Tuesday, May 28, 2013
Thursday, May 23, 2013
CNS Seminar: Harvey Karten
Tuesday, May 28th @noon
Harvey Karten
UC San Diego
How is a bird's brain wired? How does it differ from that of mammals?
Abstract. Behavioral repertoires of birds show remarkable similarities to mammals in many regards. How is their brain organized? Do birds solve problems with totally different neural circuits than mammals and using different algorithms? I will try to review the dramatically changing views of the
avian brain, and provide some guidance in understanding the new perspectives on the organization of auditory, visual and basal ganglia circuitry. These results are leading a novel understanding of the evolution of mammalian cortex and basal ganglia. The answer will help simplify your hope of understanding an avian brain, and provide some insight into the unsupportable claims of uniqueness of mammalian cortical processing.
Harvey Karten
UC San Diego
How is a bird's brain wired? How does it differ from that of mammals?
Abstract. Behavioral repertoires of birds show remarkable similarities to mammals in many regards. How is their brain organized? Do birds solve problems with totally different neural circuits than mammals and using different algorithms? I will try to review the dramatically changing views of the
avian brain, and provide some guidance in understanding the new perspectives on the organization of auditory, visual and basal ganglia circuitry. These results are leading a novel understanding of the evolution of mammalian cortex and basal ganglia. The answer will help simplify your hope of understanding an avian brain, and provide some insight into the unsupportable claims of uniqueness of mammalian cortical processing.
Thursday, May 9, 2013
CNS Seminar: Scott Freeman & Krista Perks
May 14th @ Noon
Scott Freeman
UC San Diego
How response control is exerted over a motivating stimulus during Pavlovian-to-Instrumental transfer
Abstract. We asked whether top down response control mechanisms exist that can be used to ensure that a motivating stimulus does not influence behavior. To examine this, we developed a novel hybrid Go-NoGo and Pavlovian-instrumental transfer paradigm for studying thirsty human participants. First, we validate behaviorally and physiologically that a motivating (conditioned) stimulus quickly leads to response activation when responding is required; and second, we show that this response activation is mitigated when the participant has a top down control goal in place.
Krista Perks
UC San Diego
Mechanisms of Response Integration in Multi-Signal Context
Abstract. The auditory system is challenged with attending to target signals in noisy environments. At the level of single neurons in a songbird auditory cortical region, the specific and selective response to a target conspecific song signals is modulated by the presence of other noise signals. In this system, we are testing a mechanistic model for the observed normalization-like phenomena by measuring the specific interactions of synaptic and subthreshold activity evoked by song and noise signals and their combinations.
Scott Freeman
UC San Diego
How response control is exerted over a motivating stimulus during Pavlovian-to-Instrumental transfer
Abstract. We asked whether top down response control mechanisms exist that can be used to ensure that a motivating stimulus does not influence behavior. To examine this, we developed a novel hybrid Go-NoGo and Pavlovian-instrumental transfer paradigm for studying thirsty human participants. First, we validate behaviorally and physiologically that a motivating (conditioned) stimulus quickly leads to response activation when responding is required; and second, we show that this response activation is mitigated when the participant has a top down control goal in place.
Krista Perks
UC San Diego
Mechanisms of Response Integration in Multi-Signal Context
Abstract. The auditory system is challenged with attending to target signals in noisy environments. At the level of single neurons in a songbird auditory cortical region, the specific and selective response to a target conspecific song signals is modulated by the presence of other noise signals. In this system, we are testing a mechanistic model for the observed normalization-like phenomena by measuring the specific interactions of synaptic and subthreshold activity evoked by song and noise signals and their combinations.
Friday, May 3, 2013
CNS Seminar: Tirin Moore
Tuesday, May 7th @ Noon
Control of Visual Spatial Attention by Prefrontal Cortex
Tirin Moore
Stanford University
A principal function of the prefrontal cortex (PFC) is selective attention, and this function involves the top-down modulation of sensory signals during goal-directed behavior. I will talk about recent work demonstrating the involvement of the frontal eye field (FEF), an oculomotor area within PFC, in visual spatial attention in which relevant visual information is selected at the expense of potentially distracting information. This work not only implicates the FEF in the control of voluntarily directed spatial attention but elucidates its neural circuitry.
Control of Visual Spatial Attention by Prefrontal Cortex
Tirin Moore
Stanford University
A principal function of the prefrontal cortex (PFC) is selective attention, and this function involves the top-down modulation of sensory signals during goal-directed behavior. I will talk about recent work demonstrating the involvement of the frontal eye field (FEF), an oculomotor area within PFC, in visual spatial attention in which relevant visual information is selected at the expense of potentially distracting information. This work not only implicates the FEF in the control of voluntarily directed spatial attention but elucidates its neural circuitry.
Wednesday, May 1, 2013
new Gentner Lab paper out in Neuron
Associative Learning Enhances Population Coding by Inverting Interneuronal Correlation Patterns
Jeanne, Sharpee & Gentner
Abstract. Learning-dependent cortical encoding has been well described in single neurons. But behaviorally relevant sensory signals drive the coordinated activity of millions of cortical neurons; whether learning produces stimulus-specific changes in population codes is unknown. Because the pattern of firing rate correlations between neurons—an emergent property of neural populations—can significantly impact encoding fidelity, we hypothesize that it is a target for learning. Using an associative learning procedure, we manipulated the behavioral relevance of natural acoustic signals and examined the evoked spiking activity in auditory cortical neurons in songbirds. We show that learning produces stimulus-specific changes in the pattern of interneuronal correlations that enhance the ability of neural populations to recognize signals relevant for behavior. This learning-dependent enhancement increases with population size. The results identify the pattern of interneuronal correlation in neural populations as a target of learning that can selectively enhance the representations of specific sensory signals.
Friday, April 26, 2013
CNS Seminar: Marlene Cohen
Tuesday, April 30th @ Noon
Marlene Cohen
University of Pittsburgh
Carnegie Mellon
How uncontrolled fluctuations in cognitive states affect performance
We have known for decades that using laboratory tricks to manipulate subjects’ cognitive states can have a big effect on both their perceptual abilities and the responses of cortical neurons. These experiments typically compare performance or neuronal responses in blocks of trials that differ in some aspect of the task or the instructions to the subject. Both inside and outside the lab, however, our minds wander often, and the effects of these uncontrolled fluctuations in cognitive state on performance are largely unknown. I will describe work using the responses of a few dozen simultaneously recorded neurons in visual cortex to estimate an animal’s cognitive state at a given moment. We used these methods to show that fluctuations in both visual attention and in arousal or concentration have large but often unintuitive effects on performance on psychophysical tasks. Our results suggest that the results of all psychophysical experiments should be thought of as amalgamations different cognitive states, whether or not those studies specifically addressed attention or arousal.
Marlene Cohen
University of Pittsburgh
Carnegie Mellon
How uncontrolled fluctuations in cognitive states affect performance
We have known for decades that using laboratory tricks to manipulate subjects’ cognitive states can have a big effect on both their perceptual abilities and the responses of cortical neurons. These experiments typically compare performance or neuronal responses in blocks of trials that differ in some aspect of the task or the instructions to the subject. Both inside and outside the lab, however, our minds wander often, and the effects of these uncontrolled fluctuations in cognitive state on performance are largely unknown. I will describe work using the responses of a few dozen simultaneously recorded neurons in visual cortex to estimate an animal’s cognitive state at a given moment. We used these methods to show that fluctuations in both visual attention and in arousal or concentration have large but often unintuitive effects on performance on psychophysical tasks. Our results suggest that the results of all psychophysical experiments should be thought of as amalgamations different cognitive states, whether or not those studies specifically addressed attention or arousal.
Wednesday, April 24, 2013
2013-14 CNS Speaker Suggestions
hi all, we are beginning to put our list together for who we would like to invite for the CNS seminar series next year and would love to get some input from everyone. if you have someone you think would be a good fit for series, just email adam, john, tim or i with your suggestion. please send these suggestions within the next couple of weeks since we will begin inviting the speakers next month.
Wednesday, April 10, 2013
CNS Seminar: David Leopold
tuesday@noon
April 16th
David Leopold
NIMH
Emerging strategies for studying social representation in the primate brain
Abstract. Several decades of research have revealed exquisite neural selectivity in the monkey inferotemporal cortex for complex stimuli, including those related to social perception. The importance of these selective responses for determining perception, action, and social behavior is a challenging topic. I will present preliminary data on three novel approaches for studying the nature of inferotemporal responses. The first approach employs longitudinal single unit recording to study the emergence, plasticity, and stability of selective responses over time scales of weeks. The second approach evaluates fMRI and single-unit responses in the monkey brain during active viewing of socially rich natural videos. The third approach uses fMRI to map visual category selective responses in the ventral stream of the marmoset, with the ultimate aim of understanding the homology across primate or mammalian species. Together, these approaches aim to provide new perspectives on neural mechanisms underlying visual object and social perception in primates, including humans.
April 16th
David Leopold
NIMH
Emerging strategies for studying social representation in the primate brain
Abstract. Several decades of research have revealed exquisite neural selectivity in the monkey inferotemporal cortex for complex stimuli, including those related to social perception. The importance of these selective responses for determining perception, action, and social behavior is a challenging topic. I will present preliminary data on three novel approaches for studying the nature of inferotemporal responses. The first approach employs longitudinal single unit recording to study the emergence, plasticity, and stability of selective responses over time scales of weeks. The second approach evaluates fMRI and single-unit responses in the monkey brain during active viewing of socially rich natural videos. The third approach uses fMRI to map visual category selective responses in the ventral stream of the marmoset, with the ultimate aim of understanding the homology across primate or mammalian species. Together, these approaches aim to provide new perspectives on neural mechanisms underlying visual object and social perception in primates, including humans.
Thursday, April 4, 2013
CNS Seminar: Xin Jin
April 9th @ noon
Xin Jin
Salk Institute
Dissecting the basal ganglia subcircuits for action
The basal ganglia has been thought to be involved in action learning and selection. The classic model of basal ganglia circuits suggested there are two major neural pathways, differently modulated by dopamine and working antagonistically to facilitate and inhibit movements, respectively. Despite the wide application of this model to understand basal ganglia function and diseases, the classic model itself has never been directly evaluated. I'll present the findings we have on the physiology and function of the basal ganglia subcircuits during action learning, combining in vivo recording and optogenetics in freely behaving mice. A possible updated view on classic model will also be discussed.
Xin Jin
Salk Institute
Dissecting the basal ganglia subcircuits for action
The basal ganglia has been thought to be involved in action learning and selection. The classic model of basal ganglia circuits suggested there are two major neural pathways, differently modulated by dopamine and working antagonistically to facilitate and inhibit movements, respectively. Despite the wide application of this model to understand basal ganglia function and diseases, the classic model itself has never been directly evaluated. I'll present the findings we have on the physiology and function of the basal ganglia subcircuits during action learning, combining in vivo recording and optogenetics in freely behaving mice. A possible updated view on classic model will also be discussed.
Tuesday, March 19, 2013
CNS Seminar: Eric Knudsen
April 2nd @ noon
Eric Knudsen
Stanford University
Neural Mechanisms of Spatial Attention
Abstract. Attention allows us to select the most important information at each moment in time and to enhance and differentially process that information while ignoring other, irrelevant information. This capacity is essential to nearly all cognitive processes. But, how does attention work at the level of cells and circuits? We are addressing this question by studying circuits that contribute to spatial attention in birds. We have identified a midbrain network that includes structurally specialized cholinergic, GABAergic and glutamatergic circuits, which perform many of the fundamental computations underlying attention, including filtering for stimulus salience, competitive selection of the most salient stimulus, and top-down enhancement of the quality of information. This network interacts extensively with the fronto-parietal forebrain network and is highly conserved across vertebrate evolution. We study the properties of these specialized circuits in chickens and owls, in behaving animals engaged in attention-demanding tasks, in vivo and in brain slice preparations. I will discuss our current understanding of how the computations performed by these circuits contribute to the control of attention.
Eric Knudsen
Stanford University
Neural Mechanisms of Spatial Attention
Abstract. Attention allows us to select the most important information at each moment in time and to enhance and differentially process that information while ignoring other, irrelevant information. This capacity is essential to nearly all cognitive processes. But, how does attention work at the level of cells and circuits? We are addressing this question by studying circuits that contribute to spatial attention in birds. We have identified a midbrain network that includes structurally specialized cholinergic, GABAergic and glutamatergic circuits, which perform many of the fundamental computations underlying attention, including filtering for stimulus salience, competitive selection of the most salient stimulus, and top-down enhancement of the quality of information. This network interacts extensively with the fronto-parietal forebrain network and is highly conserved across vertebrate evolution. We study the properties of these specialized circuits in chickens and owls, in behaving animals engaged in attention-demanding tasks, in vivo and in brain slice preparations. I will discuss our current understanding of how the computations performed by these circuits contribute to the control of attention.
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