was the best technique (p < 0.05); in terms of posterior echo pattern, the best was pulse-inversion harmonic imaging (p < 0.05). Real-time compound and pulse inversion harmonic imaging were better than conventional sonography in all evaluative aspects. Interobserver agreement was greater than moderate. CONCLUSION: Real-time compound and pulse-inversion harmonic imaging procedures are superior to conventional sonography in terms of both lesion conspicuity and the further characterization of breast nodules. Real-time compound imaging is the best technique for evaluation of the margin and internal echotexture of nodules, while pulse-inversion harmonic imaging is very effective for the evaluation of the posterior echo patterns.

Breast Neoplasms↗
PubMed2005

Three-dimensional inversion rendering: a new sonographic technique and its use in gynecology.

OBJECTIVE: The purpose of this presentation is to describe the use of the 3-dimensional (3D) sonographic inversion rendering mode in displaying fluid-filled structures using dedicated hardware and software in gynecology. METHODS: The 3D software used inverts anechoic into echogenic voxels, which, against the black background of the monitor screen, display the fluid-filled structure as a "cast" of it. The technique of the rendering process is described. Three-dimensional sonographic volumes of the adnexal area in 3 patients thought to have adnexal or ovarian masses were stored and rendered with the use of the laptop version of the inversion software. The same process was used in an additional 12 women for various indications: 7 with suspected uterine malformations and 5 with uterine bleeding. Of these 12 women, 11 underwent saline infusion sonohysterography. RESULTS: Rendering the inverted fluid-filled adnexal structures revealed that, in all 3 cases, they were tubal, not ovarian, in origin (chronic hydrosalpinges). Of the 7 uterine cavities suspected of malformation, 3 were normal and 4 had uterine malformations: 2 arcuate uteri and 2 incomplete septate uteri. Of the 4 woman with dysfunctional uterine bleeding, 3 had endometrial cavities with polyps and 1 had an irregular surface of the cast. One woman with postmenopausal spotting had an enlarged but otherwise normal cavity. CONCLUSIONS: After a relatively short learning curve to master the inversion rendering technique, it is possible to use it in a selected number of gynecologic cases with fluid-filled structures. In resolving the correct diagnosis of the adnexal masses, the inversion images performed better than the 2-dimensional (2D) and 3D orthogonal planes. For diagnosis of uterine disease, the inversion pictures presented marginal value over the 2D and 3D images. The 3D inversion rendering technique may have added value in selected gynecologic cases, establishing a more accurate diagnosis somewhat faster than only 2D sonography or even the 3D orthogonal planes.

Diagnosis, Differential↗
PubMed2000

Stamen development in the Ericaceae. I. Anther wall, microsporogenesis, inversion, and appendages.

Development of the introrse, tetrasporangiate, and normally dorsifixed and poricidal stamens has been studied at the gross morphological and cellular level in ten species of Ericaceae. Microsporogenesis, followed in four species, is normal, with cytokinesis simultaneous, forming tetrahedral tetrads. The tricolp(or)ate pollen is shed as permanent tetrads with each segment two-celled except in Enkianthus in which pollen grains are three-celled monads. Anther-wall development is similar in all four species initially, but no regular pattern of wall development could be recognized thereafter. The tapetum, of parietal origin, is binucleate, glandular, and mainly uniseriate. Viscin threads occur with the tetrads in the three rhododendroid species. A well-developed endothecium appears only in Enkianthus.Soon after stamen initiation, anthers of nine species invert at the eventual filament-anther junction to become introrse; in Enkianthus inversion occurs close to anthesis. Microsporogenesis starts during early inversion; greater cell elongation on the abaxial side of the young anther completes inversion by the late sporogenous-tissue stage. In Erica and, to a lesser extent Calluna, inversion results from greater abaxial than adaxial increase in cell number and length just above the filament-anther junction. The single vascular strand reflects the degree of inversion. Stamens of six species are appendaged; three have only awns, two only spurs, while one has both. Appendages arise from residual meristems after inversion is completed (or almost so) in all except Enkianthus. Awns develop at what will be the apex at maturity of each anther half. Their length and orientation vary among species. Only in Vaccinium do the awns become hollow (tubules). Spurs, varying in length, shape, and size, arise on the abaxial side from the filament, connective, or thecae.

Journal Article↗
PubMed2000

Inverse agonist activity of atypical antipsychotic drugs at human 5-hydroxytryptamine2C receptors.

Clozapine is the prototype atypical antipsychotic drug, producing little or no extrapyramidal side effects, while improving negative symptoms of psychosis. Clozapine's high affinity for serotonin receptors has been hypothesized to confer the unique antipsychotic properties of this drug. Recently, we demonstrated that both typical and atypical antipsychotic drugs are inverse agonists at constitutively active 5-hydroxytryptamine2A (5-HT(2A)) receptors. To determine whether inverse agonist activity at 5-HT(2C) receptors plays a role in antipsychotic efficacy, typical and atypical antipsychotic drugs were tested for inhibition of basal inositol phosphate production in mammalian cells expressing rat or human 5-HT(2C) receptors. Atypical antipsychotic drugs (sertindole, clozapine, olanzapine, ziprasidone, risperidone, zotepine, tiospirone, fluperlapine, tenilapine) displayed potent inverse agonist activity at rat and human 5-HT(2C) receptors. Typical antipsychotic drugs (chlorpromazine, loxapine, thioridazine, prochlorperazine, perphenazine, mesoridazine, trifluperidol, fluphenazine, spiperone, haloperidol, pimozide, penfluridol, thiothixene) were devoid of inverse agonist activity, with the exception of loxapine. We review the evidence that loxapine has unique properties characteristic of both atypical and typical antipsychotic drugs. Several typical antipsychotic drugs (chlorpromazine, thioridazine, spiperone, thiothixene) displayed neutral antagonist activity by reversing clozapine inverse agonism. These data suggest that 5-HT(2C) inverse agonist activity is associated with atypical antipsychotic drugs with moderate to high affinity for 5-HT(2C) receptors, and imply that effects of atypical antipsychotic drugs on the 5-HT(2C) receptor may play a role in their unique clinical properties. These data also imply that dysfunction of brain 5-HT(2C) receptor systems may be one of the factors involved in the etiology of psychosis.

Animals↗
PubMed2001

Discrimination of spatial relations and features in faces: effects of inversion and viewing duration.

We studied discrimination of changes in eye position, mouth position, and eye colour at viewing durations ranging from 1 second to unlimited time. With upright faces, perception was rapid and did not improve above 2 seconds viewing time. Face inversion impaired discrimination of mouth position significantly, eye position slightly, but not eye colour. The 'inversion effect' for mouth position decreased with increasing stimulus duration, and disappeared when the subject knew that the only change in a trial was in mouth position. A subsequent experiment showed that the inversion impairment in the mouth region was not specific to spatial position but affected mouth colour to a lesser degree. When the mouth region was made more salient by increasing the frequency of mouth change trials, the inversion effect for mouth position decreased, and correlated with an increase in inversion effect for eye position but not eye colour. We conclude that the dominant effect of face inversion upon perception is decreased discrimination in less salient facial regions, that this impairment lessens with increasing viewing time, and that it affects both features and their spatial relations, though the effect on the latter is greater. These results are consistent with greater dependence on a serial component search strategy in inverted faces.

Adolescent↗