Diagnosis and repair of negative polarity constructions in the light of symbolic resonance analysis

In a post hoc analysis, we investigate differences in event-related potentials of two studies (Drenhaus et al., 2004, Drenhaus et al., to appear, Saddy et al., 2004a and Saddy et al., 2004b) by using the symbolic resonance analysis (Beim Graben & Kurths, 2003). The studies under discussion, examined the failure to license a negative polarity item (NPI) in German: Saddy et al. (2004a) reported an N400 component when the NPI was not accurately licensed by negation; Drenhaus et al., 2004 and Drenhaus et al., to appear considered additionally the influence of constituency of the licensor in NPI constructions. A biphasic N400-P600 response was found for the two induced violations (the lack of licensor and the inaccessibility of negation in a relative clause). The symbolic resonance analysis (SRA) revealed an effect in the P600 time window for the data in Saddy et al., which was not found by using the averaging technique. The SRA of the ERPs in Drenhaus et al., showed that the P600 components are distinguishable concerning the amplitude and latency. It was smaller and earlier in the condition where the licensor is inaccessible, compared to the condition without negation in the string. Our findings suggest that the failure in licensing NPIs is not exclusively related to semantic integration costs (N400). The elicited P600 components reflect differences in syntactic processing. Our results confirm and replicate the effects of the traditional voltage average analysis and show that the SRA is a useful tool to reveal and pull apart ERP differences which are not evident using the traditional voltage average analysis.     

ERP correlates of auditory negative priming

Negative priming refers to slowed down reactions when the distractor on one trial becomes the target on the next. Following two popular accounts, the effect might be due either to inhibitory processes associated with the frontal cortex, or to an ambiguity in the retrieval of episodic information. We used event-related brain potentials (ERPs) to identify the processing stage primarily associated with negative priming. In an auditory categorization task, reactions in negative priming trials were compared to reactions in a standard control (unrelated primes and probes) and a repetition control (attended prime=ignored probe) condition. Reactions were slower for negative priming than for standard control (Delta32 ms) and repetition control trials (Delta64 ms). The corresponding ERP effect was reflected in an attenuation of a sustained parietal positivity extending from 300 to 600 ms. Because corresponding ERP components were found to be sensitive to stimulus recognition and familiarity, the results may be interpreted to support an episodic retrieval account of negative priming.     

Sensitivity to local sentence context information in lexical ambiguity resolution: evidence from left- and right-hemisphere-damaged individuals

Using a cross-modal semantic priming paradigm, the present study investigated the ability of left-hemisphere-damaged (LHD) nonfluent aphasic, right-hemisphere-damaged (RHD) and non-brain-damaged (NBD) control subjects to use local sentence context information to resolve lexically ambiguous words. Critical sentences were manipulated such that they were either unbiased, or biased toward one of two meanings of sentence-final equibiased ambiguous words. Sentence primes were presented auditorily, followed after a short (0 ms) or long (750 ms) interstimulus interval (ISI) by the presentation of a first- or second-meaning related visual target, on which subjects made a lexical decision. At the short ISI, neither patient group appeared to be influenced by context, in sharp contrast to the performance of the NBD control subjects. LHD nonfluent aphasic subjects activated both meanings of ambiguous words regardless of context, whereas RHD subjects activated only the first meaning in unbiased and second-meaning biased contexts. At the long ISI, LHD nonfluent aphasic subjects failed to show evidence of activation of either meaning, while RHD individuals activated first meanings in unbiased contexts and contextually appropriate meanings in second-meaning biased contexts. These findings suggest that both left (LH) and right hemisphere (RH) damage lead to deficits in using local contextual information to complete the process of ambiguity resolution. LH damage seems to spare initial access to word meanings, but initially impairs the ability to use context and results in a faster than normal decay of lexical activation. RH damage appears to initially disrupt access to context, resulting in an over-reliance on frequency in the activation of ambiguous word meanings.     

Group Intervention Studies in the Cognitive Rehabilitation of Individuals with Traumatic Brain Injury: Challenges Faced by Researchers

There are many factors to consider in designing and interpreting group studies. These include both analytic considerations, such as the selection of valid and reliable outcome measures, and subjective considerations, such as the selection of outcomes that are perceived to be important to participants and researchers. In this paper, we review key issues to consider in the design of group studies in neurorehabilitation, using problem-solving studies in traumatic brain injury as an example.     

Expect the Best and Prepare for the Worst: Anticipatory Coping and Preparations for Y2K

The Y2K Bug, the programming glitch expected to derail computerized systems worldwide when the year changed from 1999 to 2000, provided a rich context for examining anticipatory coping and preparatory behaviors. In the last 2 months of 1999, 697 respondents completed an online survey of proactivity, worry about Y2K, dispositional optimism, primary and secondary control-oriented coping efforts, estimates of Y2K-related disruptions, and household preparations. Higher levels of proactivity, worry, and optimism were independently associated with greater self-reported preparations. These predictors were positively associated with greater primary control-oriented coping efforts, but showed differential relations to secondary control efforts, such as accepting the situation or trusting a higher power, especially among participants who thought the damage would be severe and lasting. Implications for understanding multiple ways of coping with potential stressors are discussed.

Time ordering in frontal lobe patients: a stochastic model approach

Frontal lobe patients reproduced a sequence of capital letters or abstract shapes. Immediate and delayed reproduction trials allowed the analysis of short- and long-term memory for time order by means of suitable Markov chain stochastic models. Patients were as proficient as healthy subjects on the immediate reproduction trial, thus showing spared encoding and short-term memory. They failed, instead, on the delayed trials with capital letters, but not with random shapes, suggesting that their long-term memory impairment did not depend on primary deficits for ordering, but on inability to benefit from the organisational strategies that improve the retention and retrieval in normal subjects.     

The P600 as an indicator of syntactic ambiguity

In a study using event-related brain potentials, we show that the current characterization of the P600 component as an indicator of revision processes (reanalysis and repair) in sentence comprehension must be extended to include the recognition of syntactic ambiguity. By comparing the processing of ambiguous and unambiguous sentence constituents in German, we show that the P600 is elicited when our language processing system has syntactic alternatives at a certain item given in the input string. That the P600 is sensitive to syntactic ambiguity adds crucial evidence to current debates in psycholinguistic modelling, as the results clearly favour parallel models of syntactic processing which assume that ambiguity is recognized and costly.     

Grammar overrides frequency: evidence from the online processing of flexible word order

We show that online processing difficulties induced by word order variations in German cannot be attributed to the relative infrequency of the constructions in question, but rather appear to reflect the application of grammatical principles during parsing. Event-related brain potentials revealed that dative-marked objects in the initial position of an embedded sentence do not elicit a neurophysiologically distinct response from subjects, whereas accusative-marked objects do. These differences are predictable on the basis of grammatical distinctions (i.e. underlying linguistic properties), but not on the basis of frequency information (i.e. a superficial linguistic property). We therefore conclude that the former, but not the latter, guides syntactic integration during online parsing.     

Processing syntactic functions of words in normal and dyslexic readers

Readers with dyslexia were compared with normal readers for the ability to identify the grammatical function of words in the course of sentence processing by means of electrophysiological measures along with behavior measures. Participants were 18 dyslexic and 18 normally reading, native Hebrew-speaking male university students, aged 18 to 27 years. Obtained results confirmed the hypothesis (Leikin & Breznitz, 1999) that Hebrew readers used lexical-morphological properties of words to identify their grammatical roles. However, the morphologically based strategy acquired full expression only in the presence of the verb, which in the Hebrew sentence fulfills the central role. Seemingly, readers use a few different procedures to identify the grammatical roles of words. Selection of a particular strategy seems to be influenced by diverse factors, including syntactic and lexical-morphological characteristics of the stimuli and level of reading skills. In addition, the results showed significant differences in sentence processing between normal and dyslexic readers, as reflected by ERP measures. These results are in line with the hypothesis, suggesting the existence of a syntactic processing weakness in readers with dyslexia.     

Adult age differences in visual word identification: functional neuroanatomy by positron emission tomography

Adult age differences in the neural systems mediating semantic (context-independent) memory were investigated using positron emission tomography (PET). Younger (20-29 years) and older (62-70 years) participants performed lexical decision (word/nonword discrimination) and nonsemantic (simple visual search) baseline tasks during PET scanning. Within the lexical decision task, display duration and presentation rate were varied across scans. The behavioral data suggested that although an age-related slowing was evident in visual feature and response processing, the retrieval of semantic/lexical information was similar for younger and older adults. For both age groups, lexical-related activation occurred in inferior prefrontal and occipitotemporal regions of the left hemisphere. Differential activation, as a function of age group, was observed in the left occipitotemporal pathway as a result of older adults' maintaining higher levels of neural activity in striate cortex (during visual search) and in inferior temporal cortex (during lexical decision). The prefrontal activation was similar for the two age groups. Thus, although this form of semantic memory retrieval does not undergo significant age-related decline, an age-related change in the associated pattern of neural activation is evident. These findings differ from previous neuroimaging studies of episodic (context-dependent) memory retrieval, which have suggested that age-related compensatory mechanisms are expressed primarily by greater activation of prefrontal regions for older adults than for younger adults.