I - Cortical Column Functions II - Functional WebsUniformity of cortical functionTesting the claimQuote from MountcastleColumns do not store symbols!Why the usual approach won’t workWhy the usual approach won’t work (cont’d)Compare imageryThere must be another wayAnother way, for languageQuotationSlide 12Columnar Functions: Integration and BroadcastingIntegration and BroadcastingSlide 15What matters is not ‘what’ but ‘where’Operations in relational networksWhat about the rest of language?SequenceLasting activation in minicolumnNotation for lasting activationRecognizing items in sequenceDemisyllables in recognizing stopsDemisyllables [di, de, da, du]Recognizing a syllable and its demisyllablesAnother syllable and its demisyllablesMultiple connections of -ilSlide 28Slide 29Syntactic Recognition – same principleSyntactic Recognition: higher-level perceptionConclusion: All of linguistic structure is relationalFindings relating to columns (Mountcastle, Perceptual Neuroscience, 1998)Operation of the NetworkNeuronal Structure and Function (Pulverműller 2002, Chapter 2)Neuronal Structure and Function: The Cortex as a NetworkThe cortex operates by means of connectionsComputers and Brains: Different Structures, Different SkillsWhat brains but not computers can doNeuronal Structure and Function: ConnectivityPyramidal neurons and their connectionsProportion of pyramidal cells in the cortexConnecting fibers of pyramidal neuronsInterconnections of pyramidal neuronsSlide 45Cortical connectivity propertiesMore cortical connectivity propertiesDegrees of separation between cortical neurons or columnsNeural processes for learningSlide 50Pulvermüller’s functional websThe neural basis of cognitionSlide 53Hypothesis I: Functional WebsExample: The meaning of dogThe Wernicke-Lichtheim concept node (1885)The “C” Node“C” node as cardinal node of a webSome connections of the “C” node for FORKZooming in on the “V” Node..Add phonological recognition nodeAdd node in primary auditory areaAdd node for phonological productionSome of the cortical structure relating to forkFunctional web of a simple lexeme: forkPart of the functional web for FORK (showing cardinal nodes only)An activated functional web (with two subwebs partly shown)Ignition of a functional web from visual inputSlide 69Slide 70Slide 71Slide 72Slide 73Slide 74Slide 75Slide 76Slide 77Slide 78Slide 79Slide 80Slide 81Speaking as a response to ignition of a webSlide 83Slide 84An MEG study from Max Planck InstitutePulvermüller’s line of reasoningSlide 87I - Cortical Column Functions II - Functional WebsLing 411 – 12Uniformity of cortical functionIf cortical function is uniform across mammals and across different cortical areas, then the findings presented by Mountcastle can be extended to languageClaims:•Locally, all cortical processing is the same•The apparent differences of function are consequences of differences in larger-scale connectivityConclusion (if the claim is supported):•Understanding language, even at higher levels, is basically a perceptual processTesting the claimClaim:•The apparent differences of function are consequences of differences in larger-scale connectivityTo test, we need to understand cortical functionThat means we have to understand the function of the cortical columnQuote from Mountcastle“[T]he effective unit of operation…is not the single neuron and its axon, but bundles or groups of cells and their axons with similar functional properties and anatomical connections.” Vernon Mountcastle, Perceptual Neuroscience (1998), p. 192Columns do not store symbols!They only•Receive activation•Maintain activation•Inhibit competitors•Transmit activationImportant consequence:•We have linguistic information represented in the cortex without the use of symbols•It’s all in the connectivityChallenge:•How?Why the usual approach won’t workLet us suppose that words are stored in some kind of symbolic form What form?If written, there has to be..•something in there that can read them•something in there that can write them•something in there that can move them around, from one place to another•something in there to compare them with forms entering the brain as it hears someone speaking – otherwise, how can an incoming word be recognized?Why the usual approach won’t work (cont’d)If not written, then represented in some other mediumDoesn’t solve the problemYou still need whatever kind of sensory detectors can sense the symbols in whatever medium you choosePlus means of performing all those other operationsCompare imageryVisual images•Little pictures?•If so, what is in there to see them?Auditory images•Little sounds vibrating in the brain?•If so, what is in there to hear them?There has to be another way!There must be another wayVisual imagery (e.g. of your grandmother)•Reactivation of some of the same nodes and connections that operate when actually seeing herAuditory imagery (e.g. of a tune)•Reactivation of some of the same nodes and connections that operate in actually hearing itAnother way, for languageA syllable•Activation of the nodes and connections needed to recognize or produce itA word•Activation of the nodes and connections needed to recognize itA syntactic construction•Activation of the nodes and connections needed to recognize or produce itThe postulation of objects as something different from the terms of relationships is a superfluous axiom and consequently a metaphysical hypothesis from which linguistic science will have to be freed. Louis Hjelmslev Prolegomena to a Theory of Language (1943: 61)QuotationColumns do not store symbols!They only•Receive activation•Maintain activation•Inhibit competitors•Transmit activationImportant consequence:•We have linguistic information represented in the cortex without the use of symbols•It’s all in the connectivityChallenge:•How?Columnar Functions: Integration and BroadcastingIntegration: A column is activated if it receives enough activation from •Other columns •Thalamus Can be activated to varying degreesCan keep activation alive for a period of timeBroadcasting: An activated column transmits activation to other columns•Exitatory•InhibitoryLearning : adjustment of connection strengths and thresholdsIntegration and BroadcastingBroadcasting•To multiple locations•In