Neuronal correlates of subjective sensory experience

When a near-threshold stimulus is presented, a sensory percept may or may not be produced. The unpredictable outcome of such perceptual judgment is believed to be determined by the activity of neurons in early sensory cortex. We analyzed the responses of neurons in primary somatosensory cortex, recorded while monkeys judged the presence or absence of threshold stimuli. We found that these responses did not covary with the monkeys' perceptual reports. In contrast, the activity of frontal lobe neurons did covary with trial-by-trial judgments. Further control and microstimulation experiments indicated that frontal lobe neurons are closely related to the monkeys' subjective experiences during sensory detection.     

Clinical correlates of septum pellucidum cavities: an unusual association with psychosis

Cavities in the septum pellucidum are widely regarded as incidental findings of little clinical importance. The prevalence of such cava on computerized tomography in a mixed sample of 22000 neurological and psychiatric patients is found to be 0.15%. A statistical association between this anomaly and a referral diagnosis of functional psychosis is reported, and 6 cases are described. These cases were male and characterized by an early history of developmental delay, with lifelong disturbances of emotion and behaviour prior to the onset in early adulthood of an atypical schizophrenia-like psychosis with disorders of speech and movement. It is suggested that septal cavities may signal an underlying abnormality of function relevant to the pathogenesis of these illnesses.     

Intestinal spirochaetosis: an electron microscopic study of an unusual case

An unusual case of intestinal spirochaetosis is described. The rectum of a 34-year-old male, suffering from Crohn's disease and ankylosing spondylitis, was heavily infested by spirochaetes. Both absorptive and goblet cells were colonized. Spiro-chaetes were found not only on the luminal surface of these cells, but also within the cytoplasm, in occasional macrophages within the lamina propria and, even more surprisingly, within the occasional Schwann cell. The significance of these findings is discussed.     

Dance movement psychotherapy with an adult with autistic spectrum disorder: An observational single-case study

Dance movement psychotherapy (DMP) is considered to be a relevant and appropriate intervention for people with autistic spectrum disorder (ASD). A number of studies have reported DMP techniques and approaches in therapeutic work with children. Wider therapeutic practice in special education and other settings for children with ASD includes the use of structured narrative approaches in treatment. To date there is limited literature reporting DMP practice with adults with ASD. The aim of the study was to introduce a structured narrative approach in the form of the six-part story within DMP with an adult with ASD. A practice-based research approach was used to generate therapist observations and collect in-therapy responses from one patient. The study results indicate that DMP practice can incorporate structured narrative approaches in work with adults with ASD.     

Constraints on task-based control of behaviour following frontal lobe damage: A single-case study

What factors determine stimulus-driven responses in patients with utilization behaviour? We examined this question by assessing the influence of an irrelevant cue on visual search in a patient showing evidence of utilization behaviour (F.K.), following bilateral damage to the medial frontal and temporal lobes. Despite being able to repeat the instructions, F.K. often responded to an item in the search display that matched the cue rather than the target. This effect was reduced under certain conditions: (a) when the cue–search interval increased, (b) when F.K. paid less attention to the cue, and (c) when the target discrimination task was made more difficult. On the other hand, the effect arose even when the cue was always invalid. We suggest that information from the cue competed with the top-down set to determine search. F.K.'s lesion makes it difficult for him to impose top-down knowledge rapidly, leading to responses automatically being based on attended, but irrelevant, cues under short cue–display intervals.     

Objective components of individual differences in subjective sleep quality

SUMMARY The relation between subjective and objective (polysomnography) is of obvious interest in understanding sleep. The aim of the present study was to examine the item structure of the Karolinska Sleep Diary (KSD), and the covariation between KSD and sleep-stage variables, with cross-sectional (inter-individual) data obtained in natural conditions. Thirty-seven subjects had a polysomnography prior to a work day. After rising they completed the Karolinska Sleep Diary. A factor analysis of the diary yielded two factors: (1) a sleep-quality index (SQI) related to the initiation and maintenance of sleep, and (2) a second factor related to difficulties waking-up and to whether sleep was recuperative and sufficient. The strongest predictors (multiple regression) of the sleep quality index was slow-wave sleep (SWS) and sleep efficiency [and variables related to sleep continuity - total sleep time (TST) and the amount of stage 0]. The obtained results were in agreement with previous laboratory findings. It was concluded that sleep quality seems to be a matter of depth of sleep and sleep continuity.     

A comparison of lexical-gustatory and grapheme-colour synaesthesia

This study compares two different profiles of synaesthesia. One group (N?=?7) experiences synaesthetic colour and the other (N?=?7) experiences taste. Both groups are significantly more consistent over time than control subjects asked to generate analogous associations. For the colour synaesthetes, almost every word elicits a colour photism and there are systematic relationships between the colours generated by words and those generated by graphemes within the word (hence “grapheme-colour” synaesthesia). For the taste synaesthetes, by contrast, some words elicit no synaesthesia at all, and in those words that do, there is no relationship between the taste attributed to the word and the taste attributed to component graphemes. Word frequency and lexicality (word vs. nonword) appear to be critical in determining the presence of synaesthesia in this group (hence “lexical-gustatory” synaesthesia). Moreover, there are strong phonological links (e.g., cinema tastes of “cinnamon rolls”) suggesting that the synaesthetic associations have been influenced by vocabulary knowledge from the semantic category of food. It is argued that different cognitive mechanisms are responsible for the synaesthesia in each group, which may reflect, at least in part, the different geographical locations of the affected perceptual centres in the brain.     

A comparison of lexical-gustatory and grapheme-colour synaesthesia

This study compares two different profiles of synaesthesia. One group (N = 7) experiences synaesthetic colour and the other (N = 7) experiences taste. Both groups are significantly more consistent over time than control subjects asked to generate analogous associations. For the colour synaesthetes, almost every word elicits a colour photism and there are systematic relationships between the colours generated by words and those generated by graphemes within the word (hence "grapheme-colour" synaesthesia). For the taste synaesthetes, by contrast, some words elicit no synaesthesia at all, and in those words that do, there is no relationship between the taste attributed to the word and the taste attributed to component graphemes. Word frequency and lexicality (word vs. nonword) appear to be critical in determining the presence of synaesthesia in this group (hence "lexical-gustatory" synaesthesia). Moreover, there are strong phonological links (e.g., cinema tastes of "cinnamon rolls") suggesting that the synaesthetic associations have been influenced by vocabulary knowledge from the semantic category of food. It is argued that different cognitive mechanisms are responsible for the synaesthesia in each group, which may reflect, at least in part, the different geographical locations of the affected perceptual centres in the brain.     

Psychopathology following trauma: the role of subjective experience

BACKGROUND: The DSM-IV definition of posttraumatic stress disorder (PTSD) widened the stressor criterion to include objective (A1) and subjective (A2) components. The prevalence of Criterion A2, and its association with traumatic memory and psychopathology, was examined in a large community sample. METHOD: The presence of Criterion A2 and traumatic memories, as well as DSM-IV anxiety, affective and substance use disorders, were examined in a community sample of 6104 adults with a history of traumatic exposure. RESULTS: Most individuals met Criterion A2 (76%), with higher prevalence in females (81%) than males (69%). A2 was more common following certain traumas (such as assaultive violence). Excluding those people with PTSD, prevalence of most psychiatric disorders was higher in those who met Criterion A2 than in those who only met Criterion A1. Only 3% of those who did not meet A2 went on to suffer persistent traumatic memories. The prevalence of psychiatric disorders was higher in those with A2 and traumatic memories than in those with A2 and no traumatic memories. LIMITATIONS: The retrospective nature of the data raises the potential for reporting biases. The data set allowed only one of several possible predictors of posttraumatic adjustment to be examined and only 12-month, and not lifetime, prevalence of psychiatric conditions was available. CONCLUSIONS: The experience of powerful emotions at the time of traumatic exposure is common and is associated with increased prevalence not only of PTSD, but also of a range of other psychiatric conditions. Traumatic memories may mediate this association.     

Brain electrical correlates of dimensional weighting: an ERP study

In visual search, there is a reaction time (RT) cost for targets on a given trial if the previous target was defined in a different dimension. According to the "dimension-weighting" account (Müller, Heller, & Ziegler, 1995), limited attentional weight needs to be shifted to the new dimension, resulting in slower RTs. The present study aimed at identifying brain electrical correlates associated with the weight shift. Analyses of ERPs revealed several components to reflect dimension changes whether the task was to detect the target or to identify its defining dimension. N2 amplitudes were more negative whenever the dimension changed. The P3 exhibited latency differences that mirrored RTs in both tasks, but the amplitudes showed no direct relation to stimulus- or response-related processes. Finally, slow-wave amplitudes were enhanced for dimension changes. Taken together, the results provide support for relatively early, perceptual processes underlying dimension change costs.     

Visual imagery and functional connectivity in blindness: a single-case study

We present a case report on visual brain plasticity after total blindness acquired in adulthood. SH lost her sight when she was 27. Despite having been totally blind for 43 years, she reported to strongly rely on her vivid visual imagery. Three-Tesla magnetic resonance imaging (MRI) of SH and age-matched controls was performed. The MRI sequence included anatomical MRI, resting-state functional MRI, and task-related functional MRI where SH was instructed to imagine colours, faces, and motion. Compared to controls, voxel-based analysis revealed white matter loss along SH’s visual pathway as well as grey matter atrophy in the calcarine sulci. Yet we demonstrated activation in visual areas, including V1, using functional MRI. Of the four identified visual resting-state networks, none showed alterations in spatial extent; hence, SH’s preserved visual imagery seems to be mediated by intrinsic brain networks of normal extent. Time courses of two of these networks showed increased correlation with that of the inferior posterior default mode network, which may reflect adaptive changes supporting SH’s strong internal visual representations. Overall, our findings demonstrate that conscious visual experience is possible even after years of absence of extrinsic input.