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CCN Brown Bag Series: Philip Smith
September 17, 2014

The Cognition and Cognitive Neuroscience (CCN) program presents Philip Smith

Wed. 9/17/14

12:10 p.m. Room 115, Wilson Hall

From Shunting Inhibition to Dynamic Normalization: Attentional Selection and Decision-Making in Brief Visual Displays

Normalization models of visual sensitivity assume that the response of a visual mechanism is scaled divisively by the sum of the activity in the excitatory and inhibitory mechanisms in its neighborhood. Normalization models of attention assume that the weighting of excitatory and inhibitory mechanisms is modulated by attention. Such models have provided explanations of the effects of attention in both behavioral and single-cell recording studies. In this talk, I discuss how normalization models can be obtained as the asymptotic solutions of shunting differential equations, in which stimulus inputs and the activity in the mechanism control growth rates multiplicatively rather than additively.

The value of the shunting equation approach is that it characterizes the entire time course of the response, not just its asymptotic strength. I describe two models of attention based on shunting dynamics, the integrated system model of Smith and Ratcliff (Psychological Review,

2009) and the competitive interaction theory of Smith and Sewell (Psychological Review, 2013). These models assume that attention, stimulus salience, and the observer's strategy for the task determine the selection of stimuli into visual short-term memory (VSTM) and way in which stimulus representations are weighted. The models provide a unified account of a variety of accuracy and RT findings from simple attentional tasks.

 

 


Neuroscience Seminar: Keji Li
September 18, 2014

Keji Li, Department of Psychology (Casagrande Lab), Vanderbilt University

12:10 p.m. Room 316, Wilson Hall

Pulvinar projection to V1 layer 1 in primate

The lateral pulvinar (PL) forms reciprocal connections with V1 in primates. The projections from pulvinar to V1 end mostly in layer 1 (Ogren and Hendrickson, 1977) where they are able to excite pyramidal neurons in layer 2/3 (Purushothaman et al., 2012), the output neurons to higher order cortical areas. This input must overcome the heavy inhibition on layer 2/3 pyramidal neurons (Holmgren et al., 2003) to contribute to V1 output. However, little has been known beyond the existence of this projection.

V1 layer 1 primarily contains GABAergic interneurons (Gupta et al., 2000) including single bouquet cells (SBC) and neurogliaform cells (NGFC), as well as the apical dendrites of pyramidal cells in layer 2/3 and layer 5. There are a number of ways in which PL projections could positively influence V1 output. PL synapsing directly with pyramidal output cells could boost output signals directly. SBC synapses with other interneurons, and could disinhibit pyramidal cells (Jiang et al., 2013). Metabotropic glutamate receptor 2 (mGluR2) is expressed heavily in V1 layer 1. This receptor is mostly expressed post-synaptically in sensory cortex, and triggers hyperpolarization in glutamatergic synapses. Such synapses could mediate direct disinhibition of output pyramidal cells from glutamatergic pulvinar input, with only on stage of GABAergic interneurons.

Under light and electron microscope, we examined 1) the morphology and distribution of pulvinar projection axons in V1, and 2) whether pulvinar projections to V1 form direct connections with pyramidal cells or with interneurons, in the primate bush baby. We used biotinylated dextran amine for anterograde tracer, and small pressure injections in the pulvinar that is restricted to the near-central representation of the dorsal map in pulvinar (Li et al., 2013), which is architectonically in the lateral pulvinar (PL).

We have found that PL projection to V1 branch almost exclusively in the upper half of V1 layer 1, with en passant boutons and rare branches in layer 2/3. Boutons made by pulvinar projection to layer 1 are significantly smaller than those formed by pulvinar projection to V2 layer 4. At EM level, pulvinar axons were found to only synapse with the spine of non-GABAergic, presumably pyramidal cells, instead of interneurons dendritic shaft or soma.

 

 

 

 


Roberta Golinkoff - Putting the education back into 'educational' apps
September 19, 2014

Department of Psychology & Human Development: Cognitive Science of Learning and Development Talk Series

Hosting: Roberta Michnick Golinkoff, Ph.D., H. Rodney Sharp Professor, Director, UD Infant Language Project, University of Delaware

Lecture: Putting the education back into "educational apps"

Children are amidst a vast unplanned experiment, surrounded by digital technologies unavailable even five years ago. At the apex of this boom is the introduction of applications (“apps”) for tablet-based and smartphone devices many of which are so-called “educational apps” proliferating at an increasing rate. Parents often think that their children are learning a good deal from computer-based games and apps on topics like reading, vocabulary and mathematics even though many of these “educational” programs have yet to be tested or even informed by research in the science of learning. Building upon decades of work examining the ways in which children learn best, we will present a set of principles designed to guide researchers, parents, educators, and designers in evidence-based app development. In short, we hope to demonstrate how our science can help align the design and use of educational apps with known processes of children’s learning and development.


Department of Psychology Special Seminar: Frederick Verbruggen
September 19, 2014

2014 Randolph Blake Early Career Award Winner

Frederick Verbruggen, Ph.D., Professor of Cognitive Psychology, University of Exeter

115 Wilson Hall

Banishing the control homunculi in studies of action control and behaviour change

For centuries, human self-control has fascinated scientists and nonscientists alike. Current theories often attribute it to an executive control system. But even though executive control receives a great deal of attention across disciplines, most aspects of it are still poorly understood. Many theories rely on an ill-defined set of ‘homunculi’ doing jobs like 'response inhibition' or ‘updating’ without explaining how they do so. Furthermore, it is not always appreciated that control takes place across different time-scales. These two issues hamper major advances. In this presentation, I will focus on the mechanistic basis for the executive control of actions, and stopping in particular. I propose an integrated account of action control that includes the processes of attentional selection, action selection, and action execution. These processes are modulated via error-correction or outcome-evaluation mechanisms, preparation, and task rules maintained in working- and long-term memory. I will also consider how executive control of actions becomes automatised with practice. Finally, I will discuss how the application of this unified framework in clinical domains can increase our understanding of control deficits and provide a theoretical basis for the development of novel ‘behavioural change’ interventions. 

 


Quantitative Methods Colloquium Series: Harrison Kell
September 22, 2014

Are high achievers wrecked by their success? Examining career accomplishment’s association with family, well-being, and health outcomes

Harrison Kell, Quantitative Methods, Vanderbilt Dept. of Psychology & Human Development

Extraordinary career success has long been anecdotally held to cost those who achieve it their personal relationships and their mental and physical health; Freud (1916/1957) even coined the term "wrecked by success" to describe this phenomenon. Current popular work suggests this idea enjoys widespread appeal, but it has been subjected to little empirical scrutiny. We examined the tenability of this idea using two cohorts of intellectually precocious youth. Participants were classified into three "success groups" according to their primary incomes and differences compared across a wide variety of health and interpersonal measures by sex. Criteria ranged from flourishing and positive emotionality to physical and psychological health. The pattern of results does not support the hypothesis that achieving noteworthy career success, as benchmarked by income, must entail enormous personal cost. Overall, scores on health and relationship items did not covary significantly with objectively measured career success. When significant differences were observed, they tended to be small to moderate and favor those who were more successful in their careers (e.g., lower divorce rates, fewer health problems). Results generally replicated across cohorts and sexes. These findings indicate that individuals can achieve career success without necessarily sacrificing their health and personal lives.


Clinical Science Brown Bag Series: Laura Hieber
September 23, 2014

Laura Hieber, Department of Psychology, Vanderbilt University

12:10 p.m. Room 316, Wilson Hall

Title and abstract TBA


CCN Brown Bag Series: Rob Reinhart
September 24, 2014

The Cognition and Cognitive Neuroscience (CCN) program presents Rob Reinhart, Department of Psychology (Woodman Lab), Vanderbilt University

Wed. 9/24/14

12:10pm

WH 115

Electrical stimulation repairs executive dysfunction in schizophrenia

Approximately 25 million people worldwide suffer from schizophrenia, yet current knowledge of the illness and conventional treatment options are limited. Here we show that noninvasive electrical brain stimulation can effectively reduce some of the executive control deficits in schizophrenia. We found that transcranial direct-current stimulation over the medial-frontal cortex increased neural activity related to error processing in schizophrenia patients, which is characteristically reduced or absent in the illness. Second, this manipulation of medial-frontal activity caused improvements in a number of behavioral metrics of adaptive control, including task accuracy, the corrective behavior following an error, and learning rates. Third, the electrophysiology and behavior related to executive functioning in schizophrenia patients after stimulation were quantitatively indistinguishable from that of healthy participants. These results suggest an approach for remediating disrupted reward prediction error dopamine related signaling in schizophrenia. These results may have direct application to future intervention therapy development for patients with psychiatric illnesses.

 

 


Neuroscience Seminar: Jane Burton
September 25, 2014

Jane Burton, Department of Hearing & Speak (Ramachandran Lab), Vanderbilt University

12:10 p.m. Room 316, Wilson Hall

Auditory Perceptual Filters in Macaque Monkeys

The cochlea is thought to be comprised of a series of overlapping bandpass filters, which are used to detect and resolve the components of sounds. Fletcher (1940) proposed the power spectrum model of masking, which assumes that all acoustic energy that falls within an auditory filter (signal + noise) will contribute to one’s ability to perceive a stimulus using that filter. The critical band is a measure of frequency resolution that represents the bandwidth of noise at which signal threshold ceases to change and can be derived directly from auditory filter shape. The critical band has been well quantified in humans and other mammalian species, but little work has been done to examine critical bands in monkeys. This study examined the auditory perceptual filters of macaque monkeys using a noise notch widening paradigm. The monkeys were trained to detect pure tone signals in the presence of a broadband noise masker. Portions of the noise were removed around the signal frequency symmetrically and asymmetrically to examine the upper and lower edges of the auditory filters. Macaque critical bands were found to be comparable to human data, as derived from both the critical ratio and rounded exponential function modeling. The auditory filters were also asymmetric at high noise levels, as seen in humans, with a broader lower edge and narrower upper edge. This critical band data provides further support for the use of macaques as a model for human hearing. These behavioral data will be used as a basis for neurophysiological investigations of the neuronal mechanisms underlying auditory perceptual filters. Additionally, this study will serve as a normal hearing baseline for comparison to testing on monkeys with noise-induced hearing loss in the future. 

 

 


Clinical Science Brown Bag Series: Cecilia Mo
September 30, 2014

Cecilia Mo, Political Science Department, Vanderbilt University

12:10 p.m. Room 316, Wilson Hall 

Title and abstract TBA


CCN Brown Bag Series: David Ross
October 1, 2014

The Cognition and Cognitive Neuroscience (CCN) program presents David Ross, Department of Psychology, Vanderbilt University

12:10 p.m. 115 Wilson Hall

Title and abstract TBA


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