Dissociated identity and semantic priming in Broca's aphasia: how controlled processing produces inhibitory semantic priming

Broca's aphasics performed a lexical decision task in a semantic priming experiment in which the proportion of related words was manipulated with a sufficiently long stimulus onset asynchrony for expectancy-based, strategic processing to operate. The control subjects showed the typical increase in semantic facilitation as relatedness proportion increased. However, the aphasic subjects demonstrated the opposite effect such that inhibitory semantic priming occurred as relatedness proportion increased even though, in a second experiment, these same aphasics showed an increase in facilitatory identity priming as relatedness proportion increased. This striking dissociation of identity and semantic priming for the aphasics was interpreted as supporting the "center-surround" theory (Carr & Dagenbach, 1990), which accounts for the same dissociation found in the normal population under challenging word-recognition conditions.     

Crossed cerebellar diaschisis in chronic Broca's aphasia

The cerebellum has anatomical connections to the cerebral cortex, through which it can affect language function. To study these connections, we investigated patients with chronic Broca's aphasia using MRI and single-photon emission computed tomography (SPECT). We selected 15 such patients (9 male, 6 female, aged 17-64 years, mean age 56 years) from 30 chronically aphasic patients. Using the results of SPECT, we divided them into patients with (group 1) and without (group 2) crossed cerebellar diaschisis (CCD). We compared the language function of the two groups. Patients in group 1 showed classical Broca's aphasia, while patients in group 2 showed mainly word-finding difficulty. Patients with CCD hat infarcts involving the lower part of the frontal gyrus but patients without CCD did not, which suggests that this region may have functional and anatomical connections with the cerebellum. Our findings support the notion that the cerebellum contributes to language.     

Electrophysiological and behavioral evidence of syntactic priming in sentence comprehension.

Event-related potentials and eye tracking were used to investigate the nature of priming effects in sentence comprehension. Participants read 2 sentences (a prime sentence and a target sentence), both of which had a difficult and ambiguous sentence structure. The prime and target sentences contained either the same verb or verbs that were very close in meaning. Priming effects were robust when the verb was repeated. In the event-related potential experiment, the amplitude of the P600 was reduced in target sentences that followed prime sentences with the same verb but not in prime sentences with a synonymous verb. In the eye-tracking experiment, total reading times on the disambiguating region were reduced when the targets followed prime sentences with the same verb but not when targets followed prime sentences with a synonymous verb. The fact that verb overlap greatly boosted priming effects in reduced relative sentences may indicate that verb argument structures play an important role in online parsing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention mechanisms mediate the syntactic priming effect in auditory word identification.

Investigated the syntactic priming effect and the involvement of attention in that process by testing identification of white noise-masked Hebrew words. Targets were either syntactically congruent or syntactically incongruent with the structure of the sentence. Relative to a neutral condition, similar facilitation and inhibition was found for congruent and incongruent targets, respectively. When syntactic congruency was blocked, the inhibition was attenuated, whereas the facilitation remained the same. A 350-msec silent interstimulus interval between context and target increased inhibition without affecting facilitation. It is suggested that both the facilitation and the inhibition effects of syntactic priming are based on a veiled controlled process of generating expectations. The inhibition results from a controlled process of reevaluation that requires additional attention resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic and syntactic processes in aphasia: A review of the literature.

Reviews recent investigations of lexical and syntactic aspects of language comprehension in aphasia. It is argued that these studies support theoretical assumptions concerning the functional independence of various components of normal language processing. Studies of the structure of the lexicon in aphasia provide support for componential theories of lexical semantics in that different types of features of meaning can be selectively disrupted under conditions of brain damage. Studies of sentence comprehension support the existence of a syntactic mechanism that is independent of lexically based heuristic strategies for assigning meaning. There is evidence that these independent elements of language are subserved by different portions of the dominant hemisphere of the brain. Focal brain damage can thus cause selective disruption of components, allowing the separation of elements that are highly integrated in the normal adult. It is suggested that studies of aphasic language, therefore, provide a valuable source of constraints on theories of normal language processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Abstract word deficits in aphasia: Evidence from semantic priming.

J.G. and D.E. are nonfluent aphasic patients who appear to have selective problems with abstract words on a variety of standard tests. Such a pattern would normally be interpreted as indicating a central semantic deficit for abstract words. The authors show that this is not the case by means of a semantic priming task that tests for implicit knowledge of the meanings of abstract and concrete words. Spoken word pairs that were either abstract or concrete synonyms (e.g., street-road or luck-chance) were presented; both Ss showed priming for the abstract and concrete pairs. The researchers followed up by asking the Ss to produce definitions to spoken abstract and concrete words; these definitions were also normal. The priming and definition data suggest that the semantic representations of abstract words in these Ss were relatively unimpaired. The researchers found that the Ss have problems only with spoken abstract words in just those tasks where normal controls also have difficulty. In contrast, they clearly have deficits in reading abstract words aloud, which may be due to problems with output phonology. Implications of these data for claims concerning hemispheric differences in the representation of abstract and concrete words are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Episodic retrieval in negative priming and repetition priming.

Subjects identified target letters flanked by incompatible distractor letters (e.g., ABA). Distractor onset was randomly simultaneous with target onset or was delayed by 400 ms. In Experiment 1, one third of probe-trial targets were identical to the preceding prime-trial distractor. Responses were slower to repeated letters than to unrepeated letters (negative priming) only when prime and probe trials shared the same distractor-onset conditions. In Experiment 2, one third of probe-trial targets were identical to the preceding prime-trial target. Significant facilitation (repetition priming) occurred for repeated targets in all conditions but was again greater when prime and probe trials shared the same distractor-onset conditions. The results strongly support episodic retrieval theories of both negative priming and repetition priming and suggest that a common mechanism underlies both phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bias in auditory priming.

Priming for previously studied words in an implicit auditory memory task has been interpreted as evidence for a presemantic perceptual representation system that encodes acoustic representations of words (B. A. Church and D. L. Schacter, see record 1994-36069-001). In this article, 3 experiments provided evidence that such priming may result instead from a bias to respond with studied words. In forced-choice identification with similar alternative choices, there was no overall improvement in performance due to prior study. Benefits for studied test words were offset by costs for similar but nonstudied test words. Prior study had no effect when forced-choice alternatives were dissimilar. The data are discussed in relation to current models of auditory information processing and a new model (R. Ratcliff and G. McKoon, in press) for priming in visual word identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Repetition priming in music.

The authors explore priming effects of pitch repetition in music in 3 experiments. Musically untrained participants heard a short melody and sang the last pitch of the melody as quickly as possible. Each experiment manipulated (a) whether or not the tone to be sung (target) was heard earlier in the melody (primed) and (b) the prime-target distance (measured in events). Experiment 1 used variable-length melodies, whereas Experiments 2 and 3 used fixed-length melodies. Experiment 3 changed the timbre of the target tone. In all experiments, fast-responding participants produced repeated tones faster than nonrepeated tones, and this repetition benefit decreased as prime-target distances increased. All participants produced expected tonic endings faster than less expected nontonic endings. Repetition and tonal priming effects are compared with harmonic priming effects in music and with repetition priming effects in language. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Microgenesis and aphasia.

"In applying developmental principles to the analysis of aphasic speech, this study makes two basic assumptions: First, the functions underlying abnormal behavior are in their essence not different from those underlying normal behavior. Second, any human activity such as perceiving, thinking, acting, etc. is an unfolding process, and this unfolding or 'microgenesis' whether it takes seconds or hours or days, occurs in developmental sequence. In viewing speech as an unfolding event, this study suggests the feasibility of relating certain semantic aspects of aphasic language to microgenetically earlier forms of linguistic activity." 20 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive preoccupation with alcohol and binge drinking in college students: Alcohol-induced priming of the motivation to drink.

This research examined alcohol-induced motivation to drink as a factor that contributes to preoccupation with drinking. Forty undergraduates rated their degree of preoccupation with drinking. The author determined the relationship between the undergraduates' preoccupation and the degree to which alcohol primed their motivation to drink by having them rate their desire for alcohol after they consumed a dose of alcohol or a placebo. Results showed that individual differences in preoccupation were predicted by the priming effects displayed after alcohol was consumed. More preoccupied individuals reported greater priming effects. Priming effects following placebo were minimal and were not related to preoccupation. The research shows that reinforcing effects of alcohol may contribute to cognitive preoccupation with drinking and promote patterns of alcohol abuse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nature of naming errors in primary progressive aphasia versus acute post-stroke aphasia.

Objective: To compare the distribution of error types across subgroups of primary progressive aphasia and poststroke aphasia in different vascular locations. Method: We analyzed naming errors in 49 individuals with acute left hemisphere ischemic stroke and 55 individuals with three variants of primary progressive aphasia. Location of atrophy or ischemic stroke was characterized using MRI. Results: We found that distribution of error types was very similar across all subgroups, irrespective of the site or etiology of the lesion. The only significant difference across groups was the percentage of circumlocutions (F(7, 96) = 3.02, p = .005). Circumlocution errors were highest among logopenic variant PPA (24%) and semantic variant PPA (24%). Semantic coordinate errors were common in all groups, probably because they can arise from disruption of different cognitive processes underlying naming and, therefore, from different locations of brain damage. Conclusions: Semantic errors are common among all types of primary progressive aphasia and poststroke aphasia, and the type of error depends in part on the location of damage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

List-context effects in evaluative priming.

Evaluative priming effects are often found in the evaluative decision task, in which persons judge the affective connotation (positive vs. negative) of a target word. The present experiments examined list-context effects to test whether evaluative and semantic priming follow the same laws. In Experiment 1, evaluative priming was found at prime-target stimulus onset asynchronies (SOAs) of 0 ms and 100 ms, but not at SOAs of -100, 200, 600, and 1,200 ms. Experiment 2 manipulated SOA (0, 200, and 1,200 ms) and the proportion (25%, 50%, and 75%) of the prime-target pairs that were evaluatively related. Contrary to the typical finding that increases in the proportion of related prime-target pairs lead to increased priming at long but not short SOAs, an effect of consistency proportion was found at SOAs of 0 ms (for reaction times) and 200 ms (in the accuracy data), but not at the 1,200-ms SOA. The pattern of results is discussed in relation to possible explanatory mechanisms of evaluative priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative processes in repetition priming.

Three experiments that investigated alternative accounts of repetition priming are reported. All 3 experiments used semantic comparison tasks and included trials in which each of the 2 words being compared had previously occurred on separate trials. In the re-pair match condition, the response required matched that on the 2 previous trials in which the words had occurred. In the re-pair mismatch condition, the response required was opposite to that on the previous trials containing the words forming the critical pair. In all 3 experiments, responses were faster and more accurate in the re-pair match condition than in the re-pair mismatch condition. Possible accounts of this effect within the frameworks of instance theory and of transfer appropriate processing are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual priming in fragment completion.

Some researchers have claimed that fragment completion tasks are dependent primarily on data-driven processing and are insensitive to conceptually driven processing. In this article we present four experiments demonstrating that conceptually driven processing affects fragment completion by showing that under appropriate conditions, studied words can facilitate identification of their picture and word fragments. We examine two theoretical explanations of this effect. First, we consider the possibility that subjects explicitly retrieve episodic representations in fragment completion. Analyses of correlations between priming and recall performance across items and subjects do not support this explanation. The alternative explanation is that there are two separate conceptual representations in memory. The first is assumed to mediate conceptual priming in fragment completion; the second is assumed to mediate free recall performance. A final experiment supports this view by demonstrating that even when differences between experimental conditions are made to disappear in fragment completion, they remain in free recall. Further applications of the notion of two semantic representations are discussed in the General Discussion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Negative priming in auditory attention.

This article reports 3 experiments that demonstrate and analyze inhibitory (negative) priming in auditory shadowing. Participants shadowed words that were individually presented over headphones, but ignored words simultaneously presented in another voice or another location. The 1st experiment demonstrated negative priming. Ignored items are shadowed on the next trial more slowly than controls with no history of being rejected in the experiment. The 2nd experiment showed that the inhibition lasts for only one item after presentation, followed by facilitation 3 and 5 items later. The 3rd experiment showed that the inhibitory priming is exactly the same when both presentations are to the same ear as when they are to different ears. Inhibition thus adheres to the item and not to the position in space. Negative priming takes place in a modality—audition—that has no peripheral means of excluding unattended material, as vision does by shifting fixation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determinants of negative priming.

The negative priming task is widely used to investigate attentional inhibition. A critical review of the negative priming literature considers various parameters of the task (e.g., time course, relation to interference, level of occurrence, and susceptibility to changes in task context). It also takes into account life span data and the performance of patients diagnosed with schizophrenia. On these bases, the review suggests that negative priming can be produced by 2 mechanisms: memorial and inhibitory. With respect to inhibition, the review suggests that (a) there are 2 systems, one responsible for identity and the other for location information; and (b) inhibition is a flexible, postselection process operating to prevent recently rejected information from quickly regaining access to effectors, thus helping to establish coherence among selected thought and action streams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)