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Wednesday, February 22 2012

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Time Talks
All day
 
10:00 am
10:30am - 12:00pm
Barbara Shinn-Cunningham - Acoustic features and individual differences affecting auditory attentionBarbara Shinn-Cunningham
Director, Center for Computational Neuroscience and Neural Technology
Professor, Biomedical Engineering
Boston University

Abstract:

In real-world settings, the abilities to focus, maintain, and switch auditory attention are each critical for allowing us to communicate. However, we are still unraveling what acoustic features enable these feats of selective attention, let alone why some listeners are better than others in performing these feats. This talk will review results of a number of experiments in my lab looking at some of the dynamics of auditory attention, exploring some of the features important in focusing on and maintaining attention on a source in a sound mixture. Recent results that speak to why there may be large differences in individual ability will also be presented.

http://www.bu.edu/dbin/hrc/calendar
12:00 pm
12:00pm - 01:00pm
Ed Boyden - Optogenetics, Robotic Neural Recording, and Other Neuroscience ToolsEd Boyden, PhD
Benesse Career Development Professor
Leader, Synthetic Neurobiology Group
Associate Professor, MIT Media Lab
Joint Professor, MIT Dept. of Biological Engineering, MIT Dept. of Brain and Cognitive Sciences
Investigator, MIT McGovern Institute
Associate Member, MIT Picower Institute

Abstract:

Understanding how neural circuits implement brain functions, and how these computations go awry in brain disorders, is a top priority for neuroscience. Over the last several years we have developed a rapidly-expanding suite of genetically-encoded reagents that, when expressed in specific neuron types in the nervous system, enable their electrical activities to be powerfully and precisely activated and silenced in response to pulses of light. These tools are in widespread use for analyzing the causal role of defined cell types in normal and pathological brain functions. In this talk I will briefly give an overview of the field, and then I will discuss a number of new tools for neural activation and silencing that we are developing, including new molecules with augmented amplitudes, improved safety profiles, novel color and light-sensitivity capabilities, and unique new capabilities. We have begun to develop hardware to enable complex and distributed neural circuits to be precisely controlled, and for the network-wide impact of a neural control event to be measured using distributed electrodes, fMRI, and robotic intracellular neural recording. We explore how these tools can be used to enable systematic analysis of neural circuit functions in the fields of emotion, sensation, and movement, and in neurological and psychiatric disorders. Finally, we discuss our pre-clinical work on translation of such tools to support novel ultraprecise neuromodulation therapies for human patients.
01:00 pm
01:00pm - 02:00pm
John Assad - Decisions, Categories and Parietal CortexJohn Assad (Harvard Neuroscience)

Abstract:

The inferior parietal lobe is involved in the perception of visual space and the control of eye movements. Neurons in the primate lateral intraparietal area (LIP) have also been implicated in perceptual decision-making. In those experiments, monkeys typically signal their percept by making saccadic eye movements in specific directions. We asked whether parietal neurons are involved in decisions that do not have a spatially specific motor read-out. In our first experiment, we trained monkeys to group directions of motion into two180°-wide “categories”. After training, we found that LIP neurons reflected the learned category boundary, in that individual neurons tended to respond similarly within direction categories but differently between categories. We examined the generality of these effects by training animals in a paired-associate task in which the animals learned to group pairs of arbitrarily chosen static shapes. We found again that LIP neurons reflected the learned pair-associations, in that individual neurons tended to respond more similarly for associated pairs of shapes than for unassociated pairs of
shapes. In both the direction-categorization task and the shape-paired-associate task we used a delayed match-to-category (-pair) paradigm that dissociated the category (pair) identity from the hand movement the animal used to signal its report. We also controlled carefully for behavioral artifacts that could have produced the observed neuronal selectivity. Our results suggest that parietal neurons provide decisional signals that do not fit in a spatial- or motor-based framework. These findings challenge the generality of models positing that categorical
decisions are represented in an action- or intention-based framework. Action-based frameworks have been proposed for other brain representations, such as for the representation of value. However, we also find action-independent neuronal representations of value in orbitofrontal cortex. We hypothesize that non-action-based representations are prevalent in the brain and can be revealed by appropriate experimental design.

http://www.hcs.harvard.edu/decision-ws/Spring_2012.html
02:00 pm
02:00pm - 03:00pm
Ronen Segev - What can a small fish teach us about visual processing?Ronen Segev
Life Sciences Department & Zlotowski Center for Neuroscience
Ben Gurion University of the Negev

Abstract:

Vision can be defined as the process of acquiring knowledge about the environment by extracting information from the light that the objects emit or reflect. To achieve this goal, numerous different visual systems have evolved in the animal kingdom. This brings up the question whether there are universal features to the visual processing solutions we can find in nature. To address this question we use the archer fish as an animal model to study different aspect of visual processing. The selection of this fish species as model animal stems from its remarkable ability to shoot down insects settling on the foliage above the water level, and its ability to learn to distinguish between artificial targets presented on a computer monitor. Thus, the archer fish can provide the fish equivalent of a monkey or a human that can report psychophysical decisions and make controlled and complex experimental procedures possible, yet with a very different brain anatomy. I will review our recent findings that show remarkable similarities between the functionality of the visual system of the archer fish and visual systems
in mammals and try to argue that it reflects universal features of visual processing across vertebrates.

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