Magnetic Resonance Imaging of Hydrocarbon-Contaminated Porous Media

Nuclear magnetic resonance response measurement is a nondestructive and nonintrusive technique, which is potentially useful for in situ characterization, mapping, and diagnostic purposes in hydrocarbon-contaminated subsurface, including rock. Magnetic resonance measurements of a porous medium allow the determination of necessary parameters to evaluate permeability and porosity of the medium and the type of hydrocarbons present in the pore fluid. This information is of particular importance in evaluation of hydrocarbon transport in contaminated soils. This paper presents the results of a preliminary study intended to evaluate the robustness of the magnetic resonance imaging technology using well-characterized laboratory specimens of porous material containing hydrocarbon liquids. First, a dry uniform sand pack impregnated with an aqueous coal tar mixture was imaged to evaluate discernable hydrocarbon distribution in the pore space of the sand column. Then, packed columns of glass beads of various sizes, permeated with distilled water and trichloroethylene, were imaged. The discernable images of the pore space and the interface of the two liquids in the pore space indicated that magnetic resonance imaging could be a viable tool to determine spatial distribution and mass fraction of hydrocarbon liquids in contaminated subsurface.     

Amygdala Activation to Sad Pictures During High-Field (4 Tesla) Functional Magnetic Resonance Imaging.

Fear-related processing in the amygdala has been well documented, but its role in signaling other emotions remains controversial. The authors recovered signal loss in the amygdala at high-field strength using an inward spiral pulse sequence and probed its response to pictures varying in their degree of portrayed sadness. These pictures were presented as intermittent task-irrelevant distractors during a concurrent visual oddball task. Relative to neutral distractors, sad distractors elicited greater activation along ventral brain regions, including the amygdala, fusiform gyrus, and inferior frontal gyrus. In contrast, oddball targets engaged dorsal sectors of frontal, parietal, and cingulate cortices. The amygdala's role in emotional evaluation thus extends to images of grief and despair as well as to those depicting violence and threat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identifying neurologically impaired children through a test of auditory perception.

Determined if an experimental test of Auditory Perception (TAP) could discriminate between 30 neurologically impaired and 30 normal children. The relationships were established between each subtest of the Test of Auditory Perception (TAP) and the Bender Visual Motor Gestalt Test. When the TAP was administered under normal testing procedures, 4 of the 6 subtests discriminated the experimental from the control Ss at the .01 level. All of the TAP subtests discriminated the neurologically impaired from from normal Ss at the .01 level under conditions of background noise. Correlations between the TAP subtests were positive but low in value. Negative correlations were found between each of the TAP subtests and the Bender Gestalt. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speech perception from an auditory and visual viewpoint.

[Correction Notice: An erratum for this article was reported in Vol 38(1) of Canadian Journal of Psychology Revue Canadienne de Psychologie (see record 2007-03769-001). A programming error occurred in preparing Figure 6. The correct figure looks quite similar to Figure 7, except that the upper eight components are considerably smaller in Figure 6 than in Figure 7. Values quoted in the text remain unchanged.] Processing in the peripheral auditory system of the human ear profoundly alters the characteristics of all acoustic signals impinging on the ear. Some of the 1st-order properties of this peripheral processing are now reasonably well understood: Humans see a heavily overlapped set of filters, with increasingly broader bandwidths at high frequencies, which results in good spectral resolution at low frequencies and good temporal resolution at high frequencies. Results of an examination of speech and music by this system are discussed. An attempt is then made to synthesize several papers on auditory and visual psychophysics, and to speculate on auditory-signal processing analogous to visual-color processing. Several simplified auditory representations of speech are proposed. (French abstract) (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tower of London performance in relation to Magnetic Resonance Imaging following closed head injury in children.

To investigate the relationship of severity of pediatric closed head injury (CHI), the contribution of frontal lobe lesions, and age at testing (6–10 yr olds vs 11–15 yr olds) to cognitive deficit, 134 head-injured patients were given the Tower of London (TOL) task and underwent magnetic resonance imaging. 89 normal controls were given the TOL for comparison. Severity of CHI and age at testing were strongly related to cognitive performance on the TOL, including the frequency of breaking the rules. Volume of frontal lobe lesion (but not extrafrontal lesion) contributed to the prediction of perfomance on the TOL even after severity of injury was taken into account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contribution of listeners' approaching motion to auditory distance perception.

Of the several sources of acoustic information for distance perception, those arising from motion of the listener or sound source have received little attention. This motion-related information (recently called acoustic tau) is described, and experiments evaluating its utilization are presented. Accuracy and consistency at walking to the locations of briefly presented sounds were better when people listened while walking than while standing still. Manipulations of the sound to simulate shorter or longer target distances produced appropriate undershooting but not overshooting. The results indicate that people use motion-related acoustic information about distance to guide their locomotor actions, although they do not take full advantage of this information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A cardiac measure of cerebral asymmetries in infant auditory perception.

Examined the utility of cardiac habituation response recovery as a method for assessing infant cerebral asymmetries in auditory perception in a dichotic listening test. In a within-Ss design 12 3-mo-old infants were given a series of 4 10-trial tests during which their cardiac responses were habituated to a pair of dichotic speech syllables or music notes. The 10th trial in each test was a test trial on which one ear received its habituation stimulus while the other ear received a novel stimulus of the same type as the habituation pair (speech or music). Both stimulus type and ear receiving the novel stimulus were counterbalanced across tests. Overall, Ss' cardiac responses habituated during the tests and showed differential recovery to the novel stimuli. Specifically, greater response recovery occurred when a novel speech syllable was presented to the right, than to the left ear. Conversely, greater response recovery was found when a novel music note was presented to the left than to the right ear. Results indicate that young infants show a pattern of auditory perceptual asymmetries much like that found in older children and adults. Findings are consistent with the theory that in man the left hemisphere is superior at processing speech and the right hemisphere superior with nonspeech. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Note on auditory perception of physiognomic properties in short melodic structures

The present study shows that short melodies composed to conform with the Gestalt features of line-schematizations which had been drawn to be expressive of certain emotions and concepts were, in turn, judged by both 28 blind boys and girls and 87 college students sighted subjects, according to prediction. The results are interpreted as supporting the underlying hypothesis that physiognomic properties are "similar" across modalities.     

Hemispheric contributions to the integration of visual and auditory information in speech perception

Differential hemispheric contributions to the perceptual phenomenon known as the McGurk effect were examined in normal subjects, 1 callosotomy patient, and 4 patients with intractable epilepsy. Twenty-five right-handed subjects were more likely to demonstrate an influence of a mouthed word on identification of a dubbed acoustic word when the speaker's face was lateralized to the LVF as compared with the RVF. In contrast, display of printed response alternatives in the RVF elicited a greater percentage of McGurk responses than display in the LVF. Visual field differences were absent in a group of 15 left-handed subjects. These results suggest that in right-handers, the two hemispheres may make distinct contributions to the McGurk effect. The callosotomy patient demonstrated reliable McGurk effects, but at a lower rate than the normal subjects and the epileptic control subjects. These data support the view that both the right and left hemisphere can make significant contributions to the McGurk effect.     

The perception of depth through motion.

Motion perspective is the phenomenon that as an object moves, the projections of its surface features and of its contours undergo certain regular transformations. The retinal image undergoes similar transformations. This aspect of depth perception has received comparatively little attention. Theory has been primarily based on gestalt formulations, and, more recently, an empirical approach has been suggested which is based on the use of high speed computers. The latter approach appears quite promising. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acrylonitrile and Glycidyl Methacrylate Copolymers: Nuclear Magnetic Resonance Characterization

Copolymers containing acrylonitrile (A) and glycidyl methacrylate (G) units of different compositions were synthesized by free radical solution polymerization. The reactivity ratios were estimated by Kelen Tudos and nonlinear error in variable methods. The triad sequence distributions in terms of A- and G-centered triads have been obtained from 13C{1H} NMR spectroscopy. The complete spectral assignments in terms of compositional and configurational sequences of the overlapping carbon and proton spectra of these copolymers were done with the help of distortionless enhancement by polarization transfer (DEPT), two-dimensional proton-detected heteronuclear correlation (inverse-HETCOR), and total correlated spectroscopy (TOCSY) experiments. The Monte Carlo simulation was used to study the effect of the fractional conversion on the triad fractions.     

Functional segregation of color and motion perception examined in motion nulling

We examine two hypotheses about the functional segregation of color and motion perception, using a motion nulling task. The most common interpretation of functional segregation, that motion perception depends only on one of the three dimensions of color, is rejected. We propose and test an alternative formulation of functional segregation: that motion perception depends on a univariate motion signal driven by all three color dimensions, and that the motion signal is determined by the product of the stimulus contrast and a term that depends only on the relative cone excitations. Two predictions of this model are confirmed. First, motion nulling is transitive: when two stimuli null a third they also null another. Second, motion nulling is homogeneous: if two stimuli null one another, they continue to null one another when their contrasts are scaled equally. We describe how to apply our formulation of functional segregation to other behavioral and physiological measurements.     

An analysis of cues to auditory depth perception in free space.

Physical acoustics reveals a number of stimulus correlates of sound source distance. Quantitative estimates of these stimulus correlates are compared with appropriate psychophysical thesholds. Such comparisons show that most of these stimulus correlates can, with various restrictions, provide distance information detectable by the ear(s). The stimulus correlates dealt with at greatest length are: intensity, frequency spectrum at near and far distances, binaural intensity ratio, and interaural phase (or time) differences. Problems relating to the use of some of these stimulus correlates as cues are discussed. Other possible distance cues are briefly mentioned. The possible use of much of the available physical information in making distance judgments has not yet been adequately evaluated in psychophysical studies. (48 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recalibrating the auditory system: A speed-accuracy analysis of intensity perception.

Recalibration in loudness perception refers to an adaptation-like change in relative responsiveness to auditory signals of different sound frequencies. Listening to relatively weak tones at one frequency and stronger tones at another makes the latter appear softer. The authors showed recalibration not only in magnitude estimates of loudness but also in simple response times (RTs) and choice RTs. RTs depend on sound intensity and may serve as surrogates for loudness. Most important, the speeded classification paradigm also provided measures of errors. RTs and errors can serve jointly to distinguish changes in sensitivity from changes in response criterion. The changes in choice RT under different recalibrating conditions were not accompanied by changes in error rates predicted by the speed-accuracy trade-off. These results lend support to the hypothesis that loudness recalibration does not result from shifting decisional criteria but instead reflects a change in the underlying representation of auditory intensity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Embodied auditory perception: The emotional impact of approaching and receding sound sources.

Research has shown the existence of perceptual and neural bias toward sounds perceived as sources approaching versus receding a listener. It has been suggested that a greater biological salience of approaching auditory sources may account for these effects. In addition, these effects may hold only for those sources critical for our survival. In the present study, we bring support to these hypotheses by quantifying the emotional responses to different sounds with changing intensity patterns. In 2 experiments, participants were exposed to artificial and natural sounds simulating approaching or receding sources. The auditory-induced emotional effect was reflected in the performance of participants in an emotion-related behavioral task, their self-reported emotional experience, and their physiology (electrodermal activity and facial electromyography). The results of this study suggest that approaching unpleasant sound sources evoke more intense emotional responses in listeners than receding ones, whereas such an effect of perceived sound motion does not exist for pleasant or neutral sound sources. The emotional significance attributed to the sound source itself, the loudness of the sound, and loudness change duration seem to be relevant factors in this disparity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional characterisation of tachykinin receptors mediating ion transport in porcine jejunum

Reconstructed human skin was prepared from human keratinoblasts. After 1 week of cultivation at the air-liquid interface a stratified layer developed, similar to native human epidermis. Liposomes with an average diameter of 50 nm, made of phosphatidylcholine (PC), phosphatidylserine (PS) and human stratum corneum lipids (hSCL) were applied on top of this culture system. The rate of penetration through the reconstructed human epidermis was 1.38, 0.55 and 0.013 ng lipidh-1cm-2 for PC, hSCL and PS liposomes, respectively. Electron microscopy and confocal laser scanning microscopy showed that PS and hSCL liposomes aggregated at the skin surface, while PC liposomes remained homogeneously dispersed. Fluorescence measurements demonstrated that vesicles, made of native human stratum corneum lipids rapidly mixed with PS liposomes, weakly with hSCL liposomes and did not mix with PC liposomes.     

Functional topography of cat primary auditory cortex: response latencies

Minimum onset latency (Lmin) of single- and multiple-unit responses were mapped in the primary auditory cortex (AI) of barbiturate-anesthetized cats. Contralateral Lmin for multiple units was non-homogeneously distributed along the dorso-ventral/isofrequency axis of the AI. Responses with shorter latencies were more often located in the central, more sharply tuned region while longer latencies were more frequently encountered in the dorsal and ventral portions of the AI. For single units, a large scatter of Lmin values was found throughout the extent of the AI including cortical depth. The relationship between Lmin and previously reported spectral, intensity and temporal parameters was analyzed and revealed statistically significant correlations between minimum onset latency and the following response properties in some but not all studied animals: sharpness of tuning of a frequency response area 10 dB above threshold, broadband transient response, strongest response level, monotonicity of rate/level functions, dynamic range, and preferred frequency modulation sweep direction. This analysis suggests that Lmin is determined by several independent factors and that the prediction of Lmin based on relationships with other spectral and temporal response properties is inherently weak. The spatial distribution and the functional relationship between these response parameters may provide an important aspect of the time-based cortical representation of specific features in the animal's natural environment.     

Functional neuroanatomy of auditory pathways in the sound-producing fish Pollimyrus

We have described the acoustic pathway from the ear to the diencephalon in a sound-producing fish (Pollimyrus) based on simultaneous neurophysiological recordings from single neurons and injections of biotin pathway tracers at the recording sites. Fundamental transformations of auditory information from highly phase-locked and entrained responses in primary eighth nerve afferents and first-order medullary neurons to more weakly phase-locked responses in the auditory midbrain were revealed by physiological recordings. Anatomical pathway tracing uncovered a bilateral array of both first- and second-order medullary nuclei and a perilemniscal nucleus. Interconnections within the medullary auditory areas were extensive. Medullary nuclei projected to the auditory midbrain by means of the lateral lemniscus. Midbrain auditory areas projected to both ipsilateral and contralateral optic tecta and to an array of three nuclei in the auditory thalamus. The significance of these findings to the elucidation of mechanisms for the analysis of communication sounds and spatial hearing in this vertebrate animal is discussed.