Wednesday, September 30, 2009

Bye bye modular, hello cognit!

What is a cognit you ask? It's a basic unit of memory or knowledge defined by pattern of connections between a network of neurons associated by experience.

Termed by Fuster in 2006, the construct was created to solve the problematic yet popular view that the human brain is made up of discrete cortical domains dedicated exclusively to visual discrimination, language, spatial attention, face recognition, motor programming, memory retrieval, and working memory.

Although the modular modeling of the brain has utterly failed due to a lack of conclusive evidence, many neuroscientists continue to maintain this antiquated view... but why? Put quite simply, there was nothing better. However, thanks to Fuster, a new paradigm is emerging...

Introducing the cognit network model. It postulates that memory and knowledge are represented by interactive, distributed, and overlapping networks of neurons in association cortices.

The posterior-post-rolandic association cortex contains perceptual cognits and the frontal association cortex contains executive cognits. The prefrontal and posterior association cortices are linked by complex cognits in a hierarchical order. The parasensory and premotor cortex, found at the bottom of the hierarchy, contain relatively simple and small cognits which represent motor acts or simple percepts. At the top of the hierarchy is the temporo–parietal and prefrontal cortex containing larger cognits representing complex and abstract information of perception and executive control. The long reciprocal cortico–cortical connections between the posterior and frontal networks support sequential behavior, speech, and reasoning.

What I find most fascinating about the whole thing is that it's possible for a single neuron to be involved in multiple memory networks thus playing a part in many memories and units of knowledge.

Fuster JM (2009). Cortex and memory: emergence of a new paradigm. Journal of cognitive neuroscience, 21 (11), 2047-72 PMID: 19485699

FUSTER, J. (2006). The cognit: A network model of cortical representation International Journal of Psychophysiology, 60 (2), 125-132 DOI: 10.1016/j.ijpsycho.2005.12.015

6 comments:

  1. Implications for neuropsychology (esp. clinical neuropsychology which seems to lean so heavily on the modular view of cortical organization)?

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  2. Couldn't this have implications for our conceptualization of creativity, if certain memory networks overlap?

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  3. Hence the possibility of a paradigmatic shift.

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  4. RE: Cognit vs. Memophorescenicity!?

    What is a cognit you ask? It's a basic unit of memory or knowledge defined by pattern of connections between a network of neurons associated by experience. And: Hence the possibility of a paradigmatic shift.

    Hardly -- “Cognit” is only a more refined (but still static) “mapping of network” of a circuitry or a bundle of circuitry, that was previously recognized as a node or lobule or module as primarily assumed by the 1970s AI (artificial intelligence) enthusiasts and linguist-psychologists (eg, Minsky, Chomsky, Pinker, et al came to mind).

    Whereas the “implications for our conceptualization of creativity” would require a more dynamic model of circuitry and conceptualization; as one that I coined in my seminal book God, Genes, Conscience (link below) as a quantum mechanics of "memophorescenicity" as described panoramically in Chapter 15: The Universal Theory of Mind; especially, section 15.4, Memory Modulation and Recall: A New Hypothesis of Psychic Imagery, Perceptivity, Creativity, and Reflectivity; and section 15.5, Lights, Music, Matching Band, and A Spherical Cinema: An Analogy and A New Model of Mind/Gods as Perceived through Both the Scientific and Spiritual Prisms, Extrinsic and Intrinsic, respectively.

    Best wishes, Mong 10/2/9usct4:49p; practical science-philosophy critic; author "Decoding Scientism" and "Consciousness & the Subconscious" (works in progress since July 2007), Gods, Genes, Conscience (iUniverse; 2006) and Gods, Genes, Conscience: Global Dialogues Now (blogging avidly since 2006).

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  5. Hi - I just came across your post. I'm a PhD researcher in cognitive robotics (applying the lesson of biological cognition to robots, and taking the results of this to feed back understanding to biology), and Fuster's model of cortical organisation and functionality have inspired my work for a number of years (see http://paul-baxter.blogspot.com/2006/11/network-memory.html for example). I remain surprised however, that it has received relatively little attention from my field.

    I both agree and disagree with the previous comment (Mong Tan) - cognits may be conceptually similar to the associationism architectures of AI, but they go much further than that. They provide the basis of an account (which in my view is at least a promising one) which links embodiment and low-level sensory-motor competencies with conceptual thought (ie higher level aspects of cognition/'intelligence'), by taking into account the entire history of interaction between an individual and its environment (both physical and social). Individual cognits are not proposed to be individual units (such as a node in a network), but distributed, overlapping networks in themselves, thus allowing individual neurons to be a 'part' of multiple cognits, be they 'low-level' or 'high-level'.

    An interesting discussion though - thanks.

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  6. Hey- Nice post! I agree with Paul, the point about taking into account the history of the interaction is a very important one. Based on the work of Fuster, Schnelle (Language and the brain), evolutionary psychology and my speciality in modelling complex systems using quantum mechanics (Penrose mades a good point why this is appropriate) I have suggested a solution to the mind-brain problem here:

    http://www.springerlink.com/content/483476ml6t143j3p/

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