Spatial compatibility effects on the same side of the body midline

Stimulus-response compatibility effects have been hypothesized to result (a) from a subject's innate tendency to respond in the direction of the source of stimulation, (b) from a correspondence between the spatial codes associated with the effector and the stimulus, or (c) from an attentional bias favoring the effector located in the same hemispace as the command signal. Two experiments were conducted to test these three hypotheses. In Experiment 1 the subjects were requested to make unimanual discriminative key-pressing responses to two light stimuli, both appearing to either the right or left of the fixation point. In one condition the two hands were in anatomical position (uncrossed); in the other they were crossed. The procedure of Experiment 2 was similar to that of Experiment 1 with the exception that both hands, always in an uncrossed position, were placed on the same side of the body midline (on the right or left). The results showed that the compatibility effect depends on a correspondence between the spatial codes associated with the location of the effector and the location of the command stimulus.     

Ultradian cyclicity in auditory and visual reaction time during long performance

24 subjects were tested to check the hypothesis proposed by Kleitman about a "basic rest-activity cycle". Reaction time tasks were delivered at 10-min. intervals for 320 min. Spectral density function analyses showed no significant periods within the limits of the cycle. Discussion concerns fulfilling assumptions of spectral analysis and Fisher's test.     

Egocentric and relative spatial codes in S-R compatibility

Summary It has been shown that spatial compatibility is due to a comparison between the spatial codes that describe stimulus and response positions. Such codes are often defined in right-left terms. There are, however, two types of right-left codes that can be used for describing a position in space. One is formed with relation to the egocentric axes and can be termed side, whereas the other is formed with relation to an external reference location and can be termed relative position. Five experiments were conducted to determine the role of these different codes in producing spatial compatibility effects. In Experiments 1 and 2 the position of the stimulus provided the relevant cue for choosing the correct response (i.e., the situation was typical of spatial compability proper), whereas in Experiments 3, 4, and 5 the stimulus provided a locational cue that was not necessary for choosing the correct response (i.e., the situation was typical of the Simon effect). The experimental manipulations concerned the task demands and the time elapsing between availability of the stimulus code and availability of the response code. The results showed that upon stimulus presentation, both stimulus codes (that concerning side and that concerning relative position) were formed, but experimental manipulations determined the one that was effective in yielding compatibility effects. When the task required the use of one type of code, then spatial compatibility depended on that code alone. When the two coding processes were separated in time, then spatial compatibility depended only on the code that was formed simultaneously with the response code.     

Is there a link between irritable bowel syndrome and left-handedness?: An exploratory study

Recent research has found that people with Irritable Bowel Syndrome (IBS) and those with Inflammatory Bowel Disease (IBD) show a relative deficit in verbal IQ, compared to their own performance IQ, and the IQ of a healthy comparison group. It has been suggested that the elevated prevalence of left-handedness shown in previous studies investigating people with IBD is due to compromised left-hemisphere development. This may be associated with a decrement in certain cognitive functions such as verbal IQ. A shift in brain dominance from left to right has been found in many atopic and immunological diseases as well as in autonomic dysfunctions. It was uncertain whether this would apply to people with IBS, a functional disorder in which the cause or causes remain unclear. Therefore, the aim of this preliminary study was to investigate whether people with IBS have an increased prevalence of left-handedness. It was found that there was an association between IBS and left-handedness, showing that further research on this association both in IBS and other functional disorders (as well as on the similarities between IBS and IBD) is warranted.     

The Dark Night of the Soul: spiritual distress and its psychiatric implications

The Dark Night of the Soul is an expression describing phases in a person's spiritual life associated with a crisis of faith or spiritual concerns about the relationship with God, and which has intrinsic aspects of spiritual growth. This paper is concerned with the way in which those going through periods of angst and disillusionment do not see them as pathological phenomena. On the contrary, through a process of attribution of religious meaning they view them as opportunities for reflecting on their lives and as agents for beneficial change. Similarities and differences between the Dark Night and a depressive episode are discussed and illustrated using the accounts of five important religious figures. Their narratives have been constructed using original texts and their biographies. The Dark Night has clinical implications owing to the risk of its being pathologised, serving as a reminder of the importance of incorporating existential issues into clinical practice.     

Poor hand-pointing to sounds in right brain-damaged patients: not just a problem of spatial-hearing

We asked 22 right brain-damaged (RBD) patients and 11 elderly healthy controls to perform hand-pointing movements to free-field unseen sounds, while modulating two non-auditory variables: the initial position of the responding hand (left, centre or right) and the presence or absence of task-irrelevant ambient vision. RBD patients suffering from visual neglect, unlike RBD patients without neglect and healthy controls, showed a systematic rightward error in sound localisation, which was modulated by the non-auditory variables. Localisation errors were exacerbated by initial hand-position to the right of the body-midline, and reduced by the leftwards initial hand-position. Moreover, for the visual neglect patients, mere presence of ambient vision worsened localisation errors. These results demonstrate that although hand-pointing to sounds has often been considered a straightforward approach to investigate sound-localisation abilities in brain-damaged patients, in some patients it may actually reveal localisation deficits that reflect a combination of impaired spatial-hearing and spatial biases from other sensory modalities (i.e., vision and proprioception).