Search bioRxiv⌕ Search

Biology subjects

Cueva, C. J.

Publications and source records attributed to Cueva, C. J..

6 recordsLinked to original sources

Compositional Recombination Relies on a Distributed Cortico-Cerebellar Network

Human cognition depends on the ability to flexibly recombine existing knowledge in new ways. Although this capacity for compositionality has traditionally been attributed to cortical networks, its broader neural basis remains unclear. Here, we combined dimensionality reduction of task-based fMRI with recurrent neural network modelling to dissociate two processes underlying compositional cognition: the recruitment of specialised components; and the more general process of recombination. Across 87 participants performing a well-established compositional task, component processes were supported by domain-selective cortical and anterior cerebellar regions, whereas recombination engaged a distributed cortico-cerebellar network that was low-dimensional, highly integrated, and generalised across contexts. Similar functional signatures were also observed in recurrent neural networks trained to perform multiple cognitive tasks, suggesting that low-dimensional recombination is a general solution for flexible compositional cognition. Our findings revise existing models of compositional cognition by highlighting cortico-cerebellar interactions as a mechanism for flexible, integrative task generalisation.

neuroscience↗

Overcoming sensory-memory interference in working memory circuits

Memories of recent stimuli are crucial for guiding behavior, but the sensory pathways responsible for encoding these memories are continuously bombarded by new sensory experiences. How the brain overcomes interference between sensory input and working memory representations remains largely unknown. To formalize the solution space, we examined recurrent neural networks that were either hand-designed or trained using gradient descent methods, and compared these models with neural data from two different macaque experiments. Here we report mechanisms by which neural networks overcome sensory-memory interference using both static and dynamic coding strategies: gating of the sensory inputs, modulating synapse strengths to achieve a strong attractor solution, and dynamic strategies - including the extreme solution in which cells invert their feature preference during working memory. Neural data from the medial superior temporal (MST) area of macaques, where sensory and working memory signals first interact along the dorsal pathway, best aligned with a solution that combined input gating and tuning inversion. Behavioral predictions from this model also matched error patterns observed in monkeys performing a working memory task with distractors. Taken together, our results help elucidate how working memory circuits preserve information as we continue to interact with the world, and suggest intermediate cortical visual areas like MST may play a critical role in this computation.

neuroscience↗

A morphing map model for place field organization in large environments

Navigation and spatial memory, essential for animal survival, are founded on the hippocampal formations ability to host spatial neurons marking an animals position. Within controlled settings, the place cells of the hippocampus are activated in specific regions, the place fields. In this paper, we introduce a "morphing map algorithm" based on bat data from a 200-meter tunnel, highlighting a multifield, multiscale spatial representation of place fields. This algorithm posits that in vast environments, bats opt to select landmarks or anchors for spatial representation. The method introduces a hyperbolic geometry in spatial representation, aligning with bat data from vast areas. We apply Procrustes distance to evaluate similarities between neural maps of bats and model-generated maps, revealing shared structure across bat maps, which might be dictated by common anchor points. Further explorations into anchor point ablation provide insights into their crucial role in map stability. The results present an evolved neural navigation strategy in expansive habitats and guide future spatial representation research across species.

neuroscience↗

Natural constraints explain working memory capacity limitations in sensory-cognitive models

The limited capacity of the brain to retain information in working memory has been well-known and studied for decades, yet the root of this limitation remains unclear. Here we built sensory-cognitive neural network models of working memory that perform tasks using raw visual stimuli. Contrary to intuitions that working memory capacity limitation stems from memory or cognitive constraints, we found that pre-training the sensory region of our models with natural images imposes sufficient constraints on models to exhibit a wide range of human-like behaviors in visual working memory tasks designed to probe capacity. Examining the neural mechanisms in our model reveals that capacity limitation mainly arises in a bottom-up manner. Our models offer a principled and functionally grounded explanation for the working memory capacity limitation without parameter fitting to behavioral data or much hyperparameter tuning. This work highlights the importance of developing models with realistic sensory processing even when investigating memory and other high-level cognitive phenomena.

neuroscience↗

Neural dynamics and geometry for transitive inference

Relational cognition -- the ability to infer relationships that generalize to novel combinations of objects -- is fundamental to human and animal intelligence. Despite this importance, it remains unclear how relational cognition is implemented in the brain due in part to a lack of hypotheses and predictions at the levels of collective neural activity and behavior. Here we discovered, analyzed, and experimentally tested neural networks (NNs) that perform transitive inference (TI), a classic relational task (if A > B and B > C, then A > C). We found NNs that (i) generalized perfectly, despite lacking overt transitive structure prior to training, (ii) generalized when the task required working memory (WM), a capacity thought essential to inference in the brain, (iii) emergently expressed behaviors long observed in living subjects, in addition to a novel order-dependent behavior, and (iv) adopted different task solutions yielding alternative behavioral and neural predictions. Further, in a large-scale experiment, we found that human subjects performing WM-based TI showed behavior inconsistent with a class of NNs expressing an intuitive task solution. These findings provide neural insights into a classical relational ability, with wider implications for how the brain realizes relational cognition.

neuroscience↗

Delay activity dynamics: task dependent time encoding and low dimensional trajectories

Our decisions often depend on multiple sensory experiences separated by time delays. The brain can remember these experiences and, simultaneously, estimate the timing between events. To understand the mechanisms underlying working memory and time encoding we analyze neural activity recorded during delays in four experiments on non-human primates. To disambiguate potential mechanisms, we propose two analyses, namely, decoding the passage of time from neural data, and computing the cumulative dimensionality of the neural trajectory over time. Time can be decoded with high precision in tasks where timing information is relevant and with lower precision when irrelevant for performing the task. Neural trajectories are always observed to be low dimensional. These constraints rule out working memory models that rely on constant, sustained activity, and neural networks with high dimensional trajectories, like reservoir networks. Instead, recurrent networks trained with backpropagation capture the time encoding properties and the dimensionality observed in the data.

neuroscience↗