Science posts

See science posts on page 56 below.

    • 2013
    • Milky Kohno et al
    • Risk-Taking Behavior: Dopamine D2/D3 Receptors, Feedback, and Frontolimbic Activity
    • Decision-making involves frontolimbic and dopaminergic brain regions, but how prior choice outcomes, dopamine neurotransmission, and frontostriatal activity are integrated to affect choices is unclear. We tested 60 healthy volunteers using the Balloon Analogue Risk Task (BART) during functional magnetic resonance imaging. In the BART, participants can pump virtual balloons to increase potential monetary reward or cash out to receive accumulated reward; each pump presents greater risk and potential reward (represented by the pump number). In a separate session, we measured striatal D2/D3 dopamine receptor binding potential (BPND) with positron emission tomography in 13 of the participants. Losses were followed by fewer risky choices than wins; and during risk-taking after loss, amygdala and hippocampal activation exhibited greater modulation by pump number than after a cash-out event. Striatal D2/D3 BPND was positively related to the modulation of ventral striatal activation when part..
    • 2010
    • Ian Q. Whishaw et al
    • The functional origins of speech-related hand gestures
    • Many theories of language posit its recent evolution, perhaps contemporaneous with the evolution of Homo sapiens. The embodied language theory, however, in proposing that language includes gestures, provides an avenue for tracing language origins to phylogenetically earlier ancestral species. Here, evidence is presented that the structure of functional hand movements (e.g., reaching for food, climbing a ladder, or crawling), in rats and humans is similar. The structure of these functional hand movements is then compared to speech-related hand gestures in humans. The sequence of language-related gestures are also found to be characteristic of functional hand movements. It is suggested that these findings show that the arm and hand gestures that accompany human speech are derived from the same neural substrates that produce functional movements. Additionally, evidence is reviewed that supports the idea that speech-related gestures resemble the movements elicited by long-train stimulati..
    • 2011
    • Susanne Diekelmann et al
    • The whats and whens of sleep-dependent memory consolidation
    • Sleep benefits memory consolidation. The reviewed studies indicate that this consolidating effect is not revealed under all circumstances but is linked to specific psychological conditions. Specifically, we discuss to what extent memory consolidation during sleep depends on the type of learning materials, type of learning and retrieval test, different features of sleep and the subject population. Post-learning sleep enhances consolidation of declarative, procedural and emotional memories. The enhancement is greater for weakly than strongly encoded associations and more consistent for explicitly than implicitly encoded memories. Memories associated with expected reward gain preferentially access to sleep-dependent consolidation. For declarative memories, sleep benefits are more consistently revealed with recall than recognition procedures at retrieval testing. Slow wave sleep (SWS) particularly enhances declarative memories whereas rapid eye movement (REM) sleep preferentially support..
    • 2011
    • Anne Campbell et al
    • Bodily communication and personality
    • Fifteen measures of non-verbal communication were coded from videotaped interactions between a female confederate and 18–21 year old female subjects (n = 46). Three measures of extraversion and neuroticism had previously been taken from the subjects, as was a measure of IQ. Correlation and factor analysis revealed significant relationships between certain of the variables. Extraversion was strongly associated with speaking more; a teacher's rating of neuroticism was associated with touching the self, pausing during conversation, and an absence of expressive gesture; lower IQ was associated with smiling while listening; and self-report personality questionnaire neuroticism was associated with gaze aversion.
    • 2009
    • Isabell Wartenburger et al
    • On the relationship between fluid intelligence, gesture production, and brain structure
    • Individuals scoring high in fluid intelligence tasks generally perform very efficiently in problem solving tasks and analogical reasoning tasks presumably because they are able to select the task-relevant information very quickly and focus on a limited set of task-relevant cognitive operations. Moreover, individuals with high fluid intelligence produce more representational hand and arm gestures when describing a geometric analogy task than individuals with average fluid intelligence. No study has yet addressed the relationship between intelligence, gesture production, and brain structure, to our knowledge. That was the purpose of our study. To characterize the relation between intelligence, gesture production, and brain structure we assessed the frequency of representational gestures and cortical thickness values in a group of adolescents differing in fluid intelligence. Individuals scoring high in fluid intelligence showed higher accuracy in the geometric analogy task and produced ..
    • 2011
    • Uta Sassenberg et al
    • Show your hands — Are you really clever? Reasoning, gesture production, and intelligence
    • This study investigates the relationship of reasoning and gesture production in individuals differing in fluid and crystallized intelligence. It combines measures of speed and accuracy of processing geometric analogies with analyses of spontaneous hand gestures that accompanied young adults' subsequent explanations of how they solved the geometric analogy task. Individuals with superior fluid intelligence processed the analogies more efficiently than participants with average fluid intelligence. Additionally, they accompanied their subsequent explanations with more gestures expressing movement in non-egocentric perspective. Furthermore, gesturing (but not speaking) about the most relevant aspect of the task was related to higher fluid intelligence. Within the gestures-as-simulated action framework, the results suggest that individuals with superior fluid intelligence engage more in mental simulation during visual imagery than those with average fluid intelligence. The findings stress..
    • 2012
    • Siyuan Liu et al
    • Neural Correlates of Lyrical Improvisation: An fMRI Study of Freestyle Rap
    • The neural correlates of creativity are poorly understood. Freestyle rap provides a unique opportunity to study spontaneous lyrical improvisation, a multidimensional form of creativity at the interface of music and language. Here we use functional magnetic resonance imaging to characterize this process. Task contrast analyses indicate that improvised performance is characterized by dissociated activity in medial and dorsolateral prefrontal cortices, providing a context in which stimulus-independent behaviors may unfold in the absence of conscious monitoring and volitional control. Connectivity analyses reveal widespread improvisation-related correlations between medial prefrontal, cingulate motor, perisylvian cortices and amygdala, suggesting the emergence of a network linking motivation, language, affect and movement. Lyrical improvisation appears to be characterized by altered relationships between regions coupling intention and action, in which conventional executive control may b..
    • 2011
    • Theodore P Zanto et al
    • Causal role of the prefrontal cortex in top-down modulation of visual processing and working memory
    • Selective attention filters information to limit what is encoded and maintained in working memory. Although the prefrontal cortex (PFC) is central to both selective attention and working memory, the underlying neural processes that link these cognitive abilities remain elusive. Using functional magnetic resonance imaging to guide repetitive transcranial magnetic stimulation with electroencephalographic recordings in humans, we perturbed PFC function at the inferior frontal junction in participants before they performed a selective-attention, delayed-recognition task. This resulted in diminished top-down modulation of activity in posterior cortex during early encoding stages, which predicted a subsequent decrement in working memory accuracy. Participants with stronger fronto-posterior functional connectivity displayed greater disruptive effects. Our data further suggests that broad alpha-band (7–14 Hz) phase coherence subserved this long-distance top-down modulation. These results sug..
    • 2011
    • Adam Gazzaley et al
    • Top-down modulation: bridging selective attention and working memory
    • Selective attention, the ability to focus our cognitive resources on information relevant to our goals, influences working memory (WM) performance. Indeed, attention and working memory are increasingly viewed as overlapping constructs. Here, we review recent evidence from human neurophysiological studies demonstrating that top-down modulation serves as a common neural mechanism underlying these two cognitive operations. The core features include activity modulation in stimulus-selective sensory cortices with concurrent engagement of prefrontal and parietal control regions that function as sources of top-down signals. Notably, top-down modulation is engaged during both stimulus-present and stimulus-absent stages of WM tasks; that is, expectation of an ensuing stimulus to be remembered, selection and encoding of stimuli, maintenance of relevant information in mind and memory retrieval.
    • 2014
    • Katsuki F. et al
    • Bottom-up and top-down attention: different processes and overlapping neural systems.
    • The brain is limited in its capacity to process all sensory stimuli present in the physical world at any point in time and relies instead on the cognitive process of attention to focus neural resources according to the contingencies of the moment. Attention can be categorized into two distinct functions: bottom-up attention, referring to attentional guidance purely by externally driven factors to stimuli that are salient because of their inherent properties relative to the background; and top-down attention, referring to internal guidance of attention based on prior knowledge, willful plans, and current goals. Over the past few years, insights on the neural circuits and mechanisms of bottom-up and top-down attention have been gained through neurophysiological experiments. Attention affects the mean neuronal firing rate as well as its variability and correlation across neurons. Although distinct processes mediate the guidance of attention based on bottom-up and top-down factors, a com..