All events, 2013

Multisensory processes guide 3-D spatial navigation in echolocating bats

Lecture
Date:
Thursday, January 17, 2013
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Cynthia Moss
|
University of Maryland, College Park, MD

Echolocating bats exhibit an extraordinary array of solutions to the challenges of maneuvering in cluttered environments, pursuing evasive prey, taking food from water surfaces, and landing on the ceiling or walls of confined spaces. Moreover, they are equipped with a biological sonar system that permits spatial navigation and target tracking in complete darkness. By actively controlling the directional aim, timing, frequency content, and duration of echolocation signals to “illuminate” the environment, the bat directly influences the acoustic input available to its sonar imaging system. Detailed analyses of the bat’s sonar behavior suggests that the animal’s actions play into a rich 3-D representation of the environment, which then guides motor commands for subsequent call production, head aim and flight control in an adaptive feedback system. Somatosensory signaling of airflow along the wing membrane also contributes to the exquisite flight control of bats. Recent research reveals that microscopically small hairs embedded in the bat wing play a functional role in sensing air flow, which is important to it to carry out rapid and agile aerial maneuvers. Neurons in bat primary somatosensory cortex (S1) respond to directional stimulation of the wing hairs with low-speed air flow, and this response is diminished after removal of the hairs. The directional preference of cortical S1 neurons indicates that the hairs respond strongest to reverse airflow, and might therefore act as stall detectors. Further, depilation of different functional regions of the wing membrane alters flight behavior in obstacle avoidance tasks by reducing aerial maneuverability, as indicated by decreased turning angles. Collectively, these findings suggest that bat aerial navigation engages multisensory processes that guide a suite of adaptive motor behaviors.

History and News in the Human Visual Cortex

Lecture
Date:
Tuesday, January 15, 2013
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Rafi Malach
|
Department of Neurobiology, WIS

In the search for unifying principles of human visual cortex function- it will be proposed that human cortical dynamics can be viewed as shifting between two modes. The first is the well-studied active-mode, informing about visual "News"- i.e. the current perceptual state of the observer. These signals are characterized by fast "ignitions" of highly selective neuronal activity. The second, still poorly understood resting- mode is characterized by slow and wide-spread spontaneous fluctuations. It will be hypothesized that these signals inform about the "History"-i.e. the accumulated statistics of prior cortical activations. Examples of these two modes will be shown- derived from single neurons, local field potentials and functional magnetic resonance imaging (fMRI). Preliminary evidence supporting their functional significance will be presented.

Does the orbitofrontal cortex signal value?

Lecture
Date:
Tuesday, January 8, 2013
Hour: 12:45
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Geoffrey Schoenbaum
|
Cellular Neurobiology Branch Chief, NIDA, NIH

The orbitofrontal cortex is strongly implicated in good (or at least normal) “decision-making”. Key to good decision-making is knowing the general value or "utility" of available options. Over the past decade, highly influential work has reported that the neurons in the orbitofrontal cortex signal this quantity. Yet the orbitofrontal cortex is typically not necessary for apparent value-based behaviors unless those behaviors require value predictions to be derived from access to complex models of the task, and the neural correlates cited above only part of a much richer representation linking the characteristics of specific outcomes (sensory, timing, unique value) that are expected and the events associated with obtaining them. In this workshop, I will review these data to argue that this aspect of encoding in the orbitofrontal cortex is actually what is critical in explaining the role of this area in both behavior and learning, and that any contribution of this area to economic decision-making stems from its unique role in allowing value to be derived (both within and without) from these environmental models.

Cellular and Circuit Changes Underlying Cortical Learning and Pathology

Lecture
Date:
Monday, January 7, 2013
Hour: 14:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Amos Gdalyahu
|
Dept of Neurobiolgy, School of Medicine, UCLA

Sensory perception is shaped by past learning, and is mediated by neuronal circuits in the sensory cortex. However, what are the changes in these neuronal circuits following learning have remained unknown. To reveal the circuit changes, I developed a new associative fear-learning procedure, and using in vivo 2-photon microscopy measured the circuit responses to the associated stimulus following learning. I discovered that associative learning reduces the percentage of neurons responding to the associated stimulus, while the neurons that still respond increase their response strength. These changes are specific to associative learning because non-associative training triggers a very different set of circuit changes. Therefore, associative learning shapes circuit responses in the sensory cortex for more efficient processing of the conditional stimulus, and for higher signal to noise ratio. The research in my laboratory will continue to address fundamental questions at the levels of cortical neurons, circuits, and behavior. Specifically, how cortical circuits store new information, what are the cortical pathologies in mouse models of autism, and - in the long-term - what are the mechanisms of learning flexible behavior.

Neurophenomenology and the aesthetics of space flight

Lecture
Date:
Sunday, January 6, 2013
Hour: 14:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Shaun Gallagher
|
Dept of Philosophy, University of Memphis

Introduction: Shaun Gallagher is a philosopher whose interests include embodied and social cognition, perception and agency. His research focuses on phenomenology, philosophy of mind, cognitive science, and hermeneutics, especially the topics of embodied cognition and intersubjectivity. He holds the Lillian and Morrie Moss Chair of Excellence in Philosophy at the University of Memphis. He’s the author of several books, including How the Body Shapes the Mind, Hermeneutics and Education, The Inordinance of Time, and most recently Brainstorming (2008), and (with Dan Zahavi), The Phenomenological Mind (2008). He is editor of The Oxford Handbook of the Self (2011).

Epigenetic transgenerational inheritance alters stress responses in a sexually dimorphic manner

Lecture
Date:
Tuesday, January 1, 2013
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. David Crews
|
Integrative Biology Section, University of Texas, Austin TX

Ancestral environmental exposures to endocrine disrupting chemicals (EDCs) can promote epigenetic transgenerational inheritance and influence all aspects of the life history of descendants. What happens in the life of descendant is also important, and it is well established that proximate life events such as chronic stress during adolescence modify elements of the adult phenotype, including physiological, neural, and behavioral traits. We use a systems biology approach to investigate in rats to explore this interaction of the ancestral modifications carried transgenerationally in the germ line and the proximate modifications involving chronic restraint stress during adolescence. We find that a single exposure to a common-use fungicide (vinclozolin) three generations removed alters the physiology, behavior, metabolic activity, and transcriptome in discrete brain nuclei in descendant males, causing them to respond differently to chronic restraint stress. This alteration of baseline brain maturation promotes a change in neural genomic activity that correlates with changes in physiology and behavior, revealing the interaction of genetics, environment, and epigenetic transgenerational inheritance in the shaping of the adult phenotype. Further, in many of these traits females differ fundamentally from males, indicating that such effects are not general but sex-specific in how descendants of these progenitor individuals perceive and respond to a common challenges (e.g., chronic restraint stress) experienced during their own life history.

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