How people make decisions about predictive genetic testing: An analogue study

Abstract

Persons scoring high on negative affectivity (NA) have more subjective health complaints. In this study, we tested the hypothesis that high NA persons are more likely to experience internal sensations as threatening signs of health problems. Low and high NA participants (N=44) were given four breathing trials: one room air trial followed by three trials containing 5.5% CO₂ which induced transient low intensity somatic sensations. Prior to each CO₂ trial, participants received either positive, negative or uncertain labelings of the sensations that might occur. Participants rated the (un)pleasantness of the experienced somatic sensations and the perceived intensity. Also respiratory responses were measured. During CO₂ trials, reliable main effects of information were found but no effects involving NA were observed, neither on pleasantness ratings nor on respiratory responses. However, during room air breathing, high NA participants reported more intense somatic sensations than low NA participants. Post-experimental data suggested that high NA participants had more negative meanings and worries about the consequences of the physical sensations. It is concluded that interpretational biases in high NA is situated at the level of attributional processes.     

Vestibular influence on auditory metrical interpretation

When we move to music we feel the beat, and this feeling can shape the sound we hear. Previous studies have shown that when people listen to a metrically ambiguous rhythm pattern, moving the body on a certain beat--adults, by actively bouncing themselves in synchrony with the experimenter, and babies, by being bounced passively in the experimenter's arms--can bias their auditory metrical representation so that they interpret the pattern in a corresponding metrical form [Phillips-Silver, J., & Trainor, L. J. (2005). Feeling the beat: Movement influences infant rhythm perception. Science, 308, 1430; Phillips-Silver, J., & Trainor, L. J. (2007). Hearing what the body feels: Auditory encoding of rhythmic movement. Cognition, 105, 533-546]. The present studies show that in adults, as well as in infants, metrical encoding of rhythm can be biased by passive motion. Furthermore, because movement of the head alone affected auditory encoding whereas movement of the legs alone did not, we propose that vestibular input may play a key role in the effect of movement on auditory rhythm processing. We discuss possible cortical and subcortical sites for the integration of auditory and vestibular inputs that may underlie the interaction between movement and auditory metrical rhythm perception.     

焦虑性神经症的认知和躯体感觉研究

从Ｓｃｈａｃｈｔｅｒ的二因素理论和Ｂｅｃｋ的认知模式观点出发,采用信念量表、广场恐怖认知问卷、躯体感觉问卷、Ｈａｍｉｌｔｏｎ焦虑及抑郁量表,以抑郁患者和正常人两组作对照,调查了焦虑患者的焦虑、认知及躯体感觉的相互关系。初步结论是,“躯体损害性”自动想法和对躯体感觉的过分担心是临床焦虑的特征;“社会、行为后果性”想法似乎是焦虑和抑郁患者共有的。焦虑的认知内容是以“危险”为主题的,躯体感觉和认知错解在焦虑发生发展中起重要作用。“危险”的负性自动想法和焦虑关系密切,而由非理性信念所反映的特定的认知图式可能促使患者过度夸大危险性。这一结果在一定程度上支持了两因素理论和Ｂｅｃｋ的认知模式     

Five Private Language Arguments

This paper distinguishes five key interpretations of the argument presented by Wittgenstein in Philosophical Investigations I, §258. I also argue that on none of these five interpretations is the argument cogent. The paper is primarily concerned with the most popular interpretation of the argument: that which that makes it rest upon the principle that one can be said to follow a rule only if there exists a ‘useable criterion of successful performance’ (Pears) or ‘operational standard of correctness’ (Glock) for its correct application. This principle, I suggest, is untrue. The private language argument upon which it rests therefore fails.     

The phantom limb in dreams

Mulder and colleagues [Mulder, T., Hochstenbach, J., Dijkstra, P. U., Geertzen, J. H. B. (2008). Born to adapt, but not in your dreams. Consciousness and Cognition, 17, 1266–1271.] report that a majority of amputees continue to experience a normally-limbed body during their night dreams. They interprete this observation as a failure of the body schema to adapt to the new body shape. The present note does not question this interpretation, but points to the already existing literature on the phenomenology of the phantom limb in dreams. A summary of published investigations is complemented by a note on phantom phenomena in the dreams of paraplegic patients and persons born without a limb. Integration of the available data allows the recommendation for prospective studies to consider dream content in more detail. For instance, “adaptation” to the loss of a limb can also manifest itself by seeing oneself surrounded by amputees. Such projective types of anosognosia (“transitivism”) in nocturnal dreams should also be experimentally induced in normally-limbed individuals, and some relevant techniques are mentioned.     

Ketamine as a primary predictor of out-of-body experiences associated with multiple substance use

Investigation of “out-of-body experiences” (OBEs) has implications for understanding both normal bodily-self integration and its vulnerabilities. Beyond reported associations between OBEs and specific brain regions, however, there have been few investigations of neurochemical systems relevant to OBEs. Ketamine, a drug used recreationally to achieve dissociative experiences, provides a real-world paradigm for investigating neurochemical effects. We investigate the strength of the association of OBEs and ketamine use relative to other common drugs of abuse. Self-report data (N = 192) from an online survey indicate that both lifetime frequency of ketamine use and OBEs during ketamine intoxication were more strongly related to the frequency of OBEs and related phenomena than other drugs. Moreover, the apparent effects of other drugs could largely be explained by associated ketamine use. The present results, consistent with the role of NMDA receptors in OBEs, should encourage future studies of the role of neurochemical systems in OBEs.     

The tickly homunculus and the origins of spontaneous sensations arising on the hands

Everyone has felt those tingling, tickly sensations occurring spontaneously all over the body in the absence of stimuli. But does anyone know where they come from? Here, right-handed subjects were asked to focus on one hand while looking at it (convergent focusing) and while looking away (divergent focusing) and subsequently to map and describe the spatial and qualitative attributes of sensations arising spontaneously. The spatial distribution of spontaneous sensations followed a proximo-distal gradient, similar to the one previously described for the density of receptive units. The intensity and spatial extent of the reported sensations were modulated by the focusing condition, especially in respect of the left hand. Convergent focusing acted upon the conscious perception of sensations by enhancing or suppressing them. To our knowledge, this is the first ever study of spontaneous sensations, and it offers considerable insight into their sources. The presence of the proximo-distal distributional gradient is a clear sign that receptive units are involved. The enhancement/suppression effects also confirm the involvement of attention. Finally, left-hand dominance suggests several right-hemisphere processes may be involved, such as spatial and tactile perception, and probably interoception.     

Bidirectional lexical-gustatory synesthesia

In developmental lexical–gustatory synesthesia, specific words (inducers) can trigger taste perceptions (concurrents) and these synesthetic associations are generally stable. We describe a case of multilingual lexical–gustatory synesthesia for whom some synesthesias were bidirectional as some tastes also triggered auditory word associations. Evoked concurrents could be gustatory but also tactile sensations. In addition to words and pseudowords, many voices were effective inducers, suggesting increased connections between cortical taste areas and both voice-selective and language-selective areas. Lasting changes in some evoked tastes occurred during childhood suggesting that some plasticity can be present after the initial learning of associations. Inducers were often linked to taste concurrents phonologically or semantically, but also through identifiable childhood episodes (persons or events). Several inducers were phonologically linked to episodic inducers suggesting a process of secondary acquisition for many inducers. Implications of these observations are discussed.     

Review of first trial responses in balance control: influence of vestibular loss and Parkinson's disease

The reaction to an unexpected balance disturbance is unpractised, often startling and frequently associated with falls. This everyday situation can be reproduced in an experimental setting by exposing standing humans to sudden, unexpected and controlled movements of a support surface. In this review, we focus on the responses to the very first balance perturbation, the so-called first trial reactions (FTRs). Detailed analysis of FTRs may have important implications, both for clinical practice (providing new insights into the pathophysiological mechanisms underlying accidental falls in real life) and for understanding human physiology (what triggers and mediates these FTRs, and what is the relation to startle responses?). Several aspects of the FTRs have become clear. FTRs are characterized by an exaggerated postural reaction, with large EMG responses and co-contracting muscles in multiple body segments. This balance reaction is associated with marked postural instability (greater body sway to the perturbation). When the same perturbation is repeated, the size of the postural response habituates and the instability disappears. Other issues about FTRs remain largely unresolved, and these are addressed here. First, the functional role of FTRs is discussed. It appears that FTRs produce primarily increased trunk flexion during the multi-segmental response to postural perturbations, thus producing instability. Second, we consider which sensory signals trigger and modulate FTRs, placing specific emphasis on the role of vestibular signals. Surprisingly, vestibular signals appear to have no triggering role, but vestibular loss leads to excessive upper body FTRs due to loss of the normal modulatory influence. Third, we address the question whether startle-like responses are contributing to FTRs triggered by proprioceptive signals. We explain why this issue is still unresolved, mainly because of methodological difficulties involved in separating FTRs from ‘pure’ startle responses. Fourth, we review new work about the influence of perturbation direction on FTRs. Recent work from our group shows that the largest FTRs are obtained for toe-up support surface rotations which perturb the COM in the posterior direction. This direction corresponds to the directional preponderance for falls seen both in the balance laboratory and in daily life. Finally, we briefly touch upon clinical diagnostic issues, addressing whether FTRs (as opposed to habituated responses) could provide a more ecologically valid perspective of postural instability in patients compared to healthy subjects. We conclude that FTRs are an important source of information about human balance performance, both in health and disease. Future studies should no longer discard FTRs, but routinely include these in their analyses. Particular emphasis should be placed on the link between FTRs and everyday balance performance (including falls), and on the possible role played by startle reactions in triggering or modulating FTRs.     

Commanding the direction of passive whole-body rotations facilitates egocentric spatial updating

In conditions of slow passive transport without vision, even tenuous inertial signals from semi-circular canals and the haptic-kinaesthetic system should provide information about changes relative to the environment provided that it is possible to command the direction of the body's movements voluntarily. Without such control, spatial updating should be impaired because incoming signals cannot be compared to the expected sensory consequences provided by voluntary command. Participants were seated in a rotative robot (Robuter) and learnt the positions of five objects in their surroundings. They were then blindfolded and assigned either to the active group (n=7) or to the passive group (n=7). Members of the active group used a joystick to control the direction of rotation of the robot. The acceleration (25 degrees /s2) and plateau velocity (9 degrees /s) were kept constant. The participants of the passive group experienced the same stimuli passively. After the rotations, the participants had to point to the objects whilst blindfolded. Participants in the active group significantly outperformed the participants in the passive group. Thus, even tenuous inertial cues are useful for spatial updating in the absence of vision, provided that such signals are integrated as feedback associated with intended motor command.