Space and time in the parietal cortex: fMRI Evidence for a meural asymmetry

How are space and time related in the brain? This study contrasts two proposals that make different predictions about the interaction between spatial and temporal magnitudes. Whereas ATOM implies that space and time are symmetrically related, Metaphor Theory claims they are asymmetrically related. Here we investigated whether space and time activate the same neural structures in the inferior parietal cortex (IPC) and whether the activation is symmetric or asymmetric across domains. We measured participants’ neural activity while they made temporal and spatial judgments on the same visual stimuli. The behavioral results replicated earlier observations of a space-time asymmetry: Temporal judgments were more strongly influenced by irrelevant spatial information than vice versa. The BOLD fMRI data indicated that space and time activated overlapping clusters in the IPC and that, consistent with Metaphor Theory, this activation was asymmetric: The shared region of IPC was activated more strongly during temporal judgments than during spatial judgments. We consider three possible interpretations of this neural asymmetry, based on 3 possible functions of IPC

Top-Down and Bottom-Up Contributions to Understanding Sentences Describing Objects in Motion

Theories of embodied language comprehension propose that the neural systems used for perception, action, and emotion are also engaged during language comprehension. Consistent with these theories, behavioral studies have shown that the comprehension of language that describes motion is affected by simultaneously perceiving a moving stimulus (Kaschak et al., 2005). In two neuroimaging studies, we investigate whether comprehension of sentences describing moving objects activates brain areas known to support the visual perception of moving objects (i.e., area MT/V5). Our data indicate that MT/V5 is indeed selectively engaged by sentences describing objects in motion toward the comprehender compared to sentences describing visual scenes without motion. Moreover, these sentences activate areas along the cortical midline of the brain, known to be engaged when participants process self-referential information. The current data thus suggest that sentences describing situations with potential relevance to one's own actions activate both higher-order visual cortex as well brain areas involved in processing information about the self. The data have consequences for embodied theories of language comprehension: first, they show that perceptual brain areas support sentential-semantic processing. Second the data indicate that sensory-motor simulation of events described through language are susceptible to top-down modulation of factors such as relevance of the described situation to the self

Context Effects in Embodied Lexical-Semantic Processing

The embodied view of language comprehension proposes that the meaning of words is grounded in perception and action rather than represented in abstract amodal symbols. Support for embodied theories of language processing comes from behavioral studies showing that understanding a sentence about an action can modulate congruent and incongruent physical responses, suggesting motor involvement during comprehension of sentences referring to bodily movement. Additionally, several neuroimaging studies have provided evidence that comprehending single words denoting manipulable objects elicits specific responses in the neural motor system. An interesting question that remains is whether action semantic knowledge is directly activated as motor simulations in the brain, or rather modulated by the semantic context in which action words are encountered. In the current paper we investigated the nature of conceptual representations using a go/no-go lexical decision task. Specifically, target words were either presented in a semantic context that emphasized dominant action features (features related to the functional use of an object) or non-dominant action features. The response latencies in a lexical decision task reveal that participants were faster to respond to words denoting objects for which the functional use was congruent with the prepared movement. This facilitation effect, however, was only apparent when the semantic context emphasized corresponding motor properties. These findings suggest that conceptual processing is a context-dependent process that incorporates motor-related knowledge in a flexible manner

Observing, performing, and understanding actions : revisiting the role of cortical motor areas in processing of action words

Language content and action/perception have been shown to activate common brain areas in previous neuroimaging studies. However, it is unclear whether overlapping cortical activation reflects a common neural source or adjacent, but distinct, sources. We address this issue by using multivoxel pattern analysis on fMRI data. Specifically, participants were instructed to engage in five tasks: (1) execute hand actions (AE), (2) observe hand actions (AO), (3) observe nonbiological motion (MO), (4) read action verbs, and (5) read nonaction verbs. A classifier was trained to distinguish between data collected from neural motor areas during (1) AE versus MO and (2) AO versus MO. These two algorithms were then used to test for a distinction between data collected during the reading of action versus nonaction verbs. The results show that the algorithm trained to distinguish between AE and MO distinguishes between word categories using signal recorded from the left parietal cortex and pre-SMA, but not from ventrolateral premotor cortex. In contrast, the algorithm trained to distinguish between AO and MO discriminates between word categories using the activity pattern in the left premotor and left parietal cortex. This shows that the sensitivity of premotor areas to language content is more similar to the process of observing others acting than to acting oneself. Furthermore, those parts of the brain that show comparable neural pattern for action execution and action word comprehension are high-level integrative motor areas rather than low-level motor areas

Neuronal interactions between mentalizing and action systems during indirect request processing

Human communication relies on the ability to process linguistic structure and to map words and utterances onto our environment. Furthermore, as what we communicate is often not directly encoded in our language (e.g., in the case of irony, jokes, or indirect requests), we need to extract additional cues to infer the beliefs and desires of our conversational partners. Although the functional interplay between language and the ability to mentalize has been discussed in theoretical accounts in the past, the neurobiological underpinnings of these dynamics are currently not well understood. Here, we address this issue using functional imaging (fMRI). Participants listened to question-reply dialogues. In these dialogues, a reply is interpreted as a direct reply, an indirect reply, or a request for action, depending on the question. We show that inferring meaning from indirect replies engages parts of the mentalizing network (mPFC) while requests for action also activate the cortical motor system (IPL). Subsequent connectivity analysis using Dynamic Causal Modelling (DCM) revealed that this pattern of activation is best explained by an increase in effective connectivity from the mentalizing network (mPFC) to the action system (IPL). These results are an important step towards a more integrative understanding of the neurobiological basis of indirect speech processing

Shared neural processes support semantic control and action understanding

Executive-semantic control and action understanding appear to recruit overlapping brain regions but existing evidence from neuroimaging meta-analyses and neuropsychology lacks spatial precision; we therefore manipulated difficulty and feature type (visual vs. action) in a single fMRI study. Harder judgements recruited an executive-semantic network encompassing medial and inferior frontal regions (including LIFG) and posterior temporal cortex (including pMTG). These regions partially overlapped with brain areas involved in action but not visual judgements. In LIFG, the peak responses to action and difficulty were spatially identical across participants, while these responses were overlapping yet spatially distinct in posterior temporal cortex. We propose that the co-activation of LIFG and pMTG allows the flexible retrieval of semantic information, appropriate to the current context; this might be necessary both for semantic control and understanding actions. Feature selection in difficult trials also recruited ventral occipital-temporal areas, not implicated in action understanding

Shared neural processes support semantic control and action understanding

Executive-semantic control and action understanding appear to recruit overlapping brain regions but existing evidence from neuroimaging meta-analyses and neuropsychology lacks spatial precision; we therefore manipulated difficulty and feature type (visual vs. action) in a single fMRI study. Harder judgements recruited an executive-semantic network encompassing medial and inferior frontal regions (including LIFG) and posterior temporal cortex (including pMTG). These regions partially overlapped with brain areas involved in action but not visual judgements. In LIFG, the peak responses to action and difficulty were spatially identical across participants, while these responses were overlapping yet spatially distinct in posterior temporal cortex. We propose that the co-activation of LIFG and pMTG allows the flexible retrieval of semantic information, appropriate to the current context; this might be necessary both for semantic control and understanding actions. Feature selection in difficult trials also recruited ventral occipital-temporal areas, not implicated in action understanding

The genealogy of judgement: towards a deep history of academic freedom

The classical conception of academic freedom associated with Wilhelm von Humboldt and the rise of the modern university has a quite specific cultural foundation that centres on the controversial mental faculty of 'judgement'. This article traces the roots of 'judgement' back to the Protestant Reformation, through its heyday as the signature feature of German idealism, and to its gradual loss of salience as both a philosophical and a psychological concept. This trajectory has been accompanied by a general shrinking in the scope of academic freedom from the promulgation of world-views to the offering of expert opinion

Art and the State: The Visual Arts in Comparative Perspective

This book examines the impact of states and their policies on visual art. States shape the role of art and artists in society, influence the development of audiences, support artistic work, and even affect the very nature of artistic production. The book contrasts developments in the United States with art policies in Britain and in the social democratic states of Norway and Sweden. In addition, it analyzes revealing transitions - the changes brought about in East Germany after unification and the experiences of artists who left the Soviet Union for the west. The result is a significant contribution to the sociology and the political economy of art