Prof. Ilana Witten from Princeton University will be giving a talk on ‘Striatal circuits for reward learning and decision-making.’

The talk will be hosted online at 5.30 pm, while at 6.45 pm we will host a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! To join our mailing list, follow the instructions here https://cortexclub.com/join-us

Abstract:

How are actions linked with subsequent outcomes to guide choices? The nucleus accumbens (NAc), which is implicated in this process, receives glutamatergic inputs from the prelimbic cortex (PL) and midline regions of the thalamus (mTH). However, little is known about what is represented in PL or mTH neurons that project to NAc (PL-NAc and mTH-NAc). By comparing these inputs during a reinforcement learning task in mice, we discovered that i) PL-NAc preferentially represents actions and choices, ii) mTH-NAc preferentially represents cues, iii) choice-selective activity in PL-NAc is organized in sequences that persist beyond the outcome. Through computational modelling, we demonstrate that these sequences can support the neural implementation of temporal difference learning, a powerful algorithm to connect actions and outcomes across time. Finally, we test and confirm predictions of our circuit model by direct manipulation of PL-NAc neurons. Thus, we integrate experiment and modelling to suggest a neural solution for credit assignment.

Dr. Carsen Stringer from HHMI Janelia Research Campus, will be giving a talk on ‘High precision coding in visual cortex.’

The talk will be hosted online at 2.30 pm, while at 4.00 pm we will host a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! To join our mailing list, follow the instructions here https://cortexclub.com/join-us/

Abstract:

Single neurons in visual cortex provide unreliable measurements of visual features due to their high trial-to-trial variability. It is not known if this “noise” extends its effects over large neural populations to impair the global encoding of stimuli. We recorded simultaneously from ∼20,000 neurons in mouse primary visual cortex (V1) and found that the neural populations had discrimination thresholds of ∼0.34° in an orientation decoding task. These thresholds were nearly 100 times smaller than those reported behaviorally in mice. The discrepancy between neural and behavioral discrimination could not be explained by the types of stimuli we used, by behavioral states or by the sequential nature of perceptual learning tasks. Furthermore, higher-order visual areas lateral to V1 could be decoded equally well. These results imply that the limits of sensory perception in mice are not set by neural noise in sensory cortex, but by the limitations of downstream decoders.

Prof. Magdalena Gotz from Helmholz Center Munich, will be giving a talk on ‘Novel mechanisms of neurogenesis and neural repair.’

TThe talk will be hosted online at 2 pm, while at 3.30 pm we are having a virtual pub chat with the speaker. Further details on how to join both sessions will be sent through our mailing list! Please note that this virtual event will be accessible only to members of the University of Oxford. To attend the talk, please register here with an Oxford email address.

Abstract:

We study the mechanisms of neurogenesis utilizing some of them also for neuronal repair. I will first speak about novel players in neurogenesis during development, highlighting a novel centrosome protein (Akna, Camargo et al., Nature 2019). This work prompted us to explore centrosome composition at a comprehensive level. I will present unpublished data about human neural cells centrosome proteome highlighting the profound differences in centrosome composition compared to other cell types. I will show that this centrosome proteome unravels novel candidates for neurodevelopmental disease, especially those involved in misplacement of neurons, periventricular heterotopia. I will talk about a generally expressed protein that is only localized at the centrosome in neural cells and show data about disease modelling. From there I will proceed to present unpublished work on a new intrinsic disordered protein with profound effects on neural development acting as nuclear master regulator of liquid phase transition – regulating the size and function of several membrane-less nuclear compartments simultaneously. I will then show that this protein is also critical for direct neuronal reprogramming and up-date on the recent breakthrough in direct glia-to-neuron conversion after brain injury. I will then move on to discuss the integration of replaced neurons into the circuitry of the murine cerebral cortex, that normally does not integrate new neurons at adult stages and present unpublished data about the mechanisms regulating this integration. Taken together, our knowledge about basic mechanisms of neurogenesis allowed making great strides towards neuronal repair.

For our next virtual event, Lorenz Fenk from Max Planck Institute for Brain Research, will be giving a talk on Dragons, Sleep, and the Claustrum.

The talk will be hosted online at 4 pm, while at 5.30 pm we are having a virtual Q&A chat with the speaker. Further details on how to join both sessions will be sent through our mailing list!

Abstract:

The mammalian claustrum, by virtue of its dense interconnectivity with cortex and other brain structures, has been hypothesized to mediate functions ranging from decision making to consciousness. I will be presenting experimental evidence for the existence of a claustrum in reptiles, its role in generating brain dynamics characteristic of sleep, and discuss our neuroetholgical approach towards understanding fundamental aspects of sleep and claustrum function.