Science posts

See science posts on page 70 below.

    • 2007
    • Turhan Canli
    • Long story short: the serotonin transporter in emotion regulation and social cognition
    • The gene encoding the serotonin transporter (5-HTT) contains a regulatory variation that has been associated with anxiety-related traits and susceptibility for depression. Here we highlight recent discoveries related to allelic variation of 5-HTT function with respect to emotion regulation and social behavior, drawing from an interdisciplinary perspective of behavioral genetics and cognitive neuroscience. Following a reductionistic path that leads from gene-behavior association studies to neuroimaging and epigenetic studies, we compare two models of 5-HTT-dependent modulation of brain activity and discuss the role of life stress experience in modifying 5-HTT function in the brain. Integration of these findings suggests that the impact of the 5-HTT gene on behavior is much broader than is commonly appreciated and may have a role in social cognition.
    • Turhan Canli, Klaus-Peter Lesch
    • 2012
    • Anthony I. Jack
    • fMRI reveals reciprocal inhibition between social and physical cognitive domains
    • Two lines of evidence indicate that there exists a reciprocal inhibitory relationship between opposed brain networks. First, most attention-demanding cognitive tasks activate a stereotypical set of brain areas, known as the task-positive network and simultaneously deactivate a different set of brain regions, commonly referred to as the task negative or default mode network. Second, functional connectivity analyses show that these same opposed networks are anti-correlated in the resting state. We hypothesize that these reciprocally inhibitory effects reflect two incompatible cognitive modes, each of which may be directed towards understanding the external world. Thus, engaging one mode activates one set of regions and suppresses activity in the other. We test this hypothesis by identifying two types of problem-solving task which, on the basis of prior work, have been consistently associated with the task positive and task negative regions: tasks requiring social cognition, i.e., reaso..
    • Anthony I. Jacka, Abigail J. Dawsona, Katelyn L. Beganya, Regina L. Leckiea, Kevin P. Barrya, Angela H. Cicciab, Abraham Z. Snyder
    • Task-positive, Task negative, Default network, Anti-correlated networks, fMRI, Dual-process theory
    • 2013
    • Anthony I. Jack
    • A scientific case for conceptual dualism: The problem of consciousness and the opposing domains hypothesis
    • In recent years, a number of scientists and philosophers have suggested that the psychological and neural sciences provide support for, and are committed to, reductive physicalism – the view that all aspects of the mental are best explained by the physical processes of the brain. Here I suggest a different view. Emerging research in neuroscience and psychology suggests a dualism in human understanding. Our capacity for understanding physical processes appears to be in fundamental tension with our capacity for thinking about the inner mental states of others. In this essay, I first review evidence for a divide in our neural structure which maps onto thinking about minds versus thinking about the mechanical prop erties of bodies. This divide is intriguing; however it falls short of actually explaining why we perceive difficulties for integrating these two types of understanding. I then introduce a bold hypothesis – that our neural structure constrains our thinking in a way that limits ..
    • 2014
    • Uri Polat
    • ADHD subjects fail to suppress eye blinks and microsaccades while anticipating visual stimuli but recover with medication
    • Oculomotor behavior and parameters are known to be affected by the allocation of attention and could potentially be used to investigate attention disorders. We explored the oculomotor markers of Attention-deficit/hyperactivity disorder (ADHD) that are involuntary and quantitative and that could be used to reveal the core-affected mechanisms, as well as be used for differential diagnosis. We recorded eye movements in a group of 22 ADHD-diagnosed patients with and without medication (methylphenidate) and in 22 control observers while performing the test of variables of attention (t.o.v.a.). We found that the average microsaccade and blink rates were higher in the ADHD group, especially in the time interval around stimulus onset. These rates increased monotonically over session time for both groups, but with significantly faster increments in the unmedicated ADHD group. With medication, the level and time course of the microsaccade rate were fully normalized to the control level, regard..
    • Moshe Frieda, Eteri Tsitsiashvilia, Yoram S. Bonnehb, Anna Sterkina, Tamara Wygnanski-Jaffec, d, Tamir Epsteine, Uri Polat
    • Saccades, Fixational eye movements, Eye blinks, Pupil diameter, ADHD
    • 2014
    • Alicia Callejas
    • Dorsal and Ventral Attention Systems Underlie Social and Symbolic Cueing
    • Eye gaze is a powerful cue for orienting attention in space. Studies examining whether gaze and symbolic cues recruit the same neural mechanisms have found mixed results. We tested whether there is a specialized attentional mechanism for social cues. We separately measured BOLD activity during orienting and reorienting attention following predictive gaze and symbolic cues. Results showed that gaze and symbolic cues exerted their influence through the same neural networks but also produced some differential modulations. Dorsal frontoparietal regions in left intraparietal sulcus (IPS) and bilateral MT+/lateral occipital cortex only showed orienting effects for symbolic cues, whereas right posterior IPS showed larger validity effects following gaze cues. Both exceptions may reflect the greater automaticity of gaze cues: Symbolic orienting may require more effort, while disengaging attention during reorienting may be more difficult following gaze cues. Face-selective regions, identified ..
    • Alicia Callejas, Gordon L. Shulman, and Maurizio Corbetta
    • 2007
    • Antonia F. de C. Hamilton
    • Action Outcomes Are Represented in Human Inferior Frontoparietal Cortex
    • The simple action of pressing a switch has many possible interpretations—the actor could be turning on a light, deleting critical files from a computer, or even turning off a life-support system. In each of these cases, the motor parameters of the action are the same but the physical outcome differs. We report evidence of suppressed responses in right inferior parietal and right inferior frontal cortex when participants saw repeated movies showing the same action outcome, but these regions did not distinguish the kinematic parameters by which the action was accomplished. Thus, these brain areas encode the physical outcomes of human actions in the world. These results are compatible with a hierarchical model of human action understanding in which a cascade of specialized processes from occipital to parietal and frontal regions allow humans to understand the physical consequences of actions in the world and the intentions underlying those actions.
    • Antonia F. de C. Hamilton, Scott T. Grafton
    • Action understanding, Intention, Mirror neuron, Outcome, Parietal
    • 2010
    • Jessica R. Andrews-Hanna
    • Evidence for the Default Network's Role in Spontaneous Cognition
    • A set of brain regions known as the default network increases its activity when focus on the external world is relaxed. During such moments, participants change their focus of external attention and engage in spontaneous cognitive processes including remembering the past and imagining the future. However, the functional contributions of the default network to shifts in external attention versus internal mentation have been difficult to disentangle because the two processes are correlated under typical circumstances. To address this issue, the present study manipulated factors that promote spontaneous cognition separately from those that change the scope of external attention. Results revealed that the default network increased its activity when spontaneous cognition was maximized but not when participants increased their attention to unpredictable foveal or peripheral stimuli. To examine the nature of participants' spontaneous thoughts, a second experiment used self-report questionna..
    • Jessica R. Andrews-Hanna , Jay S. Reidler , Christine Huang , Randy L. Buckner
    • 2007
    • Alex Martin
    • The Representation of Object Concepts in the Brain
    • Evidence from functional neuroimaging of the human brain indicates that information about salient properties of an object—such as what it looks like, how it moves, and how it is used—is stored in sensory and motor systems active when that information was acquired. As a result, object concepts belonging to different categories like animals and tools are represented in partially distinct, sensory- and motor property–based neural networks. This suggests that object concepts are not explicitly represented, but rather emerge from weighted activity within property-based brain regions. However, some property-based regions seem to show a categorical organization, thus providing evidence consistent with category-based, domain-specific formulations as well.
    • 2014
    • Shuo Wang
    • Preferential attention to animals and people is independent of the amygdala
    • The amygdala is thought to play a critical role in detecting salient stimuli. Several studies have taken ecological approaches to investigating such saliency, and argue for domain-specific effects for processing certain natural stimulus categories, in particular faces and animals. Linking this to the amygdala, neurons in the human amygdala have been found to respond strongly to faces, and also to animals. Yet the amygdala's necessary role for such category-specific effects at the behavioral level remains untested. Here we tested four rare patients with bilateral amygdala lesions on an established changedetection protocol. Consistent with prior published studies, healthy controls showed reliably faster and more accurate detection of people and animals, as compared to artifacts and plants. But so did all four amygdala patients: there were no differences in phenomenal change blindness, in behavioral reaction time to detect changes, or in eye-tracking measures. The findings provide de..
    • Shuo Wang, Naotsugu Tsuchiya, Joshua New, Rene Hurlemann, Ralph Adolphs
    • Change Detection, Amygdala, Attention, Eye-tracking
    • 2013
    • Dionne S. Coker-Appiah
    • Looming animate and inanimate threats: The response of the amygdala and periaqueductal gray
    • Looming stimuli are processed as threatening and activate basic neural defense systems. However, it is unclear how animacy information modulates this response. Participants (N = 25) viewed threatening or neutral images that were either animate (animals) or inanimate (objects) and which either approached (loomed) or receded from the participant. The amygdala was responsive to emotional, animacy, and looming information (particularly to looming threats and looming animate stimuli). Periaqueductal gray was also sensitive to emotional information and particularly responsive to looming threats. The data are interpreted within category-specific models of the amygdala and temporal cortex.
    • Dionne S. Coker-Appiahab, Stuart F. Whitea, Roberta Clantona, Jiongjong Yangc, Alex Martind & R. J. R. Blaira
    • Amygdala, Animacy, Threat, Looming, Periaqueductal gray