How odgcrnwi becomes crowding: Stimulus-specific learning reduces crowding

Processes underlying crowding in visual letter recognition were examined by investigating effects of training. Experiment 1 revealed that training reduces crowding mainly for trained strings. This was corroborated in Experiment 2, where no training effects were obvious after 3 days of training when strings changed from trial to trial. Experiment 3 specified that after a short amount of training, learning effects remained specific to trained strings and also to the trained retinal eccentricity and the interletter spacing used in training. Transfer to other than trained conditions was observed only after further training. Experiment 4 showed that transfer occurred earlier when words were used as stimuli. These results thus demonstrate that part of crowding results from the absence of higher level representations of the stimulus. Such representations can be acquired through learning visual properties of the stimulus

A Simple Technique to Study Embodied Language Processes: The Grip-Force Sensor

Research in cognitive neuroscience has shown that brain structures serving perceptual, emotional, and motor processes are also recruited during the understanding of language when it refers to emotion, perception, and action. However, the exact linguistic and extra-linguistic conditions under which such language-induced activity in modality specific cortex is triggered are not yet well understood. The purpose of this study is to introduce a simple experimental technique that allows for the online measure of language-induced activity in motor structures of the brain. This technique consists in the use of a grip force sensor that captures subtle grip force variations while subjects listen to words and sentences. Since grip force reflects activity in motor brain structures, the continuous monitoring of force fluctuations provides a fine-grained estimation of motor activity across time. In other terms, this method allows for both the localization of the source of language-induced activity to motor brain structures and the high temporal resolution of the recorded data. To facilitate comparison of data to be collected with this tool, we present two experiments that describe in detail the technical set up, the nature of the recorded data, and analyses (including justification about data filtering and artifact rejection) that we applied. We also discuss how the tool could be used in other domains of behavioral research

At the interface between action verbs and grip force

Action verbs and motor actions activate similar cortical brain areas (Price et al., 1994; Grafton et al., 1998). An increasing number of studies reveal that the sensorimotor components of word meaning activate cortical regions overlapping with the neural systems involved in the perception and execution of actions described by the words. For example, processing verbally presented actions activates corresponding sectors of the motor system, depending on the effector (face, hand or foot) used in the listened-to action (Floël et al., 2003; Hauk & Pulvermüller, 2004; Buccino et al., 2005). Moreover, in sign language there is a close semantic relationship between the gestures and the function of the object expressed, suggesting that transmodal processes are implicated in pragmatic representations. These studies and numerous observations strongly suggest that the brain areas subtending object-oriented actions are closely related to the brain areas involved with language (e.g., Gentilucci & Dalla Volta, 2008). Recently, Boulanger et al. (2006) showed that verbs related to manual action could perturb reaching movements. Since reaching and grasping are intimately linked (Jeannerod & Biguer, 1981; Frak et al., 2006) manual action verbs could also alter aspects of grasp, such as prehension force. Reaching is a process with a recognized bi-hemispheric activity involving the proximal musculature. Thus, the influence of language on grasp is a highly pertinent subject of study: action with the preferred hand is under control by left cerebral areas, as is the case with language. A novel approach examining the relationship between language and prehension force is presented using a tactile sensing paradigm. Using their preferred hand, subjects seized and held with a precision grasp a 300 g cylinder with an integrated force sensor. With eyes closed and arm extended, subjects listened to words related or not related to a manual action. There was an increase in grasp force when subjects heard words related to manual action only. This increase began at about 100 ms following word presentation, peaked at 300-400 ms and fell abruptly after 400 ms, signalling a possible inhibition of the motor simulation of the action evoked by the words. These observations reveal the intimate relationship that exists between language and prehension force and show that it is possible to elucidate online new aspects of sensorimotor interaction. They also reveal that there is a continuum between lexical access and motor simulation. Figure 1 shows the grand average of normalized grasp force amplitude of action words (AT) and non-action words (NAT) when they are targets. A paired t-test was done on the data defining both curves. The gray part of the graph, starting at 260 msec and ending at 430 msec, shows where there’s a significative difference (p<0.05)

Grip Force Is Part of the Semantic Representation of Manual Action Verbs

Motor actions and action verbs activate similar cortical brain regions. A functional interference can be taken as evidence that there is a parallel treatment of these two types of information and would argue for the biological grounding of language in action. A novel approach examining the relationship between language and grip force is presented. With eyes closed and arm extended, subjects listened to words relating (verbs) or not relating (nouns) to a manual action while holding a cylinder with an integrated force sensor. There was a change in grip force when subjects heard verbs that related to manual action. Grip force increased from about 100 ms following the verb presentation, peaked at 380 ms and fell abruptly after 400 ms, signalling a possible inhibition of the motor simulation evoked by these words. These observations reveal the intimate relationship that exists between language and grasp and show that it is possible to elucidate online new aspects of sensorimotor interaction

Action relevance in linguistic context drives word-induced motor activity

Many neurocognitive studies on the role of motor structures in action-language processing have implicitly adopted a “dictionary-like” framework within which lexical meaning is constructed on the basis of an invariant set of semantic features. The debate has thus been centered on the question of whether motor activation is an integral part of the lexical semantics (embodied theories) or the result of a post-lexical construction of a situation model (disembodied theories). However, research in psycholinguistics show that lexical semantic processing and context-dependent meaning construction are narrowly integrated. An understanding of the role of motor structures in action-language processing might thus be better achieved by focusing on the linguistic contexts under which such structures are recruited. Here, we therefore analyzed online modulations of grip force while subjects listened to target words embedded in different linguistic contexts. When the target word was a hand action verb and when the sentence focused on that action (John signs the contract) an early increase of grip force was observed. No comparable increase was detected when the same word occurred in a context that shifted the focus toward the agent's mental state (John wants to sign the contract). There mere presence of an action word is thus not sufficient to trigger motor activation. Moreover, when the linguistic context set up a strong expectation for a hand action, a grip force increase was observed even when the tested word was a pseudo-verb. The presence of a known action word is thus not required to trigger motor activation. Importantly, however, the same linguistic contexts that sufficed to trigger motor activation with pseudo-verbs failed to trigger motor activation when the target words were verbs with no motor action reference. Context is thus not by itself sufficient to supersede an “incompatible” word meaning. We argue that motor structure activation is part of a dynamic process that integrates the lexical meaning potential of a term and the context in the online construction of a situation model, which is a crucial process for fluent and efficient online language comprehension

Grip Force Reveals the Context Sensitivity of Language-Induced Motor Activity during “Action Words

Studies demonstrating the involvement of motor brain structures in language processing typically focus on \ud time windows beyond the latencies of lexical-semantic access. Consequently, such studies remain inconclusive regarding whether motor brain structures are recruited directly in language processing or through post-linguistic conceptual imagery. In the present study, we introduce a grip-force sensor that allows online measurements of language-induced motor activity during sentence listening. We use this tool to investigate whether language-induced motor activity remains constant or is modulated in negative, as opposed to affirmative, linguistic contexts. Our findings demonstrate that this simple experimental paradigm can be used to study the online crosstalk between language and the motor systems in an ecological and economical manner. Our data further confirm that the motor brain structures that can be called upon during action word processing are not mandatorily involved; the crosstalk is asymmetrically\ud governed by the linguistic context and not vice versa

Grasp It Loudly! Supporting Actions with Semantically Congruent Spoken Action Words

Evidence for cross-talk between motor and language brain structures has accumulated over the past several years. However, while a significant amount of research has focused on the interaction between language perception and action, little attention has been paid to the potential impact of language production on overt motor behaviour