francesco-innocenti / Neuro_AI_Papers

A curated repository of Neuro-AI papers.

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Neuro-AI papers 🧠💻

This is a repository for research papers at the intersection between computational neuroscience and machine learning, a field also known as neuroscience-inspired AI or simply neuro-AI. The papers are organised as follows:

If you're new to this field, there are some great high-level articles that outline the general motivation behind looking at the brain to build intelligent systems. See, for example, Hassabis' commentary in Is the brain a good model for machine intelligence? (2012); What Intelligent Machines Need to Learn From the Neocortex by Hawkins (2017); To Advance Artificial Intelligence, Reverse-Engineer the Brain by DiCarlo (2018); The intertwined quest for understanding biological intelligence and creating artificial intelligence by Ganguli (2018); How AI and neuroscience drive each other forwards by Savage (2019); and Using neuroscience to develop artificial intelligence by Ullman (2019). In brief, the brain is the only existing proof of intelligence we have and so it's likely that we'll make faster progress on general, human-level AI if we try to reverse-engineer it.

Surveys

Neuroscience-Inspired Artificial Intelligence by Hassabis et al. (2017)

This is arguably the manifesto for neuro-AI. Reviewing past and present interactions between the two fields, the authors make a strong case for how neuroscience can help guide and accelerate AI research. Neuroscience can also benefit from AI, as shown by the success of deep learning models of the visual system.

Building machines that learn and think like people by Lake et al. (2017)

This is a highly cited paper that, drawing from research in cognitive science, argues that general AI should (i) build causal models of the world, (ii) have intuitive physics and psychology, and (iii) be able to learn compositional structure as well as "learn to learn". They emphasise probabilistic, Bayesian models and argue that psychology can provide stronger constraints than neuroscience on intelligence.

Cognitive computational neuroscience by Kriegeskorte & Douglas (2018)

This is a great review bringing together cognitive science, computational neuroscience and artificial intelligence under the name of "cognitive computational neuroscience". They emphasise the need to bridge top-down theory and bottom-up experiments, and provide a useful overview of the wide variety of models used across these disciplines.

Natural and Artificial Intelligence: A brief introduction to the interplay between AI and neuroscience research by Macpherson et al. (2021)

A review of recent interactions between neuroscience and AI focusing on models of working memory, the visual system, machine learning analysis of big neuroscience data, and computational psychiatry.

The roles of supervised machine learning in systems neuroscience by Glaser et al. (2019)

This review discusses four roles that supervised machine learning can play for systems neuroscientists: (i) solve engineering problems such as brain-machine interfaces, disease diagnosis and behaviour analysis (ii) identify predictive variables of neural activity and behaviour, (iii) benchmark simple mechanistic, hypothesis-driven models, and (iv) provide computational models (e.g., deep convolutional neural network models of the visual system).

What Learning Systems do Intelligent Agents Need? Complementary Learning Systems Theory Updated by Kumaran, Hassabis & McClelland (2016)

Computational Foundations of Natural Intelligence by van Gerven (2017)

Focusing on artificial neural networks, this reviews discusses various modelling approaches to intelligence across many disciplines and levels of analysis.

Insights from the brain: The road towards Machine Intelligence by Thiboust (2020)

Aimed primarily at AI researchers, this is a beautifully illustrated ebook outlining a variety of facts and theories about the brain that have been already used, or otherwise could be used, to power AI.

The Mutual Inspirations of Machine Learning and Neuroscience by Helmstaedter (2015)

Focusing on the topic of classification, this perspective reviews how machine learning has helped with the analysis of the complex and high-dimensional neuroscience datasets (e.g., connectomics) and highlights their limitations as a motivation for solving the classification tricks of the brain.

Deep learning

Reviews & perspectives

A deep learning framework for neuroscience by Richards et al. (2019)

Including more than 30 neuroscientists and AI researchers, this perspective argues that systems neuroscience should adopt a deep learning framework by focusing on the three key design components of artificial neural networks: architectures, learning rules, and objective functions. Neural computations and representations are therefore seen as "emergent" mostly from these properties.

How learning unfolds in the brain: toward an optimization view by Hennig et al. (2021)

Drawing particularly from research on brain machine interfaces, this paper argues that if we want to understand learning in the brain under an optimisation framework, we should integrate three key features of neural population activity not generally exhibited by artificial neural networks: (i) neural variability during learning is relatively inflexible, (ii) multiple learning rules can underlie the same task, and (iii) changes in activity can be driven by factors not specific to the task.

If deep learning is the answer, what is the question? by Saxe, Nelli & Summerfield (2021)

In contrast to many other perspectives, these authors caution against the view that focusing on deep networks in neuroscience means giving up trying to explain neural computation, emphasising that these models should make falsifiable predictions.

Biological constraints on neural network models of cognitive function by Pulvermüller et al. (2021)

A broadly scoped review of networks used to model brain function including (but not limited to) deep neural networks, with a focus on cognition, arguing for more biologically constrained models across different spatial and temporal scales, including more realistic neuron models, learning rules, inhibition and anatomical structure.

Direct Fit to Nature: An Evolutionary Perspective on Biological and Artificial Neural Networks by Hasson, Nastase & Goldstein (2020)

The authors of this perspective argue that, similar to evolution by natural selection, artificial and biological neural networks learn over-parametrised models in an iterative, mindless optimisation process they call "direct fit". Contrary to traditional statistical views, over-parametrised models do not always overfit and can allow effective generalisation based on interpolation, as opposed to extrapolation, when trained on big real-world data - simply because they'll have sampled most of the parameter space and will therefore unlikely need to extrapolate. Following the "deep learning framework", they argue that these models are fundamentally uninterpretable and we should focus on their design components, just like we tend to focus on the ingredients of natural selection.

Engineering a Less Artificial Intelligence by Sinz et al. (2019)

This perspective reviews some important limitations of modern deep networks especially in object recognition, such as poor generalisation, and suggests to focus on inductive biases or constraints inspired by brains at all of Marr's levels: multi-task training at the computational level, co-training on neural data at the algorithmic level, and mimicking network architecture and at the implementation level. This is in line with the "deep learning framework" (Richards et al., 2019).

Deep Neural Networks Help to Explain Living Brains by Ananthaswamy (2020)

This Quanta Magazine article surveys some classic deep learning models of sensory function (see below), including modalities from vision to olfaction.

Artificial Neural Networks for Neuroscientists: A Primer by Yang & Wang (2020)

Lessons From Deep Neural Networks for Studying the Coding Principles of Biological Neural Networks

A neural network walks into a lab: towards using deep nets as models for human behavior by Ma & Peters (2020)

Taking a cognitive science perspective, this paper argues that methods to train and test deep neural network models of cognition and behaviour could be both improved particularly with more complex and realistic tasks including multi- task learning.

Deep Learning for Cognitive Neuroscience by Storrs & Kriegeskorte (2019)

A similar survey that also addresses how deep neural networks can help cognitive neuroscientists study higher level cognitive functions such as language and reasoning.

Deep neural network models of sensory systems: windows onto the role of task constraints by Kell & McDermott (2019)

Another review of deep networks for modelling the sensory cortex, emphasising their use as normative models providing insights into task constraints. Generative models are suggested as a promising research directions.

What does it mean to understand a neural network? by Lillicrap & Kording (2019)

This paper argues that, despite efforts to better understand modern artificial neural networks, we should not expect them or biological networks to be easily compressible or have any compact description and that we should instead aim at a higher-level of understanding, considering a network's architecture, objective function, and learning rule. As they conclude: "Instead of asking how the brain works we should, arguably, ask how it learns to work." (p. 7).

Deep Neural Networks in Computational Neuroscience by Kietzmann, McClure & Kriegeskorte (2018)

The authors review the recent success of deep convolutional neural networks in modelling the visual system as well as how these models can be validated on both neural and behavioural data across different levels and modalities. They also address the common "black box" objection and argue, first, that understanding can come at a higher level of abstraction, by looking at the design components of these models (e.g., input statistics, architecture, learning rule, etc.), and second, that we can "look inside the box" with what has been called "in silico or synthetic neurophysiology", by for example visualising network features.

Principles for models of neural information processing by Kay (2018)

This paper reviews models in cognitive neuroscience, their utility, and criteria by which to evaluate them. It highlights a distinction between functional models, which attempt to model the input-output transformations performed by a neuron or population of neurons; and mechanistic models, which attempt to describe the actual mechanisms responsible for those transformations. It goes on to argue that deep neural networks belong to the former class and that we should be therefore careful in the explanation we claim they provide as well as try to better understand them.

Toward an Integration of Deep Learning and Neuroscience by Marblestone, Wayne & Kording (2016)

An comprehensive review focusing on objective functions, putting forward three hypothesis about the brain based on machine learning ideas: (i) the brain optimises objective functions, (ii) objective functions are diverse across areas and change over development, and (iii) specialised architectures can solve specific computational problems.

Using goal-driven deep learning models to understand sensory cortex by Yamins & DiCarlo (2016)

A highly cited perspective on modelling the sensory cortex, focused on the visual cortex, by using deep convolutional neural networks trained on specific tasks (i.e., goal-driven).

Deep Neural Networks: A New Framework for Modeling Biological Vision and Brain Information Processing by Kriegeskorte (2015)

This is one of the first introductions to deep learning for computational neuroscience, also focused on vision, and can be seen as the precursor of the deep learning framework (Richards et al., 2019).

From the neuron doctrine to neural networks by Yuste (2015)

"[T]he history of neuroscience is the history of its methods". This is a historical perspective reflecting on how the neuron doctrine emerged in the context of single-cell studies and how new multineuronal techniques are leading to - and in fact, have already led to - the "neural network paradigm".

The recent excitement about neural networks by Crick (1989)

This is a classic commentary by Francis Crick, wrote in the midst of the parallel distributed processing or connectionist movement, when the first multilayer neural networks emerged. Crick criticised neural nets as models of the brain based on Dale's law (a neuron can be either excitatory or inhibitory but not both) and the biological implausibility of backpropagation, specifically the weight transport problem (i.e., synaptic symmetry in forward and backward connections).

Implications of neural networks for how we think about brain function

Philosophical takes

This section includes papers that take an explicit philosophical perspective on deep artificial neural networks as brain models.

On logical inference over brains, behaviour, and artificial neural networks by Guest & Martin (2021)

A thought-provoking paper arguing that much of this literature commits the logical fallacy of affirming the consequent - "if the model predicts neural and behavioural data, then it does what humans do" - by ignoring the principle of multiple realisability (the same function can be performed by different mechanisms). For a similar argument see Kay (2018).

Deep Neural Networks as Scientific Models by Cichy & Kaiser (2019)

Explanatory models in neuroscience: Part 2 -- constraint-based intelligibility

Explanatory models in neuroscience: Part 1 -- taking mechanistic abstraction seriously

Vision

As clear from the above reviews and perspectives, most research to date on deep learning models of the brain has focused on vision, both because the visual system has historically been the most studied and because it was models in computer vision that led to the renaissance of neural networks.

Convolutional Neural Networks as a Model of the Visual System: Past, Present, and Future by Lindsay (2020)

This is a great review covering the origin of CNNs, methods to validate them as models of the visual system using neural and behavioural data, and lessons to be learned by using different datasets, architectures and learning algorithms. It also suggests that we don't have to give up trying to understand neural computation and can gain insights with "in silico neurophysiology" techniques such as feature visualisation and mathematical analysis. Important limitations of CNNs and attempts to make them more biologically faithful are also outlined.

Going in circles is the way forward: the role of recurrence in visual inference by van Bergen & Kriegeskorte (2020)

A great perspective that makes the case for recurrence in vision, arguing that while any recurrent neural network (RNN) can be "unrolled" in time to give a feedforward neural network (FNN), the latter are actually a special case of the former as some RNNs cannot be unrolled realistically (i.e., under real-world space, time and energy constraints). Recurrence, it is also argued, (i) affords greater and more flexible computational depth, (ii) saves hardware, (iii) integrates high-level information, (iv) exploits temporal structure in sequential data, and (v) allows iterative inference.

Capturing the objects of vision with neural networks by Peters & Kriegeskorte (2021)

A review of the cognitive science and neural network models of visual object representations, focusing on constraints and tasks to improve these models.

Deep Learning: The Good, the Bad, and the Ugly by Serre (2019)

A review of the history of CNNs, their success in predicting brain data, and some of their key failures in characterising human behaviour, as well as their more fundamental limitations including adversarial attacks and limited generalisation.

Unsupervised neural network models of the ventral visual stream by Zhuang et al. (2021)

This paper tested a variety of state-of-the-art unsupervised neural networks, finding contrastive embedding methods such as SimCLR to perform as well as supervised networks in both transfer learning and prediction of spiking data, including first-person child videos. These models show similar hierarchical correspondence to the ventral visual cortex (early layers better predict lower regions such as V1 and deeper layers better predict higher regions such as IT).

Bridging the Gaps Between Residual Learning, Recurrent Neural Networks and Visual Cortex by Liao & Poggio (2020)

Learning to see stuff by Fleming & Storrs (2019)

This perspective emphasises the importance of unsupervised learning in vision, drawing on recent architectures such as autoencoders, PredNet and GenerativeQueryNets. For a more recent argument by the same authors see Storrs & Fleming.

A Unified Theory of Early Visual Representations from Retina to Cortex through Anatomically Constrained Deep CNNs by Lindsey et al. (2019)

Visual Cortex and Deep Networks: Learning Invariant Representations

Deep Neural Networks Rival the Representation of Primate IT Cortex for Core Visual Object Recognition

Deep Neural Networks Reveal a Gradient in the Complexity of Neural Representations across the Ventral Stream

Deep Supervised, but Not Unsupervised, Models May Explain IT Cortical Representation by Khaligh-Razavi & Kriegeskorte (2014)

Performance-optimized hierarchical models predict neural responses in higher visual cortex by Yamins et al. (2014)

One of the first (if not the first) demonstration of deep convolutional neural networks as models of the visual system, showing that models with higher object recognition accuracy were better at predicting spiking macaque IT responses to natural images, and that the output layer of an optimised network better predicted IT activity at both the population and unit level whereas intermediate layers were more predictive of V4 responses.

Audition

A Task-Optimized Neural Network Replicates Human Auditory Behavior, Predicts Brain Responses, and Reveals a Cortical Processing Hierarchy by Kell et al. (2018)

This paper optimised a deep convolutional neural network to recognise words and music genres, finding that a branched architecture with shared early layers accounted best for both tasks. The network performed similar to human behaviour and made similar mistakes, predicted human fMRI responses in the auditory cortex better than previous models, and showed a hierarchical correspondence, with the intermediate layers better predicting primary regions and deeper layers better predicting higher regions.

Somatosensation

Toward goal-driven neural network models for the rodent whisker-trigeminal system by Zhuang et al. (2017)

Following the task-driven approach of Yamins et al. (2014) and Kell et al. (2018), this study optimised a variety of deep neural network architectures to recognise object shape with a 3-D model of the rodent whisker system, finding a "temporal-spatial" network (integrating over time before over space) and a recurrent neural network with long-range feedback to be the best-performing models.

Motor control

A neural network that finds a naturalistic solution for the production of muscle activity by Sussillo et al. (2015)

Further demonstrating the utility of the goal-driven approach, this paper optimised recurrent neural networks to reproduce the muscle activity of monkeys doing a reaching task, finding that a regularised (and notably, not a non-regularised) model learned similar dynamics to the motor cortex at both the single-neuron and population levels.

Validation methods

Analyzing biological and artificial neural networks: challenges with opportunities for synergy? by Barrett, Morcos & Macke (2019)

This paper reviews a number of techniques that can be used to analyse both biological and artificial neural networks, including receptive field analysis, ablation experiments, dimensionality reduction, and (related) representational analysis.

How can deep learning advance computational modeling of sensory information processing? by Thompson et al. (2018)

Closed-loop experiments

Neural population control via deep image synthesis by Bashivan, Kar & DiCarlo (2019)

In probably the first closed-loop experiment using deep neural networks, this study trained a deep convolutional neural network to predict microelectrode population responses (>100 neurons) in macaque V4 to hundreds of natural images and more complex stimuli known to drive V4 activity.

Evolving Images for Visual Neurons Using a Deep Generative Network Reveals Coding Principles and Neuronal Preferences by Ponce et al. (2019)

Inception loops discover what excites neurons most using deep predictive models by Walker et al. (2019)

This study trained a custom deep convolutional neural network to predict the optical population responses (>2000 neurons) in mouse V1 to thousands of natural images. The model could predict held-out neural responses with high accuracy. The researchers then optimised images to maximally activate particular artificial neurons (a technique called activity maximisation). Interestingly, the generated most exciting inputs (MEIs), which were confirmed to occur in natural images, were strikingly different from the standard Gabor-like filters thought to characterise V1 and, when presented back to the same neurons, produced significantly stronger response than control stimuli.

Model benchmarks

Taking inspiration from the machine learning community, computational neuroscientists have recently started developing standardised benchmarks and challenges to test and compare computational brain models, though to date they all concern vision.

Brain-Score: Which Artificial Neural Network for Object Recognition is most Brain-Like? by Schrimpf et al. (2018)

This paper introduces Brain-Score, a benchmarking platform with neural and behavioural data to test computational models of visual object recognition. The authors also report results of testing a variety of modern ImageNet-trained deep networks on three benchmarks (V4 and IT spiking data in the macaque monkey and human behavioural data): (i) DenseNet-169, CORnet-S and ResNet-101 were the best-performing models; (ii) a lot of variance in both neural and behavioural responses remains unexplained; (iii) better ImageNet performance was correlated with Brain-Score, but interestingly, some of the best ImageNet models did not better predict brain data; and (iv) smaller, brain-inspired networks outperformed many of the best ImageNet models.

Integrative Benchmarking to Advance Neurally Mechanistic Models of Human Intelligence by Schrimpf et al. (2020)

This paper makes the case for integrative benchmarks (benchmarks including both neural and behavioural data) to test computational brain models, using Brain-Score (Schrimpf et al., 2018) as an example.

The Algonauts Project 2021 Challenge: How the Human Brain Makes Sense of a World in Motion by Cichy et al. (2021)

This paper introduces the Algonauts 2021 Challenge (see Cichy et al., 2019 for the first, 2019 edition), which is to predict fMRI responses of 10 participants to over 1000 short videos of everyday events. See also The Algonauts Project by Cichy, Roig & Oliva (2019) for an overview.

Brain hierarchy score: Which deep neural networks are hierarchically brain-like? by Nonaka et al. (2021)

Taking inspiration from the Brain-Score, this paper proposes a new metric called the brain hierarchy (BH) score to quantify deep learning models on their hierarchical correspondence with the visual cortex. In contrast to other measures, BH is based on both encoding and decoding analyses. The authors also report results of 29 ImageNet-pretrained deep networks on the visual fMRI responses to over 1000 ImageNet images of 3 participants. Interestingly, in line with Schrimpf et al. (2018), there was a strong negative correlation between ImageNet top-1 % accuracy and BH score, with simpler models such as AlexNet and VGGs having the highest scores. This relationship was confirmed when the models were fine-tuned on other object recognition datasets. Other notable results were that (i) models with random weights had dramatically decreased BH scores; (ii) models with fully connected layers were the most predictive; and (iii) skip and branch connections did not improve performance.

Backprop in the brain?

Burst-dependent synaptic plasticity can coordinate learning in hierarchical circuits by Payeur et al. (2021)

Backpropagation and the brain by Lillicrap et al. (2020)

This perspective reviews how the backpropagation of error algorithm (backprop) optimally solves the credit assignment problem in multilayer artificial neural networks and outlines the biologically implausible features of backprop including the weight transport problem, the need for signed and possibly extreme-valued error signals, and the fact that feedback in the brain can modulate and drive neural activity. The authors argue that the brain could approximate backprop by computing local differences in neural activities through feedback connections - a framework they call "neural gradient representation by activity differences" (NGRAD).

Artificial Neural Nets Finally Yield Clues to How Brains Learn

Dendritic solutions to the credit assignment problem by Richards & Lillicrap (2019)

Control of synaptic plasticity in deep cortical networks by Roelfsema & Holtmaat (2018)

Focusing on reinforcement learning, this paper argues that a combination of feedback connections and neuromodulation could solve the credit assignment problem in the brain. See also Reply to ‘Can neocortical feedback alter the sign of plasticity?’ by the same authors.

Can the Brain Do Backpropagation? —Exact Implementation of Backpropagation in Predictive Coding Networks by Song et al. (2020)

Artificial & biological neurons

There is increasing evidence that biological neurons and their dendrites are much more powerful computing machines than the classic "point neurons" (McCulloch & Pitts, 1943) or "perceptrons" (Rosenblatt, 1958) of artificial neural networks. Much of the work in this area comes from Poirazi Lab.

Dendritic Computing: Branching Deeper into Machine Learning by Acharya et al. (2021)

Single cortical neurons as deep artificial neural networks by Beniaguev, Segev & London (2021)

This study attempted to characterise the computational complexity of a cortical neuron, finding that a deep convolutional neural network with 5 to 8 hidden layers was necessary to predict with high accuracy the function (spiking and somatic subthreshold membrane potential) of a highly realistic, compartmental model of a L5 pyramidal neuron (with basal, oblique and apical dendrites). Interestingly, the same model without NMDA synapses could be accurately reproduced by a much shallower fully connected network with one layer. Further analyses showed that dendritic branches acted as spatiotemporal pattern detectors. See this Quanta Magazine article How Computationally Complex Is a Single Neuron? by Whitten (2021) for an overview of the paper.

Drawing inspiration from biological dendrites to empower artificial neural networks by Chavlis & Poirazi (2021)

This paper argues that incorporating properties of dendrites including compartmentalisation, active mechanisms and multi-scale learning rules in artificial neural networks could increase computational power and reduce consumption.

Dendritic action potentials and computation in human layer 2/3 cortical neurons by Gidon et al. (2020)

This study discovered a new type of dendritic spike in human L2/3 pyramidal neurons. These spikes allow neurons to compute the XOR function, a computation that was famously proved to be impossible by Minsky and Papert (1969) for single-layer artificial networks and later shown possible for multilayer networks. See also Hidden Computational Power Found in the Arms of Neurons (Cepelewicz, 2020).

Pyramidal Neuron as Two-Layer Neural Network by Poirazi, Brannon & Mel (2003)

This is the first study to demonstrate that neurons are computationally much more capable machines than previously thought, showing that hippocampal pyramidal neurons could be modelled as a two-layer artificial neural network with dendrites as hidden units and the soma as the output unit.

Spiking neural networks

Deep learning in spiking neural networks by Ghodrati et al. (2019)

This paper reviews supervised and supervised approaches to training deep spiking neural networks.

Nature & nurture

A critique of pure learning and what artificial neural networks can learn from animal brains by Zador (2019)

The Self-Assembling Brain: How Neural Networks Grow Smarter by Hiesinger (2021)

Innateness, AlphaZero, and Artificial Intelligence by Marcus (2018)

Reinforcement learning

Reviews & perspectives

Deep Reinforcement Learning and Its Neuroscientific Implications by Botvinick et al. (2020)

This paper reviews how neuroscience can benefit from deep RL (and vice versa), highlighting representation learning, model-based RL, memory, exploration, cognitive control and social cognition as promising research directions.

A distributional code for value in dopamine-based reinforcement learning

Reinforcement Learning, Fast and Slow by Botvinick et al. (2019)

This review pushes back against the objection that deep reinforcement learning is too sample-inefficient or slow to be a useful model of animal learning. It is argued that episodic deep RL and meta-RL can enable fast learning, addressing the problems of incremental parameter adjustment and weak inductive bias respectively, which are primarily responsible for sample inefficiency. This work reveals an important interaction between forms of fast and slow learning.

Reinforcement learning in artificial and biological systems by Neftci & Averbeck (2019)

The successor representation in human reinforcement learning

Experiments

Using deep reinforcement learning to reveal how the brain encodes abstract state-space representations in high-dimensional environments by Cross et al. (2021)

In the spirit of the deep RL framework outlined by Botvinick et al. (2020), this paper used a deep Q-network (DQN) to model fMRI activity of participants playing Atari video games, finding that dimensionality-reduced hidden DQN features significantly predict (better and more uniquely than other control models) both human actions and fMRI activity in a network including the dorsal visual pathway, the posterior parietal cortex and premotor areas.

Validating the Representational Space of Deep Reinforcement Learning Models of Behavior with Neural Data by Bruch et al. (2021)

The Thousand Brains Theory

The Thousand Brains Theory is a neocortical theory of intelligence developed by Jeff Hawkins and his team at Numenta, a research company dedicated to understanding the neocortex and applying its principles to machine intelligence. The theory can be seen as an updated version of Hawkins' "Hierarchical Temporal Memory", popularly explained in his first book On Intelligence (2004). The resources below are roughly arranged in reverse chronological order, but I'd suggest starting from the last paper to get a better sense of how the theory has developed.

A Thousand Brains: A New Theory of Intelligence by Hawkins (2021)

This is Hawkins' popular book explaining the theory in non-technical terms, including its implications for AI.

A thousand brains: toward biologically constrained AI by Hole & Ahmad (2021)

Focusing on the Thousand Brains Theory, this article emphasises the importance of sparse representations, more biologically realistic neuron models, the idea of reference frames, continuous online learning, and sensorimotor processing.

Grid Cell Path Integration For Movement-Based Visual Object Recognition by Leadholm, Lewis & Ahmad (2021)

An interesting paper further extending the model of Lewis et al. (2019).

A Framework for Intelligence and Cortical Function Based on Grid Cells in the Neocortex by Hawkins et al. (2019)

This is the technical paper introducing the Thousand Brains Theory of Intelligence. The key claim is that every cortical column learns predictive models based on reference frames of complete objects - or more precisely, of whatever causes its input to change - physical and abstract. This means that the brain creates possibly 1000s models] of every object it interacts with - hence the name of the theory. They make two additional interesting proposals: (i) displacement cells exist throughout the neocortex (possibly L5) and, together with cortical grid cells, enable learning the hierarchical composition and behaviour of objects; and (ii) the famous "what" and "where" visual pathways represent allocentric (object-related) and egocentric (body-related) locations, respectively.

Locations in the Neocortex: A Theory of Sensorimotor Object Recognition Using Cortical Grid Cells by Lewis et al. (2019)

Hawkins, Ahmad & Cui (2017) did not address how cells in the neocortex could represent the location of a sensor in an object's reference frame. This paper proposes that every cortical column learns models of objects in the same way grid cells in the entorhinal cortex learn maps or models of environments. They show that a two-layer network, including a sensory layer and location layer of cortical grid-like cells, can learn and recognise 2-D synthetic objects through sensorimotor sequences. They propose a mapping of the location and sensory layers to L6 and L4, respectively.

A Theory of How Columns in the Neocortex Enable Learning the Structure of the World by Hawkins, Ahmad & Cui (2017)

This paper extended the network model of Hawkins & Ahmad (2016) with an additional layer computing the location of the sensor relative to the object being sensed, showing that a single cortical column can recognise hundreds of 3-D synthetic objects through sensorimotor sequences. Crucially, the number of sensations decreases dramatically with multiple columns.

Why Neurons Have Thousands of Synapses, a Theory of Sequence Memory in Neocortex by Hawkins & Ahmad (2016)

This paper shows how thousands of synapses on multiple dendrites allow a neuron to recognise hundreds of independent patterns robustly. They propose a neuron model where patterns detected on proximal dendrites provide feedforward input leading to action potentials, and patterns detected by basal and apical dendrites provide predictions leading to depolarisation only. They show that a single-layer network of these neurons with local inhibition can learn with an unsupervised Hebbian-like rule sequences of patterns continuously and robustly.

Background sources

Neuroscience

AI

Acknowledgements

This collection was inspired by Beren Millidge's repository of papers on the free energy principle.