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 neural mechanism


Neural Foundations of Mental Simulation: Future Prediction of Latent Representations on Dynamic Scenes

Neural Information Processing Systems

Humans and animals have a rich and flexible understanding of the physical world, which enables them to infer the underlying dynamical trajectories of objects and events, plausible future states, and use that to plan and anticipate the consequences of actions.However, the neural mechanisms underlying these computations are unclear.We combine a goal-driven modeling approach with dense neurophysiological data and high-throughput human behavioral readouts that contain thousands of comparisons to directly impinge on this question.Specifically, we construct and evaluate several classes of sensory-cognitive networks to predict the future state of rich, ethologically-relevant environments, ranging from self-supervised end-to-end models with pixel-wise or object-slot objectives, to models that future predict in the latent space of purely static image-pretrained or dynamic video-pretrained foundation models.We find that ``scale is \emph{not} all you need'', and that many state-of-the-art machine learning models fail to perform well on our neural and behavioral benchmarks for future prediction.In fact, only one class of models matches these data well overall.We find that neural responses are currently best predicted by models trained to predict the future state of their environment in the \emph{latent} space of pretrained foundation models optimized for \emph{dynamic} scenes in a self-supervised manner.These models also approach the neurons' ability to predict the environmental state variables that are visually hidden from view, despite not being explicitly trained to do so.Finally, we find that not all foundation model latents are equal.Notably, models that future predict in the latent space of video foundation models that are optimized to support a \emph{diverse} range of egocentric sensorimotor tasks, reasonably match \emph{both} human behavioral error patterns and neural dynamics across all environmental scenarios that we were able to test.Overall, these findings suggest that the neural mechanisms and behaviors of primate mental simulation have strong inductive biases associated with them, and are thus far most consistent with being optimized to future predict on \emph{reusable} visual representations that are useful for Embodied AI more generally.


Learning and processing the ordinal information of temporal sequences in recurrent neural circuits

Neural Information Processing Systems

Temporal sequence processing is fundamental in brain cognitive functions. Experimental data has indicated that the representations of ordinal information and contents of temporal sequences are disentangled in the brain, but the neural mechanism underlying this disentanglement remains largely unclear. Here, we investigate how recurrent neural circuits learn to represent the abstract order structure of temporal sequences, and how this disentangled representation of order structure from that of contents facilitates the processing of temporal sequences. We show that with an appropriate learn protocol, a recurrent neural circuit can learn a set of tree-structured attractor states to encode the corresponding tree-structured orders of given temporal sequences. This abstract temporal order template can then be bound with different contents, allowing for flexible and robust temporal sequence processing. Using a transfer learning task, we demonstrate that the reuse of a temporal order template facilitates the acquisition of new temporal sequences of the same or similar ordinal structure. Using a key-word spotting task, we demonstrate that the attractor representation of order structure improves the robustness of temporal sequence discrimination, if the ordinal information is the key to differentiate different sequences. We hope this study gives us insights into the neural mechanism of representing the ordinal information of temporal sequences in the brain, and helps us to develop brain-inspired temporal sequence processing algorithms.


Noisy Adaptation Generates Lévy Flights in Attractor Neural Networks

Neural Information Processing Systems

Lévy flights describe a special class of random walks whose step sizes satisfy a power-law tailed distribution. As being an efficientsearching strategy in unknown environments, Lévy flights are widely observed in animal foraging behaviors. Recent studies further showed that human cognitive functions also exhibit the characteristics of Lévy flights. Despite being a general phenomenon, the neural mechanism at the circuit level for generating Lévy flights remains unresolved. Here, we investigate how Lévy flights can be achieved in attractor neural networks.


Meta-Learning Neural Mechanisms rather than Bayesian Priors

Goodale, Michael, Mascarenhas, Salvador, Lakretz, Yair

arXiv.org Artificial Intelligence

Children acquire language despite being exposed to several orders of magnitude less data than large language models require. Meta-learning has been proposed as a way to integrate human-like learning biases into neural-network architectures, combining both the structured generalizations of symbolic models with the scalability of neural-network models. But what does meta-learning exactly imbue the model with? We investigate the meta-learning of formal languages and find that, contrary to previous claims, meta-trained models are not learning simplicity-based priors when meta-trained on datasets organised around simplicity. Rather, we find evidence that meta-training imprints neural mechanisms (such as counters) into the model, which function like cognitive primitives for the network on downstream tasks. Most surprisingly, we find that meta-training on a single formal language can provide as much improvement to a model as meta-training on 5000 different formal languages, provided that the formal language incentivizes the learning of useful neural mechanisms. Taken together, our findings provide practical implications for efficient meta-learning paradigms and new theoretical insights into linking symbolic theories and neural mechanisms.


Messing with mouse brains during sex leads to unexpected discovery

Popular Science

Sex comprises an intricate tangle of impulses and interactions between partners. Neuroscientists have learned a great deal about the neural mechanisms underlying sex, but questions about the processes that control the sequence of events during sex remain unanswered. While past research has identified the regions of the brain that control how mice initiate sex, other steps of copulation are still mysteries. A team of researchers in China and Japan have investigated which brain regions and neurotransmitters are responsible for different phases during sex. A paper published March 19 in the journal Neuron describes what exactly goes on in a mouse brain during sex.


From Eye to Mind: brain2text Decoding Reveals the Neural Mechanisms of Visual Semantic Processing

Feng, Feihan, Nie, Jingxin

arXiv.org Artificial Intelligence

Deciphering the neural mechanisms that transform sensory experiences into meaningful semantic representations is a fundamental challenge in cognitive neuroscience. While neuroimaging has mapped a distributed semantic network, the format and neural code of semantic content remain elusive, particularly for complex, naturalistic stimuli. Traditional brain decoding, focused on visual reconstruction, primarily captures low-level perceptual features, missing the deeper semantic essence guiding human cognition. Here, we introduce a paradigm shift by directly decoding fMRI signals into textual descriptions of viewed natural images. Our novel deep learning model, trained without visual input, achieves state-of-the-art semantic decoding performance, generating meaningful captions that capture the core semantic content of complex scenes. Neuroanatomical analysis reveals the critical role of higher-level visual regions, including MT+, ventral stream visual cortex, and inferior parietal cortex, in this semantic transformation. Category-specific decoding further demonstrates nuanced neural representations for semantic dimensions like animacy and motion. This text-based decoding approach provides a more direct and interpretable window into the brain's semantic encoding than visual reconstruction, offering a powerful new methodology for probing the neural basis of complex semantic processing, refining our understanding of the distributed semantic network, and potentially inspiring brain-inspired language models.


Neural Foundations of Mental Simulation: Future Prediction of Latent Representations on Dynamic Scenes

Neural Information Processing Systems

Humans and animals have a rich and flexible understanding of the physical world, which enables them to infer the underlying dynamical trajectories of objects and events, plausible future states, and use that to plan and anticipate the consequences of actions.However, the neural mechanisms underlying these computations are unclear.We combine a goal-driven modeling approach with dense neurophysiological data and high-throughput human behavioral readouts that contain thousands of comparisons to directly impinge on this question.Specifically, we construct and evaluate several classes of sensory-cognitive networks to predict the future state of rich, ethologically-relevant environments, ranging from self-supervised end-to-end models with pixel-wise or object-slot objectives, to models that future predict in the latent space of purely static image-pretrained or dynamic video-pretrained foundation models.We find that scale is \emph{not} all you need'', and that many state-of-the-art machine learning models fail to perform well on our neural and behavioral benchmarks for future prediction.In fact, only one class of models matches these data well overall.We find that neural responses are currently best predicted by models trained to predict the future state of their environment in the \emph{latent} space of pretrained foundation models optimized for \emph{dynamic} scenes in a self-supervised manner.These models also approach the neurons' ability to predict the environmental state variables that are visually hidden from view, despite not being explicitly trained to do so.Finally, we find that not all foundation model latents are equal.Notably, models that future predict in the latent space of video foundation models that are optimized to support a \emph{diverse} range of egocentric sensorimotor tasks, reasonably match \emph{both} human behavioral error patterns and neural dynamics across all environmental scenarios that we were able to test.Overall, these findings suggest that the neural mechanisms and behaviors of primate mental simulation have strong inductive biases associated with them, and are thus far most consistent with being optimized to future predict on \emph{reusable} visual representations that are useful for Embodied AI more generally.


Learning and processing the ordinal information of temporal sequences in recurrent neural circuits

Neural Information Processing Systems

Temporal sequence processing is fundamental in brain cognitive functions. Experimental data has indicated that the representations of ordinal information and contents of temporal sequences are disentangled in the brain, but the neural mechanism underlying this disentanglement remains largely unclear. Here, we investigate how recurrent neural circuits learn to represent the abstract order structure of temporal sequences, and how this disentangled representation of order structure from that of contents facilitates the processing of temporal sequences. We show that with an appropriate learn protocol, a recurrent neural circuit can learn a set of tree-structured attractor states to encode the corresponding tree-structured orders of given temporal sequences. This abstract temporal order template can then be bound with different contents, allowing for flexible and robust temporal sequence processing.


Noisy Adaptation Generates Lévy Flights in Attractor Neural Networks

Neural Information Processing Systems

Lévy flights describe a special class of random walks whose step sizes satisfy a power-law tailed distribution. As being an efficientsearching strategy in unknown environments, Lévy flights are widely observed in animal foraging behaviors. Recent studies further showed that human cognitive functions also exhibit the characteristics of Lévy flights. Despite being a general phenomenon, the neural mechanism at the circuit level for generating Lévy flights remains unresolved. Here, we investigate how Lévy flights can be achieved in attractor neural networks.


Mechanism of Neural Interference by Transcranial Magnetic Stimulation: Network or Single Neuron?

Neural Information Processing Systems

This paper proposes neural mechanisms of transcranial magnetic stim- ulation (TMS). TMS can stimulate the brain non-invasively through a brief magnetic pulse delivered by a coil placed on the scalp, interfering with specific cortical functions with a high temporal resolution. Due to these advantages, TMS has been a popular experimental tool in various neuroscience fields. However, the neural mechanisms underlying TMS- induced interference are still unknown; a theoretical basis for TMS has not been developed. This paper provides computational evidence that in- hibitory interactions in a neural population, not an isolated single neuron, play a critical role in yielding the neural interference induced by TMS.