The organization of the conceptual system: The case of the “object versus action” dimension

Verb generation for presurgical mapping: Gaining specificity

Verb generation is among the most frequently used tasks in presurgical mapping. Because this task involves many processes, the overall brain effects are not specific. While it is necessary to identify the whole network involving noun comprehension or semantic retrieval and lexical selection to produce the verb, isolation of those components is also crucial. Here, we present data from four patients undergoing presurgical brain mapping. The study implied a reanalysis of magnetoencephalography data with a recategorization of the used items. It aimed to extract the task component that relies on the inferior frontal gyrus (IFG). The task could be applied with higher specificity when targeting frontal areas. For that, we based item classification on the selection demands imposed by the noun. It is a robust finding that the IFG carries out this selection and that a quantitative index can be calculated for each noun, which depends on the selection effort (Proceedings of the National Academy of Sciences of the United States of America, 1997; 94(26):14792-14797, Proceedings of the National Academy of Sciences of the United States of America, 1998; 95(26):15855-15860). Data showed focality and specificity, with a correlation between this derived index and source activations in the inferior frontal gyrus for all patients. Strikingly, we detected when the right-hemisphere homologue area was involved in the selection process in two patients showing reorganization or language right lateralization. The present data are a step towards a dissection of broad specific tasks frequently used in presurgical protocols.

Naming vs. non-naming treatment in aphasia in a group setting-A randomized controlled trial

INTRODUCTION

Anomia affects numerous persons with aphasia. Treatment effects of anomia group therapy have been reported, but the evidence is not comprehensive. This study aimed to explore treatment effects of a naming treatment compared with a non-naming treatment delivered in a group setting.

METHODS

In a randomized controlled trial, 17 participants with chronic poststroke aphasia underwent group therapy, 2 hours a session, 3 times per week, for a total of 20 hours. The treatment given in the naming group was modified semantic feature analysis (SFA). Treatment content in the non-naming group comprised auditory comprehension, copying text, and reading. The primary outcome measure was accuracy in confrontation naming of participant-selected trained nouns and verbs. Generalization effects were evaluated in single-word naming, connected speech, and everyday communication.

RESULTS

Participants in both groups significantly improved their naming of trained items. There were no differences between the groups. The treatment effect did not remain at follow-up 10 weeks after therapy. No other statistically significant changes occurred in either group.

CONCLUSIONS

Group intervention can improve naming ability in individuals with chronic aphasia. However, similar treatment effects can be achieved using a non-naming treatment as using a naming treatment, such as modified SFA. Further research is warranted to identify the most important elements of anomia group therapy.

Bihemispheric Navigated Transcranial Magnetic Stimulation Mapping for Action Naming Compared to Object Naming in Sentence Context

Preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) is currently based on the disruption of performance during object naming. The resulting cortical language maps, however, lack accuracy when compared to intraoperative mapping. The question arises whether nTMS results can be improved, when another language task is considered, involving verb retrieval in sentence context. Twenty healthy German speakers were tested with object naming and a novel action naming task during nTMS language mapping. Error rates and categories in both hemispheres were compared. Action naming showed a significantly higher error rate than object naming in both hemispheres. Error category comparison revealed that this discrepancy stems from more lexico-semantic errors during action naming, indicating lexico-semantic retrieval of the verb being more affected than noun retrieval. In an area-wise comparison, higher error rates surfaced in multiple right-hemisphere areas, but only trends in the left ventral postcentral gyrus and middle superior temporal gyrus. Hesitation errors contributed significantly to the error count, but did not dull the mapping results. Inclusion of action naming coupled with a detailed error analysis may be favorable for nTMS mapping and ultimately improve accuracy in preoperative planning. Moreover, the results stress the recruitment of both left- and right-hemispheric areas during naming.

Category-specific verb-semantic deficits in Alzheimer's disease: Evidence from static and dynamic action naming

We investigated the representation and breakdown of verb knowledge employing different syntactic and semantic classes of verbs in a group of individuals with probable Alzheimer's Disease (pAD). In an action naming task with coloured photographs (Fiez & Tranel, 1997. Standardized stimuli and procedures for investigating the retrieval of lexical and conceptual knowledge for action. Memory and Cognition, 25(4), 543-569. https://doi.org/10.3758/BF03201129), pAD individuals were impaired for naming actions compared to objects. Verb tense was also affected, with simple-past (e.g., chopped) being more difficult to name than the gerundial form (e.g., chopping). Employing action-naming with short movies depicting events and states, we contrasted three verb classes based on their hypothetical structural and semantic/conceptual properties: argument structure, thematic structure, and conceptual templates. The three classes were: causatives (peel), verbs of perception (hear), and verbs of motion (run) Overall, results suggest that individuals with pAD are selectively impaired for verb tense and thematic assignment, but not conceptual-template complexity. Methodologically, we also show that dynamic scenes are more ecologically valid than static scenes to probe verb knowledge in AD.

Looking at ancillary systems for verb recovery: Evidence from non-invasive brain stimulation

Several behavioural and neuroimaging studies have suggested that the language function is not restricted into the left areas but it involves regions not predicted by the classical language model. Accordingly, the Embodied Cognition theory postulates a close interaction between the language and the motor system. Indeed, it has been shown that non-invasive brain stimulation (NIBS) is effective for language recovery also when applied over sensorimotor regions, such as the motor cortex, the cerebellum and the spinal cord. We will review a series of NIBS studies in post-stroke aphasic people aimed to assess the impact of NIBS on verb recovery. We first present results which, following the classical assumption of the Broca's area as the key region for verb processing, have shown that the modulation over this area is efficacious for verb improvement. Then, we will present experiments which, according to Embodied Cognition, have directly investigated through NIBS the role of different sensorimotor regions in enhancing verb production. Since verbs play a crucial role for sentence construction which are most often impaired in the aphasic population, we believe that these results have important clinical implications. Indeed, they address the possibility that different structures might support verb processing.

Neural representation of word categories is distinct in the temporal lobe: An activation likelihood analysis

The distinction between nouns and verbs is a language universal. Yet, functional neuroimaging studies comparing noun and verb processing have yielded inconsistent findings, ranging from a complete frontal(verb)-temporal(noun) dichotomy to a complete overlap in activation patterns. The current study addressed the debate about neural distinctions between nouns and verbs by conducting an activation likelihood estimation (ALE) meta-analysis of probabilistic cytoarchitectonic maps. Two levels of analysis were conducted: simple effects (Verbs vs. Baseline, Nouns vs. Baseline), and direct comparisons (Verbs vs. Nouns, Nouns vs. Verbs). Nouns were uniquely associated with a left medial temporal cluster (BA37). Activation foci for verbs included extensive inferior frontal (BA44-47) and mid-temporal (BA22, 21) regions in the left hemisphere. These findings confirm that the two grammatical classes have distinct neural architecture in supra-modal brain regions. Further, nouns and verbs overlapped in a small left lateral inferior temporal activation cluster (BA37), which is a region for modality-independent, grammatical class-independent lexical representations. These findings are most consistent with the view that as one acquires language, linguistic representations for a lexical category shift from the modality specific cortices which represent prototypical members of that category (e.g., motion for verbs) to abstract amodal representations in close proximity to modality specific cortices.

The motor features of action verbs: fMRI evidence using picture naming

The processing disadvantage of verbs compared to nouns and the greater vulnerability of verbs in brain damage have been ascribed to greater processing demands of morpho-syntactical or/and semantic properties for verbs, or/and visual complexity in picture-naming studies. Using picture naming, the current functional magnetic resonance imaging study examined the neural substrates underlying the semantic distinction between nouns and verbs. Under forced (externally-elicited) or free (internally-motivated) conditions, participants named a set of pictorial stimuli as objects or actions performed on/with the objects in Chinese. Use of a language with impoverished inflectional morphology (i.e., Chinese) and the same set of pictures for naming objects and actions allows for the control of both morpho-syntactical and visual confounds. The results revealed specific neural correlates for action verbs in the cortical-subcortical motor system, irrespective of the naming conditions. Plausible accounts for the motor aspects of action-verb processing were interpreted basically on a semantic basis.

Object-action dissociation: A voxel-based lesion-symptom mapping study on 102 patients after glioma removal

Data concerning the neural basis of noun and verb processing are inconsistent. Some authors assume that action-verb processing is based on frontal areas while nouns processing relies on temporal regions; others argue that the circuits processing verbs and nouns are closely interconnected in a predominantly left-lateralized fronto-temporal-parietal network; yet, other researchers consider that the primary motor cortex plays a crucial role in processing action verbs. In the present study, one hundred and two patients with a tumour either in the right or left hemisphere were submitted to picture naming of objects and actions before and after surgery. To test the effect of specific brain regions in object and action naming, patients' lesions were mapped and voxel-lesion-symptom mapping (VLSM) was computed. Behavioural results showed that left-brain damaged patients were significantly more impaired than right brain-damaged patients. The VLSM showed that these two grammatical classes are segregated in the left hemisphere. In particular, scores in naming of objects correlated with damage to the anterior temporal region, while scores in naming of actions correlated with lesions in the parietal areas and in the posterior temporal cortex. In addition, VLSM analyses carried out on non-linguistic tasks were not significant, confirming that the regions associated with deficits in object and action naming were not generally engaged in all cognitive tasks. Finally, the involvement of subcortical pathways was investigated and the inferior longitudinal fasciculus proved to play a role in object naming, while no specific bundle was identified for actions.

Action Categories in Lateral Occipitotemporal Cortex Are Organized Along Sociality and Transitivity

How neural specificity for distinct conceptual knowledge categories arises is central for understanding the organization of semantic memory in the human brain. Although there is a large body of research on the neural processing of distinct object categories, the organization of action categories remains largely unknown. In particular, it is unknown whether different action categories follow a specific topographical organization on the cortical surface analogously to the category-specific organization of object knowledge. Here, we tested whether the neural representation of action knowledge is organized in terms of nonsocial versus social and object-unrelated versus object-related actions (sociality and transitivity, respectively, hereafter). We hypothesized a major distinction of sociality and transitivity along dorsal and ventral lateral occipitotemporal cortex (LOTC), respectively. Using fMRI-based multivoxel pattern analysis, we identified neural representations of action information associated with sociality and transitivity in bilateral LOTC. Representational similarity analysis revealed a dissociation between dorsal and ventral LOTC. We found that action representations in dorsal LOTC are segregated along features of sociality, whereas action representations in ventral LOTC are segregated along features of transitivity. In addition, representations of sociality and transitivity features were found more anteriorly in LOTC than representations of specific subtypes of actions, suggesting a posterior-anterior gradient from concrete to abstract action features. These findings elucidate how the neural representations of perceptually and conceptually diverse actions are organized in distinct subsystems in the LOTC.

SIGNIFICANCE STATEMENT

The lateral occipitotemporal cortex (LOTC) is critically involved in the recognition of objects and actions, but our knowledge about the underlying organizing principles is limited. Here, we discovered a dorsal-ventral distinction of actions in LOTC: dorsal LOTC represents actions based on sociality (how much an action is directed to another person) in proximity to person knowledge. In contrast, ventral LOTC represents actions based on transitivity (how much an action involves the interaction with inanimate objects) in proximity to tools/artifacts in ventral LOTC, suggesting a mutually dependent organization of actions and objects. In addition, we found a posterior-to-anterior organization of the LOTC for concrete and abstract representations, respectively. Our findings provide important insights about the organization of actions in LOTC.

The role of the motor system in action naming in patients with neurodegenerative extrapyramidal syndromes

Previous studies of patients with brain damage have suggested a close relationship between aphasia and movement disorders. Neurodegenerative extrapyramidal syndromes associated with cognitive impairment provide an interesting model for studying the neural substrates of cognitive and motor symptoms. In this review, we focused on studies investigating language production abilities in patients with Parkinson's disease (PD), Corticobasal Syndrome (CBS) and Progressive Supranuclear Palsy (PSP). According to some reports, these patients exhibit a reduction in performance in both action and object naming or verb production compared to healthy individuals. Furthermore, a disproportional impairment of action naming compared to object naming was systematically observed in patients with these disorders. The study of these clinical conditions offers the unique opportunity to examine the close link between linguistic features and motor characteristics of action. This particular pattern of language impairment may contribute to the debate on embodiment theory and on the involvement of the basal ganglia in language and in integrating language and movement. From a translational perspective, we suggest that language ability assessments are useful in the clinical work-up, along with neuropsychological and motor evaluations. Specific protocols should be developed in the near future to better characterize language deficits and to permit an early cognitive diagnosis. Moreover, the link between language deficits and motor impairment opens a new issue for treatment approaches. Treatment of one of these two symptoms may ameliorate the other, and treating both may produce a greater improvement in patients' global clinical conditions.

Mapping nouns and finite verbs in left hemisphere tumors: a direct electrical stimulation study

Neurosurgical mapping studies with nouns and finite verbs are scarce and subcortical data are nonexistent. We used a new task that uses finite verbs in six Italian-speaking patients with gliomas in the left language-dominant hemisphere. Language-relevant positive areas were detected only with nouns in four patients, with both tasks yet in distinct cortical areas in one patient, and only with finite verbs in another patient. Positive areas and types of errors varied across participants. Finite verbs provide complementary information to nouns, and permit more accurate mapping of language production when nouns are unaffected by electrical stimulation.

Action Categories in Lateral Occipitotemporal Cortex Are Organized Along Sociality and Transitivity

How neural specificity for distinct conceptual knowledge categories arises is central for understanding the organization of semantic memory in the human brain. Although there is a large body of research on the neural processing of distinct object categories, the organization of action categories remains largely unknown. In particular, it is unknown whether different action categories follow a specific topographical organization on the cortical surface analogously to the category-specific organization of object knowledge. Here, we tested whether the neural representation of action knowledge is organized in terms of nonsocial versus social and object-unrelated versus object-related actions (sociality and transitivity, respectively, hereafter). We hypothesized a major distinction of sociality and transitivity along dorsal and ventral lateral occipitotemporal cortex (LOTC), respectively. Using fMRI-based multivoxel pattern analysis, we identified neural representations of action information associated with sociality and transitivity in bilateral LOTC. Representational similarity analysis revealed a dissociation between dorsal and ventral LOTC. We found that action representations in dorsal LOTC are segregated along features of sociality, whereas action representations in ventral LOTC are segregated along features of transitivity. In addition, representations of sociality and transitivity features were found more anteriorly in LOTC than representations of specific subtypes of actions, suggesting a posterior-anterior gradient from concrete to abstract action features. These findings elucidate how the neural representations of perceptually and conceptually diverse actions are organized in distinct subsystems in the LOTC.

SIGNIFICANCE STATEMENT

The lateral occipitotemporal cortex (LOTC) is critically involved in the recognition of objects and actions, but our knowledge about the underlying organizing principles is limited. Here, we discovered a dorsal-ventral distinction of actions in LOTC: dorsal LOTC represents actions based on sociality (how much an action is directed to another person) in proximity to person knowledge. In contrast, ventral LOTC represents actions based on transitivity (how much an action involves the interaction with inanimate objects) in proximity to tools/artifacts in ventral LOTC, suggesting a mutually dependent organization of actions and objects. In addition, we found a posterior-to-anterior organization of the LOTC for concrete and abstract representations, respectively. Our findings provide important insights about the organization of actions in LOTC.

The dissociability of lexical retrieval and morphosyntactic processes for nouns and verbs: A functional and anatomoclinical study

Nouns and verbs can dissociate following brain damage, at both lexical retrieval and morphosyntactic processing levels. In order to document the range and the neural underpinnings of behavioral dissociations, twelve aphasics with disproportionate difficulty naming objects or actions were asked to apply phonologically identical morphosyntactic transformations to nouns and verbs. Two subjects with poor object naming and 2/10 with poor action naming made no morphosyntactic errors at all. Six of 10 subjects with poor action naming showed disproportionate or no morphosyntactic difficulties for verbs. Morphological errors on nouns and verbs correlated at the group level, but in individual cases a selective impairment of verb morphology was observed. Poor object and action naming with spared morphosyntax were associated with non-overlapping lesions (inferior occipitotemporal and fronto-temporal, respectively). Poor verb morphosyntax was observed with frontal-temporal lesions affecting white matter tracts deep to the insula, possibly disrupting the interaction of nodes in a fronto-temporal network.

Persistent sparing of action conceptual processing in spite of increasing disorders of action production: A case against motor embodiment of action concepts

In this study, we addressed the issue of whether the brain sensorimotor circuitry that controls action production is causally involved in representing and processing action-related concepts. We examined the three-year pattern of evolution of brain atrophy, action production disorders, and action-related concept processing in a patient (J.R.) diagnosed with corticobasal degeneration. During the period of investigation, J.R. presented with increasing action production disorders resulting from increasing bilateral atrophy in cortical and subcortical regions involved in the sensorimotor control of actions (notably, the superior parietal cortex, the primary motor and premotor cortex, the inferior frontal gyrus, and the basal ganglia). In contrast, the patient's performance in processing action-related concepts remained intact during the same period. This finding indicated that action concept processing hinges on cognitive and neural resources that are mostly distinct from those underlying the sensorimotor control of actions.

Nonmotor aspects of action concepts

Reading an action verb elicits the retrieval of its associated body movements as well as its typical goal-the outcome to which it is directed. Two fMRI experiments are reported in which retrieval of goal attributes was isolated from retrieval of motoric ones by contrasting actions that are either done intentionally (e.g., drink) and thus have associated goal information or by accident (e.g., hiccup). Orthogonally, the actions also varied in their motoricity (e.g., drink vs. imagine). Across both levels of motoricity, goal-directedness influenced the activity of a portion of left posterior inferior parietal lobe (pIPL). These effects were not explicable by the grammatical properties, imageability, or amount of body movement associated with these different types of verbs. In contrast, motoricity (across levels of goal-directedness) activated primarily the left middle temporal gyrus. Furthermore, pIPL was found to be distinct from the portion of left parietal lobe implicated in theory of mind, as localized in the same participants. This is consistent with the observation that pIPL contains many functionally distinct subregions and that some of these support conceptual knowledge. The present findings illustrate that, in particular, the pIPL is involved in representing attributes of intentional actions, likely their typical goals, but not their associated body movements. This result serves to describe an attribute-selective semantic subsystem for at least one type of nonmotor aspect of action knowledge.

Applicability of the "An Object and Action Naming Battery" in Brazilian Portuguese

PURPOSE

To verify the performance of a sample of Brazilian subjects in the "An Object and Action Naming Battery" (OANB), according to schooling; and to describe the main error types in nouns and verbs naming.

METHODS

The OANB was applied in 100 healthy subjects, divided in two groups (GI: four to eight years of schooling; and GII: above nine years).

RESULTS

There were correct answers for 97.6% for nouns and 98.0% for verbs. There were statistically significant differences between the groups in the number of correct answers for nouns and verbs (p<0.0001) and in the proportion of semantic errors for verbs (p=0.0160), with less educated subjects performing poorer than higher educated ones.

CONCLUSION

The OANB may be used in adult Brazilian Portuguese native speakers. The group with higher education had higher scores; both groups had a higher proportion of "semantic errors" for verbs and nouns.

Putting an “End” to the Motor Cortex Representations of Action Words

Language processing is an example of implicit learning of multiple statistical cues that provide probabilistic information regarding word structure and use. Much of the current debate about language embodiment is devoted to how action words are represented in the brain, with motor cortex activity evoked by these words assumed to selectively reflect conceptual content and/or its simulation. We investigated whether motor cortex activity evoked by manual action words (e.g., caress) might reflect sensitivity to probabilistic orthographic–phonological cues to grammatical category embedded within individual words. We first review neuroimaging data demonstrating that nonwords evoke activity much more reliably than action words along the entire motor strip, encompassing regions proposed to be action category specific. Using fMRI, we found that disyllabic words denoting manual actions evoked increased motor cortex activity compared with non-body-part-related words (e.g., canyon), activity which overlaps that evoked by observing and executing hand movements. This result is typically interpreted in support of language embodiment. Crucially, we also found that disyllabic nonwords containing endings with probabilistic cues predictive of verb status (e.g., -eve) evoked increased activity compared with nonwords with endings predictive of noun status (e.g., -age) in the identical motor area. Thus, motor cortex responses to action words cannot be assumed to selectively reflect conceptual content and/or its simulation. Our results clearly demonstrate motor cortex activity reflects implicit processing of ortho-phonological statistical regularities that help to distinguish a word's grammatical class.

Use of language mapping to aid in resection of gliomas in eloquent brain regions

Studies looking at resection in high-grade gliomas have had mixed results. The authors briefly review the literature regarding the value of the extent of resection. They proceed to the preoperative and intraoperative tools available to the neurosurgeon to distinguish eloquent from noneloquent language cortex and fibers, including the emerging roles of functional magnetic resonance imaging diffusion tensor imaging tractography and direct cortical/subcortical stimulation in the surgical management of tumors in eloquent areas. Finally, the authors evaluate the postoperative course of these patients and the effect of language deficits on their quality of life.