@article{f4bf213648614770939bb4808d8bbe38,
title = "A neurocomputational system for relational reasoning",
abstract = "The representation and manipulation of structured relations is central to human reasoning. Recent work in computational modeling and neuroscience has set the stage for developing more detailed neurocomputational models of these abilities. Several key neural findings appear to dovetail with computational constraints derived from a model of analogical processing, 'Learning and Inference with Schemas and Analogies' (LISA). These include evidence that (i) coherent oscillatory activity in the gamma and theta bands enables long-distance communication between the prefrontal cortex and posterior brain regions where information is stored; (ii) neurons in prefrontal cortex can rapidly learn to represent abstract concepts; (iii) a rostral-caudal abstraction gradient exists in the PFC; and (iv) the inferior frontal gyrus exerts inhibitory control over task-irrelevant information.",
author = "Knowlton, {Barbara J.} and Morrison, {Robert G.} and Hummel, {John E.} and Holyoak, {Keith J.}",
note = "Funding Information: Preparation of this paper was supported by the Intelligence Advanced Research Projects Activity (IARPA) via Department of the Interior (DOI) contract number D10PC20022. The U.S. Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright annotation thereon. The views and conclusions contained hereon are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of IARPA, DOI, or the U.S. Government. Additional support was provided by the American Federation of Aging Research and Arthur Gilbert Foundation, the Illinois Department of Public Health, the Loyola University Chicago Dean of Arts and Sciences and the Graduate School (to R.G.M.). We thank Krishna Bharani for help in preparing the manuscript, and Paul Kogut and the rest of the Lockheed Martin FRAMES team for many helpful discussions. Two anonymous reviewers provided valuable comments on an earlier draft. Active memory information in a state of current readiness for use in processing (including the active portion of LTM), typically over a time span of around 20 seconds. Analogical mapping the process of identifying systematic correspondences between elements of two situations (analogs) based on relational structure. Cross-frequency coupling interactions between different frequency bands, such as theta and gamma, which aid in integrating neural activity across different spatial and temporal scales. Driver in LISA, an analog that is currently in active memory and serves as a generator of spreading activation. Phase set in LISA, the set of mutually desynchronized role bindings represented by neuronal oscillations. The phase set corresponds to the current focus of attention and is the most significant bottleneck for reasoning with relations. The phase set is equivalent to working memory (WM) for relations. Proposition a predicate instantiated by binding its role(s) to particular arguments (objects or other propositions). A proposition is the smallest unit of representation that can have a truth value: intuitively, a {\textquoteleft}complete thought{\textquoteright}. In LISA, a proposition is represented by a hierarchy of structure units. Proxy unit a transient representation of a structure unit, formed in prefrontal cortex in order to support structured reasoning, such as an analogical comparison. Recipient in LISA, an analog that is currently receiving activation from the driver. There may be multiple recipients in long-term memory (during retrieval) or a single recipient in active memory (during mapping, inference, and schema induction). Role-based relational reasoning reasoning that depends on the active representation and manipulation of concepts involving roles and role binding (see {\textquoteleft}proposition{\textquoteright}). Role binding the binding of a single argument (object or proposition) to a single role associated with a predicate. Schema a relatively abstract relational structure representing a category or class of situations (e.g., a schema for a type of problem). In LISA, schemas can be formed as a consequence of comparing two or more relatively specific analogs. Semantic unit a unit that represents a simple element of meaning, associated with neurons in posterior cortex. In LISA, semantic units are the sole conduits for the transmission of activation between distinct analogs. Spike-timing-dependent plasticity a phenomenon based on evidence that if a neuron is being driven at a high rate, as occurs in the high gamma band, the inputs driving it will be strengthened. It provides a neural mechanism by which the kind of synchronous activity that in the LISA model supports dynamic representations will also lead to synaptic strengthening. Structure unit in LISA, a unit representing a component of a proposition within an analog: P (proposition), RB (role binding), O (object), and R (role); or a correspondence between elements of two analogs (M). Such units may be associated with neurons in posterior cortex (when stored in LTM), but must also be associated with dynamically recruited neurons in prefrontal cortex (see {\textquoteleft}proxy unit{\textquoteright}). ",
year = "2012",
month = jul,
doi = "10.1016/j.tics.2012.06.002",
language = "English (US)",
volume = "16",
pages = "373--381",
journal = "Trends in Cognitive Sciences",
issn = "1364-6613",
publisher = "Elsevier Ltd",
number = "7",
}