Are the motor features of verb meanings represented in the precentral motor cortices? Yes, but within the context of a flexible, multilevel architecture for conceptual knowledge

Abstract

One of the most controversial issues in the cognitive neuroscience literature on concepts is whether the motor features of verb meanings are represented in the precentral motor cortices. Much of this debate stems from the fact that the empirical data are mixed with regard to (1) whether action verbs engage the precentral motor cortices in the predicted ways, (2) whether that engagement is automatic, and (3) whether it is essential for comprehension. I argue that the available data can best be accommodated by theoretical models which assume that conceptual knowledge is underpinned by a flexible, multilevel architecture that includes not only low-level modality-specific systems for perception, action, and emotion, but also high-level cross-modal convergence/divergence zones, as well as the statistical cooccurrence patterns of word-forms across discourses. From the perspective of such pluralistic approaches, the motor features of verb meanings are indeed represented in the precentral motor cortices, but their retrieval is modulated by task and context and is not always necessary for word comprehension.

The Sounds of Sentences: Differentiating the Influence of Physical Sound, Sound Imagery, and Linguistically Implied Sounds on Physical Sound Processing

“…Thus, in contrast to strong versions of the embodiment account-emphasizing the role of primary sensory activations-our findings suggest that both imagery and the processing of sentences describing auditory events result in the activation of higher level abstract representations. Indeed, a recent account of language comprehension by Fernandino et al (2016) points toward the role of gradual abstraction during comprehension even for sensory representations (see also Kemmerer, 2015). Fernandino and colleagues suggested that the meaning representation of words associated with auditory events is less associated with primary, as compared to secondary, sensory regions in the brain.…”

Arguments about the nature of concepts: Symbols, embodiment, and beyond

“…In other words, it is true by casual observation that human conceptual processing can flexibly recombine information essentially ad infinitum —the properties of the human mind that make this possible have been the topic of much theoretical work (e.g., Chomsky, 1959; Fodor, 1975, Pinker, 1994; Barsalou, 1999). Recent emphasis of ‘flexibility in concept representation’ is focused instead on the idea that concepts (i.e., the ‘representations themselves’) are dynamic with dissociable components, such that one aspect of a ‘concept’ may be used in one context or task, while another aspect of the concept may be used in another (Willems and Casasanto, 2011; Van dam et al, 2012; for discussion, see Dove, this issue; Kemmerer, this issue; Yee and Thompson-Schill, this issue). In other words, concepts do not have cores that are retrieved each time a concept is tokened: overlapping subsets of conceptual information, that collectively form the ‘full’ concept, can be solicited in a flexible manner according to task constraints.…”

“…It is also well described that semantic knowledge of actions, as opposed to semantic knowledge of entities, has specific loci of representation in the brain, widely claimed to involve frontal lobe motor-related areas, with closer examination suggesting the left posterior middle temporal gyrus (see e.g. Hickok, 2014, Kemmerer et al, 2012; this issue; Tranel et al, 2003; see also Beauchamp et al, 2002; 2003; Kable et al, 2002). More recently, it has been discovered that many regional biases by category or stimulus type, while present in what are principally ‘visual’ or ‘visually responsive’ regions of the brain, are nonetheless also present in individuals without any visual experience, and in remarkably high anatomical correspondence with sighted individuals (Büchel et al, 1998; He et al, 2013; Mahon et al, 2009; 2010; Striem-Amit et al, 2012; Strnad, Peelen, Bedny, and Caramazza, 2013; Bedny, Caramazza, Pascual-Leone and Saxe, 2012; Striem-Amit et al, 2011); the data from congenitally blind participants suggest that while vision clearly plays a critical role in shaping neural responses in high-level visual areas, the broad scaffolding of the visual system by ‘semantic domain’ originates in constraints that operate independent of visual experience.…”

“…In this regard, the patient data have formed an important part of the motivation for ‘hybrid’ accounts: on these accounts, while conceptual processing reaches into the sensorimotor systems, the center of gravity of conceptual processing is abstracted away from specific sensorimotor information, and distributed across many systems. A number of contributions in the current volume fall into this ‘hybrid’ class of proposals (Binder, this issue; Jamrozik et al, this issue; Kemmerer, this issue; Reilly et al, this issue; Zwaan, this issue; see also Dove, this issue; Hickok, 2014; Mahon and Caramazza, 2008). One generalization that emerges across this volume – which is a good trope for the broader field – is that there is general recognition that simple oppositions of ‘are concepts this or that’ do not capture the subtleties that are demanded of any reasonably sufficient theory.…”

Classification systems offer a microcosm of issues in conceptual processing: a commentary on Kemmerer (2016)

“…given concept is represented in infinitely many ways, taking different forms in different contexts to serve current goal-directed activity (e.g., Barsalou, 2016;Casasanto & Lupyan, 2015;Connell & Lynott, 2014;Kemmerer, 2015;Lebois, Wilson-Mendenhall, & Barsalou, 2015;Yee & ThompsonSchill, 2016). Classifiers similarly appear to implement context-dependence in at least two ways.…”