Dissecting the visual perception of body shape with the Garner selective attention paradigm

The visual appearance of bodies provides important social cues - how are they extracted? We studied two socially-relevant dimensions that are revealed in static body shape – sex and weight. Three experiments using the Garner selective-attention paradigm, in the first such application for body stimuli, found that when making sex judgements, body weight was successfully filtered; however, when judging weight, variation in sex could not be ignored. This asymmetric pattern was not due to differences in the perceptual salience of the dimensions. It suggests a parallel-contingent process where sex and weight are processed concurrently, and ongoing analysis of sex influences processing of weight. A priming experiment supported that view: verbal pre-cues to the sex of a body influenced categorisation of its weight, but weight cues did not influence sex categorisation. This architecture reflects relationships between the shape cues to body weight and sex that are present in the social environment

Faces and Eyes in Human Lateral Prefrontal Cortex

Much of the work on face-selective neural activity has focused on posterior, ventral areas of the human and non-human primate brain. However, electrophysiological and fMRI studies have identified face responses in the prefrontal cortex. Here we used fMRI to characterize these responses in the human prefrontal cortex compared with face selectivity in posterior ventral region. We examined a region at the junction of the right inferior frontal sulcus and the precentral sulcus (right inferior frontal junction or rIFJ) that responds more to faces than to several other object categories. We find that the rIFJ and the right fusiform face area (rFFA) are broadly similar in their responses to whole faces, headless bodies, tools, and scenes. Strikingly, however, while the rFFA preferentially responds to the whole face, the rIFJ response to faces appears to be driven primarily by the eyes. This dissociation provides clues to the functional role of the rIFJ face response. We speculate on this role with reference to emotion perception, gaze perception, and to behavioral relevance more generally

Viewpoint-Specific Scene Representations in Human Parahippocampal Cortex

AbstractThe “parahippocampal place area” (PPA) responds more strongly in functional magnetic resonance imaging (fMRI) to scenes than to faces, objects, or other visual stimuli. We used an event-related fMRI adaptation paradigm to test whether the PPA represents scenes in a viewpoint-specific or viewpoint-invariant manner. The PPA responded just as strongly to viewpoint changes that preserved intrinsic scene geometry as it did to complete scene changes, but less strongly to object changes within the scene. In contrast, lateral occipital cortex responded more strongly to object changes than to spatial changes. These results demonstrate that scene processing in the PPA is viewpoint specific and suggest that the PPA represents the relationship between the observer and the surfaces that define local space

The Sight of Others' Pain Modulates Motor Processing in Human Cingulate Cortex

Neuroimaging evidence has shown that a network including cingulate cortex and bilateral insula responds to both felt and seen pain. Of these, dorsal anterior cingulate and midcingulate areas are involved in preparing context-appropriate motor responses to painful situations, but it is unclear whether the same holds for observed pain. Participants in this functional magnetic resonance imaging study viewed short animations depicting a noxious implement (e.g., a sharp knife) or an innocuous implement (e.g., a butter knife) striking a person's hand. Participants were required to execute or suppress button-press responses depending on whether the implements hit or missed the hand. The combination of the implement's noxiousness and whether it contacted the hand strongly affected reaction times, with the fastest responses to noxious-hit trials. Blood oxygen level-dependent signal changes mirrored this behavioral interaction with increased activation during noxious-hit trials only in midcingulate, dorsal anterior, and dorsal posterior cingulate regions. Crucially, the activation in these cingulate regions also depended on whether the subject made an overt motor response to the event, linking their role in pain observation to their role in motor processing. This study also suggests a functional topography in medial premotor regions implicated in "pain empathy,” with adjacent activations relating to pain-selective and motor-selective components, and their interactio

The role of motion in the neural representation of social interactions in the posterior temporal cortex

Humans are an inherently social species, with multiple focal brain regions sensitive to various visual social cues such as faces, bodies, and biological motion. More recently, research has begun to investigate how the brain responds to more complex, naturalistic social scenes, identifying a region in the posterior superior temporal sulcus (SI-pSTS; i.e., social interaction pSTS), among others, as an important region for processing social interaction. This research, however, has presented images or videos, and thus the contribution of motion to social interaction perception in these brain regions is not yet understood. In the current study, 22 participants viewed videos, image sequences, scrambled image sequences and static images of either social interactions or non-social independent actions. Combining univariate and multivariate analyses, we confirm that bilateral SI-pSTS plays a central role in dynamic social interaction perception but is much less involved when ‘interactiveness’ is conveyed solely with static cues. Regions in the social brain, including SI-pSTS and extrastriate body area (EBA), showed sensitivity to both motion and interactive content. While SI-pSTS is somewhat more tuned to video interactions than is EBA, both bilateral SI-pSTS and EBA showed a greater response to social interactions compared to non-interactions and both regions responded more strongly to videos than static images. Indeed, both regions showed higher responses to interactions than independent actions in videos and intact sequences, but not in other conditions. Exploratory multivariate regression analyses suggest that selectivity for simple visual motion does not in itself drive interactive sensitivity in either SI-pSTS or EBA. Rather, selectivity for interactions expressed in point-light animations, and selectivity for static images of bodies, make positive and independent contributions to this effect across the LOTC region. Our results strongly suggest that EBA and SI-pSTS work together during dynamic interaction perception, at least when interactive information is conveyed primarily via body information. As such, our results are also in line with proposals of a third visual stream supporting dynamic social scene perception

A CCD Camera with Electron Decelerator for Intermediate Voltage Electron Microscopy

Electron microscopists are increasingly turning to Intermediate Voltage Electron Microscopes (IVEMs) operating at 300 - 400 kV for a wide range of studies. They are also increasingly taking advantage of slow-scan charge coupled device (CCD) cameras, which have become widely used on electron microscopes. Under some conditions CCDs provide an improvement in data quality over photographic film, as well as the many advantages of direct digital readout. However, CCD performance is seriously degraded on IVEMs compared to the more conventional 100 kV microscopes. In order to increase the efficiency and quality of data recording on IVEMs, we have developed a CCD camera system in which the electrons are decelerated to below 100 kV before impacting the camera, resulting in greatly improved performance in both signal quality and resolution compared to other CCDs used in electron microscopy. These improvements will allow high-quality image and diffraction data to be collected directly with the CCD, enabling improvements in data collection for applications including high-resolution electron crystallography, single-particle reconstruction of protein structures, tomographic studies of cell ultrastructure and remote microscope operation. This approach will enable us to use even larger format CCD chips that are being developed with smaller pixels

A Critical Role for the Hippocampus and Perirhinal Cortex in Perceptual Learning of Scenes and Faces: Complementary Findings from Amnesia and fMRI

It is debated whether subregions within the medial temporal lobe (MTL), in particular the hippocampus (HC) and perirhinal cortex (PrC), play domain-sensitive roles in learning. In the present study, two patients with differing degrees of MTL damage were first exposed to pairs of highly similar scenes, faces, and dot patterns and then asked to make repeated same/different decisions to preexposed and nonexposed (novel) pairs from the three categories (Experiment 1). We measured whether patients would show a benefit of prior exposure (preexposed > nonexposed) and whether repetition of nonexposed (and preexposed) pairs at test would benefit discrimination accuracy. Although selective HC damage impaired learning of scenes, but not faces and dot patterns, broader MTL damage involving the HC and PrC compromised discrimination learning of scenes and faces but left dot pattern learning unaffected. In Experiment 2, a similar task was run in healthy young participants in the MRI scanner. Functional region-of-interest analyses revealed that posterior HC and posterior parahippocampal gyrus showed greater activity during scene pattern learning, but not face and dot pattern learning, whereas PrC, anterior HC, and posterior fusiform gyrus were recruited during discrimination learning for faces, but not scenes and dot pattern learning. Critically, activity in posterior HC and PrC, but not the other functional region-of-interest analyses, was modulated by accuracy (correct > incorrect within a preferred category). Therefore, both approaches revealed a key role for the HC and PrC in discrimination learning, which is consistent with representational accounts in which subregions in these MTL structures store complex spatial and object representations, respectively

Effects of postnatal smoke exposure on laryngeal chemoreflexes in newborn lambs

Laryngeal chemoreflexes (LCR), which are elicited by the contact of liquids such as gastric refluxate with laryngeal mucosa, may trigger some cases of sudden infant death syndrome. Indeed, while LCR in mature mammals consist in lower airway protective responses, previous animal data have shown that LCR in immature newborns can include laryngospasm, apnea, bradycardia and desaturation. The present study was aimed at testing the hypothesis that postnatal exposure to cigarette smoke is responsible for enhancing cardiorespiratory inhibition observed with LCR. Eight lambs were exposed to cigarette smoke (20 cig/day) during 16 days and compared to seven control lambs. Urinary cotinine/creatinine ratio was measured at a level relevant to previously published levels in infants. On D15-D16, 0.5 ml of HCl (pH 2), milk, distilled water or saline was injected onto the larynx via a chronic supra-glottal catheter during sleep. Results showed that exposure to cigarette smoke significantly enhanced apneas and bradycardias during LCR while significantly decreasing swallowing and arousal. These results were observed independently of the state of alertness and of the experimental solution tested. In conclusion, 15 day-postnatal exposure to cigarette smoke increases cardiorespiratory inhibition and decreases lower airway protective mechanisms in non-sedated, full-term lambs

Effect of oral prednisolone on symptom duration and severity in nonasthmatic adults with acute lower respiratory tract infection: a randomized clinical trial

Importance: Acute lower respiratory tract infection is common and often treated inappropriately in primary care with antibiotics. Corticosteroids are increasingly used but without sufficient evidence. Objective: To assess the effects of oral corticosteroids for acute lower respiratory tract infection in adults without asthma. Design, Setting, and Participants: Multicenter, placebo-controlled, randomized trial (July 2013 to final follow-up October 2014) conducted in 54 family practices in England among 401 adults with acute cough and at least 1 lower respiratory tract symptom not requiring immediate antibiotic treatment and with no history of chronic pulmonary disease or use of asthma medication in the past 5 years. Interventions: Two 20-mg prednisolone tablets (n = 199) or matched placebo (n = 202) once daily for 5 days. Main Outcomes and Measures: The primary outcomes were duration of moderately bad or worse cough (0 to 28 days; minimal clinically important difference, 3.79 days) and mean severity of symptoms on days 2 to 4 (scored from 0 [not affected] to 6 [as bad as it could be]; minimal clinically important difference, 1.66 units). Secondary outcomes were duration and severity of acute lower respiratory tract infection symptoms, duration of abnormal peak flow, antibiotic use, and adverse events. Results: Among 401 randomized patients, 2 withdrew immediately after randomization, and 1 duplicate patient was identified. Among the 398 patients with baseline data (mean age, 47 [SD, 16.0] years; 63% women; 17% smokers; 77% phlegm; 70% shortness of breath; 47% wheezing; 46% chest pain; 42% abnormal peak flow), 334 (84%) provided cough duration and 369 (93%) symptom severity data. Median cough duration was 5 days (interquartile range [IQR], 3-8 days) in the prednisolone group and 5 days (IQR, 3-10 days) in the placebo group (adjusted hazard ratio, 1.11; 95% CI, 0.89-1.39; P = .36 at an α = .05). Mean symptom severity was 1.99 points in the prednisolone group and 2.16 points in the placebo group (adjusted difference, −0.20; 95% CI, −0.40 to 0.00; P = .05 at an α = .001). No significant treatment effects were observed for duration or severity of other acute lower respiratory tract infection symptoms, duration of abnormal peak flow, antibiotic use, or nonserious adverse events. There were no serious adverse events. Conclusions and Relevance: Oral corticosteroids should not be used for acute lower respiratory tract infection symptoms in adults without asthma because they do not reduce symptom duration or severity