Biomedical subjects

Katri Cornelissen

Publications and source records attributed to Katri Cornelissen.

4 recordsLinked to original sources

PubMed2004

Learning new names for new objects: cortical effects as measured by magnetoencephalography.

We tracked the evolvement of naming-related cortical dynamics with magnetoencephalography when five normal adults successfully learned names and/or meanings of unfamiliar objects. In all subjects, the learning of new names was associated with pronounced cortical effects. The learning effect was of long latency and emerged as a change of activation in the same cortical network that was active during naming of familiar items. In four out of five subjects, the cortical learning effect occurred in the inferior parietal lobe. In three of these subjects, the cortical effect was left-sided. These results suggest that the inferior parietal lobe plays an important role in the acquisition of novel words, presumably as a part of working memory systems.

Adult↗

PubMed2003

Adult brain plasticity elicited by anomia treatment.

We describe a study where a specific treatment method for word-finding difficulty (so-called contextual priming technique, which combines massive repetition priming with semantic priming) was applied with three chronic left hemisphere-damaged aphasics. Both before and after treatment, which focused on naming of a series of pictures, naming-related brain activity was measured by magnetoencephalography (MEG). Due to its excellent temporal resolution and good spatial resolution, we were able to track treatment-induced changes in cortical activity. All three subjects showed improved naming of the trained items. In all subjects, a single source area, located in the left inferior parietal lobe, close to the lesioned area, displayed statistically significant training-induced changes. This effect was of long latency as it started 300-600 msec after picture presentation. The change in activation was specific to training, as it could not be accounted for by variation of cortical dynamics associated with increased proportion of correct answers. Our interpretation is that the training effect reflects more effective phonological encoding and storage of the trained items through the engagement of a left hemispheric word-learning system. This is in line with recent functional imaging studies, which have linked left inferior parietal lobe activity to the phonological storage component of the verbal working memory, as well as with theoretical arguments stating that the primary role of the phonological loop is to acquire new words. Finally, the MEG results showed no evidence of increased right hemisphere participation following training, supporting the view that restoration of language-related networks in the damaged left hemisphere is crucial for anomia recovery.

Aphasia↗

PubMed2003

Naming actions and objects: cortical dynamics in healthy adults and in an anomic patient with a dissociation in action/object naming.

Neuropsychological studies have demonstrated that the production of nouns and verbs can be dissociated in aphasia. These reports have been taken as evidence for separate representations of nouns and verbs in the human brain. We used whole-head magnetoencephalography to record cortical dynamics of action and object naming in 10 healthy adults and in 1 anomic patient with superior naming of verbs compared with nouns due to a left posterior parietal lesion. A single set of 100 line drawings was used for both action and object naming. In normal subjects, the activation sequences in action and object naming were essentially identical, advancing from the occipital to posterior temporoparietal and further to the left frontal cortex, without consistent involvement of the classical left inferior frontal (Broca) and temporal (Wernicke) language areas. In the anomic patient, pronounced differences between action and object naming emerged in the left hemisphere. The activation sequence was disrupted at the level of the damaged parietal cortex and did not reach the left frontal cortex even in the relatively easier action naming. The more severely impaired object naming was associated with exceptionally strong and early activation of the left inferior frontal cortex (Broca) and subsequent pronounced activation of the left middle temporal cortex, silent in action naming. Verb and noun retrieval thus utilized a spatiotemporally similar neuronal network in healthy individuals. A clear dissociation in cortical correlates of verb and noun retrieval only became evident in our anomic patient, in whom damage to the language network has resulted in disproportionately worse performance in object than action naming.

Adult↗

PubMed2003

Naming multiple objects: neural correlates as measured by positron emission tomography.

The aim of this study was to examine the neural substrates of multi-object naming by positron emission tomography in normals. Multi-object naming is used in a technique called contextual priming (CP) to elicit contextual effects on picture naming through systematic manipulation of the relatedness of to-be-named pictures in an array. Inhibitory and facilitatory effects of CP on naming have been used both to highlight the inner dynamics of the normal word retrieval system and to treat naming difficulties caused by acquired anomia. Because of the complexity of the CP technique, it is unclear whether it merely reflects lexical retrieval or whether it also recruits general cognitive resources such as attentional control and response selection to a significant degree. When compared with a baseline situation in which colored circles were named, multi-object naming elicited increased blood flow in the occipital lobe and in the left inferior temporal and fusiform gyri. These areas have been related to visual pattern recognition and semantic access, and the pattern of activation is in line with previous functional imaging studies on single picture naming. In conclusion, multi-object naming does not appear to activate brain regions beyond those needed for single object naming. These findings thus provide independent evidence for the claim that CP is a valid paradigm for the study of word production proper.

Adult↗