Extracting noun phrases for all of MEDLINE. (9/669)

A natural language parser that could extract noun phrases for all medical texts would be of great utility in analyzing content for information retrieval. We discuss the extraction of noun phrases from MEDLINE, using a general parser not tuned specifically for any medical domain. The noun phrase extractor is made up of three modules: tokenization; part-of-speech tagging; noun phrase identification. Using our program, we extracted noun phrases from the entire MEDLINE collection, encompassing 9.3 million abstracts. Over 270 million noun phrases were generated, of which 45 million were unique. The quality of these phrases was evaluated by examining all phrases from a sample collection of abstracts. The precision and recall of the phrases from our general parser compared favorably with those from three other parsers we had previously evaluated. We are continuing to improve our parser and evaluate our claim that a generic parser can effectively extract all the different phrases across the entire medical literature.  (+info)

A statistical natural language processor for medical reports. (10/669)

Statistical natural language processors have been the focus of much research during the past decade. The main advantage of such an approach over grammatical rule-based approaches is its scalability to new domains. We present a statistical NLP for the domain of radiology and report on methods of knowledge acquisition, parsing, semantic interpretation, and evaluation. Preliminary performance data are given. A discussion of the perceived benefit, limitations and future work is presented.  (+info)

Cross-modal generalization effects of training noncanonical sentence comprehension and production in agrammatic aphasia. (11/669)

The cross-modal generalization effects of training complex sentence comprehension and complex sentence production were examined in 4 individuals with agrammatic Broca's aphasia who showed difficulty comprehending and producing complex, noncanonical sentences. Object-cleft and passive sentences were selected for treatment because the two are linguistically distinct, relying on wh-and NP movement, respectively (Chomsky, 1986). Two participants received comprehension training, and 2 received production training using linguistic specific treatment (LST). LST takes participants through a series of steps that emphasize the verb and verb argument structure, as well as the linguistic movement required to derive target sentences. A single-subject multiple-baseline design across behaviors was used to measure acquisition and generalization within and across sentence types, as well as cross-modal generalization (i.e., from comprehension to production and vice versa) and generalization to discourse. Results indicated that both treatment methods were effective for training comprehension and production of target sentences and that comprehension treatment resulted in generalization to spoken and written sentence production. Sentence production treatment generalized to written sentence production only; generalization to comprehension did not occur. Across sentence types generalization also did not occur, as predicted, and the effects of treatment on discourse were inconsistent across participants. These data are discussed with regard to models of normal sentence comprehension and production.  (+info)

Participation of the left posterior inferior temporal cortex in writing and mental recall of kanji orthography: A functional MRI study. (12/669)

To examine the neuropsychological mechanisms involved in writing kanji (morphograms), we used functional MRI (fMRI) in 10 normal volunteers, all right-handed, native Japanese speakers. The experimental paradigms consisted of kana-to-kanji transcription, mental recall of kanji orthography and oral reading and semantic judgement of kana words. The first two tasks require manual and mental transcription of visually presented kana words into kanji, respectively, whereas the last two tasks involve language processing of the same set of stimulus words without recall of kanji. The transcription and mental recall tasks yielded lateralized activation of the left posterior inferior temporal cortex (PITC). By contrast, neither oral reading nor semantic judgement produced similar activation of the area. These results, in good accordance with lesion data, provide converging evidence that the left PITC plays an important role in writing kanji through retrieval of their visual graphic images, and suggest language-specific cerebral organization of writing. The set of fMRI experiments also provides new neuroimaging data on the cortical localization of basic language functions in people using a non-alphabetical language.  (+info)

Language and thought: does grammar makes us smart? (13/669)

Many philosophers and psychologists believe that only people with rich language skills are capable of abstract reasoning. A man with a severe linguistic impairment poses a striking challenge to this view.  (+info)

Segregating semantic and syntactic aspects of processing in the human brain: an fMRI investigation of different word types. (14/669)

The processing of single words that varied in their semantic (concrete/abstract word) and syntactic (content/function word) status was investigated under different task demands (semantic/ syntactic task) in an event-related functional magnetic resonance imaging experiment. Task demands to a large degree determined which subparts of the neuronal network supporting word processing were activated. Semantic task demands selectively activated the left pars triangularis of the inferior frontal gyrus (BA 45) and the posterior part of the left middle/superior temporal gyrus (BA 21/22/37). In contrast, syntactic processing requirements led to an increased activation in the inferior tip of the left frontal operculum (BA 44) and the cortex lining the junction of the inferior frontal and inferior precentral sulcus (BA 44/6). Moreover, for these latter areas a word class by concreteness interaction was observed when a syntactic judgement was required. This interaction can be interpreted as a prototypicality effect: non-prototypical members of a word class, i.e. concrete function words and abstract content words, showed a larger activation than prototypical members, i.e. abstract function words and concrete content words. The combined data suggest that the activation pattern underlying word processing is predicted neither by syntactic class nor semantic concreteness but, rather, by task demands focusing either on semantic or syntactic aspects. Thus, our findings that semantic and syntactic aspects of processing are both functionally distinct and involve different subparts of the neuronal network underlying word processing support a domain-specific organization of the language system.  (+info)

'The-skipping' revisited in French: programming saccades to skip the article 'les'. (15/669)

Three experiments were performed to verify O'Regan's (1979) [Perception & Psychophysics, 25 (6), 501-509] finding that in reading, the eye moves further forward when going towards the word 'THE' than when going towards a three-letter verb. The experiments were performed in French instead of English, and compared the plural article 'les' with different three-letter verbs. It was confirmed that the eye did indeed move about 1.5 letters further in the case of the article 'les'. Further investigation of the phenomenon suggested that the effect was present even when the prior fixation duration was short: Only when prior fixation was around 200 ms or less, and additionally when the eye started from a launch position that was far from the word, was there a suggestion that the 'les'-skipping effect disappeared.  (+info)

mtDNA variation among Greenland Eskimos: the edge of the Beringian expansion. (16/669)

The Eskimo-Aleut language phylum is distributed from coastal Siberia across Alaska and Canada to Greenland and is well distinguished from the neighboring Na Dene languages. Genetically, however, the distinction between Na Dene and Eskimo-Aleut speakers is less clear. In order to improve the genetic characterization of Eskimos in general and Greenlanders in particular, we have sequenced hypervariable segment I (HVS-I) of the mitochondrial DNA (mtDNA) control region and typed relevant RFLP sites in the mtDNA of 82 Eskimos from Greenland. A comparison of our data with published sequences demonstrates major mtDNA types shared between Na Dene and Eskimo, indicating a common Beringian history within the Holocene. We further confirm the presence of an Eskimo-specific mtDNA subgroup characterized by nucleotide position 16265G within mtDNA group A2. This subgroup is found in all Eskimo groups analyzed so far and is estimated to have originated <3,000 years ago. A founder analysis of all Eskimo and Chukchi A2 types indicates that the Siberian and Greenland ancestral mtDNA pools separated around the time when the Neo-Eskimo culture emerged. The Greenland mtDNA types are a subset of the Alaskan mtDNA variation: they lack the groups D2 and D3 found in Siberia and Alaska and are exclusively A2 but at the same time lack the A2 root type. The data are in agreement with the view that the present Greenland Eskimos essentially descend from Alaskan Neo-Eskimos. European mtDNA types are absent in our Eskimo sample.  (+info)