LECTURE

Pieter R Roelfsema (Netherlands Institute for Neuroscience, Amsterdam): Visual awareness - and how to restore it when the eyes fail

August 17, 2023, 3 PM, Michael-Lankeit Lecture Hall, German Primate Center

A long-standing dream of scientists is to be able to directly project images from the outside world onto the visual brain, bypassing the eyes. This method could provide a solution for blind and visually impaired patients. It is the only possible solution for patients in whom the connection between eye and brain is lost so that a prosthesis in the eye is not an option. I will first give an overview of the functioning of the visual cortex, which has low level areas for the analysis of simple visual features and higher areas for the analysis for more complex properties such as object category and face recognition. I will then discuss the mechanisms that determine whether a visual stimulus will reach consciousness or not. It is well established that the electrical stimulation of electrodes in the visual brain leads to artificial percepts called "phosphenes". This method also works in patients who have been blind for decades. The goal of our own research is to bring a prosthesis for the visual brain closer. We implanted 1000 electrodes in the visual cortex to generate complex visual patterns. We demonstrated that this stimulation leads to interpretable images, in the same way that pixels form recognizable patterns on a screen. These new neurotechnological developments take important steps in the direction of prostheses that can restore a rudimantary form of vision.



WORKSHOP
Intrinsic- and information-timescales
July 5 and July 12, 9.15AM-12.30 PM; Max Planck Institute for Dynamics and Self-Organisation

Organizers: Viola Priesemann, Paul Spitzner and Lucas Rudelt

On the one hand, the intrinsic timescale can be thought of as the duration over which any perturbation reverberates within the network. It is measured by the decay time of an exponentially decaying autocorrelation function, and has been used as a key observable to investigate a functional hierarchy across the primate cortex and serves as a measure of working memory. It is also a proxy for the distance to criticality and quantifies a system’s dynamic working point.

On the other hand, the information timescale is a complementary measure based on information-theoretic predictability. Predictability quantifies the proportion of information in current neural spiking that can be predicted from the recent past. This predictable information reflects temporal redundancy, and facilitates, for instance, active information storage (maintaining past input to combine it with present input) and associative learning. The according information timescale then describes over which time past information has to be integrated until predictability no further increases.

We will be covering two software tools our group developed and apply them to data you bring in. The tools are written in python, and we will cover how to import your data from usual formats such as hdf5.



LECTURE
Jenny Tung (Max Planck Institute of Evolutionary Anthropology Leipzig): Mothers, molecules and mortality: the imprint of social relationships across teh life course in wild baboons
Jun 8, 2023, 3 PM, Michael Lankeit Lecture Hall, German Primate Center

Field studies of natural primate populations present a powerful opportunity to investigate the social and ecological determinants of health and fitness using fine-grained observations of known individuals across the life course. Here, I will summarize our emerging understanding of this process in the wild baboons of the Amboseli ecosystem in Kenya, emphasizing the insights provided by integrating behavioral and molecular data. I will review the strong evidence that early life adversity, social status, and affiliative ties in adulthood are central to life outcomes. I will then discuss how, by integrating genomic methods with longitudinal behavioral observations, we have been able to identify sex-specific signatures of social interactions and evidence for biological embedding via changes in DNA methylation. Together, our findings connect classical life course perspectives on primate behavior and life history with changes in gene regulation “under the skin.” They thus illustrate the increasing potential to understand our study subjects at both the whole-organism and molecular levels, even under field conditions.


LECTURE
Elad Schneidman (Weizmann Institute of Science): Architectural design principles of neural circuits
Jun 1, 2023, 3 PM, Old lecture Hall, German Primate Center

The map of synaptic connectivity among neurons in the brain shapes the computations that neural circuits may perform. Inferring the design principles of neural connectomes is, therefore, fundamental for understanding brain development and architecture, neural computations, learning, and behavior. We learn probabilistic generative models for the connectomes of the olfactory bulb of zebrafish, part of the mouse visual cortex, and of C. elegans. We show that in all cases, models that rely on a surprisingly small number of simple biological and physical features accurately predict the existence of individual synapses and their strength, distributions of synaptic indegree and outdegree of the neurons, frequency of sub-network motifs, and more. Furthermore, we simulate synthetic circuits generated by our model and show that they replicate the computation that the real circuit performs. Thus, our results reflect surprisingly simple design principles of real connectomes. We then explore the architectural features that may shape the computation that connectomes may carry. We measure the similarity of simulated spiking neural networks of neurons in terms of their response to different stimuli, and learn a functional metric between networks based on their synaptic differences. We show that unlike common graph theory tools, our metric accurately predicts the similarity of novel networks, relying on a sparse set of architectural features. We then identify potential key architectural features that control the computations that particular connectomes may implement.


WORKSHOP
SFB Theory Days
May 31st/June 1st, 2023, seminar rooms, German Primate Center


LECTURE
Brandon Munn (U Sydney): Neuronal modelling bridges macroscale adaptive signatures across arousal
May 16, 2023, 3 PM, Michael Lankeit Lecture Hall, German Primate Center

The human brain displays a rich repertoire of states that emerge from the microscopic interactions of cortical and subcortical neurons. Unfortunately, difficulties inherent within large-scale simultaneous neuronal recording limit our ability to link biophysical processes at the microscale to emergent macroscopic brain states. Here we introduce a microscale biophysical network model of layer-5 pyramidal neurons that display graded coarse-sampled dynamics matching those observed in macroscale electrophysiological recordings from macaques and humans. We invert our model to identify the neuronal spike and burst dynamics that differentiate unconscious, dreaming, and awake arousal states and provide novel insights into their functional signatures. We further show that neuromodulatory arousal can mediate different modes of neuronal dynamics around a low-dimensional energy landscape, which in turn changes the response of the model to external stimuli. Our results highlight the promise of multiscale modelling to bridge theories of consciousness across spatiotemporal scales.





CONFERENCE
13th Annual Primate Neurobiology Meeting
April 26-28, 2023

The meeting is organized by Melanie Wilke and SFB members Stefan Treue, Alexander Gail, Hansjörg Scherberger, Igor Kagan, Caspar Schwiedrzik and Raymundo Baez-Mendoza. Participants may present any aspect of their work at any stage – from the presentation of methods to that of concepts, from the introduction of very first results to the discussion of work that may have already been presented at other conferences. Students and postdocs working in nonhuman primate laboratories to are particularly invited to participate. The registration is open until March 31st


Insights into the neural basis of cognition from human intracranial electrophysiology
March 24, 2023, 1 PM - 3 PM; ZHG

The human brain produces complex cognitive operations and behaviors, some of which are arguably uniquely human. The primary means to investigate their neural basis have been noninvasive techniques. However, the limited spatiotemporal resolution of noninvasive imaging hampers progress in understanding health and disease. Human intracranial electrophysiology has emerged as a key technology in overcoming these difficulties. In particular, the high spatiotemporal resolution of intracranial EEG (iEEG) in epilepsy patients undergoing presurgical evaluation enables studying (sub)cortical dynamics underlying human cognition. With specialized research electrodes, it has become possible to extend these investigations across spatial scales, to the level of cortical layers and single cells. This allows unraveling the neural basis of complex behavior directly in the human brain in unprecedented detail.
This symposium, organized by SFB member Caspar Schwiedrzik aims to elucidate neural mechanisms underlying human cognitive processes using intracranial recordings. We will address different facets of cognition, taking complimentary perspectives from different recording and analysis techniques; as well as providing insight into ethical aspects and technical challenges when working with patients. Hui Zhang (Bochum) will demonstrate how the reinstatement and transformation of stimulus-specific memories can be studied using multivariate analyses to identify meso- and macroscale networks. Lucia Melloni (Frankfurt) will show how continuous input is segmented into episodic memories using tasks involving sequences and visual narratives using electrocorticography. Randolph Helfrich (Tübingen) will talk about how population dynamics of human prefrontal cortex integrate contextual cues and prior evidence to guide human goal-directed behavior. Caspar Schwiedrzik (Göttingen) )will present recordings with laminar resolution investigating neural computations underlying predictive processing in perception. Marcel Bausch (Bonn) will address the question how content and context are combined to process relevant memories using single neuron recordings in the medial temporal lobe. Together, these talks will provide an exciting overview of the burgeoning field of human intracranial electrophysiology.


Neuroscience of naturalistic navigation and foraging in non-human primates
March 23, 2023, 11 AM - 1 PM; ZHG

A core topic of the SFB 1528 will be featured in a symposium organised by SFB speaker Alexander Gail and Irene Lacal. SFB members Zurna Ahmed and Neda Shahidi will present their work, and international guest speakers Jan Zimmermann (U of Minnesota) and Dora Angelaki (NY University) will also give talks in a SFB satellite lecture on March 20 and/or 21.
A main aim of system neuroscience research in primates is to understand the neural underpinnings of goal directed behavior. With the advance in wireless technologies for neural recordings, video-based motion tracking and powerful tools for full-body behavior quantification, unprecedented opportunities arise for studying brain networks during naturalistic behaviors. In particular, ecologically highly relevant behaviors such as multi-source foraging, free exploration in complex environments and social interactions have become accessible for neurophysiological studies. This symposium brings together international researchers pioneering the field of neurophysiology in non-human primates during unrestrained behaviors in complex environments. Daniel Huber (University of Geneva) will present the latest development of EthoLoop, a novel tracking system able to follow movements and analyze complex behaviors of unrestrained mouse lemurs in real time in combination with wireless neural recordings. Dora E. Angelaki (NY University) will show how hippocampal and cortical activity in unrestrained rhesus monkeys relate to foraging behavior both in freely moving and virtual reality environments. Zurna Ahmed (German Primate Center & SFB 1528) will introduce the Exploration Room, a novel modular experimental setting encouraging unrestrained, yet repetitive full-body behaviors beyond walking in rhesus macaques while recording from the frontoparietal reach network. Irene Lacal and Neda Shahidi (German Primate Center & SFB 1528) will highlight novel paradigms in the Exploration Room for studying spatial cognition during naturalistic solo or dyadic foraging and the frontoparietal representations of dynamic evaluation of choices. Jan Zimmermann (University of Minnesota) will present how unconstrained behavior is organized across multiple spatial and temporal scales in rhesus monkeys and how electrophysiology experiments can give us a unique insight into these processes.



DOUBLE LECTURE
March 21, 2023, 3 PM Michael-Lankeit-Hörsaal, German Primate Center

Jan Zimmermann (University of Minnesota): Timescales of behavior and neural processing
Behavior is organized across multiple spatial and temporal scales, ranging from sub-second motor commands over multi-second movement plans to long term foraging patterns. Currently it is unclear how the brain solves this coordination of multiple intertwined temporal demands. While classical neuroscience experiments typically look at or engage a fixed temporal scale or horizon, ethological studies have long focused on the analysis of naturalistic behavior across freely elicited temporal scales. Here I will show some of the approaches my lab is taking to understand the organization of timescales in behavior and neural processing ranging from ultra-high field fMRI to multi-region wireless electrophysiology in freely moving rhesus macaques.

Dora Angelaki (NY University): Active sensing and flexible neural coding during visually guided navigation
Natural behavior is flexible and supported by abstracted away beliefs. To understand dynamic neural processing underlying natural behaviour, we use continuous-time foraging tasks either in virtual reality or in a freely-moving arena. Although task rules do not require any particular eye movement, we find that where subjects look is an important component of the behavior. For example, during a simple task in which macaques use a joystick to steer and catch flashing fireflies in a virtual environment lacking position cues, we find that subjects physically tracked this latent task variable with their gaze – an instance of embodied cognition. Restraining eye movements worsened task performance suggesting that embodiment plays a computational role. The above findings are well explained by a neural model with tuned bidirectional connections between oculomotor circuits and circuits that integrate sensory input. In contrast to other task optimized models, this model correctly predicted that leading principal components of the monkey posterior parietal cortex activity should encode their position relative to the goal. These results explain the computational significance of motor signals in evidence-integrating circuits and suggest that plasticity between those circuits might enable efficient learning of complex tasks via embodied cognition.

UNFORTUNATELY, THE TALK BY JAN ZIMMERMANN HAD TO BE CANCELLED!



LECTURE
Oliver Tüscher (University Medical Center Mainz): Neurobiological candidate mechanisms for resilience - goal directed behaviour under stress
Feb 16, 2023, 10 AM; Michael-Lankeit-Hörsaal, German Primate Center

The ability to control our behavior is fundamental to individual and social functioning as well as for our resilience to adversity. Acting in accord with long-term goals requires control of interfering stimuli and impulses, the success of which depends on the several different processes. Over the last decade, we have empirically established a behavioral/cognitive component model of cognitive interference control and, using multimodal imaging and neurophysiological methods, described the neural networks primarily of response-related interference. Recently, we could reliably reveal that response inhibition is initiated by the right inferior frontal gyrus (rIFG) implemented by beta-band oscillations using spatially high-resolved electrophysiological source localization. Furthermore, emotional strain on response interference control is both, integrated within the IFG and functionally segregated among three subregions of the IFG. IFG activity is related to resilience and, intriguingly, better performance in emotional interference control predicts resilience longitudinally. These mechanistic insights pave the way for physiologically informed and precise interventions in real world social environments.


LECTURE
Constantin Rothkopf (TU Darmstadt): Computational models of naturalistic sensorimotor decisions and actions
Dec 1st, 2022, 3 PM; Michael-Lankeit-Hörsaal, German Primate Center

Models of human behavior ranging from decision making to sensorimotor control have been classically dichotomized as either being normative, i.e. prescribing how people ought to act, or as descriptive, i.e. capturing how people actually do act, often with the notion that they violate the prescriptions of normative theories. We will present a string of work from my lab, in which we use probabilistic inference methods to invert normative models thereby asking: for what uncertainties about the state of the world, subjective utilities including effort, and for what, possibly false, internal models is observed human behavior optimal? This not only reconciles normative and descriptive models but additionally allows recovering meaningful cognitive quantities describing participants’ behavior on an individual by individual and trial by trial basis. This framework provides computational level explanations and predictions for phenomena ranging from the adaptability of human blinking strategies, learning of active vision behaviors, to perceptual biases in continuous psychophysics, and strategies in visuomotor behavior such as ball catching or navigation.


LECTURE
Luca Bonini (University of Parma): Coding of actions of self and others in the monkey presupplementary motor cortex
October 20th, 2022, 2 PM; via zoom

The presupplementary motor cortex (pre-SMA, or area F6 in the macaque) is one of the brain areas most frequently activated in fMRI studies, and it is thought to play a role in a variety of motor and executive functions. A hallmark of this area is its rich set of connections with prefrontal regions, on one side, and dorso-lateral premotor regions, on the other, thereby acting as a bridge between high-order cognitive functions and motor planning. In recent years, the research on this region has gained momentum because of its role in social interactions and in the encoding of actions of self and others. I will overview recent evidence indicating that largely shared neural mechanisms and substrates underlie the motor processing of objects, contextual cues, observed actions and nonbiological motion in area F6, suggesting that a basic property of this area consists in a multimodal and flexible recruitment of motor plans based on a variety of stimuli from the outside world. This unitary and coding principle may be shared by a variety of different processes, enabling to account for the manifold of functional properties and roles attributed to this brain area.


RESEARCH COLLOQUIUM SOCIAL NEUROSCIENCE
October 12th, 2022: 11.30 AM - 1 PM:
Camille Testard: Social connection in primates: adaptive function and underlying neural circuitry
Social distancing measures implemented to slow the spread of COVID-19 have triggered a worldwide craving for social contact, leading to surges in anxiety and depression. This social desire is deeply rooted in our evolutionary history: most of our closest nonhuman primate relatives live in groups in which they form strong friendships. After a devastating hurricane destroyed over 60% of the vegetation on a small Caribbean island, instead of being more competitive, resident rhesus macaques became more tolerant of each other, less aggressive, and expanded their social networks. However, some monkeys increased their social connectedness by a lot –leading to better chances of survival almost 5 years after the storm– while others did not. What are the neurobiological underpinnings of macaques’ ability to socially connect? In this same free-ranging rhesus macaque population before the storm, we found that the number of social connections individuals maintained predicted the volume of specific structures –the mid–superior temporal sulcus (mSTS) and ventral-dysgranular insula– implicated in social decision-making and empathy, respectively. Moreover, single-unit recordings in anatomically connected areas to the mSTS in freely-moving, socially-interacting rhesus macaques demonstrate that neural ensembles carry a wealth of information about species-typical social behavior and contexts important for success in the wild –including neighboring monkeys’ identity and preceding interactions.

Neda Shahidi: Population Codes and their Correlates in Decision Making
My goal is to understand the neural correlates of natural decision-making. During my Ph.D., I pursued this goal by investigating the coordinated activity of neurons in visual cortices of macaques prior to the animals’ reports, discriminating between two natural scenes. The accuracy of animals’ reports was correlated with the strength of coordination within a mid-way visual cortex (area V4), and between this area and the primary visual cortex (area V1), but not within V1. The results indicate that while stimulus encoding is related to the spiking rates of neurons, perceptual accuracy is correlated with the precise spiking coordination within visual cortical populations. I also investigated the foraging behavior of unrestrained macaques and the representation of reward expectation and choices in the dorsolateral prefrontal cortex (dlPFC). We found that monkeys predict the reward outcomes to subsequently decide ‘when’ and ‘where’ to forage. Canonical components of the neural population activity represented animals’ reward expectations. These components predicted the next choices better than the true reward expectation and as well as the entire neural population. Together, the findings of the mentioned projects shaped my curiosity to study natural decision-making, highlighting the importance of linking behavior and neural activity in multiple dimensions and the significance of inter-area cortical communication..


LECTURE
Karen J Parker (Stanford University): Developing a monkey model to drive streamlined translation and clinical impact for autism
October 6th, 2022; 5 PM (via Zoom)
Autism spectrum disorder (ASD) is a prevalent and poorly understood neurodevelopmental disorder. There are currently no laboratory-based diagnostic tests to detect ASD, nor are there any disease-modifying medications that effectively treat ASD’s core behavioral symptoms. Scientific progress has been impeded, in part, by overreliance on model organisms that fundamentally lack the sophisticated social and cognitive abilities essential for modeling ASD. We therefore saw significant value in studying naturally low-social rhesus monkeys to model human social impairment, taking advantage of a large outdoor-housed colony for behavioral screening and biomarker identification. Careful development and validation of our animal model, combined with a strong commitment to evaluating the translational utility of our preclinical findings directly in patients with ASD, yielded a robust neurochemical marker (cerebrospinal fluid vasopressin concentration) of trans-primate social impairment and a medication (intranasal vasopressin) shown to improve social cognition in naturally low-social monkeys and in children with ASD. This translational primate research approach stands to advance our understanding of ASD in a manner not readily achievable with existing animal models, and can be adapted to investigate a variety of other human brain disorders which currently lack valid preclinical options, thereby streamlining translation and amplifying clinical impact more broadly.


WORKSHOP
Social Curiosity
October 6th-7th, 2022
The last decades have seen a resurgence of interest in understanding how individuals actively solicit information about events and entities in the world around them. This work typically characterises the individual as a "lone scientist", intrinsically motivated to explore the world in order to garner more information. However, humans and nonhuman primates are rarely detached from the sociocultural contexts they live in and even very young children have been shown to interact with their social partners and make inferences about their thoughts and beliefs. Such interactions are likely to influence how we explore the world. This workshop will bring together researchers aiming to understand the role of primate sociality in curiosity, bringing together varied perspectives across a range of formats, such as structured talks, podium discussions, flash talks and posters.


LECTURE
Peter Carruthers (University of Maryland): Questioning and model-free meta-cognition
September 28th, 2022, 3 PM (via zoom)
There has been a flurry of recent work on the cognitive neuroscience of curiosity. But everyone in the field offers definitions of curiosity that are metacognitive in nature. Curiosity is said to be a desire for knowledge, or a motivation to learn about something, and so on. This appears problematic. It either makes it difficult to see how curiosity can properly be attributed to cats and rats (let alone birds and bees), or it commits us to attributing capacities for self-awareness in these creatures for which we lack evidence. The goal of the talk is to offer a re-interpretation of the main findings in the literature, showing how it is possible for creatures to be curious while lacking any conception of their own or others’ minds. But at the same time I will argue that there is something that a metacognitive conception of curiosity gets right. The talk will first situate curiosity among affective states generally, before going on to elucidate both its contents and its dependence on forms of model-free sensitivity to one's own ignorance.


LECTURE
Hyowon Gweon (Stanford University & Research Training Group 2070): Curious, cooperative and communicative: How we learn from others and help others learn
July 7, 2022; 3 PM, Michael-Lankeit-Hörsaal, German Primate Center
Humans are not the only species that learns from others, but only humans learn and communicate in rich, diverse social contexts, and build repertoires of abstract, structured knowledge. What makes human social learning so distinctive, powerful, and smart? In this talk, I argue that social learning is inferential at its core (inferential social learning); rather than copying what others do or trusting what others say, humans learn from others by drawing rich inferences from others’ behaviors, and help others learn by generating evidence tailored to others’ goals and knowledge states. I will present a series of studies that support this view and describe how they reveal the remarkably curious minds of young children, not only about the physical world but also about others and themselves. Children are curious about what others do & what their actions mean, what others know & what they ought to know, and even what others think of them and how to change their beliefs. The results collectively paint a picture of young children as active social learners who voraciously yet intelligently gather useful information from others to learn about the world, and generously share what they know with those around them.


LECTURE
Helen Blank (University Medical Center Hamburg Eppendorf): You say "tomato", I say "tumatu" - The influence of prior expectations on perception in social interaction
June 27, 2022, 11 AM, Room 1.136, Georg-Elias-Müller-Institute for Psychology
Our ability to successfully interact with other people depends on recognizing and understanding other persons in different contexts. Especially, when sensory signals are degraded, informative priors can improve perception but may also lead to deception. Therefore, unravelling how the human brain combines sensory input from face and voice with prior knowledge is important. In my talk, I will present data from several studies investigating how prior expectations influence perception in social interaction. Firstly, I will contrast two functionally distinct computational mechanisms by which prior expectations can influence sensory representations of speech. Expected features of the input can be enhanced or sharpened. Alternatively, in Prediction Error accounts, expected features are suppressed and unexpected signals are processed further. We aimed at distinguishing between these two accounts by combining behavioural, univariate, and multivariate fMRI measures with computational models. Secondly, I will address the question why we are better in understanding familiar speakers with data from behavioural online studies, in which listeners could use voice context to normalize vowel perception. Finally, I will discuss how the human brain could represent the strength of prior expectations during face-identity recognition.