Search

Contains fulltext : 287206.pdf (Publisher’s version ) (Open Access) Lexical access is commonly studied using bare picture naming, which is visually guided, but in real-life conversation, lexical access is more commonly contextually guided. In this fMRI study, we examined the underlying functional neuroanatomy of contextually and visually guided lexical access, and its consistency across sessions. We employed a context-driven picture naming task with fifteen healthy speakers reading incomplete sentences (word-by-word) and subsequently naming the picture depicting the final word. Sentences provided either a constrained or unconstrained lead–in setting for the picture to be named, thereby approximating lexical access in natural language use. The picture name could be planned either through sentence context (constrained) or picture appearance (unconstrained). This procedure was repeated in an equivalent second session two to four weeks later with the same sample to test for test-retest consistency. Picture naming times showed a strong context effect, confirming that constrained sentences speed up production of the final word depicted as an image. fMRI results showed that the areas common to contextually and visually guided lexical access were left fusiform and left inferior frontal gyrus (both consistently active across-sessions), and middle temporal gyrus. However, non-overlapping patterns were also found, notably in the left temporal and parietal cortices, suggesting a different neural circuit for contextually versus visually guided lexical access. 14 p.

Item does not contain fulltext Conventional neurocognitive assessment does not account for the complex interplay between neurocognitive functions that gives rise to (goal-directed) behavior. This study aims to explore the value of the application of network analysis to individual neurocognitive data, in order to investigate neurocognitive network organization (i.e., the neurocognome). Participants were healthy young adults (N = 51, average age: 26 years [range: 18-34], 49% female) that underwent a single comprehensive neurocognitive assessment. To allow implementation of network analysis, we developed a new measure of connectivity between neurocognitive functions that can be calculated on a single neurocognitive assessment. Connectivity values between all possible pairs of neurocognitive functions were used to reconstruct individual neurocognitive networks. Graph theory was applied to extract measures of global and local network organization from neurocognitive networks at the individual level. The results confirmed the expectation that neurocognitive connectivity values should be higher for connections between neurocognitive functions that are more closely related (i.e., within neurocognitive domains) than for connections between neurocognitive functions that are less closely related (i.e., across neurocognitive domains). The results further showed that reconstruction of the neurocognitive network at the individual level has considerable agreement with a group-based approach, providing preliminary evidence for the validity of our approach. The reconstructed neurocognitive network also showed considerable consistency among (randomly selected) independent subgroups, supporting the stability of our approach. Lastly, neurocognitive network parameters were related to intelligence and behavior problems, reflecting relevance of neurocognitive network organization for other important domains of functioning. Moreover, local network parameters (i.e., the relative importance of neurocognitive functions in the network) may have stronger relevance for behavioral functioning than conventional measures of neurocognitive functioning (i.e., z-scores reflecting performance on individual neurocognitive tests). Taken together, this study indicates that analysis of individual neurocognitive network organization has potential value for neurocognitive assessment in research and clinical practice. 17 p.

Contains fulltext : 219554.pdf (Publisher’s version ) (Closed access) Individuals with sequence-space synesthesia (SSS) perceive sequences like months, days and numbers in certain spatial arrangements. Several cognitive benefits have been associated with SSS, such as enhanced mental rotation, more vivid visual imagery and an advantage in spatial processing. The current study aimed to further investigate these cognitive benefits, focusing on spatial navigation skills, to explore if their enhanced sensitivity to spatial relations is reflected in enhanced navigational performance. Synesthetes were distinguished from controls by means of a questionnaire, a consistency test and drawings. A virtual Morris Water Maze (MWM) task with two allocentric and two egocentric navigation conditions was used to assess spatial navigation abilities. For the allocentric tasks, participants had to use object cues to find a hidden platform and for the egocentric tasks, they had to use their own position as a reference. Results showed that synesthetes performed significantly better compared to controls on the allocentric and egocentric tasks that reflected real life situations more accurately. However, this significant result was only found for the time taken to find the platform and not for the length of the path that was taken. In exploratory analyses, no significant relations were found between task performance and the specific features of the manifestation of each individual's synesthesia. Our hypothesis that synesthetes with the ability to mentally rotate their spatial arrangements would perform better on the allocentric task was not confirmed. Results add to the growing body of literature concerning the cognitive benefits of SSS and are consistent with the possibility that enhanced spatial navigation skills emerge from generally enhanced visuospatial abilities in SSS. 15 p.

Item does not contain fulltext Franz Joseph Gall (1758-1828) introduced a new theory of mind and brain at the end of the eighteenth century, which he referred to as organology, dealing with mental functions and their cortical localizations. Gall wrote that observations regarding the verbal learning capacities of his schoolmates brought about his new way of thinking. This widely accepted view, however, requires qualification. Although Gall's experiences and observations as a schoolboy were relevant, especially for his craniology, these childhood memories might have been recalled and reinterpreted after he had started to think about the faculties of mind --- specifically after he had met Bianchi, a 5-year-old girl with a special talent for music. 9 p.

Item does not contain fulltext Kurt Goldstein was a founder of clinical neuropsychology. This thesis is illustrated with a description of Goldstein's test battery that he used as a screening instrument in a special clinic for soldiers in World War I. Parts of the battery were also used for neuropsychological rehabilitation. Goldstein's early work in Germany focused on both neuropsychological assessment and rehabilitation. He was interested in how individuals go about compensating for their deficits, The notion of ecological validity (Lebenswahr vsLebensfremd), only becoming widely popular in the nineteen-eighties, played an important role in Goldstein's selection of test procedures. 11 p.

Item does not contain fulltext Background: Aphasia formed a central topic in the discussion on localization of function in the nineteenth century, in particular in France, Germany and Great Brittain. Little is known on contributions from the Netherlands. Aim: This paper aims to discuss the contents of Arnoldus Van Rhijn's dissertation on aphasia, written in 1868 and one of the very few Dutch contributions to aphasiology in the nineteenth century. Added to this paper is a translation of the "Physiological Part" of Van Rhijn's dissertation. Outcome: Van Rhijn discussed three cases with acquired aphasia. He rejected Broca's notion of a cortical center for the articulation of speech and instead regarded the cortex as the site where the will exerted its influence. He argued that there is a certain form of specialization: the will to say something is localized at a different place than the will to write. According to Van Rhijn, the highest motor centers are localized in the subcortical gray areas. Van Rhijn concluded that aphasia may result from lesions to the cortical centers involved in speaking, or from a disconnection of the cortical and subcortical centers. Conclusion: Very little work was done on aphasia in the 19th century in the Netherlands. Van Rhijn's thesis, from an aphasiological point of view of limited value, does show that the notions of "centers", "connections", and "disorders due to disconnections" were generally known before Wernicke, also in the Netherlands.

Item does not contain fulltext 3 p.

Contains fulltext : 87495.pdf (Publisher’s version ) (Closed access) Asymmetry in performance and an association with non-lateralized attention are often mentioned as two important aspects of the clinical manifestation of visuospatial neglect. Both these aspects were investigated in 21 left (LH) and 24 right hemisphere (RH) stroke patients and in 20 healthy subjects. The letter and star cancellation subtests of the Behavioural Inattention Task (BIT) and a computerized visual reaction time task (CVRT) with stimuli presented either left, central or right in extrapersonal space were administered. In LH patients, the calculation of BIT asymmetry scores allowed a better distinction between patients with and without neglect than raw omission scores. However, in RH patients, raw and asymmetry scores led to similar classifications. In the CVRT, raw and asymmetry scores for the number of omissions also produced identical classifications. Thus, the computation of asymmetry scores for omissions did not substantially refine the diagnosis of neglect. On the other hand, more patients were classified as neglect patients by using CVRT reaction time (RT) asymmetry scores than by using BIT or CVRT omission scores. Ipsilesional RT's were chosen as a measure of general, non-lateralized attention. The ipsilesional RT's of the LH and RH patients did not differ from the healthy subjects' lateral RT's. However, within the RH group, patients with both RT asymmetries and BIT scores above cut-off level showed longer ipsilesional RT's than patients with defective RT asymmetries but normal BIT scores. This supports the idea of an interaction between lateralized and non-lateralized attentional components in neglect, in which the presence of general attentional deficits exacerbates the severity of neglect symptoms. RT tasks may contribute to the detection of asymmetries in visuospatial attention in patients with subclinical neglect symptoms, who might compensate for their lateralized deficit in paper-and-pencil tasks employing intact general attention. 01 mei 2010