brain anatomy and artificial intelligence -...

Brain anatomy and artificial intelligence

L. Andrew CowardAustralian National University, Canberra, ACT 0200, Australia

The Fourth Conference onArtificial General Intelligence August 2011

Functional Architecture

Control ArithmeticLogic

RegistersProcessor

Physical Architecture

Architectures and Information Processes

Memory

CallProcessing

Diagnostics

Maintenance

Billing

Medulla

Thalamus

Hypothalamus

Basalganglia

Cerebellum

PrecentralGyrus

CentralSulcus

Post CentralGyrus

MammillaryBody

LateralVentricle

CorpusCallosum

Fornix

Pons

Tectum

Tegmentum

Cortex

SpinalCord

Major Brain Structures

Behaviourselection

ResourceManagement

Rewardmanagement

Behavioursequencemanagement

Information flowmanagement

Behaviour Implementation

condition definitionand detection

behaviourselection

Behaviour typeprobabilitymanagement

Amygdala

Dorsal BasalGanglia

Hippocampus

Ventral BasalGanglia

Cerebellum

Brain stem;Spinal cord

Cortex

Thalamus

Brain Architecture and Information Processes

400 µm column All pyramidal neurons in all layersof a column have similar receptive fields

Receptive Fields of Cortical Columns

68B

8A

9

9/46d

9/46v10

46

47/1245A 45B

44

3,1,2 57

17

1819

4

43

40

22

3837

2120

52 42 41

39

24

33

25

29

34

27

38 20

36

2835 37

86 4

32

11

9

10

2331

7

19

1918

1817

5

26 30

12

Remembering past event

Elaborating

Conceiving

Imagining future event

Activity of Cortical Areas During Mental Imaging

apicaldendrite

basal dendrite

axon

synapses from differentcortical pyramidals withvarious weights

inhibitory synapsesfrom local interneuron

A

C

B

a1

a2

a3

a4

soma

Inputs

Outputs

Conditions that arecombinations of inputs frompreceding array

Conditions that arecombinations of conditionsdetected by previous level

Conditions that arecombinations of conditionsdetected by previous level

IV

II/III

V/VI

Cortical layers Type of condition detected in layer

Receptive Fields Must Change as Little and as Rarely as Possible

Cortex

Perirhinal andparahippocampalcortices

Hippocampus

Entorhinal cortex

CA1 CA3 DG

Hippocampus gets Information on Internal Column Activityfrom All Over the Cortex

pyramidalneuron

granule cell

inhibitiveinterneuron

mossycell

dentate gyrus

CA1

CA3

Inputs from entorhinal cortex

Outputs to cortex

Hippocampal Competition Determines Which Cortical Columnswill Change Receptive Fields

BIRD

inactivecolumn

column detecting itsreceptive field

column expanding andtherefore detecting itsreceptive field

familiarbirds

unfamiliarbird

Receptive Field Detection in One Area in Response to Different Objectsof Same Category

columns oftenactive whenbirds areperceived

BIRD

Some Columns are Often (but Not Always) Active When a Bird is Seen

≈ groups ofobjects

≈ visualobjects

≈ group ofgroups of

objects

Columns active when perceiving a novel event

inactivecolumn

column detecting itsreceptive field

column expanding andtherefore detecting itsreceptive field


≈ visualobjects


objects

Columns active when hearing words that relate to novel past event


≈ visualobjects


objects

Capability to indirectly activate columns on the basis ofpast simultaneous receptive field expansion

~ groups ofobjects

~ visualobjects

~ group ofgroups of

objects

= group ofgroups duringoriginalexperience

Column population indirectly activated on the basis ofpast simultaneous receptive field expansion

Behaviourselection

ResourceManagement

Rewardmanagement





behaviourselection


Amygdala

Dorsal BasalGanglia

Hippocampus


Cerebellum


Cortex

Thalamus

SNc

STN

GPe

Thalamus

Directpathway

Indirectpathway

D2D1Striatum

Cortex

GPi/SNr

Modulationpathway

Excitatory(glutamatergic)

Inhibitory(GABAergic)

Modulatory(dopaminergic)

DorsalBasalganglia

Behaviour Selection, Including At Least and Only One Behaviour

Shell}}

}}

Core

Centralstriatum

Dorsolateralstriatum

}}

}}

orbital andmedialprefrontal

dorsolateralprefrontal premotor motor

VTA

SNc

Cortex

Shell

Core

Centralstriatum

Dorsolateralstriatum

Midbrain dopamine neurons

Striatum

Striatum

Implementation of Strategic, Tactical and Detailed Reward Behaviours

Behaviourselection

ResourceManagement

Rewardmanagement





behaviourselection


Amygdala

Dorsal BasalGanglia

Hippocampus


Cerebellum


Cortex

Thalamus

VA AN

VL

VPLP

P

LD

MD

Thalamicreticularnucleus

front

right

Massaintermedia

supplementarymotor cortex

motor cortex;supplementarymotor cortex

hippocampus

somatosensorycortex

visual and otherassociation areas

prefrontalcortex

entorhinalcortex

medialprefrontalcortex

touch, propiocepticsensory information

LGN MGN

primaryauditorycortex

primaryvisualcortex

visualinformation

auditoryinformation

VI

V

IV

thalamicreticularnucleus

thalamicnucleus

corticallayers

TRN inhibitoryinterneuron

thalamocorticalprojectionneuron

corticalpyramidalneuron

basalganglia

inhibitoryconnection

excitatoryconnection

inhibitoryconnection

Implementation of Release Behaviours by Imposing Frequency Modulation

Behaviourselection

ResourceManagement

Rewardmanagement





behaviourselection


Amygdala

Dorsal BasalGanglia

Hippocampus


Cerebellum


Cortex

Thalamus

Parallel Cerebellar Path for ImplementingFrequently Used Sequences of Actions

To design an artificial general intelligence system

Focus on the information processesthat are requiredIf a system needs to

Perform many different behavioursDetect many different conditionsDefine most of the conditions heuristicallyLimit the resources required

Then the information processes willneed to be

Condition definition and detectionCondition resource managementInformation flow managementBehaviour selectionReward behaviour selectionBehaviour priority managementBehaviour sequence management

Behaviourselection

Rewardmanagement

Informationflowmanagement

behaviourselection


BehaviourImplementation

ResourceManagement

conditiondefinition

anddetection

Behaviourtypeprobabilitymanagement

a. Boundary of objectin visual field

b. Some of boundaryelement receptivefields detected in V1

c. Retinal area forwhich one boundaryelement receptivefield detectionrecommendsmodulation of inputsfrom area

d. Total recommendationstrengths for modulation muchstronger for area within objectboundary

20105 15 25 30 35

msecinput actionpotential spikes

threshold

postsynapticpotential

total

time window ofone third of themodulation cycle

integration windowclose to modulationmaximum

integration windowclose to modulation

minimum

source neurons target neuron

I

II

III

dentategyrus

entorhinalcortex

II

III

V/VICA2

CA1pyramidalneurongranulecellinhibitiveinterneuronmossycell

supra-mammillaryarea

mammillarybodies

anteriorthalamus

amygdala

subicular complex

CA3

cortex

Connectivity

parallel fibreoutputs fromgranule cells

Purkinje celldendritic treeperpendicular toparallel fibres

Purkinje cellbodies

granulecells

Purkinje cell outputtargets cerebellumnuclei

mossy fibreinput targetsgranule cells

climbing fibre inputtargets small group ofPurkinje cells (~10)

InferiorOlive

PontineNucleus

24

33

25

29

34

27

38 20

36

2835 37

86 4

32

11

9

10

2331

7

19

1918

1817

5

26 30

12

68B

8A

9

9/46d

9/46v10

46

47/1245A 45B

44

3,1,2 57

17

1819

4

43

3940

22

3837

2120

52 42 41

Areas concerned with working memory

Areas with receptive fields corresponding withgroups of cortical columns often active atsimilar times in the past

Areas with receptive fields corresponding withgroups of cortical columns that expanded theirreceptive fields at similar times in the past

left cerebralhemisphere

basal nucleicerebellum lateral ventricles some of basal

gangliathalamus

striatum

claustrum

amygdalahippocampus

hypothalamus

i ii iii

ivvvi

fornix

septal nucleinucleusaccumbens

substantianigra

caudatenucleus putamen

the striking commonalities in medial left prefrontal and parietal activity during theelaboration of (a) past and (b) futureevents (relative to the control tasks)

From Addis, D.A., Wong, A.T. and Schacter, D.L. (2007). Remembering the past andimagining the future: Common and distinct neural substrates during event construction andelaboration. Neuropsychologia 45, 1363-1377.

brain anatomy and artificial intelligence -...

Documents