1,721,116 research outputs found
Short-term memory impairment and spontaneous speech
No full textThe spontaneous speech of a patient with a specific repetition deficit was studied. The amount of pausing and of paraphasic errors was found to be normal. It was concluded that the repetition difficulty arose from an auditory-verbal short-term memory impairment and not a high-level speech production deficit. It was further concluded that the STM store involved was not part of the speech output syste
Discrete and analogue quantity processing in the parietal lobe: a functional MRI study.
No full textThe human intraparietal sulcus (IPS) is implicated in processing symbolic number information and possibly in nonsymbolic number information. Specific IPS activity for discrete quantities (numerosities) as compared with continuous, analogue quantity has not been demonstrated. Here we use a stimulus-driven paradigm to distinguish automatic estimation of "how many things" from "how much" and "how long." The discrete analogue response task (DART) uses the perception of hues which can change either abruptly (discrete, numerous stimuli) or smoothly (analogue, nonnumerous stimuli) in space or in time. Subjects decide whether they saw more green or more blue. A conjunction analysis of spatial and temporal conditions revealed that bilateral IPS was significantly more active during the processing of discrete stimuli than during analogue stimuli, as was a parietal-occipital transition zone. We suggest that processing numerosity is a distinct process from processing analogue quantity, whether extended in space or time, and that an intraparietal network connects objects' segmentation to the estimation of their numerosity
The Development af automaticity in accessing Number Magnitude
No full textThis study traces developmental changes in automatic and intentional processing of Arabic numerals using a numerical-Stroop paradigm. In Study 1, university students compared the numerical or physical size of Arabic numerals varying along both dimensions. in Study 2, first graders (mean age = 6 years 6 months), third graders (mean age - 8 years 1 months), and fifth graders (mean age = 10 years 3 months) were tested to examine developmental changes in numerical and physical comparisons. In the numerical comparison task, a size congruity effect was found at all ages (i.e., relative to a neutral control, congruent physical sizes facilitated, and incongruent sizes interfered with, the numerical comparison). The pattern of facilitation and interference. however, was modulated by age- In the physical comparison task, the incongruity between physical and numerical size affected only older children and adults. These findings strongly suggest that the automatization in number processing is achieved gradually us numerical skills progress. (C) 2000 Academic Press
Chinese pure alexia
No full textTwo Chinese pure alexic patients are reported. C.Y.T. had a circumscribed lesion in the left occipital lobe, the same location as the classic cases of pure alexia in other languages. Y.Y.X. was diagnosed with Balint's syndrome characterized by bilateral damage in the parietal and occipital lobes. The Chinese script is logographic and non-alphabetic. Nevertheless, the neuroanatomy of early processing in reading Chinese appears to be the same for readers of alphabetical and non-alphabetical scripts. Both patients displayed a 'radical-by-radical' reading strategy which is analogous (and possibly functionally equivalent) to 'letter-by-letter' reading in alphabetic patients. There was an association between constructional apraxia and a deficit in processing the visual form of Chinese characters for Y. Y. X. However, C. Y. T. had intact visuospatial function and displayed no impairment to the processing of character form. The implications of the data from pure alexic patients to our understanding of oral reading in Chinese are discussed
Where numerical cognition interacts with spatial attention
No full textWestern people tend to represent numbers spatially, with small numbers toward the left of mental space and large numbers towards the right, and responses to small numbers are faster when the effector is in left space; responses to large numbers are faster with the effector in right space (SNARC effect). It is generally claimed that the spatial representation of number is function of the posterior parietal cortex (Hubbard et al 2005), however the representation of space and covert orienting to it can involve frontal brain areas (Corbetta & Shulman 2002
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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