Abstracts – SPEAKERS
Joseph Barnby, PhD – Walking a Mile in Their Shoes: Using Computational Models to Understand Social Cognition in Health and Disorder
From the very start of life, humans engage in interactions that are foundational to development. Through interactions with parents, family, and friends, we acquire self-regulation, social, cognitive, and emotional skills. These pivotal relationships furnish us with a suite of psychological processes essential for learning and adaptation in adulthood. Although significant scientific advances have delineated the algorithms underlying these psychological mechanisms, there remains a lack of a formal, interoperable framework to unify the critical components that foster social bonding. In this presentation, I will propose a theoretical structure designed to frame and precisely testing of facets of social cognition in both healthy individuals and those with disorders, spanning phenomena from social contagion to hierarchical mentalizing. I will share novel empirical and experimental data that test these assertions drawn from diverse groups, including the general population, adolescents, and individuals with psychiatric diagnoses. Finally, I will discuss synthetic simulations that predict and test the conditions under which different algorithmic configurations may become adaptive or maladaptive, potentially leading to distress and disability.
Jaime de la Rocha, PhD -The dynamics of evidence accumulation and response execution during rule-guided decisions.
Deciding requires integrating information from multiple sources over multiple time-scales. In perceptual decisions, for instance, ambiguous stimuli require fast accumulation of sensory evidence, a process largely studied but whose underlying mechanisms remain largely debated. Recent experiences on the other hand, can also impact the way we decide by reinforcing rewarded choices and strategies creating a dynamic prior framework that guides subsequent decisions. Where in the brain these decision variables are represented, updated and integrated to drive responses, it still unknown. In this talk I will present extensive data from rats performing a two-alternative decision-making task, which requires temporal integration within or/and across trials. I will show that rats can leverage on the latent statistical structure of the task and consistently develop a tendency to predict the upcoming stimulus from the previous responses and outcomes. Then I will show that the timing and the orienting response trajectory can be explained by a novel model which, building on the standard accumulation to evidence models, incorporates proactive responses whose trajectories can be updated as the stimulus information reaches the decision bounds. Finally, using this behavioral model, pharmacological and optogenetic manipulations as well as electrophysiological recordings, I will characterize the role of several brain areas in this behavior, particularly of the dorsal striatum. Together, these results reveal that the accumulation of evidence across trials can exhibit complex dynamics and that the striatum plays a critical role in encoding this evidence and the choice biases it causes.
Mateusz Ambrożkiewicz, PhD – Proteostatic mechanisms of cellular diversification in the developing brain”
Formation of functional circuits in the adult brain is a biological fundament for its executive role in the living organism and requires specification of neurons, their correct positioning, formation of dendrites and synapses. In this talk, I will present our current research on the translational mechanisms and post-translational modifications orchestrating neuronal diversification in the developing brain. Particularly, I will shed light on the specific post-transcriptional requirements for neuronal progenitors, including the dynamics of protein synthesis as well as the role of ubiquitination-dependent degradation in healthy and diseased brain.
Jan Antolik, PhD – Learning stimulation protocols for cortical visual prosthetic systems
Cortical visual prosthetic systems are investigated as a means of restoring vision in subjects with impaired eye-brain connection. A central hypothesis of such endeavor is that induction of an activity pattern in visual cortex similar to that evoked by a given visual stimulus, will elicit perception of similar visual stimulus. Existing V1 prostheses stimulation strategies take into account only the retinotopic aspect of visual coding [1,2], overlooking other important coding properties of V1 neurons such as selectivity for stimulus orientation. Here we introduce a novel stimulation protocol that stimulates cortical tissue according to both retinotopy and orientation columns. To obtain this protocol, we implemented a bottlenecked rotationally equivariant convolutional neural network, that learns to predict neural responses to arbitrary stimuli solely based on the neuron’s receptive field position and orientation preference. Our model outperforms the standard energy model of V1 complex cells. The high correlation between target and predicted responses suggests that position and orientation alone can explain a large portion of V1 neural response variability. To test whether stimulation of cortical tissue according to our model would indeed induce desired activity in the dynamic recurrent cortical networks, we utilized a previously published simulation framework [3] composed of a large-scale recurrent spiking V1 model to simulate optogenetic prosthetic stimulation delivered via an LED array placed on the cortical surface. Our simulations show that the newly proposed retinotopic-and-orientation-based stimulation protocol recruits neural patterns that more accurately mimic natural vision processing than analogous protocols only relying on coding of retinotopy.
1. Fernández, Eduardo, et al. “Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex.” The Journal of clinical investigation 131.23 (2021)
2. Chen, Xing, et al. “Shape perception via a high-channel-count neuroprosthesis in monkey visual cortex.” Science 370.6521 (2020): 1191-1196.
3. Antolik, Jan, et al. “Assessment of optogenetically-driven strategies for prosthetic restoration of cortical vision in large-scale neural simulation of V1.” Scientific reports 11.1 (2021): 10783.
Mark Hunt, PhD, DSc, Associate Professor – The Role of the Olfactory Bulb in Ketamine-Induced Abnormal Fast Brain Rhythms
First synthesized in 1962 as an anesthetic, ketamine was initially found to produce short-lasting, psychotic-like dissociative states, which led to its use in modeling certain features of schizophrenia. Perhaps surprisingly, over the past two decades, ketamine has gained increased attention for its antidepressant potential. Despite ketamine’s history, its mechanisms of action are still not fully understood. In this talk, I will focus on one notable electrophysiological feature reliably reported in rodents: the enhancement of abnormal high-frequency oscillations (HFOs, 130-180 Hz). These oscillations are coherent and observed across many brain regions, including cortical and subcortical areas. Interestingly, HFO increases following ketamine have been reported in various mammals. Unexpectedly, our research has identified the olfactory bulb (OB) as a critical generator of ketamine-induced HFOs, and appears to be essential for ketamine-induced HFO recorded in other brain regions. HFOs couple with slow oscillations driven by nasal respiration. Our recent findings highlight the importance of the olfactory epithelium in generating ketamine-induced HFOs, as reduced input from olfactory sensory neurons disrupts the ketamine rhythm. Notably, it seems that changes in nasal pressure, rather than specific odor presentation, provide the initial drive underpinning the generation of ketamine-induced HFOs. In summary, the OB orchestrates a hypersynchronous HFO brain rhythm produced by ketamine, and further work is required to understand the functional significance of this activity.
Fun fact: I recently learned how to do a Rubik’s cube in less than 5 min.
Doc. Otto Lappi – Gaze behavior in the wild 3+1 paradigms
Eye movements modulate all visual input to the brain. Understanding them is therefore is essential for understanding all aspects of visual brain function, such as perception, attention, memory and dynamic real-world decision making. For neuroscientists who want to venture outside of the lab, mobile eye tracking offers means to investigate how active gaze is deployed “in the wild”.
I natural task environments, the movement of the eye is always embedded in head movement and locomotor patterns. Yet much what we think goes on in the visuomotor system during active visual tasks is extrapolated from oculomotor research in highly simplified laboratory paradigms, where (1) observable parameters of interest are fixed a priori (independent and dependent variables) and (2) the physical implementation of stimulus features and response options (e.g. images rendered on displays, e.g. response buttons or head-fixed eye-movements) are chosen based on this task parametrization and (3) a statistical model determines the sampling of different “conditions” (trial structure).
By contrast, when investigating natural everyday & expert performance the primary concern is often how to determine useful ways to parametrize (1) the naturally occurring patterns of complex dynamic behavior, and (2) the rich environmental structure and (3) the dynamic patterns in how gaze is used to actively sample the visual world. Different parametrization choices yield different “natural paradigms” (different ways of seeing the phenomena) and are appropriate for posing and answering different research questions.
In this talk I will identify and compare four approaches to parametrizing gaze behavior in the wild, which I will call the #1 Oculomotor, #2 Scene, #3 Timing and #4 Localization paradigms. I will argue that #1 – #3 make sense also in the lab, but #4 (which is based on localizing the point of vantage) only makes sense in locomotor contexts) and therefore remains underused, unrecognized as conceptually distinct, and consequently the associated research questions relatively unexplored. Paradigmatic examples from high-speed sport are discussed.