What's in a name? Brain activity reveals categorization processes differ across languages

The linguistic relativity hypothesis proposes that speakers of different languages perceive and conceptualize the world differently, but do their brains reflect these differences? In English, most nouns do not provide linguistic clues to their categories, whereas most Mandarin Chinese nouns provide explicit category information, either morphologically (e.g., the morpheme “vehicle” che1 in the noun “train” huo3che1 ) or orthographically (e.g., the radical “bug” chong2 in the character for the noun “butterfly” hu2die2 ). When asked to judge the membership of atypical (e.g., train) vs. typical (e.g., car) pictorial exemplars of a category (e.g., vehicle), English speakers ( N = 26) showed larger N300 and N400 event-related potential (ERP) component differences, whereas Mandarin speakers ( N = 27) showed no such differences. Further investigation with Mandarin speakers only ( N = 22) found that it was the morphologically transparent items that did not show a typicality effect, whereas orthographically transparent items elicited moderate N300 and N400 effects. In a follow-up study with English speakers only ( N = 25), morphologically transparent items also showed different patterns of N300 and N400 activation than nontransparent items even for English speakers. Together, these results demonstrate that even for pictorial stimuli, how and whether category information is embedded in object names affects the extent to which typicality is used in category judgments, as shown in N300 and N400 responses. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78215/1/20974_ftp.pd

Early occipital sensitivity to syntactic category is based on form typicality

Syntactic factors can rapidly affect behavioral and neural responses during language processing; however, the mechanisms that allow this rapid extraction of syntactically relevant information remain poorly understood. We addressed this issue using magnetoencephalography and found that an unexpected word category (e.g., “The recently princess . . . ”) elicits enhanced activity in visual cortex as early as 120 ms after exposure, and that this activity occurs as a function of the compatibility of a word’s form with the form properties associated with a predicted word category. Because no sensitivity to linguistic factors has been previously reported for words in isolation at this stage of visual analysis, we propose that predictions about upcoming syntactic categories are translated into form-based estimates, which are made available to sensory cortices. This finding may be a key component to elucidating the mechanisms that allow the extreme rapidity and efficiency of language comprehension

DO STRATEGIC PRIMING PROCESSES DIFFER FOR CATEGORY VS. ASSOCIATIVE PRIMING? AN EVENT-RELATED POTENTIALS STUDY OF PROACTIVE EXPECTANCY STRATEGIES.

An extension of Becker's 1980 semantic priming study challenges the Verification Model by proposing that there are two different priming processes, one at a perceptual level and one at a semantic level. Participants performed a lexical decision task with a category-dominant or associative-dominant list while ERPs were recorded. We predicted that the associative effects would be mediated by facilitation and would influence the N170 and that the categorical effects would be indexed by the N300 for inhibitory effects and the N400 for facilitatory effects. Inhibition was not seen for unrelated targets in the categorical condition. The fillers in the categorical condition produced an inhibition effect but not a N300 effect. The N170 effect was not significant. An N400 effect was observed only for the associative list. It is suggested that this finding is consistent with a previously proposed (Franklin, et al., 2007) post-lexical semantic expectancy updating account for the N400

The Effects of Linguistic Labels on Object Categorization and Perception

The linguistic relativity hypothesis (Whorf, 1956) claims that speakers of different languages perceive and conceptualize the world differently. Language-thought interaction is likely to be more complex in bilinguals because they have two languages that could influence their cognitive and perceptual processes.Lupyan’s (2012) Label-feedback Hypothesis proposes a mechanism underpinning language-thought interactions, arguingthat linguistic labels affect our conceptual and perceptual representations through top-down feedback.This thesis tested the Label-feedback Hypothesis by capitalizing on an interesting feature of Chinese. In English, most nouns do not provide linguistic clues to their categories (an exception issunflower), whereas in Chinese, some nouns provide explicit category information morphologically (e.g., ostrichand robinhave the morpheme bird embedded in their Chinese names), while some nouns do not (e.g., penguin and pigeon). In Chapter 2, I investigated the effects of Chinese word structure on bilinguals’ categorization processes in either a Chinese or English-speaking environment with ERP. Chinese-English bilinguals and English monolinguals judged the membership of atypical (e.g., ostrich, penguin) vs. typical (e.g., robin,pigeon) pictorial and word exemplars of various categories (e.g., bird). Half of the exemplars in each group had a category clue in their Chinese name and half did not. English monolinguals showed typicality effects in categorization RT data, the N300 and N400 of ERP data, regardless of whether the object name had a category clue in Chinese. In contrast, Chinese-English bilinguals showed a larger typicality effect for objects without category clues in their name (e.g., penguin, pigeon) than objects with clues (e.g., ostrich, robin), even when Chinese-English bilinguals were tested in English. These results demonstrate that linguistic information embedded in object names has an effect on people’s categorization processes. Furthermore, linguistic information in bilinguals’ L1 has an effect on their categorization processes even when they are using their L2. In Chapter 3, I investigated the effects of Chinese word structure on bilinguals’ object perception. A visual oddball detection task with ERP was used where pictures of four birds (robin, ostrich, pigeon, and penguin) were used as standards and deviants. In Chinese-English bilinguals that have lived in Canada for a short period of time, the visual mismatch negativity (vMMN) elicited by deviant stimuli was larger for pairs without category clues (pigeon-penguin) than pairs with clues (robin-ostrich). In contrast, long-stay bilinguals and English monolinguals showed similar vMMN for the two pairs. These results demonstrate that linguistic information embedded in object names affects people’s object perception. The influences of L1 word structure on object perception diminish as bilinguals live in the L2 country for a longer time

Dissociable electrophysiological measures of natural language processing reveal differences in speech comprehension strategy in healthy ageing

Healthy ageing leads to changes in the brain that impact upon sensory and cognitive processing. It is not fully clear how these changes affect the processing of everyday spoken language. Prediction is thought to play an important role in language comprehension, where information about upcoming words is pre-activated across multiple representational levels. However, evidence from electrophysiology suggests differences in how older and younger adults use context-based predictions, particularly at the level of semantic representation. We investigate these differences during natural speech comprehension by presenting older and younger subjects with continuous, narrative speech while recording their electroencephalogram. We use time-lagged linear regression to test how distinct computational measures of (1) semantic dissimilarity and (2) lexical surprisal are processed in the brains of both groups. Our results reveal dissociable neural correlates of these two measures that suggest differences in how younger and older adults successfully comprehend speech. Specifically, our results suggest that, while younger and older subjects both employ context-based lexical predictions, older subjects are significantly less likely to pre-activate the semantic features relating to upcoming words. Furthermore, across our group of older adults, we show that the weaker the neural signature of this semantic pre-activation mechanism, the lower a subject's semantic verbal fluency score. We interpret these findings as prediction playing a generally reduced role at a semantic level in the brains of older listeners during speech comprehension and that these changes may be part of an overall strategy to successfully comprehend speech with reduced cognitive resources

Event-related brain potentials in the study of inhibition: cognitive control, source localization and age-related modulations

In the previous 15 years, a variety of experimental paradigms and methods have been employed to study inhibition. In the current review, we analyze studies that have used the high temporal resolution of the event-related potential (ERP) technique to identify the temporal course of inhibition to understand the various processes that contribute to inhibition. ERP studies with a focus on normal aging are specifically analyzed because they contribute to a deeper understanding of inhibition. Three time windows are proposed to organize the ERP data collected using inhibition paradigms: the 200 ms period following stimulus onset; the period between 200 and 400 ms after stimulus onset; and the period between 400 and 800 ms after stimulus onset. In the first 200 ms, ERP inhibition research has primarily focused on N1 and P1 as the ERP components associated with inhibition. The inhibitory processing in the second time window has been associated with the N2 and P3 ERP components. Finally, in the third time window, inhibition has primarily been associated with the N400 and N450 ERP components. Source localization studies are analyzed to examine the association between the inhibition processes that are indexed by the ERP components and their functional brain areas. Inhibition can be organized in a complex functional structure that is not constrained to a specific time point but, rather, extends its activity through different time windows. This review characterizes inhibition as a set of processes rather than a unitary process

Applauding with Closed Hands: Neural Signature of Action-Sentence Compatibility Effects

BACKGROUND: Behavioral studies have provided evidence for an action-sentence compatibility effect (ACE) that suggests a coupling of motor mechanisms and action-sentence comprehension. When both processes are concurrent, the action sentence primes the actual movement, and simultaneously, the action affects comprehension. The aim of the present study was to investigate brain markers of bidirectional impact of language comprehension and motor processes. METHODOLOGY/PRINCIPAL FINDINGS: Participants listened to sentences describing an action that involved an open hand, a closed hand, or no manual action. Each participant was asked to press a button to indicate his/her understanding of the sentence. Each participant was assigned a hand-shape, either closed or open, which had to be used to activate the button. There were two groups (depending on the assigned hand-shape) and three categories (compatible, incompatible and neutral) defined according to the compatibility between the response and the sentence. ACEs were found in both groups. Brain markers of semantic processing exhibited an N400-like component around the Cz electrode position. This component distinguishes between compatible and incompatible, with a greater negative deflection for incompatible. Motor response elicited a motor potential (MP) and a re-afferent potential (RAP), which are both enhanced in the compatible condition. CONCLUSIONS/SIGNIFICANCE: The present findings provide the first ACE cortical measurements of semantic processing and the motor response. N400-like effects suggest that incompatibility with motor processes interferes in sentence comprehension in a semantic fashion. Modulation of motor potentials (MP and RAP) revealed a multimodal semantic facilitation of the motor response. Both results provide neural evidence of an action-sentence bidirectional relationship. Our results suggest that ACE is not an epiphenomenal post-sentence comprehension process. In contrast, motor-language integration occurring during the verb onset supports a genuine and ongoing brain motor-language interaction

The neural correlates of categorizing rotated objects

The effects of categorizing rotated objects on the neural correlates of the N400 was investigated using a word-picture match task. The level of categorization was manipulated by presenting a basic or subordinate word prior to an image displayed at one of four orientations (0°, 60°, 120°, 180°). Participants’ task was to identify if the word and the image matched. The N400 component, which shows effects of semantic incongruity, was measured from the time phase 250 to 580 ms. Behavioural results found that reaction times were quicker for matched conditions over mismatched conditions. Basic mismatch conditions also showed faster reaction times versus subordinate mismatch as expected, however basic level categorization matched showed slower reaction times than subordinate level which was not expected. As predicted, reaction times for orientation showed a significant quadratic trend with 0° displaying the quickest reaction time. This increased for 60° and 120°, whereas reaction time then decreased for 180°. EEG results showed basic categorization had a lower amplitude on the N400 versus subordinate categorizations, as did mismatch conditions due to the higher level of semantic incongruity which has been identified in previous studies. The effect of orientation on the N400 differed depending on the level of categorization with only subordinate showing significantly more negative amplitudes. Possible reasoning of this is due to basic categorization not requiring transformation. The N400 correlates with semantic processing as when basic categorization mismatches was involved, less semantic information and higher incongruity correlated with more negative amplitudes of the N400