Merging the senses into a robust percept

To perceive the external environment our brain uses multiple sources of sensory information derived from several different modalities, including vision, touch and audition. All these different sources of information have to be efficiently merged to form a coherent and robust percept. Here we highlight some of the mechanisms that underlie this merging of the senses in the brain. We show that, depending on the type of information, different combination and integration strategies are used and that prior knowledge is often required for interpreting the sensory signals.     

Connectives Stranger than Tonk

Many logical systems are such that the addition of Prior's binary connective to them leads to triviality, see [1, 8]. Since is given by some introduction and elimination rules in natural deduction or sequent rules in Gentzen's sequent calculus, the unwanted effects of adding show that some kind of restriction has to be imposed on the acceptable operational inferences rules, in particular if these rules are regarded as definitions of the operations concerned. In this paper, a number of simple observations is made showing that the unwanted phenomenon exemplified by in some logics also occurs in contexts in which is acceptable. In fact, in any non-trivial context, the acceptance of arbitrary introduction rules for logical operations permits operations leading to triviality. Connectives that in all non-trivial contexts lead to triviality will be called non-trivially trivializing connectives.     

Gaze-eccentricity effects on road position and steering

The effects of gaze eccentricity on the steering of an automobile were studied. Drivers performed an attention task while attempting to drive down the middle of a straight road in a simulation. Steering was biased in the direction of fixation, and deviation from the center of the road was proportional to the gaze direction until saturation at approximately 15 degrees gaze-angle from straight ahead. This effect remains when the position of the head was controlled and a reverse-steering task was used. Furthermore, the effect was not dependent on speed but reversed when the forward movement of the driver was removed from the simulation. Thus, small deviations in a driver's gaze can lead to significant impairments of the ability to drive a straight course.     

Effects of pointing direction and direction predictability on event-related lateralizations of the EEG

In two experiments, we investigated hemispheric electroencephalography (EEG) differences in 9(12) healthy volunteers during pointing to lateral and central targets. The questions addressed were whether horizontal pointing direction and the predictability of pointing direction modulated hemispheric differences (event-related lateralizations of the EEG = ERLs). To vary pointing direction predictability, targets were displayed either randomly at one of nine different positions on a screen (random) or at the same horizontal position in five subsequent trials (sequenced) while vertical positions varied randomly. Event-related lateralizations (ERLs) varied with pointing direction. This was true across changes in target eccentricity and pointing distance. Foci of the ERLs were in premotor and posterior parietal cortex, which might reflect the critical involvement of these areas in the control of visually guided reaching. Direction predictability reduced the parietal and premotor ERL before pointing onset, probably reflecting a lesser effort in visuomotor transformation. Predictability also added an overlying N2pc component to the early ERL after target onset and increased direction effects during movement.     

Cortical plasticity associated with stuttering therapy

Neuroimaging studies have indicated that persistent developmental stuttering (PDS) may be associated both with an abnormality in white matter of left-hemispheric speech areas and a right-hemispheric hyperactivity. The latter may compensate for the deficient structural connectivity in the left hemisphere. To investigate the effects of stuttering therapy on brain activity nine male adults with PDS underwent functional magnetic resonance imaging (fMRI) before and within 12 weeks after fluency shaping therapy. Brain response differences during overt sentence reading before and after therapy were assessed by utilizing random effects analyses. After therapy, a more widespread activation was observed in frontal speech and language regions and temporal areas of both hemispheres, particularly and more pronounced on the left side. Interestingly, distinct posttreatment left-sided activation increases were located directly adjacent to a recently detected area of white matter anomaly [M. Sommer, M.A. Koch, W. Paulus, C. Weiller, C. Buchel (2002). Disconnection of speech-relevant brain areas in persistent developmental stuttering. The Lancet, 360, 380-383] suggesting that fluency shaping techniques reorganize neuronal communication between left-sided speech motor planning, motor execution, and temporal areas. Hence, a therapeutic mechanism can be assumed to remodel brain circuitry close to the source of the dysfunction instead of reinforcing compensation via homologous contralateral brain networks. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to: (1) describe brain activation changes detected shortly after fluency-shaping therapy; (2) identify left-hemispheric regions where a (re)functionalization after fluency-shaping therapy seems to occur adjacent to a recently described abnormal white matter region in PDS subjects; and (3) discuss how an effective cerebral compensation mechanism for stuttering could work.     

Aktuelle Entwicklung in der Transaktionsanalyse

Zusammenfassung Die Transaktionsanalyse (Berne 1958) sollte vom ursprünglichen Konzept her dazu dienen, personale Strukturen und psychodynamische Prozesse auch dem Laien verstehbar und nutzbar zu machen. Obwohl dieser Anspruch bei manchen Autoren zu Oberfl?chlichkeit und „happy-go-lucky” Sicht verw?sserte, zeigt die vor allem unter europ?ischen Transaktionsanalytikern übliche Rückbesinnung auf die ursprünglichen Inhalte den Umfang klinischer Relevanz der Konzepte für Verst?ndnis und Behandlung der verschiedensten St?rungen. Dies anhand einer sog. frühen St?rung, dem Borderlinesyndrom, aufzuzeigen, ist Anliegen des vorliegenden Beitrags. Das Strukturmodell der Ich-Zust?nde dient dabei als Beschreibungsansatz für die Borderlinestruktur, Bezugsrahmen und Skript als Muster für die Entstehung und Aufrechterhaltung der Pathologie, Transaktionen, Spiele, Symbiosen und Passivit?t als Merkmale stabiler Instabilit?t der Beziehungen und Abwertungen und Grandiosit?ten als Beispiele für Abwehrmuster. Es folgen praxisorientierte überlegungen und Hinweise zum therapeutischen Vertrag als Grundlage des Arbeitsbündnisses, zu Methoden der Ent?ngstigung im Therapieproze?, zu Begegnung und Beziehung als Substrat für korrigierende Erfahrungen, heilendes Klima und Entdramatisierung des realen Geschehens. Die Ausführungen enden mit transaktionsanalytischen überlegungen zu übertragung, Gegenübertragung und dem Umgang mit Regressionsprozessen.      

Prevalence and situational causes of stereotyped behaviors in blind infants and preschoolers

Parents of 85 blind children aged from 10 months to the 6th year of life were asked regarding the frequency, duration and typical situations of the occurrence of various stereotypic behavors in their children. The Bielefeld Parents' Questionnaire for Blind and Sighted Infants and Preschoolers was used as the instrument of measurement. All of the children displayed at least one stereotypic behavior; most displayed several stereotypic behaviors according to the parents' reports. Eye poking and body rocking dominated within the prevalence hierarchy. Four typical situations could be identified in which stereotypic behaviors were shown: monotony, arousal, demand, and during feeding or eating. The results suggested that repetitive hand and finger movements, stereotypic manipulation of objects, and making a face(s) mainly occur within arousal situations whereas eye poking, whimpering, and sucking thumbs or fingers especially are linked to monotony.This research was carried out within a research program on early intervention and family care for blind infants and preschoolers. This program is part of the Special Research Unit on Prevention and Intervention in Childhood and Adolescence (Sonderforschungsbereich No. 227) at the University of Bielefeld funded by the German Research Association (DFG). The authors would like to thank Gail Weingart and Jonathan Harrow (University of Bielefeld) for translating this paper from German.     

A general possible worlds framework for reasoning about knowledge and belief

In this paper non-normal worlds semantics is presented as a basic, general, and unifying approach to epistemic logic. The semantical framework of non-normal worlds is compared to the model theories of several logics for knowledge and belief that were recently developed in Artificial Intelligence (AI). It is shown that every model for implicit and explicit belief (Levesque), for awareness, general awareness, and local reasoning (Fagin and Halpern), and for awareness and principles (van der Hoek and Meyer) induces a non-normal worlds model validating precisely the same formulas (of the language in question).