Science posts

See science posts on page 44 below.

    • 2009
    • Giorgio Coricellia et al
    • Neural correlates of depth of strategic reasoning in medial prefrontal cortex
    • We used functional MRI (fMRI) to investigate human mental processes in a competitive interactive setting—the “beauty contest” game. This game is well-suited for investigating whether and how a player's mental processing incorporates the thinking process of others in strategic reasoning. We apply a cognitive hierarchy model to classify subject's choices in the experimental game according to the degree of strategic reasoning so that we can identify the neural substrates of different levels of strategizing. According to this model, high-level reasoners expect the others to behave strategically, whereas low-level reasoners choose based on the expectation that others will choose randomly. The data show that high-level reasoning and a measure of strategic IQ (related to winning in the game) correlate with the neural activity in the medial prefrontal cortex, demonstrating its crucial role in successful mentalizing. This supports a cognitive hierarchy model of human brain and behavior.
    • 2010
    • Shengfu Lu et al
    • Recruitment of the pre-motor area in human inductive reasoning: An fMRI study
    • Recent studies indicated that the pre-motor area may be recruited in human higher level cognitive functions, including inductive reasoning. In the present study, a typical task of inductive reasoning, function-finding, was explored using functional MRI. fMRI results showed the significant activation of bilateral pre-motor cortex (BA 6), and its left lateralization. Taking together the previous studies and the present experimental design, we concluded that the left pre-motor cortex in the present study may associate with implicit relation synthesis, while the right pre-motor cortex may reflect spatial information processing involved in arithmetic rules.
    • 2009
    • Solène Kalénine et al
    • The sensory-motor specificity of taxonomic and thematic conceptual relations: A behavioral and fMRI study
    • Previous behavioral data suggest that the salience of taxonomic (e.g., hammer–saw) and thematic (e.g., hammer–nail) conceptual relations depends on object categories. Furthermore, taxonomic and thematic relations would be differentially grounded in the sensory-motor system. Using a picture matching task, we asked adult participants to identify taxonomic and thematic relations for non-manipulable and manipulable natural and artifact targets (e.g., animals, fruit, tools and vehicles, respectively) inside and outside a 3 T MR scanner. Behavioral data indicated that taxonomic relations are identified faster in natural objects while thematic relations are processed faster in artifacts, particularly manipulable ones (e.g., tools). Neuroimaging findings revealed that taxonomic processing specifically activates the bilateral visual areas (cuneus, BA 18), particularly for non-manipulable natural objects (e.g., animals). On the contrary, thematic processing specifically recruited a bilateral t..
    • 2011
    • Frank Van Overwalle
    • A dissociation between social mentalizing and general reasoning
    • It has recently been suggested that brain areas crucial for mentalizing, including the medial prefrontal cortex (mPFC), are not activated exclusively during mentalizing about the intentions, beliefs, morals or traits of the self or others, but also more generally during cognitive reasoning including relational processing about objects. Contrary to this notion, a meta-analysis of cognitive reasoning tasks demonstrates that the core mentalizing areas are not systematically recruited during reasoning, but mostly when these tasks describe some human agency or general evaluative and enduring traits about humans, and much less so when these social evaluations are absent. There is a gradient showing less mPFC activation as less mentalizing content is contained in the stimulus material used in reasoning tasks. Hence, it is more likely that cognitive reasoning activates the mPFC because inferences about social agency and mind are involved.
    • 2007
    • Penny M. Pexman et al
    • Neural Correlates of Concreteness in Semantic Categorization
    • In some contexts, concrete words (CARROT) are recognized and remembered more readily than abstract words (TRUTH). This concreteness effect has historically been explained by two theories of semantic representation: dual-coding [Paivio, A. Dual coding theory: Retrospect and current status. Canadian Journal of Psychology, 45, 255–287, 1991] and context-availability [Schwanenflugel, P. J. Why are abstract concepts hard to understand? In P. J. Schwanenflugel (Ed.), The psychology of word meanings (pp. 223–250). Hillsdale, NJ: Erlbaum, 1991]. Past efforts to adjudicate between these theories using functional magnetic resonance imaging have produced mixed results. Using event-related functional magnetic resonance imaging, we reexamined this issue with a semantic categorization task that allowed for uniform semantic judgments of concrete and abstract words. The participants were 20 healthy adults. Functional analyses contrasted activation associated with concrete and abstract meanings of am..
    • 2008
    • Kristiina Kompus et al
    • Dynamic switching between semantic and episodic memory systems
    • It has been suggested that episodic and semantic long-term memory systems interact during retrieval. Here we examined the flexibility of memory retrieval in an associative task taxing memories of different strength, assumed to differentially engage episodic and semantic memory. Healthy volunteers were pre-trained on a set of 36 face–name pairs over a 6-week period. Another set of 36 items was shown only once during the same time period. About 3 months after the training period all items were presented in a randomly intermixed order in an event-related fMRI study of face–name memory. Once presented items differentially activated anterior cingulate cortex and a right prefrontal region that previously have been associated with episodic retrieval mode. High-familiar items were associated with stronger activation of posterior cortices and a left frontal region. These findings fit a model of memory retrieval by which early processes determine, on a trial-by-trial basis, if the task can be ..
    • 2014
    • Laura M. Skipper et al
    • Semantic memory: Distinct neural representations for abstractness and valence
    • The hypothesis that abstract words are grounded in emotion has been supported by behavioral research and corpus studies of English words. A recent neuroimaging study reported that a single brain region, the rostral anterior cingulate cortex (rACC), is responsive to abstract words, and is furthermore modulated by the emotional valence. This finding is surprising because the rACC is not commonly associated with semantic processing. It is possible that the effects observed were driven not by abstractness, but rather by valence, since the abstract words used in that study were significantly more emotional than the concrete words. We tested this hypothesis by presenting participants with words that were abstract/concrete, as well as emotionally valenced/neutral in a 2 × 2 factorial design. Activations to emotional words overlapped with both abstract and concrete activations throughout the brain. An ROI analysis revealed that the rACC was responsive to valence, not abstractness, when concr..
    • 2007
    • Robert F. Goldberg et al
    • Selective Retrieval of Abstract Semantic Knowledge in Left Prefrontal Cortex
    • Research into the representation and processing of conceptual knowledge has typically associated perceptual facts with sensory brain regions and executive retrieval mechanisms with the left prefrontal cortex. However, this dichotomy between knowledge content and retrieval processes leaves unanswered how the brain supports concepts less reliant on direct sensory experiences. We used neuroimaging methods to investigate whether an increased abstractness in semantic decisions, in contrast to increased response difficulty, is associated with increased left prefrontal activation. Participants were presented with concrete animal names and asked to verify sensory and abstract properties that corresponded only to the animal category. Candidate semantic regions were localized in left inferior, frontopolar, and dorsolateral prefrontal cortex in contrast to a pseudoword control. Activity in each of these prefrontal regions was associated with significantly increased activity for abstract relativ..
    • 2005
    • Silvia A. Bunge et al
    • Analogical Reasoning and Prefrontal Cortex: Evidence for Separable Retrieval and Integration Mechanisms
    • The present study examined the contributions of prefrontal cortex (PFC) subregions to two component processes underlying verbal analogical reasoning: semantic retrieval and integration. Event-related functional magnetic resonance imaging data were acquired while subjects performed propositional analogy and semantic decision tasks. On each trial, subjects viewed a pair of words (pair 1), followed by an instructional cue and a second word pair (pair 2). On analogy trials, subjects evaluated whether pair 2 was semantically analogous to pair 1. On semantic trials, subjects indicated whether the pair 2 words were semantically related to each other. Thus, analogy — but not semantic — trials required integration across multiple retrieved relations. To identify regions involved in semantic retrieval, we manipulated the associative strength of pair 1 words in both tasks. Anterior left inferior PFC (aLIPC) was modulated by associative strength, consistent with a role in controlled semantic ret..
    • 2011
    • Seth J. Gillihan and Martha J. Farah
    • Is Self Special? A Critical Review of Evidence From Experimental Psychology and Cognitive Neuroscience
    • Varied research findings have been taken to support the claim that humans’ representation of the self is “special,” that is, that it emerges from systems that are physically and functionally distinct from those used for more general purpose cognitive processing. The authors evaluate this claim by reviewing the relevant literatures and addressing the criteria for considering a system special, the various operationalizations of self, and how the studies’ findings relate to the conclusions drawn. The authors conclude that many of the claims for the special status of self-related processing are premature given the evidence and that the various self-related research programs do not seem to be illuminating a unitary, common system, despite individuals’ subjective experience of a unified self.