How General Is The How General Is The Concept Of A Concept Of A Receptive Field?Receptive Field?

Gregg RosenbergGregg Rosenberg

April 7, 2004April 7, 2004

Towards A Science of Towards A Science of ConsciousnessConsciousness

Talk OutlineTalk Outline

FoundationsFoundations The classic example of a receptive fieldThe classic example of a receptive field A rough attempt at generalizing the classic definition of A rough attempt at generalizing the classic definition of

receptive fieldreceptive field An attempt at precision in the generalized definitionAn attempt at precision in the generalized definition

The ontology of consciousnessThe ontology of consciousness Hypothesis 1Hypothesis 1: The field of conscious experience is : The field of conscious experience is

determined by the contents of a receptive field at the level determined by the contents of a receptive field at the level of the whole person.of the whole person.

Hypothesis 2Hypothesis 2: The subjective phenomenal contents of : The subjective phenomenal contents of consciousness are Russellian intrinsic contents within the consciousness are Russellian intrinsic contents within the receptive field.receptive field.

SummarySummary

The Classic Example of The Classic Example of a Receptive Fielda Receptive Field

Definition(s) of the Definition(s) of the Classic Receptive FieldClassic Receptive FieldFor the prototypical retinal example:For the prototypical retinal example: Proximate cause definition:Proximate cause definition: A retinal cell’s receptive field A retinal cell’s receptive field

is the area of the retina where stimulation elicits a response is the area of the retina where stimulation elicits a response in the cell.in the cell.

Ultimate cause definition:Ultimate cause definition: A retinal cell’s receptive field is A retinal cell’s receptive field is the area in the visual field where a stimulus elicits a the area in the visual field where a stimulus elicits a response in the cell.response in the cell.

Definition(s) of the Definition(s) of the Classic Receptive FieldClassic Receptive FieldFor the prototypical retinal example:For the prototypical retinal example: Proximate cause definition:Proximate cause definition: A retinal cell’s receptive field A retinal cell’s receptive field

is the area of the retina where stimulation elicits a response is the area of the retina where stimulation elicits a response in the cell.in the cell.

Ultimate cause definition:Ultimate cause definition: A retinal cell’s receptive field is A retinal cell’s receptive field is the area in the visual field where a stimulus elicits a the area in the visual field where a stimulus elicits a response in the cell.response in the cell.

For arbitrary neural cells:For arbitrary neural cells: Proximate cause definition:Proximate cause definition: A neuron’s receptive field is A neuron’s receptive field is

the map of neurons in the brain where stimulation elicits a the map of neurons in the brain where stimulation elicits a response in the cell.response in the cell.

Ultimate cause definition:Ultimate cause definition: A neuron’s receptive field is A neuron’s receptive field is the area or feature in the organism’s stimulus field where a the area or feature in the organism’s stimulus field where a stimulus elicits a response in the cell.stimulus elicits a response in the cell.

Generalization of the Generalization of the concept of receptive concept of receptive fieldfieldFrom here:From here: I will focus on the Proximate I will focus on the Proximate

Cause definition.Cause definition.

For arbitrary kinds of entities:For arbitrary kinds of entities: Proximate cause definition:Proximate cause definition: An entity’s receptive field An entity’s receptive field

consists of the entities in its immediate environment whose consists of the entities in its immediate environment whose interactions with the receiving entity elicit responses from it.interactions with the receiving entity elicit responses from it.

An attempt at An attempt at precision in the precision in the generalized conceptgeneralized concept What kinds of entities are What kinds of entities are

candidates for having receptive candidates for having receptive fields? fields?

What is a “response”?What is a “response”? What is an “immediate What is an “immediate

environment”?environment”? What kinds of “interactions”?What kinds of “interactions”?

Defining Defining characteristics of characteristics of “entities”“entities”

What kinds of entities? How are they What kinds of entities? How are they identified?identified?– A receptive entity must be an entity that A receptive entity must be an entity that

can take on a “single” state.can take on a “single” state.– CAS criteria relevant (Holland 1996, 1998): CAS criteria relevant (Holland 1996, 1998):

CAS mechanisms: Tags, building blocks, internal CAS mechanisms: Tags, building blocks, internal models. models.

CAS properties: Aggregation, Flows, Diversity, CAS properties: Aggregation, Flows, Diversity, Non-linearity.Non-linearity.

Defining Defining characteristics of characteristics of “entities” “entities” Self/non-self recognitionSelf/non-self recognition – Tagging that – Tagging that

enables the aggregation of components within enables the aggregation of components within a boundary.a boundary.

Selectively permeable boundarySelectively permeable boundary – Tagging that – Tagging that enables selective interaction with environment.enables selective interaction with environment.

Attractor statesAttractor states – A set of stable states towards – A set of stable states towards which neighboring states in a given basin of which neighboring states in a given basin of attraction asymptotically approach in the attraction asymptotically approach in the course of the entity’s dynamic evolution. course of the entity’s dynamic evolution.

Lever pointsLever points – Points of interaction where small – Points of interaction where small amounts of input can produce large, directed amounts of input can produce large, directed changes.changes.

Defining Defining characteristics of a characteristics of a “response”“response” Stable state Stable state – Prior to the response the entity is – Prior to the response the entity is

evolving within the basin of attraction of an attractor evolving within the basin of attraction of an attractor state.state.

Controlled trigger Controlled trigger – The response is a reaction to – The response is a reaction to validly tagged signals received through the permeable validly tagged signals received through the permeable boundary.boundary.

Detectable difference Detectable difference – The trigger causes the entity – The trigger causes the entity to move sharply away from the attractor it had been to move sharply away from the attractor it had been approaching in a way that makes a difference to its approaching in a way that makes a difference to its interactions with its environment. interactions with its environment. – Cycles through one or more limit cycles.Cycles through one or more limit cycles.– Jump to a new basin of attraction.Jump to a new basin of attraction.– Jump to a qualitatively different traversal path Jump to a qualitatively different traversal path

within its existing basin.within its existing basin.

Example: PersonsExample: Persons

Coarse grained stable states Coarse grained stable states – At the most coarse – At the most coarse grain, a living person has a limit cycle of two state grain, a living person has a limit cycle of two state attractors: Waking and sleeping.attractors: Waking and sleeping.

Controlled trigger Controlled trigger – Human beings cycle between – Human beings cycle between these two states reliably in response to circadian these two states reliably in response to circadian rhythms or external stimuli. Circadian rhythms are rhythms or external stimuli. Circadian rhythms are good examples of hormones being injected into the good examples of hormones being injected into the system as tagged messages right at structured lever system as tagged messages right at structured lever points. points.

Detectable difference Detectable difference – The response consists of the – The response consists of the person moving sharply away from the attractor he or person moving sharply away from the attractor he or she had settled near. she had settled near. – Person cycles from waking to sleeping or sleeping to Person cycles from waking to sleeping or sleeping to

waking.waking.

Defining an Defining an “immediate “immediate environment”environment”

An entity’s An entity’s immediate immediate environmentenvironment is the set of other is the set of other entity’s at the same level from entity’s at the same level from which signals flow to the which signals flow to the receiving entity without having to receiving entity without having to flow through any other entity at flow through any other entity at the same level as the receiving the same level as the receiving entity.entity. Receivin

g EntityNot Immediate

Not Immediate

Immediate

Immediate

The definition of a The definition of a receptive field receptive field understood preciselyunderstood precisely Proximate cause definition Proximate cause definition

(original):(original): An entity’s receptive field An entity’s receptive field consists of the entities in its immediate consists of the entities in its immediate environment whose interactions with environment whose interactions with the receiving entity elicit responses the receiving entity elicit responses from it.from it.

Sharpening:Sharpening: An entity An entity BB is in the is in the receptive field of an entity receptive field of an entity AA at time at time tt if, and only if, if, and only if, BB is in the immediate is in the immediate environment of environment of AA at time at time tt and is and is capable of contributing to a possible capable of contributing to a possible perturbation wave with respect to perturbation wave with respect to AA. .

Example: Neural firingExample: Neural firing

Token responsesToken responses – Neural firings. A typical – Neural firings. A typical neural activation is a response to a set of neural activation is a response to a set of convergent signals received through its convergent signals received through its dendritic boundary.dendritic boundary.

Perturbation wavesPerturbation waves – This set of signals – This set of signals constitutes a perturbation wave, a wave of constitutes a perturbation wave, a wave of tagged causal influence, eliciting a firing tagged causal influence, eliciting a firing response from the neuron. response from the neuron.

Immediate environment Immediate environment – Every perturbation – Every perturbation wave must come through a set of entities in wave must come through a set of entities in the receiving neuron’s immediate the receiving neuron’s immediate environment.environment.

How general? Example 1: How general? Example 1: Atoms?Atoms? EntityEntity – –

– Self/non-self recognitionSelf/non-self recognition – The integrity of – The integrity of nuclear forces in a nucleus.nuclear forces in a nucleus.

– Selectively permeable boundarySelectively permeable boundary – Orbital – Orbital shells. shells.

– Attractor statesAttractor states – Stable orbital configurations. – Stable orbital configurations. – Lever pointsLever points – Conditions under which orbital – Conditions under which orbital

configurations can change.configurations can change. Responses Responses – Changes in ionic – Changes in ionic

configurations.configurations. Immediate environmentImmediate environment – Other atoms. – Other atoms. PerturbationsPerturbations – Collisions. – Collisions.

How general? Example 2: How general? Example 2: Cells other than Cells other than neurons?neurons? EntityEntity – –

– Self/non-self recognitionSelf/non-self recognition – The selectivity of – The selectivity of transport and messenger proteins.transport and messenger proteins.

– Selectively permeable boundarySelectively permeable boundary – Cell walls. – Cell walls. – Attractor statesAttractor states – Energy production states and – Energy production states and

message release via proteins. message release via proteins. – Lever pointsLever points – Protein and ionic concentrations. – Protein and ionic concentrations.

ResponsesResponses – Cell division? Release of proteins – Cell division? Release of proteins into bloodstream?into bloodstream?

Immediate environmentImmediate environment – Other cells. – Other cells. PerturbationsPerturbations – Hormones and proteins – Hormones and proteins

absorbed through the cell wall.absorbed through the cell wall.

How general? Example 3: How general? Example 3: Neural columns and Neural columns and assemblies?assemblies? EntityEntity – –

– Self/non-self recognitionSelf/non-self recognition – Harmony of wave – Harmony of wave characteristics.characteristics.

– Selectively permeable boundarySelectively permeable boundary – The cloud of – The cloud of neurotransmitter junctions associated with its dendrite neurotransmitter junctions associated with its dendrite and axon projections to other neural and axon projections to other neural columns/assemblies.columns/assemblies.

– Attractor statesAttractor states – Discrete frequency ranges in its group – Discrete frequency ranges in its group firing characteristics. firing characteristics.

– Lever pointsLever points – Neurotransmitter imbalances. – Neurotransmitter imbalances. ResponsesResponses – Changes in the group harmonics of its – Changes in the group harmonics of its

neural firings.neural firings. Immediate environmentImmediate environment – Other neural – Other neural

columns/assemblies.columns/assemblies. PerturbationsPerturbations – Waves with competing harmonics. – Waves with competing harmonics.

Do Persons Have Do Persons Have Receptive Fields?Receptive Fields? EntityEntity – –

– Self/non-self recognitionSelf/non-self recognition – Immune system. – Immune system.– Selectively permeable boundarySelectively permeable boundary – An epidermal layer with – An epidermal layer with

sensory receptors.sensory receptors.– Attractor statesAttractor states – The Sleep/wake cycle. More importantly, – The Sleep/wake cycle. More importantly,

the wakefulness attractor is a very complex landscape the wakefulness attractor is a very complex landscape composed of a variety of sub-attractors and limit cycles we composed of a variety of sub-attractors and limit cycles we can identify with motor and attentional programming. can identify with motor and attentional programming.

– Lever pointsLever points – An integrated control system with person – An integrated control system with person level responses modulated by attentional focus & level responses modulated by attentional focus & emotional salience within consciousness.emotional salience within consciousness.

ResponsesResponses – Changes in the priming of motor programming. – Changes in the priming of motor programming. Immediate environmentImmediate environment – The array of perceptual and – The array of perceptual and

introspectible objects capable of being represented in the introspectible objects capable of being represented in the global workspace of consciousness.global workspace of consciousness.

PerturbationsPerturbations – High saliency changes in the contents of the – High saliency changes in the contents of the global workspace.global workspace.

Ontology of Ontology of Consciousness: Consciousness: Hypothesis 1Hypothesis 1

The field of conscious experience is The field of conscious experience is determined by the contents of a receptive determined by the contents of a receptive field at the level of the whole person.field at the level of the whole person.

Ontology of Ontology of Consciousness:Consciousness:Hypothesis 2Hypothesis 2

TheThe subjective phenomenal contents subjective phenomenal contents of consciousness are Russellian of consciousness are Russellian intrinsic contents within a person’s intrinsic contents within a person’s receptive field.receptive field.– These intrinsic contents carry the convergent These intrinsic contents carry the convergent

influences active at the personal level.influences active at the personal level.– These perturbation waves are composed of signals These perturbation waves are composed of signals

defined by, and structured according to, their defined by, and structured according to, their command content for the person, not their micro command content for the person, not their micro constitution.constitution.

– The person receives perturbation waves as unified The person receives perturbation waves as unified command structures converging on it through its command structures converging on it through its receptive field.receptive field.

– There is no “combination problem”.There is no “combination problem”.

SummarySummary

– The concept of having a “receptive field” The concept of having a “receptive field” can be generalized so that it includes can be generalized so that it includes persons.persons.

– The contents of consciousness may be The contents of consciousness may be determined by the contents of a person’s determined by the contents of a person’s receptive field.receptive field.

– The qualitative content of consciousness The qualitative content of consciousness may be the Russellian intrinsic content of may be the Russellian intrinsic content of perturbation waves received by the person.perturbation waves received by the person.

– The metaphysics of how all this may occur The metaphysics of how all this may occur is explained in detail in my book, is explained in detail in my book, A Place A Place For ConsciousnessFor Consciousness to be published by OUP to be published by OUP later this year (2004).later this year (2004).