Frequency effects in lexical decisions: A test of the verification model.

Lexical decisions about high-frequency words are faster than about low-frequency words. It has been suggested that the locus of this effect is in a verification stage in which a frequency-ordered comparison takes place that requires the continuous availability of a sensory representation of the stimulus. This proposal was tested in 4 lexical-decision experiments, using 64 undergraduates. In Exp I, high- and low-frequency words and nonword stimuli remained visible until Ss responded. The stimuli in Exp II were illuminated for only 1 retrace on a video monitor (16.7 msec), and in Exp III, the single retrace was followed by a pattern mask 50 msec later. The latter 2 conditions have been suggested as manipulations that would eliminate the verification stage of recognition. Nevertheless, the effect of word frequency on decision latencies was comparable in all 3 experiments. Data from Exp IV eliminated orthographic regularity as a factor contributing to the obtained frequency effect. It is suggested that frequency has its effects prior to verification and that the notion of verification as the sole basis for frequency effects needs to be revised. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sentential context effects on lexical decisions with a cross-modal instead of an all-visual procedure

J. L. Nicol and D. Swinney (1989) reported facilitation in a cross-modal lexical-decision task as evidence that implicit objects of verbs (WH-traces) are reinstated during comprehension. G. McKoon and R. Ratcliff (1994) found the same priming effects in the absence of implicit objects, suggesting that the effects are attributable to some factor other than a syntactic process that would fill in implicit objects. J. L. Nicol, J. D. Fodor, and D. Swinney (1994) questioned the relevance of McKoon and Ratcliff's findings because they were obtained with all-visual rather than cross-modal presentation. In 2 experiments, the authors replicated McKoon and Ratcliff's results using cross-modal lexical decision.     

Are lexical decisions a good measure of lexical access? Repetition blocking suggests the affirmative.

Examined the suggestion by D. A. Balota and J. I. Chumbley (see record 1985-05804-001) that lexical decisions can be based on computed values of a frequency/meaningfulness (FM) dimension for words and nonwords. Two experiments with 200 university students manipulated repetition of words and nonwords. Word repetition had a facilitating effect on response latencies for both words and nonwords, but nonword repetition had little or no effect. Results support a deadline decision model in which lexical decisions are based on lexical entries being activated beyond some criterion threshold within a prescribed period of time. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lateralized word recognition: Assessing the role of hemispheric specialization, modes of lexical access, and perceptual asymmetry.

The processing advantage for words in the right visual field (RVF) has often been assigned to parallel orthographic analysis by the left hemisphere and sequential by the right. The authors investigated this notion using the Reicher-Wheeler task to suppress influences of guesswork and an eye-tracker to ensure central fixation. RVF advantages obtained for all serial positions and identical U-shaped serial-position curves obtained for both visual fields (Experiments 1–4). These findings were not influenced by lexical constraint (Experiment 2) and were obtained with masked and nonmasked displays (Experiment 3). Moreover, words and nonwords produced similar serial-position effects in each field, but only RVF stimuli produced a word-nonword effect (Experiment 4). These findings support the notion that left-hemisphere function underlies the RVF advantage but not the notion that each hemisphere uses a different mode of orthographic analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional resource demands of visual word recognition in naming and lexical decisions.

Attentional demands of lexical access were assessed with dual-task methodology. Ss performed an auditory probe task alone (single-task) or combined (dual-task) with either a lexical decision or a naming task. In Exp 1, probe performance showed a decrement from single- to dual-task conditions during recognition of words in both lexical decision and naming tasks. In addition, decrements of probe performance were larger during processing of low-frequency compared with high-frequency words in both of the word recognition tasks. Exp 2 showed that the time course of frequency-sensitive demands was similar across lexical decision and naming tasks and that attention is required early in the word recognition sequence. The results support the assumption that lexical access is both frequency sensitive and attention demanding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vasoreactivity and prostacyclin release in streptozotocin-diabetic rats: effects of insulin or aldose reductase inhibition

1. Alterations in vasoreactivity and endothelial cell function could underlie some of the vascular abnormalities in diabetes. To examine aspects of these phenomena we studied the effects of 4-6 weeks streptozotocin-induced diabetes in the rat on basal and angiotensin II (AII)-stimulated prostacyclin release from isolated lung, perfused at constant flow. In addition, pressure was monitored throughout the lung perfusion as an index of vasomotor tone. 2. The experiment also included lungs from groups of diabetic rats treated with either insulin or an aldose reductase inhibitor (imirestat), to determine whether these treatments influenced the development of any defects seen in untreated diabetes. 3. Despite some indication of a trend towards reduced prostacyclin release in lungs from diabetic rats, neither the basal nor AII-stimulated release was significantly different from that seen in tissues from control animals. There were no significant differences between groups in the average basal perfusion pressure and in either the absolute pressure response to AII or the time of this peak. 4. The area under the perfusion pressure curve during AII infusion was greater in lungs from diabetic animals than in controls indicating a prolonged vasoconstrictor response. This increased pressor response may indicate increased sensitivity of diabetic tissue to AII or a reduced production of vasodilators in response to the vasoconstriction. 5. Whichever mechanism was responsible, this alteration was prevented by insulin treatment but not by aldose reductase inhibition, implicating mechanisms probably unrelated to exaggerated polyol pathway flux.     

Frequency effects and lexical access: On the interpretation of null pseudohomophone base-word frequency effects.

Several researchers have recently argued that pseudohomophone (e.g., phocks) naming latency is not sensitive to base-word (e.g., fox) frequency. When interpreting this null base-word frequency effect on pseudohomophone naming latency, it is important to rule out the possibility that the selection of base words is responsible. Reliable word-frequency effects were found on word-naming latency (i.e., higher frequency words were associated with shorter naming latencies) when using R. S. McCann and D. Besner's (1987) and C. U. Herdman, J. LeFevre, and S. L. Greenham's (1996) word stimuli. In contrast, no such frequency effect on word-naming latency was found when using M. S. Seidenberg, A. Petersen, M. C. MacDonald, and D. C. Plaut's (1996) stimuli. A null pseudohomophone base-word frequency effect is rendered uninterpretable in the absence of a reliable base-word frequency effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autoreceptor-mediated regulation of GABA release: role of uptake inhibition and effects of novel GABAB antagonists

While the role of GABAB autoreceptors in the regulation of GABA release in synaptosomes and brain slices is well established, little is known about their role in vivo. Doubts have arisen because there is an apparent discrepancy between the frequencies at which GABA neurons fire and the frequency range within which autoreceptor regulation is observed in vitro. To see whether this apparent mismatch could be due to the use of a GABA uptake inhibitor in the release experiments in slices, we have compared the frequency dependencies of GABA release in the presence and absence of uptake inhibition. Before-hand, the previously incomplete frequency curve in the presence of uptake inhibition was extended at the lower end. To achieve this, stimulation was performed by means of groups of 4 pseudo-one-pulses (POP's) at inter-POP intervals corresponding to frequencies of 0.015625-0.5 Hz. It could be shown that activation of the GABAB autoreceptor by endogenously released GABA begins at a stimulation frequency as low as 0.0625 Hz. Experiments with the antagonist, CGP 35348, at inter-POP intervals of 1 min, at which the preceding POP has no longer an effect on GABA release during the next one, showed that basal release alone already substantially activated the autoreceptor. The frequency dependence in the absence as compared to the presence of uptake inhibition was shifted towards higher frequencies by a factor of 4. We do not consider this enough to remove our doubts about the in vivo operativity of GABAB autoreceptors.(ABSTRACT TRUNCATED AT 250 WORDS)     

A study of visual processes in a case of interhemispheric disconnexion

A 75-year-old right-handed woman, after a probable cerebral infarct, developed an irregular constriction of the visual fields, a left-sided agraphia, and an anomia for objects in the left hand. Subsequent testing demonstrated an inability to name, though ability to recognize, letters and objects flashed in the homonymous left visual field. An inter-hemispheric disconnexion syndrome was inferred from these findings. The present publication concerns mainly the visual aspects of this disconnexion syndrome. Tasks were devised to test the abilities of the major and minor hemisphere: (a) the left hemisphere demonstrated a complete dominance for language expression and an incomplete dominance for written language comprehension; (b) the right hemisphere appeared to be dominant for some visuo-spatial tasks including number comprehension; (c) when the hemispheres were given contradictory visual informations on a non-verbal task (chimeric stimuli) there was a predominance of the right hemisphere. The right hemisphere appeared able to process complex information. Specialization of functional activities in each hemisphere is briefly discussed.     

Theta-burst stimulation of the right neocerebellar vermis selectively disrupts the practice-induced acceleration of lexical decisions.

The present study reports an experiment of cerebellar transcranial magnetic stimulation in a lexical decision task. In contrast to the study by Argyropoulos (2011), no effect of cerebellar stimulation was observed on priming sizes. However, when subjects confronted the same stimuli in the second session of participation, lexical decision latencies did not become any shorter after stimulation of the right neocerebellar vermis, in contrast to all other conditions. This finding is discussed in the light of current research in cerebellar cognitive and linguistic functions, and provides some first evidence for the recently entertained hypothesis that neocerebellar loci are significant in acquiring, storing, and retrieving associative memory traces of repeatedly co-occurring neural events in the language domain. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Frequency effects in lexical tasks: Reply to Balota and Chumbley.

In replying to D. A. Balota and J. I. Chumbley's (see record 1990-24407-001) commentary on the article by S. Monsell et al (see record 1989-24836-001), the author addresses four issues. New data show that the effect of frequency on semantic categorization time reported by Monsell et al. was not a disguised typicality effect. An account of the small size of the effect of stress pattern on immediate naming latency observed by Monsell et al. is supplied. Inferences that may and may not be drawn from effects of frequency on delayed naming latency are discussed. The main conclusions and methodological recommendations of Monsell et al. are clarified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Topography of fibers in the human corpus callosum mediating interhemispheric inhibition between the motor cortices

We have previously shown, using human T-cell lymphocytotrophic virus-I (HTLV-I)-infected cell lines, that soluble interleukin-6 receptor (sIL-6R) is generated through an alternative splicing mechanism. In this study, we examined human sera for the presence of alternatively spliced soluble IL-6R (AS-sIL-6R). We produced a monoclonal antibody (mAb) recognizing the unique sequence of AS-sIL-6R peptide, generated by an altered reading frame. We also made recombinant AS-sIL-6R protein in Spodoptera frugiperda-9 (Sf-9) cells carrying baculovirus, which encoded altered sIL-6R or conventional IL-6R cDNA. mAbs specifically recognized AS-sIL-6R, but not conventional IL-6R, as demonstrated by Western blot analyses, fluorescence-activated cell sorter, immunofluorescence analyses and enzyme-linked immunosorbent assay (ELISA). We adapted an ELISA system and used it for detection of altered sIL-6R in sera from 23 healthy persons, 12 patients with adult T-cell leukaemia (ATL) and 13 patients with HTLV-I-associated myelopathy (HAM). Serum levels of AS-sIL-6R were 6.4 or 6.1 times greater in ATL (28.7+/-20.4 ng/ml, P<0.0001) and in HAM patients (27.5+/-12.1 ng/ml, P<0.0001) than in healthy individuals (4.5+/-2.1 ng/ml). High levels of AS-sIL-6R were also observed in plasma from rheumatoid arthritis patients and in persons with elevated levels of alanine aminotransferase (ALT), antinuclear antibody (ANA), or alpha-fetoprotein (AFP). However, in human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV) or hepatitis C virus (HCV)-infected individuals, AS-sIL-6R levels were not elevated. In this study, we confirmed that AS-sIL-6R is indeed present in human sera. These observations suggest that alternative splicing of IL-6R mRNA is of consequence in ATL, HAM and in some autoimmune diseases. The HTLV-I-infected T cells appeared to play an important role in AS-sIL-6R production.     

Word recognition and identification: Do word-frequency effects reflect lexical access?

Tested the assumption that word-frequency effects on recognition result from differential ease of access to lexical entries for high- and low-frequency words. Previous researchers (McCann & Besner, 1987) found that pseudohomophones (e.g., TRAX) were named faster and more accurately than controls (e.g., PRAX), but pseudohomophone performance was not sensitive to base word frequency. In Exp 1 of the present series, performance on the same set of pseudohomophones and controls was assessed in the context of the lexical decision task (does this letter string spell a word?). Pseudohomophone performance was impaired relative to controls, which is commonly taken as evidence of contact with entries in a phonological lexicon. As in the naming task, however, pseudohomophone performance was insensitive to base word frequency. In Exp 2, pseudohomophone performance was examined in the context of a phonological lexical decision task (does this letter string sound like an English word?). Pseudohomophone performance was sensitive to base word frequency in phonological lexical decision. Word-frequency effects in binary decision tasks such as lexical decision and phonological lexical decision are attributed to a familiarity discriminatiion process that contributes bias to the decision stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency and neighborhood effects on lexical access: Activation or search?

Four experiments investigated the conjoint effects of word frequency and neighborhood size on performance in lexical decision, word naming, and delayed naming tasks. Neighborhood size refers to the number of words that can be created by changing one letter of a target word. Facilitatory effects of neighborhood size were observed for low- but not high-frequency effect in the lexical decision as compared with the naming task. This effect was influenced by the nature of the nonwords that had to be discriminated from words and therefore appeared to reflect the processes involved in the decision component of the lexical classification task. Overall, the results demonstrate that neighborhood size influences the lexical access process. The facilitatory nature of the neighborhood effect and its interaction with frequency provide strong support for the view that lexical access relies on an activation mechanism that is sensitive to word frequency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context effects in visual word recognition: lexical relatedness and syntactic context

In three experiments, we investigated how associative word-word priming effects in German depend on different types of syntactic context in which the related words are embedded. The associative relation always concerned a verb as prime and a noun as target. Prime word and target word were embedded in visually presented strings of words that formed either a correct sentence, a scrambled list of words, or a sentence in which the target noun and the preceding definite article disagreed in syntactic gender. In contrast to previous studies (O'Seaghdha, 1989; Simpson, Peterson, Casteel, & Burgess, 1989), associative priming effects were not only obtained in correct sentences but also in scrambled word lists. Associative priming, however, was not obtained when the definite article and the target noun disagreed in syntactic gender. The latter finding suggests that a rather local violation of syntactic coherence reduces or eliminates word-word priming effects. The results are discussed in the context of related work on the effect of gender dis-/agreement between a syntactic context and a target noun.     

Financial effect of clinical decisions: case study of a dialysis center

This paper explores, in the isolated guinea-pig ileum, the effects of temperature on the acute development of opioid dependence and on the precipitation of the abstinence response, using as reference the effect of temperature on the response to a standard nicotine concentration. Additionally, the influence of temperature on acute morphine neurodepression was examined. Three experimental groups were included. In the first, the bath temperature was adjusted and maintained along the experimental session (2.5 h) at one of the following values: 28, 32, 36 or 40 degrees C. In the second, the different values of bath temperature were applied only during the period of morphine exposure before testing the abstinence response at 36 degrees C. In the third, all segments were initially incubated at 36 degrees C for 1 h, and afterwards, abstinence and the nicotine response were elicited at the different temperatures mentioned. In all the series, a single challenge naloxone dose (3.1, 10, 31, 100, 316, 1000 or 3160 nM) was administered after 1h of morphine and complete naloxone concentration-response curves were obtained. The abstinence response was expressed as a percentage of the nicotine reference response. All segments showed robust nicotine responses at all the experimental protocols tested indicating that, at the temperature range studied, the contractile mechanisms were impaired. This study showed that changes in bath temperature modify the magnitude of acute morphine neurodepression, and of the abstinence response but did no affect the development of acute opioid dependence. These data, along with several lines of evidence, strongly suggest that acute neurodepression, the development of opiate dependence and antagonist-precipitated abstinence are separable. Results are discussed on the basis of drug-receptor interactions.     

Components of activation: Repetition and priming effects in lexical decision and recognition.

Examined activation decay functions in 4 experiments in which 52 undergraduates performed 2 different tasks: lexical decision and word recognition. Activation (amount of facilitation) was measured both for item repetition and for priming between newly learned associates. Results indicate that there were at least 3 different components of activation: a short-term component that decayed with 1 or 2 intervening items and appeared to be common to priming and repetition, an intermediate component for repetition in recognition, and a long-term component for repetition. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Orthographic neighborhood effects in lexical decision: The effects of nonword orthographic neighborhood size.

The effects of large neighborhoods (neighborhood size) and of higher frequency neighbors (neighborhood frequency) were examined as a function of nonword neighborhood size in lexical decision tasks. According to the multiple read-out model (J. Grainger & A. M. Jacobs, 1996), neighborhood size and neighborhood frequency effects should vary systematically as a function of nonword neighborhood size. In these experiments, the nonword context was more extensively manipulated than in previous studies, providing a more complete test of the model's predictions. In addition, simulations were conducted examining the model's ability to account for the facilitatory neighborhood size and neighborhood frequency effects observed in these experiments. The results suggest that the model overestimates the role of inhibition in the orthographic processing of English words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pseudohomophone effects in lexical decision: Still a challenge for current word recognition models.

Computational models that implement a serial mechanism of phonological assembly predict interactions between the size of the pseudohomophone (PsH) effect and stimulus length. Models with frequency-sensitive word representations predict baseword frequency effects. These predictions were tested in a lexical-decision task. The results showed constant PsH effects across different word lengths (in favor of parallel phonological activation) and baseword frequency effects (in favor of frequency-sensitive representations). However, the baseword frequency effect was opposite of what the models predicted. This result is most easily accommodated by models that assume an orthographic verification mechanism. The plausibility of such a mechanism was further supported by the results of 2 additional experiments investigating the effects of response speed and spelling probability (feedback consistency) on the size of the PsH effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)