Abstract not found

Concepts are the elementary units of reason and linguistic meaning. They are conventional and relatively stable. As such, they must somehow be the result of neural activity in the brain. The questions are: Where? and How? A common philosophical position is that all concepts—even concepts about action and perception—are symbolic and abstract, and therefore must be implemented outside the brain’s sensory-motor system. We will argue against this position using (1) neuroscientific evidence; (2) results from neural computation; and (3) results about the nature of concepts from cognitive linguistics. We will propose that the sensory-motor system has the right kind of structure to characterise both sensory-motor and more abstract concepts. Central to this picture are the neural theory of language and the theory of cogs, according to which, brain structures in the sensory-motor regions are exploited to characterise the so-called “abstract ” concepts that constitute the meanings of grammatical constructions and general inference patterns.

The cortical motor system has been classically considered as the unitary, output stage of the brain processing of sensory information. According to this idea, the motor cortex � the acting brain � receives the result of the perceptual processing Ž visual, acoustical, tactile, etc.. elaborated by the ‘associative cortex’. During the last two decades this perspective has been challenged by a series of anatomical, hodological, and neurophysiological data. This converging evidence delineates a dramatically changed picture. Far from being unitary, the cortical motor system appears to be constituted by a constellation of distinct areas, each of those endowed with specific functional properties and linked by reciprocal connections with distinct sectors of the parietal cortex. Furthermore, several ‘motor ’ neurons in addition to their motor discharge, are also activated by somatosensory and visual stimulation Ž somatomotor and visuomotor neurons.. In the present paper we will discuss the functional properties of those sensorimotor neurons located in the ventral part of the monkey premotor cortex. On the basis of electrophysiological data, we will propose that the apparent parodox stemming from the coexistence within the same neuron of motor and sensory properties can be solved by postulating that the motor system not only executes actions but also internally represents them in terms of ‘motor ideas’. These motor ideas may provide the neurobiological basis for space representation, understanding of actions made by others and, possibly, semantic categorization of objects.

A strong correspondence has been repeatedly observed between actually performed and mentally imagined object rotation. This suggests an overlap in the brain regions involved in these processes. Functional neuroimaging studies have consistently revealed parietal and occipital cortex activity during dynamic visuospatial imagery. However, results concerning the involvement of higher-order cortical motor areas have been less consistent. We investigated if and when premotor structures are active during processing of a three-dimensional cube comparison task that requires dynamic visuospatial imagery. In order to achieve a good temporal and spatial resolution, single-trial functional magnetic resonance imaging (fMRI) and scalp-recorded event-related slow cortical potentials (SCPs) were recorded from the same subjects in two separate measurement sessions. In order to reduce inter-subject variability in brain activity due to individual differences, only male subjects (n � 13) with high task-specific ability were investigated. Functional MRI revealed consistent bilateral activity in the occipital (Brodmann area BA18/19) and parietal cortex (BA7), in lateral and medial premotor areas (BA6), the dorsolateral prefrontal cortex (BA9), and the anterior insular cortex. The time-course of SCPs indicated that task-related activity in these areas commenced approximately 550–650 ms after stimulus presentation and persisted until task completion. These results provide strong and consistent evidence that the human premotor cortex is involved in dynamic visuospatial imagery. © 2001 Academic Press

Research has illustrated dissociations between "cognitive " and "action " systems, suggesting that different representations may underlie phenomenal experience and visuomotor behavior. However, these systems also interact. The present studies show a necessary interaction when semantic processing of an object is required for an appropriate action. Experiment 1 demonstrated that a semantic task interfered with grasping objects appropriately by their handles, but a visuospatial task did not. Experiment 2 assessed performance on a visuomotor task that had no semantic component and showed a reversal of the effects of the concurrent tasks. In Experiment 3, variations on concurrent word tasks suggested that retrieval of semantic information was necessary for appropriate grasping. In all, without semantic processing, the visuomotor system can direct the effective grasp of an object, but not in a manner that is appropriate for its use. Dissociations between cognition and action have been proposed in several domains, including perception (Gibson, 1979), attention (Mack & Rock, 1998), and the neural substrate of the visual system (Jeannerod, 1997; Milner & Goodale, 1995). It has been repeatedly demonstrated that phenomenal experience and visuomotor

Abstract not found

Computer games are being approached from a wide range of perspectives, but the activity of playing games, with the player and her actions in focus has, so far, not received much attention in academic research. Approaching games from a cognitive science perspective, however, it is argued in this paper that theories on embodied and situated cognition provide a strong basis for research on this particular issue since game play is a socially embodied and situated activity, shaped by the player’s bodily experience and her interactions with the game environment.

There is increasing experimental and neuropsychological evidence that action selection is directly constrained by perceptual information from objects as well as by more abstract semantic knowledge. To capture this evidence, we develop a new connectionist model of action and name selection from objects—NAM (Naming and Action Model), based on the idea that action selection is determined semantic knowledge. We show that NAM is able to simulate evidence for a direct route to action selection from both normal subjects (Experiments 1 and 2) and neuropsychological patients (Experiments 3–6). The model provides a useful framework for understanding how perceptual knowledge influences action selection. SEMANTICALLY MEDIATED ACTION SELECTION What are the mental operations involved when we select an action to an object, when we make a cutting action with a knife? Traditional cognitive models have emphasized that this process involves the retrieval of semantic knowledge about the object, with the semantic knowledge then being used to guide retrieval of the action (e.g., Roy & Square, 1985, for one example). For instance, for the knife, this may involve accessing knowledge that it is a utensil frequently found in the kitchen, that it is used in the preparation and eating of food, that it is employed along with a fork, and so forth. This semantic information, based on contextual and associative knowledge, is then used to “look up ” a

We describe a computational framework that explores the interaction between focal visual attention, the recognition of objects and actions, and the related use of language. We introduce the notions of "minimal subscene" and “anchored subscene ” to provide a middle ground representation, in which an agent is linked to objects or other agents via some action. We offer a preliminary model of visual attention which links bottom-up salience, contextual cues, object recognition, top-down attention, and short-term memory in building representations of subscenes. We then examine how this framework links to low-level visual perception, on the one end, and to sentences which describe a subscene or raise questions about the scene, on the other.

2. The propositional view of concepts and meaning: some reasons of its success