Lack of awareness despite complex visual processing: Evidence from event-related potentials in a case of selective metamorphopsia.

Visual awareness is thought to result from integration of low- and high-level processing; instances of integration failure provide a crucial window into the cognitive and neural bases of awareness. We present neurophysiological evidence of complex cognitive processing in the absence of awareness, raising questions about the conditions necessary for visual awareness. We describe an individual with a neurodegenerative disease who exhibits impaired visual awareness for the digits 2 to 9, and stimuli presented in close proximity to these digits, due to perceptual distortion.

Implicit Measures of Receptive Vocabulary Knowledge in Individuals With Level 3 Autism.

Implicit measures of cognition are essential for assessing knowledge in people with Level 3 autism because such individuals are often unable to make reliable overt behavioral responses. In this study, we investigated whether three implicit measures-eye movement (EM) monitoring, pupillary dilation (PD), and event-related potentials (ERPs)-can be used to reliably estimate vocabulary knowledge in individuals with Level 3 autism. Five adults with Level 3 autism were tested in a repeated-measures design with two tasks.

Visual and linguistic narrative comprehension in autism spectrum disorders: Neural evidence for modality-independent impairments.

Individuals with autism spectrum disorders (ASD) have notable language difficulties, including with understanding narratives. However, most narrative comprehension studies have used written or spoken narratives, making it unclear whether narrative difficulties stem from language impairments or more global impairments in the kinds of general cognitive processes (such as understanding meaning and structural sequencing) that are involved in narrative comprehension. Using event-related potentials (ERPs), we directly compared semantic comprehension of linguistic narratives (short sentences) and visual narratives (comic panels) in adults with ASD and typically-developing (TD) adults.

Linguistic and Non-Linguistic Semantic Processing in Individuals with Autism Spectrum Disorders: An ERP Study.

Individuals with autism spectrum disorders (ASD) experience difficulties with language, particularly higher-level functions like semantic integration. Yet some studies indicate that semantic processing of non-linguistic stimuli is not impaired, suggesting a language-specific deficit in semantic processing. Using a semantic priming task, we compared event-related potentials (ERPs) in response to lexico-semantic processing (written words) and visuo-semantic processing (pictures) in adults with ASD and adults with typical development (TD).

The concurrent use of three implicit measures (eye movements, pupillometry, and event-related potentials) to assess receptive vocabulary knowledge in normal adults.

Recent years have seen the advent and proliferation of the use of implicit techniques to study learning and cognition. One such application is the use of event-related potentials (ERPs) to assess receptive vocabulary knowledge. Other implicit assessment techniques that may be well-suited to other testing situations or to use with varied participant groups have not been used as widely to study receptive vocabulary knowledge.

Capturing additional information about the organization of entries in the lexicon from verbal fluency productions.

Troyer and colleagues [Troyer, A. K., Moscovitch, M.

Impaired retrieval of semantic information in bipolar disorder: a clustering analysis of category-fluency productions.

On category-cued verbal fluency tasks, such as animal naming, respondents often report exemplars in semantically related clusters. We (Sung et al., 2012) used this tendency to elucidate sources of semantic dysfunction in adults with schizophrenia (SZ).

Altering automatic verbal processes with transcranial direct current stimulation.

Background: Word retrieval during verbal fluency tasks invokes both automatic and controlled cognitive processes. A distinction has been made between the generation of words clusters and switches between such clusters on verbal fluency tasks. Clusters, defined by the reporting of contiguous words that constitute semantic or phonemic subcategories, are thought to reflect relatively automatic processing.

Semantic clustering of category fluency in schizophrenia examined with singular value decomposition.

Decreased productivity on verbal fluency tasks by persons with schizophrenia has been attributed to semantic system abnormalities. Semantic structure is often assessed using multidimensional scaling (MDS) to detect normal and aberrant semantic clustering. However, MDS has limitations that may be particularly problematic for such assessments.

Disruption of spelling-to-sound correspondence mapping during single-word reading in patients with temporal lobe epilepsy.

Processing and/or hemispheric differences in the neural bases of word recognition were examined in patients with long-standing, medically-intractable epilepsy localized to the left (N=18) or right (N=7) temporal lobe. Participants were asked to read words that varied in the frequency of their spelling-to-sound correspondences. For the right temporal lobe group, reaction times (RTs) showed the same pattern across spelling-to-sound correspondence conditions as previously reported for normal participants.

Coreference and lexical repetition: mechanisms of discourse integration.

The use of repeated expressions to establish coreference allows an investigation of the relationship between basic processes of word recognition and higher level language processes that involve the integration of information into a discourse model. In two experiments on reading, we used eye tracking and event-related potentials to examine whether repeated expressions that are coreferential within a local discourse context show the kind of repetition priming that is shown in lists of words. In both experiments, the effects of lexical repetition were modulated by the effects of local discourse context that arose from manipulations of the linguistic prominence of the antecedent of a coreferentially repeated name.

Syntactic priming in comprehension: evidence from event-related potentials.

Syntactic priming is the facilitation of processing that occurs when a sentence has the same syntactic form as a preceding sentence. Such priming effects have been less consistently demonstrated in comprehension than in production, and those that have been reported have depended on the repetition of verbs across sentences. In an event-related potential experiment, subjects read target sentences containing reduced-relative clauses.

Interruption-similarity effects during discourse processing.

We examined the effect of interruption on reading to determine if discourse processing is susceptible to similarity-based interference. Participants read pairs of passages, either one before the other (in the continuous condition) or with the sentences of the two passages interleaved (in the interruption condition). In addition, the similarity of the types of passages (narrative or expository) in a pair was manipulated.

Processing new and repeated names: effects of coreference on repetition priming with speech and fast RSVP.

Previous research has shown that the process of establishing coreference with a repeated name can affect basic repetition priming. Specifically, repetition priming on some measures can be eliminated for repeated names that corefer with an entity that is prominent in the discourse model. However, the exact nature and timing of this modulating effect of discourse are not yet understood.

Reading words in discourse: the modulation of lexical priming effects by message-level context.

Repetition and semantic-associative priming effects have been demonstrated for words in nonstructured contexts (i.e., word pairs or lists of words) in numerous behavioral and electrophysiological studies.