Point-light facial displays enhance comprehension of speech in noise

Seeing a talker's face can improve the perception of speech in noise. There is little known about which characteristics of the face are useful for enhancing the degraded signal. In this study, a point-light technique was employed to help isolate the salient kinematic aspects of a visible articulating face. In this technique, fluorescent dots were arranged on the lips, teeth, tongue, cheeks, and jaw of an actor. The actor was videotaped speaking in the dark, so that when shown to observers, only the moving dots were seen. To test whether these reduced images could contribute to the perception of degraded speech, noise-embedded sentences were dubbed with the point-light images at various signal-to-noise ratios. It was found that these images could significantly improve comprehension for adults with normal hearing and that the images became more effective as participants gained experience with the stimuli. These results have implications for uncovering salient visual speech information as well as in the development of telecommunication systems for listeners who are hearing impaired.     

Fluctuations and phase symmetry in coordinated rhythmic movements.

Investigated the assertion that pendular, clocking movements typify mammalian terrestrial locomotion, using a procedure in which people swing hand-held pendulums at the wrists, comfortably and rhythmically. Previous work by P. N. Kugler and the 2nd author (1986) suggests that the periodic timing and powering of rhythmic movements in the comfort state follow from different laws. One law guides the assembling of the reference frame for clocking. Another law guides the assembling of the muscular, escapement processes determining the cycle energy. Pendular, clocking behavior was examined in 4 adult males for in-phase and out-of-phase coordinations. A. M. Wing and A. B. Kristofferson's (see record 1974-08195-001) method for parsing periodic-timing variance into independent clock and motor sources was applied. Results show that mean periodicity was unaffected by phase. Clock fluctuations, however, were larger out of phase than in phase. Motor fluctuations were indifferent to phase but reflected the departures of individual wrist-pendulum systems from their preferred periods. It is suggested that an intended phase relation is realized as a constraint on clock states. These states are more stable under the in-phase constraint than under the out-of-phase constraint. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of nerves to cerebral and extracerebral blood vessels: a differential effect of alpha methyl tyrosine on norepinephrine content

Alpha methyl tryosine (AMT), and inhibitor of norepinephrine (NOR) synthesis, was injected intraperitoneally (200 mg/kg) in Sprague Dawley rats, kept in a cold room, or at room temperature for 16 hours. Using formaldehyde induced NOR fluorescence, nerve counts were made on whole mounts of cerebral and femoral arterioles 14-300 micronm in diameter, utilizing a grid superimposed on the vessels. Cold had no effect on the number of visible (i.e. fluorescing) nerves. AMT had an appreciable effect but only on nerves to femoral arterioles, where a significant reduction in nerve count was observed in both cold stressed and non stressed rates, when compared with animals not given AMT. Since the counting technique is sensitive only to large depletions of NOR, we cannot conclude that AMT failed to affect NOR content in cerebrovascular nerves. However, if such an effect was present, it was much less than the effect of AMT on nerves to femoral vessels. We suggest that the differential effect of AMT on these 2 vascular beds may indicate a lower basal level of NOR release from cerebrovascular nerves, which would correlate with the difficulty of demonstrating basal sympathetic tone in this vascular bed.     

Herpes varicella zoster encephalitis in immunocompromised patients

The authors describe specific MRI features that suggest the diagnosis of varicella zoster encephalitis. MRI initially revealed discrete, subcortical, nonenhancing lesions that coalesced and developed enhancement. Gray matter involvement was seen later. Autopsy revealed spherical lesions of demyelination and hemorrhagic cavitation confirmed as varicella zoster encephalitis. Characteristic MR features may suggest the diagnosis of varicella zoster encephalitis, enabling definitive diagnostic testing and early institution of antiviral treatment.     

Selective impairment of response to acetylcholine after ischemia/reperfusion in mice

BACKGROUND AND PURPOSE: We previously reported that the endothelium-dependent dilation of pial arterioles by either topical acetylcholine (ACh) or bradykinin (BK) was markedly inhibited after 10 minutes of near total ischemia after bilateral carotid occlusion. The present study tests the responses after 10 minutes of reperfusion and investigates the effect of either oxygen or oxygen radical scavengers on the results. METHODS: Mice were subjected to bilateral carotid ligation or sham ligation. Pial arteriolar diameters were monitored by an image-splitting technique at a craniotomy site. In separate studies, the responses to topically suffused ACh, BK, or sodium nitroprusside (SNP) were tested before ischemia. After 10 minutes of ischemia and 10 minutes of reperfusion, the response was assessed again. Sham-operated mice were observed in each study. Cerebral blood flow was continuously monitored with a laser-Doppler technique. Additional separate studies were conducted as follows: presence of superoxide dismutase plus catalase during ischemia and reperfusion, or increase in the inspired oxygen (arterial oxygen) and oxygen in suffusate. RESULTS: The response to ACh was significantly impaired after 10 minutes of reperfusion. The responses to BK and SNP were unaffected. Radical scavengers failed to influence the impaired response to ACh. Elevations of arterial and suffusate oxygen levels to over 300 mm Hg failed to prevent the impairment. CONCLUSIONS: After 10 minutes of reperfusion, a selective impairment of the response to ACh remains. The response to another endothelium-dependent dilator, BK, recovered, and the response to endothelium-independent SNP was unaffected. Because neither radical scavengers nor oxygen altered the outcome with respect to ACh, I suggest that neither radical generation nor hypoxia accounts for the selective impairment of dilation by ACh. Rather, I hypothesize that reduced shear during ischemia diminishes the ability of the endothelium to synthesize and/or release the endothelium-derived relaxing factor for ACh. I hypothesize further that this impaired release or synthesis persists throughout the 10-minute period of reperfusion.     

Intramolecular Electronic Energy Transfer in the Naphthalene—Anthracene Bichromophoric Molecular Complex in a Supersonic Jet Expansion

Intramolecular electronic energy transfer (intra-EET) was investigated in an isolated bichromophoric naphthalene ( N ) and anthracene ( A ) 1:1 molecular cluster. Investigation of the spectroscopic properties of these chromophores, separately and loosely bound in a van der Waals complex, helps to understand the dependence of the EET rate on the initially excited vibronic level and on the cluster's interchromophoric orientation. Measurement of fluorescence excitation spectra of anthracene at different anthracene pressures shows bands that can be assigned to dimers of anthracene. From measurement of the anthracene excitation spectrum at increasing naphthalene pressures one can identify other spectral features, characterized by different spectral shifts from excitations of the bare molecule. Some transitions are probably due to a 13.5-cnr⁻¹ progression associated with an interchromophore cluster bond. Pressure dependence of fluorescence intensity gives evidence for 1:1 cluster composition, and for a slow intra-EET rate that is associated with an unfavored orientation of the two chromophores in one of the two possible conformers of the A-N cluster, as supported by a calculation of the cluster geometry and by comparison with a recent study of intra-EET in the A–(CH₂)_n-N bichromophoric molecules.     

Face and mouth inversion effects on visual and audiovisual speech perception.

Three experiments examined whether image manipulations known to disrupt face perception also disrupt visual speech perception. Research has shown that an upright face with an inverted mouth looks strikingly grotesque whereas an inverted face and an inverted face containing an upright mouth look relatively normal. The current study examined whether a similar sensitivity to upright facial context plays a role in visual speech perception. Visual and audiovisual syllable identification tasks were tested under 4 presentation conditions: upright face-upright mouth, inverted face-inverted mouth, inverted face-upright mouth, and upright face-inverted mouth. Results revealed that for some visual syllables only the upright face-inverted mouth image disrupted identification. These results suggest that upright facial context can play a role in visual speech perception. A follow-up experiment testing isolated mouths supported this conclusion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection and evaluation of NO stores in awake rats

We demonstrated and substantiated the possibility of detection and evaluation of NO stores in freely moving awake rats. NO stores were created by administering NO donor or by heat shock and were then detected by hypotensive reaction to diethyldithiocarbamate (blood pressure monitoring) under conditions of NO synthase inhibition. Electron paramagnetic resonance revealed NO release from its stores by incorporation into paramagnetic mononitrosyl-iron complexes with diethyldithiocarbamate. Five hours after administration of NO donor or heat shock diethyldithiocarbamate induced a blood pressure drop and the appearance of electron paramagnetic resonance signals from the mononitrosyl-iron-diethyldithiocarbamate complex in rat heart, liver, kidneys, and brain. The hypotensive reaction to diethyldithiocarbamate and electron paramagnetic resonance signals were absent in control rats.     

Virtual and augmented reality 2020

With roots going back to Ivan Sutherland's research in the 1960s, virtual reality (VR) reached a plateau in the early 1990s when the promise was demonstrable in universities and research laboratories. Although we all knew we had a long way to go, hype overtook the field, leading to impossible expectations. Fortunately, a few years later the Internet became the latest hot topic, leaving VR researchers free to go back to work. Almost a decade later, VR has gone from “almost there” to “barely there”. That's a big step! Perhaps by 2020 we will be “pretty well there”! In this article, I venture a few remarks about progress over the next two decades. However, the safest prediction is that unanticipated science and technology advances will make this forecast seem overly conservative