Towards a Unified Theory of Neocortex: Laminar Cortical Circuits for Vision and Cognition

A key goal of computational neuroscience is to link brain mechanisms to behavioral functions. The present article describes recent progress towards explaining how laminar neocortical circuits give rise to biological intelligence. These circuits embody two new and revolutionary computational paradigms: Complementary Computing and Laminar Computing. Circuit properties include a novel synthesis of feedforward and feedback processing, of digital and analog processing, and of pre-attentive and attentive processing. This synthesis clarifies the appeal of Bayesian approaches but has a far greater predictive range that naturally extends to self-organizing processes. Examples from vision and cognition are summarized. A LAMINART architecture unifies properties of visual development, learning, perceptual grouping, attention, and 3D vision. A key modeling theme is that the mechanisms which enable development and learning to occur in a stable way imply properties of adult behavior. It is noted how higher-order attentional constraints can influence multiple cortical regions, and how spatial and object attention work together to learn view-invariant object categories. In particular, a form-fitting spatial attentional shroud can allow an emerging view-invariant object category to remain active while multiple view categories are associated with it during sequences of saccadic eye movements. Finally, the chapter summarizes recent work on the LIST PARSE model of cognitive information processing by the laminar circuits of prefrontal cortex. LIST PARSE models the short-term storage of event sequences in working memory, their unitization through learning into sequence, or list, chunks, and their read-out in planned sequential performance that is under volitional control. LIST PARSE provides a laminar embodiment of Item and Order working memories, also called Competitive Queuing models, that have been supported by both psychophysical and neurobiological data. These examples show how variations of a common laminar cortical design can embody properties of visual and cognitive intelligence that seem, at least on the surface, to be mechanistically unrelated.National Science Foundation (SBE-0354378); Office of Naval Research (N00014-01-1-0624

Consciousness CLEARS the Mind

A full understanding of consciouness requires that we identify the brain processes from which conscious experiences emerge. What are these processes, and what is their utility in supporting successful adaptive behaviors? Adaptive Resonance Theory (ART) predicted a functional link between processes of Consciousness, Learning, Expectation, Attention, Resonance, and Synchrony (CLEARS), includes the prediction that "all conscious states are resonant states." This connection clarifies how brain dynamics enable a behaving individual to autonomously adapt in real time to a rapidly changing world. The present article reviews theoretical considerations that predicted these functional links, how they work, and some of the rapidly growing body of behavioral and brain data that have provided support for these predictions. The article also summarizes ART models that predict functional roles for identified cells in laminar thalamocortical circuits, including the six layered neocortical circuits and their interactions with specific primary and higher-order specific thalamic nuclei and nonspecific nuclei. These prediction include explanations of how slow perceptual learning can occur more frequently in superficial cortical layers. ART traces these properties to the existence of intracortical feedback loops, and to reset mechanisms whereby thalamocortical mismatches use circuits such as the one from specific thalamic nuclei to nonspecific thalamic nuclei and then to layer 4 of neocortical areas via layers 1-to-5-to-6-to-4.National Science Foundation (SBE-0354378); Office of Naval Research (N00014-01-1-0624

How Does the Cerebral Cortex Work? Developement, Learning, Attention, and 3D Vision by Laminar Circuits of Visual Cortex

A key goal of behavioral and cognitive neuroscience is to link brain mechanisms to behavioral functions. The present article describes recent progress towards explaining how the visual cortex sees. Visual cortex, like many parts of perceptual and cognitive neocortex, is organized into six main layers of cells, as well as characteristic sub-lamina. Here it is proposed how these layered circuits help to realize the processes of developement, learning, perceptual grouping, attention, and 3D vision through a combination of bottom-up, horizontal, and top-down interactions. A key theme is that the mechanisms which enable developement and learning to occur in a stable way imply properties of adult behavior. These results thus begin to unify three fields: infant cortical developement, adult cortical neurophysiology and anatomy, and adult visual perception. The identified cortical mechanisms promise to generalize to explain how other perceptual and cognitive processes work.Air Force Office of Scientific Research (F49620-01-1-0397); Office of Naval Research (N00014-01-1-0624

Vision, Action, and Make-Perceive

In this paper, I critically assess the enactive account of visual perception recently defended by Alva Noë (2004). I argue inter alia that the enactive account falsely identifies an object’s apparent shape with its 2D perspectival shape; that it mistakenly assimilates visual shape perception and volumetric object recognition; and that it seriously misrepresents the constitutive role of bodily action in visual awareness. I argue further that noticing an object’s perspectival shape involves a hybrid experience combining both perceptual and imaginative elements – an act of what I call ‘make-perceive.

Final report key contents: main results accomplished by the EU-Funded project IM-CLeVeR - Intrinsically Motivated Cumulative Learning Versatile Robots

This document has the goal of presenting the main scientific and technological achievements of the project IM-CLeVeR. The document is organised as follows: 1. Project executive summary: a brief overview of the project vision, objectives and keywords. 2. Beneficiaries of the project and contacts: list of Teams (partners) of the project, Team Leaders and contacts. 3. Project context and objectives: the vision of the project and its overall objectives 4. Overview of work performed and main results achieved: a one page overview of the main results of the project 5. Overview of main results per partner: a bullet-point list of main results per partners 6. Main achievements in detail, per partner: a throughout explanation of the main results per partner (but including collaboration work), with also reference to the main publications supporting them

An investigation of fast and slow mapping

Children learn words astonishingly skilfully. Even infants can reliably “fast map” novel category labels to their referents without feedback or supervision (Carey & Bartlett, 1978; Houston-Price, Plunkett, & Harris, 2005). Using both empirical and neural network modelling methods this thesis presents an examination of both the fast and slow mapping phases of children's early word learning in the context of object and action categorisation. A series of empirical experiments investigates the relationship between within-category perceptual variability on two-year-old children’s ability to learn labels for novel categories of objects and actions. Results demonstrate that variability profoundly affects both noun and verb learning. A review paper situates empirical word learning research in the context of recent advances in the application of computational models to developmental research. Data from the noun experiments are then simulated using a Dynamic Neural Field (DNF) model (see Spencer & Schöner, 2009), suggesting that children’s early object categories can emerge dynamically from simple label-referent associations strengthened over time. Novel predictions generated by the model are replicated empirically, providing proofof- concept for the use of DNF models in simulations of word learning, as well emphasising the strong featural basis of early categorisation. The noun data are further explored using a connectionist architecture (Morse, de Greef, Belpaeme & Cangelosi, 2010) in a robotic system, providing the groundwork for future research in cognitive robotics. The implications of these different approaches to cognitive modelling are discussed, situating the current work firmly in the dynamic systems tradition whilst emphasising the value of interdisciplinary research in motivating novel research paradigms

Challenges and advanced concepts for the assessment of learning and memory function in mice

The mechanisms underlying the formation and retrieval of memories are still an active area of research and discussion. Manifold models have been proposed and refined over the years, with most assuming a dichotomy between memory processes involving non-conscious and conscious mechanisms. Despite our incomplete understanding of the underlying mechanisms, tests of memory and learning count among the most performed behavioral experiments. Here, we will discuss available protocols for testing learning and memory using the example of the most prevalent animal species in research, the laboratory mouse. A wide range of protocols has been developed in mice to test, e.g., object recognition, spatial learning, procedural memory, sequential problem solving, operant- and fear conditioning, and social recognition. Those assays are carried out with individual subjects in apparatuses such as arenas and mazes, which allow for a high degree of standardization across laboratories and straightforward data interpretation but are not without caveats and limitations. In animal research, there is growing concern about the translatability of study results and animal welfare, leading to novel approaches beyond established protocols. Here, we present some of the more recent developments and more advanced concepts in learning and memory testing, such as multi-step sequential lockboxes, assays involving groups of animals, as well as home cage-based assays supported by automated tracking solutions; and weight their potential and limitations against those of established paradigms. Shifting the focus of learning tests from the classical experimental chamber to settings which are more natural for rodents comes with a new set of challenges for behavioral researchers, but also offers the opportunity to understand memory formation and retrieval in a more conclusive way than has been attainable with conventional test protocols. We predict and embrace an increase in studies relying on methods involving a higher degree of automatization, more naturalistic- and home cage-based experimental setting as well as more integrated learning tasks in the future. We are confident these trends are suited to alleviate the burden on animal subjects and improve study designs in memory research

Word Learning in the Developing Brain : ERP Dynamics of Learning Word-Object Associations

This dissertation investigated electrophysiological measures of individual differences in toddlers’ ability to learn novel object labels and process familiar object words and their referents. The studies measured both visual and auditory event-related potentials (ERPs) in response to pictures of objects and words in a longitudinal sample of 20- to 24-month-olds, an age of dynamic vocabulary development. These ERP measures were related to the children’s productive vocabulary size as well as behavioral measures of word comprehension and object recognition.Study I aimed to test children’s ability to map familiar words to versions of their referents displaying reduced visual information (only overall shape or isolated parts), and whether this ability correlated with vocabulary size. Children with larger vocabularies showed a stronger N400 incongruity effect in response to words paired with correct vs. incorrect shape referents specifically, and the N400 effect in the shape condition also correlated with the children’s ability to overtly identify objects from their overall shape in a behavioral test. These results are discussed in relation to previous research demonstrating the emergence of a shape bias in children’s Word extension, as well as improvements in object shape recognition, during the second year of life.Study II investigated individual differences in novel word-object mapping andchanges with age in this ability. The overall sample showed ERP evidence of novel word learning (an N400 semantic incongruity effect) after five consistent word-object pairings at 24 months but not at 20 months. Children with large vocabularies demonstrated the same linear attenuation of N400 amplitude during novel word repetition as is commonly seen in adults, while children with smaller vocabularies did not show such attenuation until the end of the learning phase.Study III focused on the 20 month data set and explored how visual ERPs weremodulated as object-word pairs were presented repeatedly, and how these measures of visual object processing related to successful fast mapping of the novel words to the objects. A larger attenuation of the Nc component (associated with attention) predicted successful word learning, measured as a larger N400 incongruity effect to the novel words after training. Furthermore, better initial recognition of familiar objects correlated with a stronger N400 effect to the words for those objects. The results present novel evidence for a link between efficient visual processing of objects and word learning ability.Taken together, these findings demonstrate that the rapid vocabulary growth and striking individual differences in productive vocabulary development seen during children’s second year are linked to the dynamics of specific brain mechanisms involved in semantic processing of words and their referents