Seminars

Matthew J. Girgenti discusses how research on individual brain cells and the three-dimensional organization of DNA is changing the biological understanding of post-traumatic stress disorder. The seminar examines how these approaches reveal trauma-associated brain changes and identify possible targets for more effective, personalized treatments. Girgenti is a neuroscientist in Yale School of Medicine’s Department of Psychiatry. Jeffrey Borenstein moderates this Meet the Scientist session. Online via the BBRF Zoom webinar. Tuesday 13 October 2026, 14:00 EDT (America/New_York; UTC−4). Follow Register Today on the organizer’s event page to the event-specific Zoom form. Advance registration is available to researchers, students, healthcare providers, mental-health organizations, patients and family members.

Shantanu Jadhav presents work on coordinated hippocampal-prefrontal activity and the neural mechanisms that support memory-guided cognition and decisions. The seminar draws on systems electrophysiology and circuit analysis to connect distributed network dynamics with behavior.

Yun Xia presents macrophage–kidney assembloids that address missing immune and vascular components in stem-cell organoids. Directed differentiation, self-organization, genetic perturbation, xenotransplantation and single-cell analysis reveal immune–epithelial interactions. Macrophages from the same parental cells acquire resident phenotypes; diabetic and polycystic kidney models show context-dependent effects on inflammation, epithelial injury and disease progression. Minoru Takasato addresses kidney organoids’ missing urinary outflow by generating bladder tissue from human pluripotent cells. Stepwise differentiation passes through endoderm, hindgut and cloaca; FGF4 posteriorization and growth-factor screening promote urothelial identity. The resulting sacs contain stratified urothelial cell types, stretch and form a barrier, supporting developmental, disease and future therapeutic studies. Online via Zoom. Tuesday 13 October, 11:00–12:30 SGT (Asia/Singapore). Both talks share this session; individual start times are unspecified. Register through the organizer page. Professional, trainee or student status in stem cells, regenerative medicine or an adjacent field is required; organizer approval and recording restrictions apply.

Galaxy images and spectra map large-scale cosmic structure and constrain fundamental physics. While galaxy-clustering bias models are well developed, forthcoming datasets can also trace the intergalactic medium and recover complementary cosmic-web information. Jamie Sullivan discusses models for both neutral and ionized intergalactic material. Neutral-hydrogen work includes the environments of Lyman-alpha emitters at redshifts 2.5–5, relevant to future DESI extensions and Spec-S5, together with the measured Lyman-alpha forest and an observationally practical compression of its bispectrum. Ionized-gas research studies momentum through an effective-field-theory kinetic Sunyaev–Zel’dovich bispectrum, and density through fast-radio-burst clustering and cross-correlations. Together, these approaches aim to map intergalactic modes alongside galaxy tracers and improve precision cosmological constraints.

This seminar investigates Anderson localization in subwavelength elastic periodic systems with random perturbations. For the unperturbed structure, layer-potential methods recast the eigenvalue problem as boundary integral equations, yielding asymptotic expressions for subwavelength eigenvalues and establishing a band gap above the subwavelength band. A Floquet transform then brings the perturbed problem into a periodic formulation and produces equations for resonant frequencies under general perturbations. Numerical experiments on monomer and dimer structures test agreement with the analysis. Increasing the strength and number of random perturbations demonstrates localization, providing a mathematical basis for elastic metamaterial design.

Takaki Komiyama will discuss how cortical circuits maintain information about the value of behavioral options across trials and transform past experience into future choices. The talk draws on longitudinal imaging and circuit manipulation in mice to examine distinct neuronal populations and local and long-range interactions in history-dependent decision-making.

Tom Nowakowski explains lineage barcoding and single-cell sequencing approaches for reconstructing neural stem-cell family trees and early wiring programs in developing mouse and human brains.

This public discussion examines the factors that help preserve brain health during aging. Researchers working on neuroscience, brain stimulation, the microbiome and brain health consider how stress, everyday behavior and social and environmental conditions can affect resilience over a lifetime. The panel discusses emerging evidence about early vulnerability, possible interventions through lifestyle changes and stress management, and more targeted approaches. It also addresses the limits of current knowledge and the uncertainties that remain when translating these findings into ways to protect cognitive health.

Navigation and memory require coordination between map-like allocentric representations and body-centered egocentric actions. Aaron Wilber examines how the parietal–retrosplenial–anterior thalamic–hippocampal network performs these transformations, and how disrupted coordination contributes to spatial deficits in aging and Alzheimer’s disease. Rat sequence-task experiments reveal bidirectional hippocampal–parietal interactions across route-centered, place and egocentric representations. Because that task does not isolate reference-frame use, the laboratory developed a freely available task separating egocentric, allocentric and transformation conditions. Validation indicates that parietal cortex and anterior thalamus are required for transformation; ongoing work examines population states associated with each condition. The talk then connects impaired hippocampal–cortical communication during sleep to navigation deficits in 3xTg-AD mice, reporting recovery of circuit function and cognition after early, circuit-targeted 40 Hz entrainment. Related investigations examine this network during waking navigation. In TgF344-AD rats, egocentric impairments appear before transformation deficits, addressing the shortage of rodent studies of reference-frame coordination in Alzheimer’s disease.

How do humans stabilize an inverted pendulum, and why does a balanced pole eventually fall? Drawing on 25 years of fingertip pole-balancing research, this talk examines neural correction delays: longer poles move more slowly relative to the nervous system’s response time. Delay-differential models can stabilize the upright position, yet skilled people still experience falls. The proposed explanation is microchaos arising from interactions among delay, sensory dead zones and frequency-dependent force encoding. A region of transient falling solutions lies next to stable microchaotic dynamics. Such microchaos is absent in virtual frontal-plane balancing tasks, while models of standing postural sway lack the corresponding transient regime. The comparison suggests that human falls, unlike pole falls, are more plausibly associated with medical events or slips and trips.

Anthony Letai discusses how understanding programmed cell death can guide the selection of cancer treatments. The seminar explains how apoptotic signalling can be measured and how these measurements can identify drugs capable of killing cancer cells. Hybrid: New Research Building Auditorium, Georgetown University Medical Center, Washington, DC, and Zoom. Monday 5 October 2026, 16:30–17:30 EDT (America/New_York; UTC−4). Use the attendance registration form or the event’s Zoom link on the organizer page. Organized by Georgetown’s Distinguished Scientist Seminar Series. Letai is Director of the National Cancer Institute. An in-person reception follows the seminar.

To orchestrate complex behaviors in mammals, the cerebral cortex must continuously transmit its processing results to subcortical regions. While internal cortical processing relies on highly selective sparse codes, these descending cortical output streams employ an enigmatic dense code, characterized by high firing rates and low feature selectivity. This dense population code presents a profound paradox: how can downstream regions extract precise, cognitively relevant signals when most cortical output neurons can be active at any moment? We address this paradox by testing the hypothesis that cortex does not lose information when switching to a dense code. Instead, it utilizes a mechanism for sparse-to-dense coding transformations discovered by my laboratory: thalamocortical synapses target specifically the dendritic initiation zone for calcium action potentials (APs), which enables cortical output neurons to transmit multiple information streams simultaneously via a multiplexed 1-2-3 AP syntax. I will provide first evidence that this remarkable synaptic specificity and coding syntax generalize across long-range pathways. Information coupling via an anatomically and biophysically distinct dendritic nexus may hence be a ubiquitous mechanism for sparse-to-dense coding transformations in cortex. Dissecting these mechanistic origins of cortical output streams is only now possible due to a unique in vivo – in silico approach, perfected over two decades, that my laboratory developed for bridging the gaps between dendritic and population-level computations

Picower Institute Colloquium on the Brain and Cognition featuring Christopher Harvey, PhD, of Harvard University, held in Singleton Auditorium (46-3002) at MIT Building 46, 43 Vassar Street.

Scott J. Russo examines how chronic psychosocial stress alters communication between the immune system and the brain in depression and anxiety. Human observations and mouse experiments connect persistent increases in circulating monocytes and inflammatory signals with stress-related illness. The talk describes stress-responsive neurons that project to bone marrow and regulate monocyte production, release and trafficking. It also considers how stress disrupts the blood–brain barrier, allowing peripheral inflammatory proteins to affect reward regions such as the nucleus accumbens. Together, these findings examine how peripheral immune cells act at the neurovascular interface to change brain circuits and behaviour, providing potential mechanisms relevant to treatment-resistant mood disorders. Online via Rutgers Brain Health Institute Zoom. Thursday 1 October 2026, 12:00–13:00 EDT (America/New_York; UTC−4). Open the organizer’s event page and follow its Zoom link; the meeting ID and passcode are supplied there. Hosted by Yong Kim as part of the BHI Plenary Seminar Series. This listing advertises the verified remote option.

Lenka Zdeborová introduces the Rules-and-Facts model, in which some observations follow a shared rule while others are isolated exceptions requiring memorization. The framework studies when a learner can acquire the rule and retain those exceptions simultaneously. Its results emphasize how capacity is organized and deployed, rather than capacity alone. The talk examines how regularization and the geometry of kernels or learned feature maps can reserve resources for memorization without undermining rule learning. It connects the balance between abstraction and memory to architectural and algorithmic choices, providing a theoretical account of neural networks that both generalize and recall specific facts.

Mansi Chhajed examines how the move from home sleep patterns to disrupted hospital sleep relates to cognitive outcomes after surgery. The session combines longitudinal sleep measurements with clinical assessments of postoperative delirium to identify baseline markers of vulnerability and consider practical ways to improve recovery. It connects sleep architecture, biological and environmental influences, and preoperative risk with proactive, sleep-informed patient care. Chhajed is a Clinical Research Coordinator at Massachusetts General Hospital. Online via Zoom Webinar. Tuesday 29 September 2026 at 14:00 ET / 13:00 CT (America/New_York; EDT, UTC−4). Organized by the Sleep Research Society — Virtual Seminar Series. Follow Register Today on the organizer's page to the event-specific Zoom form, which requests name and email. The form is publicly accessible; advance registration supplies webinar access.

Vanessa Siffredi explores why the corpus callosum is central to typical brain development, yet some children born without it or with callosal abnormalities develop comparably to their peers. The talk connects callosal structure and communication between hemispheres with cognition, attention, executive function, memory, language and socio-emotional development. Structural and functional neuroimaging studies of typical development and callosal dysgenesis examine how developing brains compensate for alterations in this major white-matter pathway. Siffredi is affiliated with CHUV and UNIL; Carole Guedj chairs the seminar. Hybrid: Auditoire de pédiatrie Fred Bamatter, HUG, Hôpital des Enfants, Geneva; online via Zoom. Tuesday 29 September 2026, 09:30–10:30 CEST (Europe/Zurich; UTC+2), followed by CIBM news and networking until 11:00. Organized by CIBM Center for Biomedical Imaging — Breakfast and Science. In-person attendance is free without registration. Remote attendees must register through the Zoom link on the event page and select the 29 September occurrence.

Merav Ahissar examines how expertise emerges through learning the statistics of task-relevant stimuli. Slow learning builds familiarity with stable regularities, such as syllable patterns in language, while fast adaptation supports flexible responses to changing situations, including surprising social interactions. The talk considers atypical learning dynamics in dyslexia and autism and how these may explain difficulties in linguistic and social skill acquisition, respectively. The discussion draws on Gertsovski and Ahissar, Trends in Cognitive Sciences, 2026. Speaker: Merav Ahissar, Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem. Organized by Cornell Cognitive Science. Friday 25 September 2026, 15:00–16:30 America/New_York (EDT). Attend online through the public Join via Zoom link on the official event page; the link opens Zoom’s app and browser join options. Cornell advertises the source event as hybrid, but this listing covers the verified online attendance route.

Mark Harnett presents work on how synaptic organization, nonlinear dendritic processing, and neuronal activity patterns interact to support computation, flexibility, and learning in the adult mammalian neocortex. The Brain and Cognitive Sciences colloquium is followed by a reception.

Leonid Berlyand discusses mathematical models for the onset of cell motion driven by myosin contraction. A two-dimensional free-boundary PDE model links cell-shape evolution to diffusion and Keller–Segel-type transport. The talk examines linear stability, a stability-determining eigenvalue and the way nonlinear diffusion changes the bifurcation from supercritical to subcritical. It also considers the curvature of the bifurcation curve, connections to bistability, and the role of non-self-adjoint operators. An example illustrates why a spectral gap alone need not guarantee stability. This is an in-person Analysis of Fluids and Related Topics seminar at Princeton.