Evaluating the establishment and maintenance of visual-visual and gustatory-visual equivalence relations in adults with developmental disabilities

Four adults with developmental disabilities were taught to make conditional discriminations between either pictures and their corresponding printed English and Spanish words, or tastes and their corresponding printed English and Spanish words. Participants required more training trials to master the visual-visual conditional discriminations than the gustatory-visual conditional discriminations, and 3 of the 4 participants performed with higher accuracy on visual equivalence class test trials than gustatory-visual equivalence class test trials. A follow-up equivalence test conducted 30 to 40 days later showed substantially greater stability over time for the gustatory-visual classes than for the visual classes, for all participants. That participants acquired gustatory-visual conditional discriminations, as well as equivalence classes based on those conditional discriminations, may have relevance for incorporating gustatory stimuli into mand training sessions, as well as for teaching individuals with sensory impairments in other modalities.     

Time course of Chinese monosyllabic spoken word recognition: evidence from ERP analyses

Evidence from event-related potential (ERP) analyses of English spoken words suggests that the time course of English word recognition in monosyllables is cumulative. Different types of phonological competitors (i.e., rhymes and cohorts) modulate the temporal grain of ERP components differentially (Desroches, Newman, & Joanisse, 2009). The time course of Chinese monosyllabic spoken word recognition could be different from that of English due to the differences in syllable structure between the two languages (e.g., lexical tones). The present study investigated the time course of Chinese monosyllabic spoken word recognition using ERPs to record brain responses online while subjects listened to spoken words. During the experiment, participants were asked to compare a target picture with a subsequent picture by judging whether or not these two pictures belonged to the same semantic category. The spoken word was presented between the two pictures, and participants were not required to respond during its presentation. We manipulated phonological competition by presenting spoken words that either matched or mismatched the target picture in one of the following four ways: onset mismatch, rime mismatch, tone mismatch, or syllable mismatch. In contrast to the English findings, our findings showed that the three partial mismatches (onset, rime, and tone mismatches) equally modulated the amplitudes and time courses of the N400 (a negative component that peaks about 400 ms after the spoken word), whereas, the syllable mismatched words elicited an earlier and stronger N400 than the three partial mismatched words. The results shed light on the important role of syllable-level awareness in Chinese spoken word recognition and also imply that the recognition of Chinese monosyllabic words might rely more on global similarity of the whole syllable structure or syllable-based holistic processing rather than phonemic segment-based processing. We interpret the differences in spoken word processing between Chinese and English listeners as being due to morphosyllabic structural differences between the two languages.     

How reading in a second language protects your heart

Reading words in a second language spontaneously activates native language translations in the human bilingual mind. Here, we show that the emotional valence of a word presented in English constrains unconscious access to its Chinese translation. We asked native speakers of Chinese fluent with English to indicate whether or not pairs of English words were related in meaning while monitoring their brain electrical activity. Unbeknownst to the participants, some of the word pairs hid a sound repetition if translated into Chinese. Remarkably, English words with a negative valence such as "violence" did not automatically activate their Chinese translation, even though we observed the expected sound repetition priming effect for positive and neutral words, such as "holiday" and "theory." These findings show that emotion conveyed by words determines language activation in bilinguals, where potentially disturbing stimuli trigger inhibitory mechanisms that block access to the native language.     

Using Pictures and Words To Understand Recognition Memory Deterioration in Amnestic Mild Cognitive Impairment and Alzheimer's Disease: A Review

Difficulty recognizing previously encountered stimuli is one of the earliest signs of incipient Alzheimer's disease (AD). Work over the last 10?years has focused on how patients with AD and those in the prodromal stage of amnestic mild cognitive impairment make recognition decisions for visual and verbal stimuli. Interestingly, both groups of patients demonstrate markedly better memory for pictures over words, to a degree that is significantly greater in magnitude than their healthy older counterparts. Understanding this phenomenon not only helps to conceptualize how memory breaks down in AD, but also potentially provides the basis for future interventions. This review critically examines recent recognition memory work using pictures and words in the context of the dual-process theory of recognition and current hypotheses of cognitive breakdown in the course of very early AD.     

Observational learning and the formation of classes of reading skills by individuals with autism and other developmental disabilities

We investigated whether individuals with developmental disabilities will demonstrate stimulus classes after observing another individual demonstrate the prerequisite conditional discriminations. In Experiment 1, participants learned conditional discriminations among dictated words, pictures, and printed words. They also observed a model without disabilities demonstrate conditional discriminations among a different set of dictated words, pictures, and printed words. The classes assigned to each participant belonged to a larger superordinate category, as did the classes assigned to each model. The superordinate categories were different for participants and models. All participants subsequently demonstrated full stimulus classes with the stimuli involved in direct training: They named pictures, read printed words, and matched pictures and words to one another. However, based on observing a model, none of the participants demonstrated full stimulus classes. In Experiment 2, participants learned conditional discriminations among the stimuli in three sets, and observed a model's training with the stimuli in three different sets. The classes assigned to each participant belonged to the same larger superordinate category as did those assigned to their respective model. All participants subsequently demonstrated full stimulus classes with the stimuli involved in direct training. They also demonstrated full classes with at least one of their model's sets of training stimuli. When full stimulus classes did not occur from observing a model, participants named the model's pictures, read the model's printed words, or matched the model's pictures and words. Stimulus class technology, coupled with the opportunity to observe another individual perform a skill, may be an economical and efficient means of teaching persons with developmental disabilities.     

Common basal extrastriate areas for the semantic processing of words and pictures.

OBJECTIVE: The recognition potential (RP) is an electrophysiological brain response which is sensitive to the semantic processing of meaningful stimuli. In this study we attempt to elucidate the topography and neural origin of the RP evoked by pictures and to compare it with the RP evoked by words. METHODS: Words, pictures, Chinese characters and control stimuli were presented to 20 subjects following the rapid stream stimulation procedure. The activity was recorded using 60 cephalic electrodes. RESULTS: We found a RP displaying its maximal amplitude at the left inferior parieto-occipital electrode (PO7) for words and at the right homologue electrode (PO8) for pictures and Chinese characters. Both the amplitude and the latency of the RP were larger in the case of words. A profile analysis indicated that the neural generators of the RP were common regardless of the type of stimulus, and a dipole analysis placed them about the lingual gyrus. CONCLUSIONS: Words and pictures share the same neural generators for the RP despite of subtle differences in lateralization. This is interpreted as an index of a multimodal semantic processing in basal extrastriate areas.     

Retrieval orientation and the control of recollection

Event-related potentials (ERPs) were employed to investigate whether recognition test items are processed differently according to whether they are used to probe memory for previously studied words or pictures. In each of two study-test blocks, subjects encoded a mixed list of words and pictures, and then performed a recognition memory task with words as the test items. In one block, the requirement was to respond positively to test items corresponding to studied words, and to reject both new items and items corresponding to the studied pictures. In the other block, positive responses were made to test items corresponding to pictures, and items corresponding to words were classified along with the new items. ERPs elicited during the test phase by correctly classified new items differed according to whether words or pictures were the sought-for modality. This finding was interpreted as a neural correlate of the different retrieval orientations adopted when searching memory for words versus pictures. Relative to new items, correctly classified items studied in both target modalities elicited robust, positive-going "old/new" effects. When pictures were targets, test items corresponding to studied words also elicited large effects. By contrast, when words were targets, old/new effects were absent for the items corresponding to studied pictures. These findings were interpreted as evidence that, in some circumstances, adoption of an appropriate retrieval orientation permits retrieval cues to be employed with a high degree of specificity.     

Negative content enhances stimulus‐specific cerebral activity during free viewing of pictures,faces, and words

Negative visual stimuli have been found to elicit stronger brain activation than do neutral stimuli. Such emotion effects have been shown for pictures, faces, and words alike, but the literature suggests stimulus‐specific differences regarding locus and lateralization of the activity. In the current functional magnetic resonance imaging study, we directly compared brain responses to passively viewed negative and neutral pictures of complex scenes, faces, and words (nouns) in 43 healthy participants (21 males) varying in age and demographic background. Both negative pictures and faces activated the extrastriate visual cortices of both hemispheres more strongly than neutral ones, but effects were larger and extended more dorsally for pictures, whereas negative faces additionally activated the superior temporal sulci. Negative words differentially activated typical higher‐level language processing areas such as the left inferior frontal and angular gyrus. There were small emotion effects in the amygdala for faces and words, which were both lateralized to the left hemisphere. Although pictures elicited overall the strongest amygdala activity, amygdala response to negative pictures was not significantly stronger than to neutral ones. Across stimulus types, emotion effects converged in the left anterior insula. No gender effects were apparent, but age had a small, stimulus‐specific impact on emotion processing. Our study specifies similarities and differences in effects of negative emotional content on the processing of different types of stimuli, indicating that brain response to negative stimuli is specifically enhanced in areas involved in processing of the respective stimulus type in general and converges across stimuli in the left anterior insula.     

Differences in word associations to pictures and words

Normal subjects were asked to produce the "first word that comes to mind" in response to pictures or words that differed with respect to manipulability and animacy. In separate analyses across subjects and items, normal subjects produced a significantly higher proportion of action words (that is, verbs) to pictures as compared to words, to manipulable as compared to non-manipulable stimuli and to inanimate as compared to animate stimuli. The largest proportion of action words was elicited by pictures of non-living, manipulable objects. Furthermore, associates to words matched standard word associates significantly more often than those elicited by pictures. These data suggest that pictures and words initially contact different forms of conceptual information and are consistent with an account of semantic organization that assumes that information is distributed across different domains reflecting the mode of acquisition of that knowledge.     

Recognition of visual stimuli and memory for spatial context in schizophrenic patients and healthy volunteers

Verbal and visual recognition tasks were administered to 40 patients with schizophrenia and 40 healthy comparison subjects. The verbal recognition task consisted of discriminating between 16 target words and 16 new words. The visual recognition task consisted of discriminating between 16 target pictures (8 black-and-white and 8 color) and 16 new pictures (8 black-and-white and 8 color). Visual recognition was followed by a spatial context discrimination task in which subjects were required to remember the spatial location of the target pictures at encoding. Results showed that recognition deficit in patients was similar for verbal and visual material. In both schizophrenic and healthy groups, men, but not women, obtained better recognition scores for the colored than for the black-and-white pictures. However, men and women similarly benefited from color to reduce spatial context discrimination errors. Patients showed a significant deficit in remembering the spatial location of the pictures, independently of accuracy in remembering the pictures themselves. These data suggest that patients are impaired in the amount of visual information that they can encode. With regards to the perceptual attributes of the stimuli, memory for spatial information appears to be affected, but not processing of color information.     

Spatiotemporal brain activation pattern during word/picture perception by native Koreans

The purpose of this study is to explore spatiotemporal brain activation patterns during perception of words from three different languages (Korean, English, Chinese) and pictures. Using 64 channel event-related potential (ERP) recording and source localization using distributed source model, we investigated, with high temporal resolution, whether similar or different spatiotemporal patterns of brain activation are involved in the perception of words of different languages and/or pictures. Experimental results seem to corroborate left hemispheric dominance in language processing, and temporal/spatial characteristics in word perception revealed by previous ERP and neuroimaging studies. Observed differences in spatial pattern of activation at specific time periods between English and Korean, and Korean and Chinese, could be explained in terms of required visual pattern analysis due to the orthographic characteristics of each language.     

Dual functional hemispheric asymmetry in visual perception: Effects of ocular dominance and postexposural processes

The authors investigated laterality differences in visual perception by assessing the effects of the directional post-exposure scanning movements associated with reading habits, the visual half-field (VHF) in which stimuli were presented, and eye dominance on an immediate recall task. Forty Chinese bilingual subjects (20 right-eye dominant and 20 left-eye dominant) were tested for their recall of forms, Chinese words and English words. The stimuli were projected tachistoscopically in the left and/or right VHFs under conditions of simulataneous and successive presentation. The results demonstrated a right field superiority for verbal stimuli under both conditions and a left field superiority for nonverbal stimuli when presented successively. Right-eyed subjects were better in processing verbal materials and left-eyed subjects were better in the perception and recall of nonverbal materials. The study supported the validity of the psychophysiological model of asymmetrical cerebral functioning and demonstrated the importance of reading habits and eye dominance. The findings were interpreted as preliminary support for Piaget's postulated relationship between perceptual and organic development.     

Picture the difference: electrophysiological investigations of picture processing in the two cerebral hemispheres

The nature of semantic memory and the role of the two cerebral hemispheres in meaning processing were examined using event-related brain potentials (ERPs) elicited by pictures in sentences. Participants read sentence pairs ending with the lateralized presentation of three target types: (1) expected pictures, (2) unexpected pictures from the expected semantic category, and (3) unexpected pictures from an unexpected category. ERPs to contextually unexpected pictures were more negative 350-500ms (larger N400s) than those to expected pictures in both visual fields. However, while N400s to the two types of unexpected items did not differ with left visual field presentations, they were smaller to the unexpected items from the expected category with right visual field presentations. This pattern, previously observed to words [Brain Language 62 (1998) 149], suggests general differences in how the two hemispheres use context on-line. Other aspects of the N400 response-and effects on earlier ERP components-reveal differences between pictures and words, suggesting that semantic memory access is not modality-independent. The P2 component varied with ending type for right but not left visual field presentations, suggesting that the left hemisphere may use contextual information to prepare for the visual analysis of upcoming stimuli. Furthermore, there was clear evidence for an earlier negativity ("N300"), which varied with ending type but, unlike the N400, was unaffected by visual field of presentation. Overall, the results support our hypothesis that the left hemisphere actively uses top-down information to preactivate perceptual and semantic features of upcoming stimuli, while the right hemisphere adopts a "wait and see" integrative approach.     

Prefrontal activity and diagnostic monitoring of memory retrieval: FMRI of the criterial recollection task

According to the distinctiveness heuristic, subjects rely more on detailed recollections (and less on familiarity) when memory is tested for pictures relative to words, leading to reduced false recognition. If so, then neural regions that have been implicated in effortful postretrieval monitoring (e.g., dorsolateral prefrontal cortex) might be recruited less heavily when trying to remember pictures. We tested this prediction with the criterial recollection task. Subjects studied black words, paired with either the same word in red font or a corresponding colored picture. Red words were repeated at study to equate recognition hits for red words and pictures. During fMRI scanning, alternating red word memory tests and picture memory tests were given, using only white words as test stimuli (say "yes" only if you recollect a corresponding red word or picture, respectively). These tests were designed so that subjects had to rely on memory for the criterial information. Replicating prior behavioral work, we found enhanced rejection of lures on the picture test compared to the red word test, indicating that subjects had used a distinctiveness heuristic. Critically, dorsolateral prefrontal activity was reduced when rejecting familiar lures on the picture test, relative to the red word test. These findings indicate that reducing false recognition via the distinctiveness heuristic is not heavily dependent on frontally mediated postretrieval monitoring processes.     

Stimulus pairing training for Kanji reading skills in students with developmental disabilities

Japanese students with developmental disabilities often exhibit difficulties in reading, particularly in Kanji (ideogram) reading, and in acquiring the equivalence relations between pictures, written words, and sounds. Previous research suggested that one student with autism could acquire Kanji reading along with equivalence relations through stimulus pairing training. However, maintenance rates tended to be very low, possibly due to the lack of picture stimuli. In this study, we examined the acquisition and maintenance of Kanji reading skills through stimulus pairing training using corresponding pictures for six students with developmental disabilities. We prepared stimulus pairs consisting of picture stimuli that the students could name along with a corresponding Kanji character that they could not read. All students successfully acquired and maintained the Kanji reading skills through this procedure. These findings suggest that the nameability of picture stimuli in stimulus pairing training may facilitate the acquisition and maintenance of equivalence relations for reading.     

Metacognition and false recognition in patients with frontal lobe lesions: the distinctiveness heuristic

The distinctiveness heuristic is a response mode in which participants expect to remember vivid details of an experience and make recognition decisions based on this metacognitive expectation. Whereas much is known about the cognitive processes that are involved in using the distinctiveness heuristic, little is known about the corresponding brain processes. Because such metacognitive processes that involve the evaluation and control of one's memory are believed to be dependent upon the frontal lobes, the authors examined whether the distinctiveness heuristic could be engaged to reduce false recognition in a repetition lag paradigm in patients with lesions of their frontal lobes. Half of the participants studied pictures and corresponding auditory words; the other half studied visual and auditory words. Studied and novel items were presented at test as words only, with all novel items repeating after varying lags. Controls who studied pictures were able to reduce their false recognition of repeated lag items relative to those controls who studied words, demonstrating their use of the distinctiveness heuristic. Patients with frontal lobe lesions showed similar levels of false recognition regardless of whether they studied pictures and words or words only, suggesting that they were unable to use the distinctiveness heuristic. The authors suggest that the distinctiveness heuristic is a metacognitive strategy, dependent upon the frontal lobes, that may be engaged by healthy individuals to reduce their false recognition.     

Electrophysiological evidence for language interference in late bilinguals

The mechanism by which late bilinguals access the meaning of words presented in their second language (conceptual mediation or word association) is highly debated. Here we asked late Chinese-English bilinguals undergoing event-related potential (ERP) recordings to indicate whether pairs of English words were related or unrelated in meaning. Participants were unaware that half of the pairs concealed a repeated Chinese character when translated into Chinese. As expected, native English controls showed no sensitivity to this hidden factor. However, pairs of words unrelated in meaning and concealing form repetition through Chinese translation elicited longer reaction times, greater error rates, and larger N400 ERP shifts in Chinese participants. These findings demonstrate that Chinese participants unconsciously translate words into Chinese while reading English.     

Visual object priming differs from visual word priming: an ERP study

Implicit memory is inferred from repetition priming effects in tasks such as word identification, word fragment completion, and perceptual recognition with masking or brief exposures. In this experiment, we explored whether the visual word and object repetition priming effects can be reflected by features of ERP and whether visual word repetition priming differs from visual object repetition priming. We have observed that (1) pre-exposure to recognizable stimuli (both word and object picture) shortened the response time in identifying their repetitions; (2) repetition of unrecognized scrambles of words or object pictures did not show any effects on ERP patterns; (3) ERPs distinguished recognizable from unrecognizable stimuli; and, (4) repetitions of both words and pictures strongly influenced the patterns of ERPs, though the ERPs to word stimuli differed from the ERPs to picture stimuli.     

Acquisition of output irregular orthographic representations in normal adults: an experimental study.

Twenty normal controls without previous knowledge of French were asked to learn 12 French words that could not be written by Italian correspondence rules. After acquisition of the phonological representations, participants were presented the pictures and asked to write the corresponding words (baseline). They were then presented 3 times with the pictures and the corresponding written words. After a filled delay of 10 min, they were re-presented the pictures and asked to write the corresponding words (testing). A week later, participants were again requested to write the words (follow-up). Number of words correctly written at testing and at follow-up significantly differs from baseline, as well as number of words correctly written at testing and at follow-up. These results are discussed and it is suggested that acquisition of irregular output orthographic representations can be supported by knowledge of orthographic representations for reading and that rehabilitation of patients with damage to output orthographic representations can utilize input orthographic representations.