The Microgenetic Dynamics of Cortical Attractor Landscapes

Mark H. BickhardLehigh University

mark@bickhard.name http://bickhard.ws/

Abstract

• Attractor landscapes are dispositional models of neural processes, but those landscapes themselves have a dynamics. I will outline how such landscapes are ongoingly created and modified, and how primitive representation emerges from these processes.

Context:The Broader Model

• Ontological Emergence• Conceptual barriers from Pre-Socratics

– Hume– Kim

• Emergence of Normativity• Also ancient problems

– Biological function– Representation

Representation

• Cognition and Representation emerge in interaction systems– Self-maintenant systems– Recursively self-maintenant systems

• Selection of interaction = presupposition of appropriateness; anticipation of appropriateness

– ‘Appropriateness’ is normative– Derives from underlying model of normative function

• Yields truth value — representation

Pragmatism

• An interaction based, pragmatic, model of representation– Kinship to Piaget

• More complex representations– Objects– Abstractions: e.g., numbers

Interaction Requires Timing

• Successful interaction requires timing coordination– This is coordinative, neither too fast nor too

slow

• Turing machines cannot handle timing

• Computers have central clocks– Not plausible for the brain

Timing Requires Oscillators

• Solution: Put clocks everywhere• But clocks are “just” oscillators

– Functional relationships are relationships among oscillators: modulations

– Trivially at least TM powerful

• Need a tool kit of different forms and scales of modulation– Modulations of modulations … of oscillatory

activity

And This is What We Find

• Neurons are standardly modeled as:– Threshold switches– Connectionist nodes– Frequency encoders

• All have in common the assumption that neurons are ‘just’ input processors

• And that neurons are the only functional units

Both Are Wrong

• Neurons and neural circuits are endogenously active– In multiple ways– They do not just process inputs

• And neurons are not the only functional units– Glia, for example, are also functional, not

just supportive

NeuronsAnd local circuits

• Oscillators– Resonators

• Multiple interesting implications

– Modulations of endogenous activity, not switches of otherwise inert units

Neurons II

• Silent neurons• Interneurons• Short connections• Volume transmitters

• L-Dopa

• Graded release of transmitters• Gap junctions• Why multiple transmitters if all synapses are

classical?• Transmitters evolved from hormones• Classical synapses evolved from volume transmitters

Astrocytes (Glia)

• Receive transmitters• Emit transmitters• Form functional “bubbles”• Gap junction connections• Calcium waves• Modulate synaptogenesis• Modulate synaptic functioning

– Release, uptake, degree of volume diffusion, …

Confirmation of Implication of Model of Representation

• So, we do find a rich toolbox of multiple scales of modulatory relations

Now In Reverse

• CNS functioning implies anticipatory cognition

Multiple Scales

• These are all modulatory influences at multiple scales– Large and small spatial scales– Slow and fast temporal scales

– There are also variations in delay times

• Evolution has created a large tool box of multiple kinds and scales of modulatory influences

Microgenesis:Large Temporal Scale

• Larger and slower processes set the context for smaller and faster processes

• They set the parameters for the faster and smaller processes– Ion and transmitter concentrations– Modes of synaptic functioning

• They generate vast concurrent micro-(and meso-) modes of processing across the brain: Microgenesis

Dynamic Programming

• Parameter setting for dynamic processes is the dynamic equivalent of programming in a discrete system

• Microgenesis sets and changes the programs across the brain

• Microgenesis is ongoing and occurs in real time

Functional Anticipation

• Microgenetic set-up may or may not be appropriate to the actual flow of interactive processing that occurs in the organism

• Microgenesis is functionally anticipatory– The anticipation is that the microgenetic

set-up will be appropriate

Emergence of Truth Value

• Microgenetic anticipations can be true or false– And can be functionally determined to be

false if the interaction violates anticipations

• This is the emergence of representational truth value out of pragmatic functional success and failure

Content

• Microgenetic anticipations will be true in some environmental conditions, and false in others

• Microgenetic anticipations, then, presuppose that the appropriate conditions — whatever they are — obtain in the current environment.– The flow of anticipated conditions is implicit in the flow of

microgenesis

• Those conditions constitute the content of the representing– An implicit content

How Does This Differ?

• Endogenously active

• Interaction based, not input processing• Future oriented, not past oriented “spectator”

model (Dewey)• Inherently modal: anticipations of interaction

possibilities, not foundationally built on encoding correspondences with actual particulars

• Implicit, thus unbounded, not explicit– Frame problems

• Etc.

Two Way Implication

• So, analysis of representation yields a required substrate of multi-scale modulatory, interactive brain processes

• And an oscillatory/modulatory tool kit is precisely what we find

• And, analysis of how the brain functions yields an anticipatory, interactive model of representation

• Each implies the other

Microgenesis:Larger Spatial Scale —Attractor Landscapes

• The slower scale processes engage in microgenetic programming of faster processes

• The larger scale of these processes — astrocytes, volume transmitters, short range connections, reciprocal

connections with thalamus, etc. — induces weak coupling among oscillatory processes

• Such weak coupling induces attractor landscapes– Within which faster processes proceed

Modulation of Attractor Landscapes

• Modulation of microgenesis, therefore, modulates attractor landscapes

Modulation of slower, larger scale process — astrocytes, etc. — modulates attractor landscapes

• Provides a new framework for interpreting functionality of prefrontal - basal ganglia - thalamus - cortex loops– As engaged in modulation of attractor landscapes

Thought

• These loops generate a kind of internal interaction with the dynamic spaces within which other CNS processes take place

• This fits well with Pragmatic/Piagetian conception of thought as internal (inter)action

Further Issues

• Other models of representation– Millikan– Dretske– Fodor– Cummins– Encodingism

Further Issues II

• Other phenomena of mind• Perception• Memory• Motivation• Learning• Emotions• Reflective consciousness• Language• Rationality• Social ontology• Personality, psychopathology• Ethics

Conclusion

• In being intrinsically interactive, representation and cognition are inherently:

• Future oriented, anticipative• Pragmatic• Modal• Situated• Embodied• …

Conclusion II

• And they are realized in:– Internal interactive modulations of– Attractor landscapes for– Oscillatory/ modulatory control of– Interactions of organism with environment

Fini

What’s Wrong with Standard Models of Representation?

• Encodingism– Error, system detectable error — radical

skeptical argument– Which correspondence?– Copy argument — Piaget– Externally related content: regress of

interpreters– Partial recognition of problems: empty

symbol problem, grounding problem

What’s Wrong With Standard Models? II

• Millikan– Representation as function– Etiological function is causally epiphenomena

• Dretske– Etiological function again, learning history rather

than evolutionary history

• Fodor– Asymmetrically dependent counterfactual relations

• Counter example of crank molecule

What’s Wrong With Standard Models? III

• Error– From observer perspective

• Millikan OK• Dretske OK• Fodor Sort of OK

• System detectable error– Content is not system accessible for any of these

models– Comparing content with what is supposed to be being

represented to determine truth or error is representational problem all over again

– They are circular with respect to this criterion

What’s Wrong With Standard Models? IV

• Symbol system hypothesis– Transduced encoding

• Connectionism– Trained encoding

What’s Wrong With Standard Models? V

• Dynamic systems

• The interactive model is clearly a dynamic, process model

• Dynamic approaches, however, are often anti-representational– E.g., Van Gelder, Thelen

Dynamic Systems Approaches

• But, dynamic systems as agents must select interactions, must functionally indicate interaction

potentialities,

must yield representational truth value

must involve normative representation, whether that terminology is used or not

– Criticisms of representation are in fact criticisms of encodingist approaches to representation

Encodingism

• Encodings do exist– But they borrow content– E.g., Morse code– They cannot generate emergent content

• Serious problem for learning• E.g., Fodor’s innatism

• Encodingism assumes that all representation is of encoding form

• Encodingism does not work

Further Issues

• Contemporary work pervasively assumes encodingism:– Perception– Rationality– Language– Memory– Learning– Emotions– Consciousness– …

Conclusion I

• Representation is interactive, future oriented, pragmatic, non-encoding, modal, situated, embodied, and so on.

Conclusion II

• These force multiple further changes:– Perception– Language– Memory– Motivation– Learning– Models of Brain Processes– And so on

Conclusion III

• A major reworking of our models of and approaches to the whole person is required– The Whole Person