United States

Recording the neural activity of multiple and large neural populations in the brain is becoming widely available with modern recording techniques. It still remains a challenge, however, to understand how distinct and anatomically different neural populations interact with each other to control behaviour. We propose a new method to discover causal interactions between neural populations based on recurrent switching dynamical systems. We introduce an extended dynamics model that incorporates the current time-step when calculating the latent state variables. We also introduce an acyclicity constrain in learning the parameters of the model. These mechanisms enable rich causal interactions between neuronal populations to be identified from the learned model. Our model outperforms previous work on discovering interactions between neural populations in simulated datasets, without sacrificing the prediction performance of firing rates. We also apply our method on real neural recordings from two macaque monkey brains performing a behavioral task, and show that the proposed method is able to detect causal interactions between brain regions related to the different time windows of the task.

CogSci 2023

Discovering Low-Dimensional Causal Pathways between Multiple Interacting Neuronal Populations

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The 45th Annual Meeting of the Cognitive Science Society will take place in Sydney, Australia as a modified hybrid conference. Presentations from the main-session room will be live-streamed every day for all events. This will include all invited talks and award sessions. Recordings of all CogSci 2023 sessions will be made available for on-demand viewing after the conference.<br>
The in-person component will be held at the International Convention Centre Sydney at Darling Harbour. The Conference will take place Wednesday July 26th – Saturday July 29th, 2023 (Wednesday, July 26th is the Workshops Day).

Join us!

<br>[**The Program at a Glance can be found here**](https://cognitivesciencesociety.org/wp-content/uploads/2023/07/COgSci-PAAG-V2.pdf)
<br>[**The Detailed Program can be found here**](https://online.fliphtml5.com/ebtyf/mswz/)
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#### **CogSci 2023 Program Book**
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The 45th Annual Meeting of the Cognitive Science Society presents the latest research across cognitive science and highlights the theme of Cognition in Context.

Non-CNS cancer and its treatment have been shown to affect memory in survivors, which is both objectively measurable and self-reported by patients. 

However, the traditional memory sum score measurement grants little insight into which memory processes are specifically impaired. 

The current research used a computerized visual-presentation version of the Auditory Verbal Learning Test, which is part of the Amsterdam Cognition Scan, to gather more detailed and precise data on test performance. 

Participants of this study were breast cancer survivors who received chemotherapy (n=68), and women controls (n=157). 

We analyzed these data through various hierarchical Bayesian cognitive models, with the goal to disentangle general performance metrics into more theoretically meaningful concepts. 

Results indicate that the memory processes in cancer patients are not generally impaired across all functions, but rather a selective impairment in 'memory retrieval'. 

There seemed to be no significant issues with patients in 'learning' or 'storage' processes.

Computational Modeling of Memory Processes in non-CNS Cancer Survivors

How does our environment impact what we will later remember? Early work in real-world environments suggested that a matching encoding / retrieval context improves memory. However, some laboratory-based studies have not replicated this advantageous context-dependent memory effect. Across three virtual reality studies, we find support for context-dependent memory effects: participants remembered more when placed in the same context as during encoding. This advantage has a tradeoff of falsely ‘recognizing’ similar lures, however. In addition, we do not find that the object-environment relationship is as impactful on context-dependent memory effects as prior studies suggest. Lastly, we find that differences in the presence (or absence) of dynamic background components differentially elicits the benefits of context-dependent memory. These findings not only add to our understanding of when and how context affects our memory, but they also present an exciting and more naturalistic approach to studying such effects.

Unpacking how Context Reinstatement aids Memory using Virtual Reality

A basic question in the study of human cognition concerns the ability to encode and retrieve associations between pairs of meaningful elements such as words. We employed a standard version of a paired-associate learning task using novel, arbitrary word pairs (restricted to nouns) presented one pair at a time during study without direct warning of a memory test to follow. After a distraction task, participants were provided with a cued-recall task which provided either the first or second word from each of the studied pairings. This paradigm was used to investigate the impact of two study tasks inspired by research in the domain of higher-order cognition. Specifically, we proposed a benefit in cued recall due to either: 1) articulating a conceptual combination of the two provided concepts, i.e., generating a novel integrative concept that might be referenced by the noun-noun pairing; or 2) articulating a specific proposition about how the two provided concepts could interact by fulfilling the roles of a semantic relationship. To illustrate, a pair of words like "cloth" and "donkey" might be integrated via conceptual combination to refer to a stuffed animal or via relational linking to indicate that a cloth could be draped over a donkey. The control condition in the experimental design was a simple imagery-based support task to allow assessment of the impact of the novel support tasks above and beyond the role of imagery. The results show that both study tasks dramatically improve memory performance.

Conceptual Integration and Semantic Relational Processing as Study Tasks to Promote Cued-Recall of Word Pairs

Memory retrieval is influenced by both prior and current experiences. The various factors (e.g., frequency, recency, or similarity) may interfere with retrieval due to prior experiences, while the context-dependent memory effect may enhance based on present experiences. Most memory research has been limited to controlled laboratory settings, but this study aims to examine memory retrieval in a more natural setting by using a GPS application (e.g., Traccar Client) to track participants’ daily GPS locations every 60 seconds for 5 weeks. Participants were then asked to recall their locations at a specific time, choosing from all locations visited in the previous 4 weeks. Results demonstrated the existence of context-dependent memory effect in real-world settings, with more frequent or recent visits leading to increased correct responses. This study is the first to use the current methodology to study the context-dependent memory effect and to measure an individual’s genuine memories in a more ecologically valid way.

Context Dependent Memory in the Wilds

Research has demonstrated an advantage for self-associated stimuli for a range of mental functions (Sui & Humphreys, 2017). However, relatively less is known about whether the prioritization also exists for internal representations (Yin et al., 2019). In the current study we first asked participants to associate social – labels (self, friend, stranger) with arbitrary geometrical shapes (triangle, quadrilateral, and pentagon) as in (Sui et al., 2012) and then tested them for the maintenance of one or more features (shape, location, or a combination) of the target stimuli during a delayed match – to – sample task. In line with our expectations, our participants indeed showed a distinct advantage for self- associated stimuli not only for the maintenance of single features (identity, location) but also for a combination (shape & location). Our findings are in line with the proposal that self-refence may aid in binding information in working memory (Sui & Humphreys, 2015).

I Remember Me the best, always? Evidence for Self-Prioritization in Working Memory Binding using a Visuo-Spatial Working Memory Task.

Episodic memory proves fragile and undergoes a protracted development, as it often requires a combination of multiple elements, during which interference occurs as different sets of learned information partially overlap. One way of preventing interference is a complex representation that links together multiple components of an experience (i.e., three-way binding between items and context). The present study aimed to examine the developmental trajectory of the ability to form complex memory structures. Twenty-two 5-year-olds and 26 adults participated in this study and performed a memory task that required binding two items to a context. The results showed that adults were able to form three-way binding; however, 5-year-olds exhibited difficulties in both three-way binding and binding between two items. Moreover, 5-year-olds did not benefit from extra learning opportunities, indicating that their difficulty in forming complex binding structures did not result from insufficient learning, but from a property of immature episodic memory.

Examination of Developmental Changes in Complexity of Memory Structures

Bilingualism is highly heterogeneous, in terms of language background, age of acquisition, and learning environment... Mapping these variations to brain structure is important to understand the relationship between language and brain. However, these differences in neuroanatomy are entangled with the variation from individual differences unrelated to bilingualism, for example, age and sex. Our goal is to disentangle bilingual-specific neuroanatomical variation from the common variation. First, we build a dataset including 12,000+ brain 3D images from bilinguals and monolinguals along with demographic and linguistic measures. Second, we train a contrastive neural network (Contrastive Variational Autoencoder, CVAE) on the dataset to learn the variations from bilingual-specific variations from variations shared with monolingual groups. We examine if the bilingual-specific neuroanatomical variations correlate with individual differences in linguistic measures through Representational Similarity Analysis. The initial results reveal that the common variation in brain structure shared by two groups can be identified by CVAE.

Contrastive neural network reveals the structure of neuroanatomical variation within bilingualism

The simple brain time theory of time perception states that the temporal properties of the neural processing of sensory features are isomorphic to the temporal properties represented in experience. If true, this theory provides a simple solution to the temporal binding problem. I argue that the theory cannot account for an adaptive trade-off between, the speed of perceptual availability and the accuracy of temporal integration. I hold, that a theory of time perception must get this trade-off right to account for temporal binding. This requires solving two timing problems: the problem of neural delay and the problem of desynchronization. The simple brain time theory is unable to give a unified solution to these problems. Either it fails to answer one of these problems, and veers too much on one side of the trade-off, or it violates its commitment to its central theses. I end by sketching a few possible solutions.

Neural Delay & Desynchronization problems for the Simple Brain Time Theory

Lighthouse beams are often perceived as bent rather than straight, and observers sometimes infer that a rotating lighthouse beam originates from a "phantom lighthouse" that lies in the opposite direction from the true source of the beam. We argue that both illusions arise as a result of Bayesian inference based on natural scene statistics and support our argument by implementing a formal computational model. In addition to capturing both illusions, our model makes the novel prediction that the phantom lighthouse illusion should only emerge at a critical point at which the observer is located around 75 metres in front of the true source of a rotating lighthouse beam. Our theory therefore motivates a future line of experimental work, and contributes to a broader body of research that explains perceptual phenomena (including visual illusions) in terms of Bayesian inference.

A Bayesian account of two visual illusions involving lighthouse beams

Approximate number perception is noisy, but it is unclear whether that noise reflects an error-prone attempt to report one's best guess of the value, or an inherently stochastic process such as sampling. Here we demonstrate that approximate number estimation should be thought of as a sampling procedure, as the average of two estimates of the same stimulus tends to outperform either estimate alone. Additionally, the average difference between the two estimates of a given number linearly increases as a function of number, consistent with Weber's law. Finally, we provide evidence that the classic psychophysical curves associated with number representation are represented within the mind after a single brief viewing of a stimulus, and not only useful for describing a summary of behavior over many trials.

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Discovering Low-Dimensional Causal Pathways between Multiple Interacting Neuronal Populations

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Computational Modeling of Memory Processes in non-CNS Cancer Survivors