!!Quantum Holography is It Relevant to Brain Function T-214

8/13/2019 !!Quantum Holography is It Relevant to Brain Function T-214

1/6

NFOlZMATIONS IEN ESELSEVIER 1nSc)rmation Sciences 15 (19 99) 97-102

Survey PaperQuantum holography: Is it relevant to brainfunction?

Karl H PribralnCent er f i r Brcrir~ Re.reorc.11~ ~ t t~ J i ) r ~ i i o t i o i i ~ ~ I~~C ' I I ( . ( ' .F .(~d f i ) rdU I I ~ U C J I . S ~ ~ J ~ ,o.\ 6977,

Rci(firc(. I'A 24142, USReceived 4 July 1998; accepted 20 Seplemb er 1998

In 1951, reviewing the state of our knowledge of auditory processes forSteven's H an db oo k of Experimental Psychology, Licklider ended with: If wecould find a convenient way of showing not merely the amplitudes of the en-velopes but the actual oscillations of the array of resonators, we would have anotation [ I ] of even greater generality and flexibility, one th t would reduceunder certain idealizing assumptions to the spectru~ii nd under others to thewave form the analog y [to] the position-momentum an d energy-timeproble ms that led Heisenberg in 1927 to state his uncer tainty principle has ledGabor to suggest that we may find the solution [to the problem of sensoryprocessing] in quantum mechanics.Du ring the 1970's it became a ppa rent tha t Gab or's notation a lso applied tothe cerebral cortical aspect o f visual an d som atic sensory processing. The m ostelegant work w as done with regard t o the visual system. A recent review by TaiSinge Lee [2] in the IE EE casts these advances in terms of 2D Gabor waveletsand indicates the importance of frames and specifies them for different Sam-pling schemes. For the monkey, the physiological evidence indicates that thesampling density of the visual cortical receptive fields for orientation and fre-quency provides a tight fram e representation through oversampling.The 2D Gabor function achieves the resolution limit only in its complexform . Pollen a nd R onner did find qua dritu re phase (even-symmetric cosine andodd-sy mm etric sine) pairs of visual receptive fields. Cur rently, recordings ma dewith multiple microelectrodes and data analysis with sufficiently powerful

Fax +I 540 831 6236: e-mail: [email protected]/99/$19.00 6 1999 Elsevier Science Inc. All rights reservetl.PII S 0 0 2 0 - 0 2 5 5 ( 9 8 ) 1 0 0 8 2 - 8


2/6

computers makes i t possible to readily obtain additional data of this sort andto determine on the conditions under which phase encoding might occur.The neurophysiological community has come to terms with the distributednatur e of wha t can be conceptualized as the deep structure of cortical pro-cessing [3]. The accepted view is that distribution entails the necessity ofbinding together the disparate sites of processing. t is thus prop erty of asurface structure composed of widely separated n ~o du lesmade up of circuits ofneurons. Binding is accomplished by temporal synchronization of spatiallydistinct oscillating neural processes. The empliasis has been that under theconditions which produce binding, no phase lead or lag is present. However,Saul and Humphrey [4 5] have found cells in the iateral geniculate nucleus thatproduce phase lead and phase lag within n ~o du les n the cortical processinginitiated by them. In the somatosensory system, Simons and his gro up [6] havebeen analyzing the timing of the tliala~nocorticalprocess to show how it en-hances preferred features and damp ens non-preferred ones; that is, itsharpens sensory discrimination. The process thus can act as a frame, thatcaptures relevant features or com bina tion of features. These results givepromise to Gabor's prediction that we might find the solution to sensory(image) processing in the formalism, and perhaps even in the neural imple-mentation of quantum information processing.What makes the implementation so difficult is that, as noted, the deepstructilre of cortical processing goes on in the syna ptode ndri tic processing web,the dendritic arborizations where brain cells connect with each other.One of the most intractable problems facing brain neurophysiologists hasbeen to trace the passage of signals through these dendritic trees of neurons.The received opinion is that such signals accumulate from their origins atsynapses by simple summation of excitatory and inhibitory postsynaptic po-

tentials to influence the cell body an d its axon an d th us the cell's outp ut. This isnot the case. Each synaptic site is f ~~ nc tio na llyipolar it bo th projectssynapses onto and receives synapses from many other processes. Hence inputand output are each distributed over the entire dendritic arborizationwhere[ever] dendrodendritic interactions are important [ 7 ] , p. 82). The ana-tomical complexity of the dendritic network has led to the opinion summarizedby Szentagothai ([8], p. 40): The simple laws of histodynamically polarizedneurons indicating the direction of flow of excitation came to an end whenunfam iliar types of synapses between dend rites, cell bodies and d end rites, serialsynapses etc. w ere found in infinite variety.The received opinion also focuses on the transt~iissivenature of synapses:thus the term neurotransmitters is, more orten than not, ubiquitously ap-plied to the variety of molecular processes stimulated by the arr ival of anaxonic depolarization at the presynaptic site. This focus appears to us to bemisplaced. In any signal processing device, the last thing one wants to do ifunimpeded tran sn~ issio n is required, is to physically inter rup t the carrier


3/6

medium. Interruption is necessary, liowever, i the signal is to bc processedin any fashion. Interruption allows switching, amplification, and storage toname a few purposes to wliich physical interruptions such as synapses couldmake possible.W hat then lnight bc the use to wliich synapses could be put when input a ~ i doutp ut a re each distributed over an extent of dendritic arborization? I n Ref. [9]suggested th at any model we make o f perceptual processes must tak e intoaccount both the importance of Imaging, a process that constitutes a portion ofou r subjective (conscious) experience, and the fact tha t there are influences onbehavior of which we are not aware. Airtonlatic behavior a n d awarcness areoften opposed, the more efficient a per for ~n an ce, lie less aware we become.Sherring ton noted this antagonism in a succinct statement: Between reflex[autonlatic] action an d m ind there seems to be actual op pos ition . Reflex actionan d mind seem alm ost mutu ally exclusive the mo re tlie reflex the less mindaccompanies it.Evidence was then presented that indicates tliat autonliitic behavior isprogrammed by neural circuitry mediated by nerve impulses, whereas aware-

ness is due to the sy naptod endritic microprocess, the excitatory and inhibitorypostsy naptic p otentials a nd their effect on dend ritic processing. The longer tliedelay between the initiation in the dendritic network of postsynaptic arrivalpatterns and the ultimate production of axonic departure patterns, the longerthe duration of awareness.Recent suppo rt for this proposal comes from the work of David Alkon andhis colleagues who showed t hat as the result of Pavlovian con ditioning there isan unequivocal reduction in the boun dary volume o f tlie dendritic arboriza-tions of neurons. These neurons had previously been shown to increase theirsynthesis of m R N A and specific proteins under the same Pavlovian conditions.Although these experiments were carried out in niolluscs, such conditioninginduced structural changes akin to the synapse clirnination tliat accompaniesdevelopment as the organism gains in experience, and therefore, automaticityin the appropriate sites in the cortex of rats exposed to enriched environments.Th e hypothesis put forward thus states that as behavioral skills are attained,there is a progressive shortening of the duration of dendritic processing thatoccurs between the initiation of post-synaptic arrival patterns and the pro-duction of axonic departure patterns. This shortening is presumed due tostructural changes in tlie dendritic network which facilitate transmission.But, a s we have seen, signal transniission in the deridritic network is far fromstraightforw ard. A s Alkon points o ut in a Scientific Am erican article [lo]:Many of the molecular [and structural] transforniation take place in dendritictrees, which receive incoming signals. The trees are amazing for their com-plexity as well as for their enornious surface area. A single neuron can receivefrom 100,000 to 200,000 signals from sep arate input fibers ending on its den-dritic tree. Any given sensory pattern p robably s tin ~u late s relatively small


4/6


5/6


6/6

102 I. Prihrcllri It fi~ ~l itr t io r~c i ~ ~ ~ r t ~ o s1 5 I Y YY Y 7 1 2[I I] G .M . Slieplicril, 1I.K. Rruyto n. J.1 . Millcr, I Segey. J. Rindsel. W . Kall, Signal enhancementin distal cortic i~l dendrites by mea ns of inte ractions between active dendr itic spines,

Proceedings of the National Academy of Sciences 82 (1985) 2192-2195.[12] S. HameroK, Ultimate Computing: Biomolecular Consiousness and Na no Technology, North-Holl ;~nd,A m s t e r d i ~ n ~ .987.[13] S. Hamerofl; J.E. DayholT. K. Lahoz-Reltra. S. Rasmussen. E.M. Insinna, D. Koruga,Nanoneurology and the cytoskeleton: Quantum signal i~ig and protein conformational

dyn;~micsas cognitive substrate, in: K .H . Pribr:lm (E d. ). Kethiukitig Neura l Netwo rks:Quantum Fields and Biologic;~l lata, Lawrence Ilrlbai~niAssoci;lles, M :~liwah.NJ, 1993, pp.3 17-376.

[I41 K. Penrose. Th e Shado ws of the Min d. Oxford U niv. Press, Oxforcl, 1994.[I51 H. Hydn , Activation of nuclear KN A in neurons a n d glia in learning, in: D.P. Kimble (Ed.),The Anatomy of Memory. Science and Behavior Books, Palo Alto, CA, 1965, pp 178-239.

Documents

!!Quantum Holography is It Relevant to Brain Function T-214