j gen physiol 1940 allen 105 21

8/6/2019 J Gen Physiol 1940 Allen 105 21

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THE EFFECT OF STIMULATION OF THE SENSES OF VISION,HEARING, TASTE, AND SMELL UPON THE SENSIBILITY

OF THE ORGANS OF VISION

BY FRA NK ALL EN AND MAN UEL SCHWARTZ

(From tke Department of Physics, University of Manitoba, Winnipeg, Canada)

(Received for publication, April 29, 1940)

H I S T O R I C A L

I t has long been known that the s t imulat ion of one sense organ inf luences in somedegree the sensitivity of the organs of anoth er sense. Bu t wheth er the influence isexer ted upon the receptors or upon their centra l areas in the cor tex has not been withcer ta inty determined. This behavior of the nervous system ma y readi ly be inferredfrom i ts synapt ical arrangement and intemunciatory const i tu t ion whereby al l par ts aresuscept ible of comm unicat ion with each other. These ideas have thus been summsrizedby Sherr ington (12) : "All par ts of the nervous system are connected together andn opart of i t i s probably ever capable of react ion without affect ing and being affected byvar ious other par ts , and i t i s a system cer ta inly never absolute ly a t res t ."

The two senses which seem to be best adapted for the purpose of measurement arethose of hearing and vision. As long ago as 1888, Urba ntschitsc h (13) observed tha tsounds of di fferent tones ma y act di fferently upon the sensi t iv i ty of the visual apparatusfor var ious colors , but no def ini te quant i ta t ive re la t ion between sound and color wasdetected by him. In la ter investigat ions Lazarev (11) concluded that the visual sensi-bility of the retinal periphery, that is of rod vision, increased under the influence of

acoust ical s t imulat ion of the ear. Yakov lev (15) found that s t imulat ion of the ear bysound conspicuously enlarged th e area of the field of cone vision especially for green light.Krav kov (8) observed that under the inf luence of sound the cr i tical f requency of f l ickerof white light increases for central or cone vision, and diminishes fo r peripheral or rodvision.

In a recent investigation Yakovlev (16) has studied in much detail the influence ofacoust ic s t imulat ion, both by musical tones of f requency 780 cycles per second and noisesof 75 decibels in loudness, upon the limits of the areas of the retinal fields for extremered, orange-red, green, and blue colors. The colors were not spectral but were obtain edfrom Wra tten color filters. The m axim um transmissions of the filters were at 700 m/~,680 m#, 540 m~, and 440 m~ respect ively. Two observers were employed and fromtheir measurem ents the following results were obtained. Und er the influence of bothtones and noises the color field for extreme red was unaltered, tha t for orange-red wasdlmluished, and those for green and blue enlarged in area. Noise was more effective as a

stimulus than musical tones, possibly because of its greater intensity, and under itsinfluence the color fields were diminished and enlarged to the greatest extent.

In a more detailed research Kravkov (9) has investigated the influence of acousticstimulation of the ear upo n the light, or rod, an d th e color, or cone, sensibility of the

105

The Journal of General Physiology

Published September 20, 1940


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1 06 E]~FECT OF STIMULATION OF SENSES ON VISION

v i s u a l a p p a r a t u s . T h e e x p e r i m e n t s w e r e p e r f o r m e d w i t h t h e r i g h t e y e w h e n b o t h e y e sw e r e i n d a r k n e ss a d a p t a t i o n . A n o b s e r v e r v i e w e d in a s p e c t r o m e t e r a s m a l l p a t c ho f s o m e s p e c t r a l c o l o r w h i c h w a s g r a d u a l l y d i m i n i s h e d i n i n t e n s i t y b y m e a n s o f a na b s o r b i n g w e d g e o f n e u t r a l t i n t e d g l a s s p l a c e d b e t w e e n t h e s l i t a n d t h e s o u r c e ' o f l ig h t .A s t h e v i s u a l f ie l d g r a d u a l l y b e c a m e d a r k e r , t h e o b s e r v e r f ir s t i n d i c a t e d t h e m o m e n tw h e n c o l o r d i s a p p e a r e d , a n d , s e c o n d , w h e n l i g h t v a n is h e d . T h e l i g h t a n d c o l o r t h r e s h -o lds o r s ens ib i l it i e s were measu red b y the r ec ip roca l s o f t he th i ckness o f t he p a r t o f t hewedge in f ron t o f t he s l i t a t t he two pos i t i ons . The e xpe r im en t s were con t inued fo r 1 .5h o u r s , a n d d u r i n g t h i s p e r i o d v i su a l m e a s u r e m e n t s w e r e t a k e n a t i n t e r v a l s o f f r o m 8 t o1 3 m i n u t e s . A f t e r 4 0 m i n u t e s o f d a r k n e s s a d a p t a t i o n a c o n d i t i o n o f s t e a d y v i s u a ls e n s i b i l it y w a s a s s u m e d t o h a v e b e e n a t t a i n e d , a n d t h e n a n a c o u s t i c s t im u l u s , c o n s i s t i n gof a mus ica l t one o f 2100 cyc le s pe r s econd an d 100 dec ibe l s in i n t e ns i ty, f rom a gen e ra to ro f l ow f r equency, was conveyed to bo th ea r s o f t he obse rv e r by a t e l ephone r ece ive r fo r ap e r i o d o f 10 m i n u t e s . W h i l e t h e s o u n d w a s m a i n t a i n e d t h e v i s u a l m e a s u r e m e n t s w e r er e p e a t e d . A t t h e e n d o f t h i s p e r i o d t h e so u n d w a s s t o p p e d a n d t h e m e a s u r e m e n t s w e r e

c o n t i n u e d a s a t f ir s t . I t w a s f o u n d b y t h r e e o b s e r ve r s o f n o r m a l v i s io n t h a t l i g h t ( r o d )s e n s i b il i t y, c o n t r a r y t o L a z a r e v ' s f i n d i n g, w a s g r e a t l y d i m i n i s h e d u n d e r t h e i n f l u en c e o fs o u n d . F o r t h e c o l o r s g r e e n a n d o r a n g e - r e d o p p o s i t e r e s u l t s w e r e o b t a i n e d . T h esens ib i l i t y fo r g reen (528 m# ) was r a i sed an d th a t fo r o range - red (610 m/~) was lowered .

The w ave - l eng th 560 m/~ d iv ides t he two e ff ec t s. Fo r o range - red co lo rs g rea t e r t ha nt h i s w a v e - l e n g th t h e s e n s i b il i t y o f t h e v i s u a l a p p a r a t u s w a s d i m i n i s h e d . F o r g r e e n a n db l u e c o l o r s s h o r t e r t h a n t h i s i n t e r m e d i a t e w a v e - l e n g t h t h e s e n s i b i l i ty w a s i n c re a s e d .The ends o f t he spec t ru m be yon d the wave - l eng th s 460 m/~ and 620 m/~ were no t obse rved .

T h e c o n t r a d i c t i o n b e t w e e n L a z a r e v ' s a n d K r a v k o v ' s f i nd i n g s f o r l i g h t, o r r o d , s e n s i-b i l i t y m a y b e d u e t o t h e f a c t t h a t t h e o b s e r v a t i o n s o f t h e f o r m e r w er e m a d e u p o n t h er e t i n a l p e r i p h e r y a n d t h o s e o f t h e l a t t e r u p o n t h e m a c u l a . I f b o t h s e t s o f o b s e r v a t i o n sa r e c o r r e c t i t f o l lo w s t h a t t h e m a c u l a r a n d p e r i p h e r a l r o d s r e s p o n d i n o p p o s i t e w a y s t oth re sho ld in t ens i t i e s o f s t imu la t ion .

The Present InvestigationsIn the present investigations the writers have confirmed the work of

Kra vko v on the influence of hearing upon color vision, and in addi tion theyhave studied the effect of stimulation of the senses of taste and smell uponthe perception of colors. Th ey have also extended the observations toinclude the oscillation of sensitivi ty of the sensations of vision whichresults from stimulation of the senses of vision, hearing, taste, and smell.

For convenience of investigation the critical frequency of flicker of thecolors of the spectrum was observed before and after the stimulation of theother senses. By comparing the measur ements obtained under bothconditions, the influence of the other senses upon vision was determined.

T h e m e t h o d o f e x p e r i m e n t a t i o n w a s a s f o l l o w s : A s p e c t r u m w a s o b t a i n e d f r o m a ni n c a n d e s c e n t l a m p o f 7 5 w a t t s w h i c h w a s k e p t a t a s t e a d y b r i g h t n e s s b y a f i n e r h e o s t a tw i t h a v o l t m e t e r p l a c e d a c r o s s th e t e r m i n a l s o f t h e l a m p t o i n s u r e a c o n s t a n t p o t e n t i a ld i ff e re n c e. A H i l g e r s p e c t r o m e t e r w i t h t h e e q u i v a l e n t o f t h r e e 6 0 p r i s m s g a v e as p e c t r u m o f w i d e d i s p er s i o n , a s m a l l p o r t i o n o f w h i c h o f a n y d e s i r e d w a v e - l e n g th w a s



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FRANK ALLEN AND MANUEL SCHWARTZ 107

isolated in the eyepiece by adjustable shut ters . Between the lamp and the s l i t a sectored

disk was rotated by an electr ic motor whose speed was control led by a leather brakerest ing upon the axle . To the rear end of the axle was at tached a speed-counter whichmad e electr ic contact every f i f t ie th rotat ion of the arma ture and disk, and the m om ent ofcontact was recorded on a s t r ip of paper on a chronograph s imultaneously with t imeindicat ions from a clock beat ing half-seconds. By m easuring these two records, thet ime of rotat ion of the disk, and h ence the durat ion of a flash of color upon the ret ina ati ts cr it ical f requency of f l icker was accurately determined. In m aking a normal graphof the spectrum fo r purposes of comparison with those obtained af ter s t im ulat ion of theother sense organs, the eyes were kept adapted to ordinary dayl ight i l luminat ion of theroom between the hours of l0 a .m. and 3 p.m. A selected patc h of the spectrum whosewave-length was obtained from the cal ibrat ion curve was viewed in the eyepiece, thedisk was rapidly increased in rota t ion unt i l the cr i t ical f requency of f licker was reached,and while this speed was maintain ed s teady b y the brake, the record was ma de upon thechronograph. The sense of hearing, taste or smell , or vis ion i tself , was then adeq uately

s t imula ted fo r 2 m inu tes and the measurements o f the c r i ti ca l f requency were repeatedimm ediately or af ter var ious intervals of t ime. This procedure was repeated for colorsthrough out the spectrum. The graphs for the normal and induced s tates of vis ion werethen drawn together, as shown in the f igures , and f rom their differences th e effect ofs t imulat ion of any sense organ upon vis ion was determined. Since the physical br ight-ness of the spectrum remained unchanged, the differences between the two grap hs

reveal the physiological changes in br ightness , whether increased or diminished, andhence the alter ation s in responsiveness or sensitivi ty of the visua l sensations, whichst imulat ion of anoth er sense had induced.

The Effect of Stimulation of the Retina upon Color Vision

I n m a k i n g t h e m e a s u r e m e n t s t h e n o r m a l c u r v e f o r t h e c r it ic a l f r e q u e n c y

o f f l ic k e r w a s f i r s t o b t a i n e d f o r t h e r i g h t e y e w h e n b o t h e y e s w e r e i n d a y l i g h t

a d a p t a t i o n . T h e m e a s u r e m e n t s w e r e t h e n r ep e a t e d t h r o u g h o u t t h es p e c t r u m w i t h t h e r i g h t e y e i n c o n s t a n t a d a p t a t i o n f o r r e d o r y e l l o w l i g h t

o f w a v e - l e n g t h s 6 87 m / ~ a n d 5 8 9 m ~ . T h i s c o n d i t i o n w a s m a i n t a i n e db y s t i m u l a t i n g t h e r e t i n a w i t h t h e r e d c o l o r f r o m a s e c o n d s p e c t r o m e t e rf o r 2 m i n u t e s b e f o r e e a c h o b s e r v a t i o n o f t h e c r i t i c a l f r e q u e n c y o f f li c k erw a s t a k e n . Tw o s e ts o f m e a s u r e m e n t s w e r e m a d e ; o n e, w h e n n o r e s ti n t e r v a l w a s t a k e n , a n d , s e c o n d , w h e n a r e s t i n t e r v a l o f 3 m i n u t e s w a sa l l o w e d b e t w e e n t h e t e r m i n a t i o n o f s t i m u l a t i o n o f th e r e t i n a a n d t h e r e a d -i n g of t h e c r i t i c a l f r e q u e n c y o f f l i ck e r. I n a l l o t h e r r e s p e c t s t h e c o n d i t i o n so f e x p e r i m e n t w e r e a l i ke .

T h e m e a s u r e m e n t s a r e g iv e n in Ta b l e I , a n d t h o s e f o r t h e n o r m a l a n df o r s t i m u l a t i o n b y y e l l o w li g h t w i t h n o r e s t i n t e r v a l a x e s h o w n i n g r a p h i c a l

f o r m i n F i g . 1. T h e n o r m a l is t h e b r o k e n l in e . T h e h o r i z o n t a l s c al er e p r e s e n t s w a v e - l e n g t h s a n d t h e o r d i n a t e s a r e t h e v a l u e s of t h e d u r a t i o no f a f l a s h o f l i g h t u p o n t h e r e t i n a a t t h e c r i t i c a l f r e q u e n c y o f f l i ck e r , o rt h e e q u a l i n t e r v a l o f t i m e d u r i n g w h i c h n o l i g h t i s s e en . T h e p e r s i s te n c e



4/17

10 8 E F F E C T O F S T I M U L AT IO N 0 ~ ' S E N S E S O N V I S I O N

of v i s ion ca rr i e s the im press ion o f one f la sh o f co lo r over th e d a rk in te rva l

w i t h n o a p p e a r a n c e o f i n t e r r u p t i o n .T h e d i ff e re n c es b e tw e e n t h e t w o g r a p h s a r e a ls o sh o w n m o r e d e a r l y i n

t h e l ow e r p a r t o f F i g . 1. T h e n o r m a l g r a p h is r e p r e s e n t e d b y t h e s t r a i g h tb roke n hor izon ta l l ine , and the d i ffe rences be twe en the two se t s o f measure -m e n t s b y t h e c o n t i n u o u s l in e . I t i s k n o w n t h a t t h e b r i g h t e r th e l i g h t t h eshor te r i s the dura t ion o f s t imula t ion a t the c r i t i ca l f r equency o f f l i cke r.Th e e leva t ion o f the con t in uous l ine above the norm al , the re fo re , ind ica testha t the cor respond ing co lo r s a re pe rce ived wi th d im in i shed b r igh tness , andi t s depress ion be low the n orma l shows tha t th e cor respond ing co lo r s appeare n h a n c e d i n b r i g h tn e s s .

TA B L E I

W&ve-length

m#

72O70 O68 066 O64062059055 053 050O4 8 0465

N o r m a l

$~ .

0 . 0 1 3 8

0 . 0 1 2 5

0 . 0 1 1 6

0 . 0 1 1 2

0 . 0 1 0 9

0 . 0 1 0 7

0 . 0 1 0 5

0 . 0 11 40 . 0 11 90 . 0 1 3 40 . 0 1 5 60 . 0 1 7 5

S t i m u l a t i o n w i t hX 589 m/~.

R e s t p e r i o d - 0

s ~ . d i . y.

0 . 0 1 4 3 + 50 . 0 1 2 9 40 . 0 1 1 9 30 . 0 11 2 00 . 0 1 0 9 00 . 0 111 40 . 0 11 2 60 . 0 11 7 30 . 0 1 2 2 30 . 0 1 3 2 " 20 . 0 1 5 1 - - 50 . 0 1 6 9 - - 6

S t i m u l a t i o n w i t hR X 5 8 9 n ~ .

e a t p e r i o d - 3 m l n .

0 . 0 1 3 4 - -4

0 . 0 1 2 2 ~ - - 30 . 0 11 3 - - 3

0 . 0 1 0 9 - - 3

0 . 0 1 0 8 - - 1

0 . 0 1 0 5 - - 20 . 0 1 0 2 - - 40 . 0 1 0 5 - - 80 . 0 11 3 - - 60 . 0 1 3 6 + 20 . 0 1 6 0 40 . 0 1 8 0 5

Stimulation withX 6 8 7 m # .

Res t per io d- 0

0 . 0 1 4 3 + 50 . 0 1 3 0 50 . 0 11 8 20 . 0 11 2 00 . 0 1 0 7 : - - 20 .0103 I - -4

0 . 0 1 0 11 - - 50 , 0 1111 - 3o .o1161 - 3

0 . 0 1 3 2 ; - - 20 . 0 1 5 3 - - 3

S t i m u l a t i o n w i t hX 687 m~.

R e s t p e r i o d - 3 m l n .

s e c . ~ .

0 . 0 1 3 4 - - 40 . 0 1 2 2 - - 30 . 0 11 4 - - 20 . 0 11 2 00 .0112 - t -30 . 0 11 0 30 . 0 11 2 60 . 0 11 7 30 . 0 1 2 0 1

0 . 0 1 3 7 3

0 . 0 1 5 9 3

T h e g r a p h s f o r s t i m u l a t i o n b y r e d l i g h t o f w a v e - l e n g t h 68 7 m p , w i t h n ores t in te rva l and wi th a r es t pe r iod o f 3 minu tes a re shown in F ig . 2 A an d2 B . Th ere i s r evea led in the l a t t e r a com ple te r eversa l o f the e ffect s o fs t i m u l a t i o n s h o w n i n t h e fo r m e r. F o r t h e l a t t e r g r a p h in d i c a t e s t h a t t h ered co lo r i s now inc reased in b r igh tness and the g reen and v io le t co lo r sd i m i n i sh e d . I n o t h e r w o r d s , t h e i m m e d i a t e i n fl u e nc e o f s ti m u l a t i o n b yred l igh t i s to depress the red and enhance the g reen and v io le t sensa t ions ;whi le dur ing a r es t pe r iod o f 3 minu tes the neura l r eac t ions have c omp le te lyreversed the respons iveness o f the sensory appara tu s , so th a t the redsensa t ion becomes enhanced and the g reen and v io le t sensa t ions a re de -pressed in sens i t iv i ty.

Af te r s t imula t ion by ye l low spec t ra l l igh t o f wave- leng th 589 m/~ ,s i m il a r m e a s u r e m e n t s w e re m a d e w i t h n o r e s t i n t e rv a l a n d a f t er o n e o f 3



5/17

o.oa6 ~,

0.01~ / /

0.012 '~

0.0101 0 -

_~o~mal

rn/z 450 550 650 750

3avs-lencj ~,h

Fxo. I. Effect of stimulation of the retinawith yellow light, wave-length 589 m #, for 2minutes. No rest interval. The normal graphfor the tmstimulated retina is the broken line.The lower graph represents differences betweenthe two graphs above.

~ , ~ . . . ~ . ~ . . . . . ~

:1!1 ~ .-..,ReB~ - 0 589nv

o'-- ~ 3_t 3~in

~ 450 500 550 BOO 5,50 700Wa v e - l e n g t h

FIe. 2. Effects of no rest inte rval and of oneof 3 minutes after stimulation with red (687 m~)and yellow light (589 m~). ~T he effect of restis to reverse the immediate effect of stimula-tion. The broken line is the normal.

20

10

0 ~ - -O

0

20

10

A

K 2 2 -

-10

]~eBt = 7 rain.

m/.z 450 500 550 BOO B50 700

~gave- lenq~h

FIG. 3. Visual effect of stimulating the earwith tones of 150 cycles per second, after vari-ous rest periods from 0 to 7 minutes. Thebroken line is the normal.

/ 550rap

}fin. 0 1.5 3 ,t.5 6 7.5

FIG. 4. Oscillation of visual sen sitivity a fterstimulation of the ear by sound. Abscissae arerest periods. Ordin ates are differences betw eennorm al values of the critical frequency of flickerand the values afte r various periods of rest.The lines at zero represent normal values.

109



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11 0 EFFECT OF STIMULATION OF SENSES ON VISION

minu tes durat ion. The d ata are a lso given in Table I . The former are

shown in Fig . 1 as jus t descr ibed, and th ey are both shown in the two lowergraphs , C and D, in Fig . 2. As the yel low sensat ion is com poun ded ofthe red an d green sensations , the graph for no res t in terval shows tha t thesesensat ions have been diminished in sensi t iv i ty and the viole t has beenenha nced by di rect s t imulat ion. Wh en res t in tervals of 3 minu tes weretaken af ter s t imulat ion before readings of the cr i t ica l f requency of f l ickerwere mad e, the sensi tiv i t ies of the sensat ions were reversed. These re-versa ls occurred throug h the inf luence of in ternal react ions a lone.

These observat ions , as far as the immediate effects obta ined wi th norest interv als are co ncerned , confirm the findings of Allen (1) in form erinvestigations.

The Visua l Effect of Stimulation of the Sense of HearingThe inf luence of s t imulat ion of the sense of hear ing upon vis ion, wi th

which th is inves t igat ion s tar ted , wi ll now be descr ibed. For the purposeof s t imulat ion of the ear a Stern Ton var ia t or was used. This i s a Koenigresona to r wi th the bo t tom l ike a p i s ton which can be moved inwards toproduce a pure tone of an y f requen cy wi thin one octave. The tone, whichis genera ted by blowing a s t ream of a i r obl iquely across the or i f ice a t thetop of the tonvar ia tor, i s very pure and f ree f rom over tones . In th epresent inves t igat ion two ins t ruments were used, one giving a tone of 150and th e other 1200 cycles per second. Two intens i t ies were used, one givenby a i r pressure of 2 era . of water and th e other by 2 mm. of water. Ther ight e ar was held ve ry c lose to the or if ice where the sound was g enerated,and thu s a tone of fa i r ly h igh in tens i ty was di rec ted in to it . The ton egiven by the lower pressure was very weak. The lef t ear of the observerwas prote cted f rom sound b y a t uf t of cot ton wool inser ted in the passage,though th is precaut ion, under the condi t ions of s t imulat ion, was found tobe unnecessary.

In mak ing observat ions the procedure was invar iable. The norm alcurve for the cr i t ica l f requency of f l icker was f i rs t obta ined by the r ighteye when the eyes and ea r s were in no rma l uns t imula t ed cond i t ion , o r,more accura t ely, when bo th o rgans were adap ted to the day l igh t and soundsof an o rd ina r ily qu ie t room. The r igh t ea r was then s t imula t ed by thesound for 2 minu tes and the readings of the cr i t ica l f requency of f l icker

immed ia t e ly t aken . M te r r ead ju s tmen t o f t he in s t rumen t s the au ra ls t imulat ion was renewed, fo l lowed again by the visual measurements .This procedure was repeated unt i l observat ions were made over the spec-t rum. The tonva r i a to r was p l aeed nea r the f li cke r appa ra tus so tha t t he



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Y RA _N K A L L E N A N D M A N U E L S C H WA RT Z 111

observer could turn immediat ely from one to the other. Sets of measure-

ments were made with no rest interval, and with rest i ntervals of 1.5, 3, 5,and 7 minutes between the termination of aural stimulation and the visualobservation. The data are given in Table II and are shown graphicallyin Fig. 3. As before, the broken horizontal lines represent the normalcurves, an d the continuous lines those for the critical frequency of flickeraft er aural stimulation. Again, elevations and depressions of the con-tinuous lines indicate respectively diminished and enhanced conditions

TA B L E I I

Visu al Effect of Stimulation of the Sense of Hearing. Stimulation of Right Ear

Wave-length

74072070 068 066 064062059 05505305OO48 0465450

435

Normal

$~ .

0 . 0 1 9 40 . 0 1 7 00 . 0 1 5 00 . 0 1 3 20 . 0 1 2 10 . 0 11 60 . 0 11 20 . 0 1 0 60 . 0 11 20 . 0 11 80 . 0 1 3 10 . 0 1 4 80 . 0 1 6 50 . 0 1 8 7

0 . 0 2 1 6

R e s t p e r i o d -0 rain.

s e c . d i f f .

0 . 0 1 7 9 + 90 . 0 1 5 8 8

0 . 0 1 2 9 + 80 . 0 1 2 9 + 60.011~ + 40 . 0 1 0 9 + 30 . 0 1 0 6 - - 60 . 0 11 2 - - 60 . 0 1 3 2 + 10 . 0 1 5 4 + 60 . 0 1 7 8 + 1 30 . 0 2 0 4 + 1 7

0 . 0 2 4 0 + 2 4

R~tpef iod -1.$min.

s ~ . d i g .

0 . 0 1 6 9 - - 10 .0148! - -20 . 0 1 3 0 - - 20 . 0 1 2 3 + 2

0 . 0 1 0 70 . 0 11 30 . 0 11 70 . 0 1 3 1

0 . 0 1 6 7

R e s t p e r i o d -3 r a i n .

s ~ . d i f f .

0 . 0 1 5 90 . 0 1 3 80 . 0 1 2 50 . 0 11 8

+ 1 0.0108+ 1 0 . 0 11 9- - 1 0 . 0 1 2 4

0 0 .0132- - 0 . 0 1 5 3+ 2 0 . 0 1 7 3

0 . 0 2 0 1

R e s t p e r i o d -5 min.

s ec . d / J .

- - 11- - 1 2 0 . 0 1 4 9 - - 1

- 7 0 . 0 1 3 3 + I- - 3

+ 2 - -

+ 7 0 . 0 11 3 + 1+ 6 0 . 01 1 9 + 1 - -+ 1 - -

+ 5 - -+ 8 0 . 01 6 7 + 2

+ 1 4

Rest period -7min .

s s t . d i S .

0 . 0 1 5 8 - 1 20 . 0 1 4 1 - 90 . 0 1 2 7 - 5

0 . 0 11 4 - - 2

0 . 0 1 0 8 + 20 . 0 11 8 + 6

0 . 0 1 4 3 + 1 20 . 0 1 5 6 + 1 80 . 0 1 7 9 + 1 4

I n a l l c a s e s f r e q u e n c y ffi 1 50 v i b r a t i o n s o r c y c l e s p e r s e c .To n v a r i a t o r p re s s u r e = 2 c m . o f w a t e r .S t i m u l a t i o n p e r i o d = 2 m i n .

of the brightness of the corresponding colors, which are due to similarchanges in the responsiveness of the fundamental color sensations.

The graph in Fig. 3 A, for no rest interval, indicates that the red colorof the spectrum appears of lowered intensity, the green of enhanced, andthe violet of lowered intensity. This result confirms the experiments ofKravkov, with aural stimulation of 100 decibels in loudness, for red andgreen colors. He did not c arry his measurements into the blue and violet

regions. With a rest interv al of 1.5 minutes, the graph (Fig. 3 B) showsthat the measurements of the critical frequency of flicker are almost ofnormal value but with a slight indication of a reversal of the conditionrepresented by Fig. 3 A. When a rest interva l of 3 minutes was taken,



8/17

1 1 2 EI~I~ECT O]r STIMULATION 0]~ SENSES ON VISION

the g ra ph (F ig . 3 C) r evea l s t ha t a comple t e r eve r sa l o f s e n s i t i v i t yof the

red an d g reen sensa t ions has occu r red , t he r ed co lo r now appea r i ng b r igh te ra n d t h e gr e e n d i m m e r t h a n n o r m a l . Wi t h a u r a l s t i m u l a t i o n , t h e bl u e a n d

TABLE III

Visua l Effec t o f S t imula t ion o f the Sense o f Hear ing

Wave-length Normal

$ $ $ ,

740 0.0194720 0.0170700 0.0150680 0.0132

660 0.0121640 0.0116620 0.0112590 0.0106550 0.0112530 0.0118500 0.0131480 0 . 0 1 4 8465 0.0165450 0.01874 35 0.0216

Wtve-leagth

m / t

74072070068066064062059O5505305OO480465

Normsl

0.01810.01660.01440.01340.01250.01220.01140.01090.01180.01250.01440.01630.0184

Stimulus requency -150 cycles per sec.Premure *- 2 cm.

Right ear

s~. diJ.

0.0179 +90.0158 +8

0.0129 +80.0122 +60.0116 +40.0109 +30.0106 --60.0112 --60.0132 + I0.0154 +60.0178 +130.0204 +170.0240 +24

Stimulus requency1200cycles per sec.PreMure -- 2 era.

Right err

s~. i diJ.0.0202 k21

0.0155 ~11

0.0131 +6

0.0119 +50.0113 +40.0112 --60.0117 -80.0135 --9!0.0165 +20.0187 i +3

Stimulus requency ==150 cycles per sec.l : ) r e s s t t r e m 2 n ~ .

Righte a r

s~. di.y.0.0197 +30.0163 --70.0138 --120.0127 -50.0121 00.0118 +20.0115 +30.0111 +50.0115 +30.0119 +10.0132 +I0.0150 +20.0163 --20.0184 --3

Stimulus requency1200 cycles pe~sec.Pressure -- 2 ram.

R i g h tear

$ ~ .

0.0128

0.0119

0.01120.0116

0.0159

Stimulus requency150 cycles per sec.Pressure s 2 cm.

Left ear.

s ~ . ! d i ~ .

0.0166 --40.0145 --50.0126 --6

i!

I0.0106 -60.0113 --5

+3

+5

-- 6-- 9

-- 4

v io l e t co lor s expe r i ence no r eve r sa l i n b r igh tnes s . Af t e r a r e s t i n t e rv a lo f 5 minu te s , t he b r igh tnes s o f t he spec t rum, a s shown by F ig . 3 D , appea r s

o f no r ma l va lue . Whe n the r e s t i n t e rva l was inc reased to 7 minu te s

(F ig . 3 E ) t he cu rve ind ica t e s much the same changes in co lor i n t ens i t i e s a s

shown in Fig . 3 C for 3 min ute s of res t .



9/17

] ~ R A N K , AT. T. ~ T A N D M A N U E L S C H WA R T Z 11 3

CE

)-Zcm.10 D ~ ~ .f=lZ)0 cy c~

~c ~A

-I0 ~-2cm.

-E

-10 ]5 ~ - 2 c ~

m ~ 450 ~00 550 500 550 700Wa v e - l e n g t h

FIG. 5. Visual effects of aural stimulationby tones of different frequencies and inten-sities. Graph E is contralatera l effect of auralstimulation. The broken lines are the normaN.

O-

g O -

~"o-100 -

-lO

\ ._~ e . ~ n i u m

. . . . E e , ~ = ~

Cass i a- " ~ - - ~ ~ " - - ~ - - - ~ m .

,, 450 500 550 500 550Wa ve -len~th

700

FIG. 6. Visual effect of olfactory stimula-tion with various substances, after no restperiods and after 45 minutes of rest. The lastshows reversal of effect. The bro ken lines are

the normals.

10 jO- - . . - - ~ "-z ' '~- - '0= '~- ~ '"R~ Q ~ eC " ~ " ~ . _'I--~ ~ . _

~ 0 B - .~ -10 ]~e ~t-3min .

mSz 450 500 550 B00 550 700Wa v e - l e n ~ h

FIG. 7. Visual effect of gusta tory stimulationwith solution of quinine sulfate, after no restperiod and after 3 minutes. Reversal of effectis shown. Bro ken lines are normals.

Thus by i n t e rna l r e ac t i o n s a lon e w h i ch a r e i nh e ren t s om e w her e i n t h ev i sua l appa ra tu s , r eve r s a l s o f s e ns i t i v i t y o f t he v i s ua l o rg a n s occ u r i n ade f i n i te o sc i ll a t o ry mann e r. B y p l o t t i ng c ro s s - se c t io n s of t h e f i ve cu rv es



10/17

114 EFFEC T OF STIMULATION OF SENSES ON VISION

i n F ig . 3 , t he osc i l l a to ry e ff ec t i s m ore s t r ik ing ly d i sp layed . Th i s has been

done in F ig . 4 fo r t he wave- l eng ths 700 m/z , and 550 m/z . I t w i ll be no t i cedtha t t he osc i l l a t ions o f s ens i t i v i ty o f t he r ed and g reen sensa t ions a reoppos i t e in phase .

I n o r d e r t o s t u d y t h e i n f l u e n c e o f a u r a l s t i m u l a t io n o f d i f f e re n t i n t e n si -f i e s , a g r a p h w a s o b t a i n e d a f t e r s t i m u l a t i o n b y a w e a k t o n e o f 1 5 0 c y c l e sp e r s e c o n d, p r o d u c e d b y a l o w p r e s s u r e o f o n l y 2 m m . o f w a t e r. T h e d a t aa r e g iv e n i n Ta b l e I I I , a n d a r e p l o t t e d i n F i g . 5 B i n c o n t r a s t w i t h F i g . 5 Awh ich is a r epe t i t i on o f F ig . 3 A fo r 150 cyc le s pe r second and a p res su re o f2 c m . I t w i l l b e s ee n t h a t a u r a l s t im u l a t i o n b y t h e w e a k e r t o n e h a s e v o k e da r eve r sa l o f t he v i sua l e ff ec t caused by the lou de r ton e o f the sam e f r e -quency, i nc lud ing , i n th i s case , t he v io l e t end o f the spec t rum.

W i t h a u r a l s t i m u l a t i o n b y a h i g h - p i t c h e d t o n e o f 1 2 0 0 cy c l e s p e r s e c o n do f s t r o n g a n d w e a k i n t e n s i t i e s g i v e n b y a i r p r e s s u r e s o f 2 c m . a n d 2 m m .of wa te r r e spec t ive ly, t he v i sua l e ff ec t s were those shown in F ig . 5 C an d5 D . T h e s e g r a p h s a r e p lo t t e d f r o m t h e m e a s u r e m e n t s i n Ta b l e I I I .T h e y b o t h s h o w d e p r e ss i o n o f s e n s i t iv i t y o f t h e r e d a n d p r o b a b l y o f t h ev i o l et s en s a ti o n s , b u t e n h a n c e m e n t o f t h e g r e e n . T h e r e i s n o e v i d e n c e o fr e v e r s a l o f v is u a l s e n s it i v i ty u n d e r t h e in f l u en c e o f th e w e a k e r t o n e . I t i sposs ib l e tha t fo r t he h ighe r and more p i e rc ing tones , a s t i l l l ower in t ens i tyt h a n t h a t o b t a i n e d w i t h a p r e s s u r e o f 2 m m . o f w a t e r i s r e q u i r e d t o e v o k ereve r sa l s o f v i sua l s ens i t i v i t i e s , o r e l se wi th s t imula t ion by ve ry h igh toneson ly depres s ion o f s ens i t i v i ty occur s .

A f e w r e a d i n g s w e r e o b t a i n e d t o s h o w t h e c o n t r a l a t e r a l i n f l u e n c e o fa u r a l s t im u l a t i o n o f t h e le f t e a r u p o n t h e r i g h t e y e. T h e m e a s u r e m e n t s a r eg i v e n in Ta b l e I I I , a n d s h o w n g r a p h i c a l l y i n F ig . 5 E . A l l c o lo r s i n t h erang e ob se rved f rom 530 m/~ to 720 m/z a re seen to be en han ced in b r igh tness .

The Visua l E ffec t o f S t imula t ion o f the Sense o f Sm el l

I n o r d e r t o s t u d y t h e i n f l u e n c e o f s t im u l a t i o n o f t h e s e n s e o f s m e l l u p o nco lo r v i s ion , a vo la t i l e odorous ma te r i a l was p l aced in a bo t t l e t h ro ught h e r u b b e r s t o p p e r o f w h i c h t w o g l as s t u b e s w e r e p a s s ed . O n e o f t h e md i p p e d b e l o w t h e s u r f a c e o f t h e li q u id . A c u r r e n t o f a i r w a s t h e n g e n t l yb l o w n t h r o u g h i t w h i c h c o n v e y e d a s t e a d y s t r e a m o f o d o r o u s m a t e r i a lt h r o u g h t h e s e c o n d t u b e t o t h e r i g h t n o s tr i l. T h e s e n s e o f s m e l l w a s t h e ns t i m u l a t e d b y t h e o d o r f o r 2 m i n u t e s a n d r e a d i n g s o f t h e c r i ti c a l f r e q u e n c y

o f f li c k er t a k e n i m m e d i a t e l y a ft e r w a r d s w i t h n o r e s t in t e r v a l . T h r e esubs tances were used , o i l o f Mr ican ge ran ium , o il o f Cassi a, and a n a l coho l i cs o l u ti o n o f v a n i ll i n , a l l o f w h i c h g a v e t h e s a m e r e s u l t. T h e m e a s u r e m e n t s



11/17

YRANK ALLEN AND MANUEL SCHWARTZ 11 5

a r e g i v e n in Ta b l e I V a n d a r e p l o t t e d i n F i g . 6 , A , B , a n d C , r e s p e c ti v e l y.

W i t h t h e o d o r o f o il o f g e r a n i u m a s t h e s t i m u l a t i n g s u b s t a n c e , t h e r e d a n dv io le t s ensa t ions , a s shown in F ig . 6 A , were dep res sed in sens i t i v i ty andt h e g re e n e n h a n c e d . W i t h t h e o t h e r t w o s u b st a n c es t h e m e a s u r e m e n t sg a v e s i m i la r r e s u l ts e x c e p t t h a t t h e y w e r e n o t e x t e n d e d i n t o t h e b l u e - v i o l e tr e g i o n of t h e s p e c t r u m .

TABLE IV

Visua l Effect o f S t imula t ion o f the Sense o f Smel l

Wa v e - l e n g t h [ Normal

m~ $~.

680 0.0134

660 0.0125640 0.0119620 0.0114590 0.0111550 0.0117530 0.0125500 0.0148480 0.0169465 0.0185

Wave-length Normal

720 0.0138

700 0.0125680 0.0113660 0.0106640 0.0100620 0.0094

Stimulation with o ilo f g e r a n i u m .

R e s t interval m 0

0.0140 +6

0.0134 +90.0127 +80.0119 +50.0114 +30.0112 --50.0119 --60.0150 +20.0175 +60.0194 +9

Stimulation with o ilof cass ia .

R e s t i n t e r v a l m 4 5mln.

s e c . diff.0.0131 --7

0.0117 --80.0106 - 70.0102 -40.0099 -10.OO97 +3

Stimulation with o ilo f cassia.

R e s t interval - 0

s ~ . dig.0.0136 +2

0.0130 +50.0128 +90.0119 +50.0114 +30.0112 --50.0119 --~0.0150 +2

Wavelength Norm~

590 0.0091

550 0.0097530 0.0102500 0.0117480 0.0130

Stimulation with vanillin.R e s t i n t e r v a l = 0

0.0138 +4

0.0132 +70.0126 +70.0118 +40.0114 +30.0112 --50.0117 --8

Sthnulatlon with o ilof cass ia .

R e s t interval - 45 rain.

s ~ . ~ g .

0.OO95 - I - 4

0.0102 +50.0104 +20.0114 -30.0125 --5

A n u m b e r o f a t t e m p t s w e r e m a d e , b u t w i t h o u t s u c c e s s , t o d i s c o v e rw h e t h e r, w i t h v a r i o u s s h o r t r e s t p e r i o d s u p t o 1 5 m i n u t e s , a n y r e v e r s a lo f co lo r sens i t i v i ti e s occu r red a s a r e su l t o f i p s i la t e ra l o l f ac to ry s t imula t ion .S ince in ma ny w ays the sense o f sme l l i s r a the r s lugg ish , i t was dec ide d toa l lo w a r e s t i n t e r v a l o f fr o m 4 0 t o 5 0 m i n u t e s a f t e r s t i m u l a t i o n w i t h t h eo d o r o f o i l o f c a s si a b e f o r e m e a s u r e m e n t s o f t h e c r i ti c a l f r e q u e n c y o f f l ic k e rw e r e m a d e . T h e r e s u l t s h o w e d ( F ig . 6 D ) t h a t i n t h e p r o l o n g e d r e s t

in t e rv a l a de c ided r eve r sa l o f s ens i t i v i ty o f al l t h ree co lo r sensa t ions oc -c u r r e d . A s th e g r a p h i n d i c a te s , t h e r e d a n d v i o l e t s e n s a ti o n s a r e e n h a n c e da n d t h e g r e e n d e p r e s se d i n s e n s i t i v i ty.



12/17

116 E F F E C T O F S T I M U L AT I O N O F S E N S E S O N V I S I O N

The Visua l E ffec t o f S t imu la t ion o f the Sense o f Tas t e

Tw o s e t s o f m e a s u r e m e n t s a f t e r s t i m u l a t i o n o f t h e s e n s e o f t a s t e w e r em a d e , i n b o t h o f w h i c h t h e s t i m u l a t i n g s u b s t a n c e w a s a n a q u e o u s s o l u t io no f s u l f a te o f q u i n in e . T h i s s u b s t a n c e w a s c h os e n so t h a t t h e b i t t e r s e n s a -t i on , w h i c h i s m u c h t h e m o s t s e n s it i v e o f t h e f o u r t a s t e s e n s a ti o n s , w o u l db e s t i m u l a t e d . A p i e c e o f a b s o r b e n t c o t t o n w a s s o a k e d i n t h i s so l u t io na n d p l a c e d o n t h e b a c k o f t h e t o n g u e f o r 2 m i n u t e s , t h e n i t w a s r e m o v e da n d t h e r e a d i n g o f t h e c r i t ic a l f r e q u e n c y o f f l ic k e r t a k e n . T h e m o u t hw a s t h e n r i n s e d w i t h w a t e r a n d t h e s ti m u l a t i o n r e p e a t e d w i t h a f r e s h p i e c eo f co t t on . I n t he f i r s t c a se no r e s t i n t e rva l , and , i n t he s econd , a r e s t

TA B L E V

Visual E ffect of Stimulation o f the Sense of T aste

Wave-length Normal Stimulation with quinine sulfate. Stimulation with quinine sulfate.Rest interval - 0 Rest interv al - 3 rain.

m~

7207OO680660640620590,55053 050O48 0

0 . 0 1 4 40 . 0 1 2 80 . 0 11 50 . 0 1 0 90 . 0 1 0 40 . 0 1 0 00 . 0 0 9 90 . 0 1 0 50 . 0 11 00 . 0 1 2 20 . 0 1 3 4

s e c . d i . ~ .

0 . 0 1 4 8 + 40 . 0 1 3 1 + 30 . 0 1 1 7 + 20 . 0 111 + 20 . 0 1 0 5 + 10 . 0 1 0 2 + 20 . 0 0 9 7 - -20 . 0 1 0 2 - - 30 . 0 1 0 5 - - 40 . 0 1 2 0 - - 20 . 0 1 4 0 + 6

$~.

0 . 0 1 3 70 . 0 1 2 40 . 0 11 30 . 0 1 0 80 . 0 1 0 40 . 0 1 0 30 . 0 1 0 30 . 0 1110 . 0 11 60 . 0 1 2 40 . 0 1 3 9

di~.

- - 7- - 4- - 2- -1

0+ 3

+ 4

+ 6+ 6

+ 2

+ 5

i n t e r v a l o f 3 m i n u t e s w a s a l l o w e d b e t w e e n t h e c e s s a t i o n o f s t i m u l a t i o na n d t h e m e a s u r e m e n t o f t h e c r it i c a l f r e q u e n c y o f f li c ke r. T h e r e a d i ng sa r e g i v e n in Ta b l e V a n d a r e s h o w n g r a p h i c a l l y i n F i g . 7 A a n d 7 B .W i t h n o r e s t i n t e r v a l t h e r e d s e n s a t i o n i s d e p r e s s e d a n d t h e g r e e n e n h a n c e din s ens i t i v i t y, wh i l e a f t e r a r e s t pe r iod o f 3 minu te s a r eve r sa l occu r r ed i nw h i c h t h e r e d s e n s a t i o n w a s e n h a n c e d a n d t h e g r e e n d e p r e s s e d i n s e ns i -t i v i t y. I n b o t h c a s e s t h e v i o l e t s e n s a t io n a p p e a r s t o s u f f e r d e p r e s s io n o fsens i t i v i t y.

I t m a y b e r e m a r k e d t h a t s t i m u l a t i o n w i t h a s o lu t i o n of s u g a r w a s t ri e db u t w i t h n o a p p a r e n t v i s u a l e f fe c t . T h e s w e e t s e n s a t i o n i s, h o w e v e r , t h e

m o s t i n s e ns i t iv e o f t h e f o u r g u s t a t o r y s e n s a t i o n s. P o s s i b l y a so l u t i o n ofs a c c h a ri n e m i g h t h a v e b e e n s u c c e ss f u l a s a s t i m u l a n t t o p r o d u c e a c h a n g eo f v i sua l s ens i t i v i t y.



13/17

~'RANK ALLEN AND MANUEL SCHWARTZ 1 1 7

DISCUSSION OF ~SULTS

There i s in the human body a wide-spread sys tem of ne rvous channe l sth rough which ce r ta in e ffec t s o f s t imula t ion o f one o rgan a re conveyedto o ther o rgans bo th s imi la r and d i s simi la r in charac te r. One of thewr i te r s (6 ) has shown tha t s t imula t ion o f the r igh t foo t by a fo rwardpressure aga ins t a wa l l d imin i shes the magni tude o f the pos t -con t rac t ionm uscular ref lex in the r ight arm . This is a case of par t ia l ipsi la teralinh ib it ion . Th e oppos i te e ffec t had p rev ious ly been inves t iga ted byWh is le r (14) in a spec ia lly comple te ma nner. In h i s researches he em-p loyed the pos t -con t rac tion o f the l e f t l eg as the normal response . Im-media te ly a f te r s t imula t ion o f the l e f t a rm, he found tha t the responsesof the l e f t l eg were augm ented . He th en s t imu la ted bo th a rm s s imul -taneous ly and found a g rea te r augm enta t ion o f the subsequen t responseof the leg . The p re l im inary s t imula t ion was then ex tended to inc lude a tonce bo th a rms and the r igh t l eg , wi th s t i l l g rea te r augmenta t ion o f theresponse o f the l e f t l eg . F ina l ly, wi th these th ree he inc luded s t imula t ionof the m usc les o f the neck , a nd o b ta ined the g rea tes t degree o f augmen ta t ionof the response of the lef t leg. Sim ilar ly, s t imu lat ion of different organsby fa rad ic cur ren t s , p ic tu res , mus ic , and co lors was fo l lowed by augm entedpost-co ntract ion responses of the lef t leg.

The in f luence o f va r ious types o f s t imula t ion upon g landula r sec re t ionhas been s tud ied by severa l inves t iga to rs . The rma l s t imula t ion o f themouth above 55C. and below 15C. , was found to be effect ive in exci t ingthe sa l iva ry g lands to inc reased ac t iv i ty. Lash ley (10) observed tha t

violent chew ing of a tas te less substan ce such as rub ber, e l ic i ted a veryla rge inc rease in the am ount o f sa l iva sec re ted . Ac t iv i ty o f the sa l iva ryglands is a lso great ly promoted by acids , a lkal is , and sal ts held in themo uth , an d a l so by m an y k inds o f food espec ia l ly when th ey a re p resen tin the s tomach . M enta l work a lso enhances the ac t iv i ty o f g landula rorgans o f severa l types . Inh ib i to ry in f luences upon the sa l iva ry g landsar i se f rom v io len t e ffo r t, r ap id movem ent , and pro longed s tra in . M os tpeople a re aware o f the d ryness o f the mouth which occurs in runn ing , ingames such as foo tba ll and t enn is , and in a th le t i c spor t s genera l ly ; and i t isa com mon prac t i ce to co unte rac t the inh ib i t ion o f the sa l iva ry g lands thusproduced by the enhanc ing ac t ion o f the chewing re f lex p romoted by theuse o f gum . Lash ley found no sa l iva ry in f luence exer ted by v i sua l, aud i -to ry, o r t ac t i l e s t imu la t ion und er the condi t ions o f h is exper iments .

M u s c u l a r f a ti g u e m a y d e p r es s t h e m e m o r y, w h i l e e x c i te m e n t a n d a p p re -hens ion a re o f ten found to enhance it . Impass ioned em ot iona l s t a tes



14/17

11 8 E F F E C T O F S T I M U L A T I O N O F S E N S E S O N V I S I O N

have widespread physical effects. Fear inhibits the flow of saliva as many

an inexperienced speaker has found to his discomfiture. Hunger, whichis due to the muscular contraction of the stomach, induces weakness ofthe knees. Ma ny additional instances of the influence of stimulation ofone part of the organism upon the responses of other parts can no doubtbe found.

In nerves themselves Erlanger an d Gasser (7) have found evidence of anoscillation in excitability. Afte r a nerve fibre has been excited by electri calstimulation, the threshold of response falls to a steady state through aseries of three oscillations of diminishing amplitudes in which the thresholdvalues are alternately lowered and raised. The period of these oscillations,0.005 second, is, however, of an order of magnitude much different fromthose of 3 minutes which are described in this communication. The twovalues are perhaps scarcely comparable, since the short period oscillationsare those of a single nerve fibre, while the long period oscillations areconcerned with large numbers of fibres, t heir receptors, and their corticalterminations.

1. In the present investigation the writers have brou ght forward evidenceof a precise character to show how stimulation of three sense organs influ-ences the responsiveness of vision. It is found tha t stimulation with redlight, sound, quinine, and odors produces by its immediate action muchthe same effect upon vision, which is the depression of the red sensationand the enhancement of the green; the violet sensation for some reasonbeing sometimes depressed and at other times enhanced in sensitivity.The magnitude of the visual effect seems in all cases to be about the same.Since stimulation of various senses demons trably affects vision, stimulationof the eyes proba bly reciprocally affects those senses. Perhaps all senseorgans are so interrelated that stimulation of any one of them influencesall others either by enhancing or depressing their responsiveness. Itcannot therefore be maintained that the sense modaiities are whollyindep enden t of each other. While the validity of Miiller's law of "specificenergy " is not impugned, some modifying power upon the quality ofresponse of one organ is nevertheless exerted by stimulation of othersensory receptors.

2. An examination of the graphs presented above shows tha t stimulationof each of the senses selected for experimentation has affected the re-

sponsiveness of the visual organs in the three pa rts by which the colors,red, green, and violet, are perceived. These results afford, therefore, astriking confirmation of the provisions of Young's tricomponent theoryof color vision which postulates the existence of three fundamental color



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I ~ RA N K A L L E N A N D M A N U E L S C H W A I ~ TZ 11 9

sensa t ions , r ed , g reen , and v io le t . I t i s fu r th e r show n tha t these p r im ary

s e n s a ti o n s a re n o t i n d e p e n d e n t of ea c h o t h e r a n d t h a t t h e y a r e n o t al la ffec ted in the same way. For w hi le the red sensa t ion i s depressed insens i t iv i ty, the g reen i s enhanced . I t seems to be imposs ib le to s t imu la teor in f luence in a ny ma nne r a s ing le co lo r sensa t ion a lone .

3 . I t i s shown a l so in the case o f s t imula t ion o f the ea r, tha t the in ten s i tyo f t h e s t i m u l u s m a y b e a d e t e r m i n i n g f a c t o r i n p r o d u c i n g e n h a n c e m e n t o rdepress ion o f the sen s i t iv i ty o f the v i sua l sensa tions . For i t was foundt h a t l o u d a n d w e a k t o n e s o f t h e s a m e l o w p i t c h e v o k e d o p p o s i te c o n d i ti o n sof r espons iveness in the o rgan o f v i s ion . Also , i t was shown tha t s t imula -t i o n o f t h e l e f t e a r e v o k e d a n e n h a n c e d v i s u a l r es p o n s e in t h e r i g h t e y e .I t was fo rmer ly demons t ra ted by Al len (2 ) , HoUenberg (3 ) , and Weinberg(5) tha t weak and s t rong s t imula t ion o f the senses o f v i s ion , touch , andtas te s imi la r ly p roduced oppos i t e e ffec t s on the sens ib i l i ty o f the o rgansd i r e c t ly i n v o l v e d .

4 . One o f the mos t ou t s t and ing charac te r i s t i c s o f the g raphs underd i scuss ion i s the reversa l o f sens i t iv i ty o f the v i sua l sensa t ions which theyrevea l a s apparen t ly a func t ion o f the dura t ion o f the in te rva l o f r e s tb e t w e e n t h e t e r m i n a t i o n o f s t i m u l a t i o n o f a n y s e ns e o rg a n a n d t h e m e a s u r e -m en t o f the c r i t i cal f r equen cy o f f l icke r. W hi le in the exper imen ts de -sc r ibed in th i s com mu nica t ion the o rgan o f v i s ion i s the o n ly one t e s tedfor the osc i l l a to ry e ffec t, i t i s doub t less the case tha t a l l the sense o rganspossess the same remarkab le charac te r. Th i s osc il l a tion o f r espons ivenessh a s b e e n s h o w n b y A l l en a n d O ' D o n o g h u e ( 4) t o o c c u r i n t h e p o s t - c o n tr a c -t ion o f the a rm a f t e r bo th ips i la t e ra l and con t ra la te ra l s t imula t ion . I tseems to be the case , the re fo re , tha t when s t imula t ion o f any pa r t o f theorgan i sm occurs , the respons iveness no t on ly o f tha t pa r t b u t a l so o f al lo t h e r p a r t s n e u r a l l y c o n n e c t e d w i t h i t i s d is t u r b e d , a n d t h e n o r m a l r e s t i n gequ i l ib r ium i s r e s to red by a shor t se r i e s o f osc i l l a t ions o f sens i t iv i ty inwhich the o rgans a re a l t e rna te ly depressed and enhanced in respons ivenessor exc i t ab i l i ty. Th ou gh the osc i l la t ion appears a s a func t ion o f t ime , i t i sp rob ab ly a ce l lu la r o r molecu la r cond i t ion o f the cen t ra l a reas tha t f luc tua tesin ac t iv i ty.

S ince the respons iveness of the sense o f v i s ion osc i ll a t es a f t e r s t imu la t ionh a s o c c u r r e d , t h e c h a r a c t e r o f o b s e r v a t i o n s o r m e a s u r e m e n t s m a d e i ns u c h c i r cu m s t a n c e s w o u l d a p p e a r t o d e p e n d o n t h e t i m e w h i c h h a s e l a p s e d

a f t e r t h e t e r m i n a t i o n o f s t i m u l a t i o n ; o r, i n o t h e r w o r d s , o n t h e p h a s e o fo s c il la t io n w h i c h i s p r e d o m l u a n t a t t h e m o m e n t . B y n e g l e c ti n g t h i sf a c to r, m a n y c o n t r a d i c t o r y o b s e r v a t io n s i n e x p e r i m e n t a l i n v e s t i g a ti o n s i nco lo r v i s ion have doub t less occur red .



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120 EFF ECT 01~ STIMUL ATION OF SENSES ON VISION

5. In the s tud y of condi t ioned reflexes i t has been found tha t ne w ref lexes

can be gradual ly subst i tu ted for habi tual or uncondi t ioned ones on a veryexact and extensive scale. Those ref lexes have dem onstra ted the exis tenceof unused neural channels which connect the cor t ica l areas and to someex ten t new ac t iv i t ie s have been bu i l t upon them. Whi l e muc h knowledgehas been acq uired concerning the ch aracter of these reflexes and the m ann erof es tabl ishing them, l i t t le seems to be known of the neural mechanismsupon which they are founded. The present inves t igat ion seems to dealwi th those modes of behavior of the centra l organs which l ie a t the bas isof condi t ioned ref lexes. The cerebral cor tex has been descr ibed by My ersas a vas t unravel led complex. The prese nt exper iments on the rec iprocalact ions of centra l areas seem to const i tu te an addi t ional method by whichmater ia l progress can be made in the unravel l ing process .

6 . I t m ay be safe ly inferred tha t s t imulat ion of any sense organ influencesall oth er sense organs in their excitabil i ty. Th ere results, in consequence,an osci l la tory condi t ion of sensi t iv i ty which changes in s ta te in each caseby in tern al react ions govern ed by the lapse of t ime. The f ie ld of conscious-ness , to the extent in which i t i s based on the f luctuat ing responses of adel ica te ly in ter locked sys tem of the senses, can scarcely remain cons tantunder the ceaseless impact upon i t of s t imul i ar is ing f rom the outer worldand f rom the organism itse lf . These requirements , therefore , afford somephysiological bas is for the widely accepted Gesta l t sys tem of psychology,in which sensory presenta t ion s are not to be regarded as the narro wlyres t r ic ted pheno men a of individual organs , but as perceptual pat ter nswhere now one and then ano the r sensa t ion p redomina te s above the r e st .

7 . One of the wri ters (Al len) has in numerous researches on sensoryact iv i t ies genera l ly regarded the c entra l organs as unchang ing in sensi t iv i ty,and the receptor organs as mechanisms which f luctuate in exci tabi l i tywhen s t imulated. One resul t of the present exper iments i s the demonstra-t ion that a centra l sensory area osci l la tes in sensi t iv i ty when the receptorsof o ther sense organs are s t imulated, and a lso when the receptors to whichi t is d i rec t ly a t tach ed are s t imulated. To ascr ibe those phe nom ena ofvis ion, in which f luctuat ion or a l tera t ion of in tens i ty of response is con-cerned, to the re t inal receptors exclus ively is now de af l y seen to be er-roneous . Many such phenomena mus t o r ig ina te in f luc tua t ions o fresponsiveness of the centra l organs . The modif ica t ion of the hues of

cont iguous f ie lds of color by thei r mutual ac t ion upon each other, knownas s imul taneous con tras t , i s one group of pheno men a which would nowappear to ar ise in the centra l centres of v is ion and not in the v isual re-ceptors in the re t ina . One cannot , however, arbi t rar i ly ass ign e i ther to the



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FRANK ALL EN AND MANU EL SCHWARTZ 1 21

per iphera l o r to the cen t ra l o rgans the phenom ena of osc il la t ion . Al l

par t s o f the sensory appara tus , p e r iphera l, in te rmedia ry, and cen t ra l , haveimpo r tan t func t ions to pe r fo rm in the exc i ta t ion o f sensa tions. Th ecomple te sensory appara tus f rom per iphery to cen t re mus t be regardedessent ia l ly as a uni t ; and s t imulat ion, response, and radiat ing inf luenceupon o ther o rgans a re to be v iewed as bu t the severa l a spec t s o f i t s comple teand complex func t ion .

REFERENCES

1. Allen,F., J. Opt. Soc. Amer ica,1923, 7, 583.2. Allen,F., Y. O pt. Soc. America,1926,13, 383.3. Allen, F., an d HoUenberg, A.,Quart. y. Exp. Physiol.,1924, 14, 351.4. Allen, F., and O'Donoghue, C . H.,Quart. J. Exp. Physiol.,1927,18, 199.5. Allen, F., and W einberg, M.,Quart. Y. Exp. P hy ~l. ,1925, 15, 385.

6. Allen, F.,Quart. J. Exp. Physiol.,1937, 26, 305.7. Erlanger, J., a nd Gasser, H. S., Electrical signs Of nervous ac tivity , Philadelphia,

Universi ty of Pen nsylvania Press, 1937, 108.8. Kra vko v, S. V., Action des excitations auditlves sur la fr6quence critique des papil-

lotements lumineux,A~a Opk tha~ l . Sca~ . ,1935,18, 260.9. Kra vko v, S. V., Th e influence of sound upon th e fight and colour sensibility of th e

eye, Acta Oph~hnlmol. Sc a~ .,1936, 14, 348 .10. Lashley, K. S. , The hu ma n sal ivary reflex and i ts use in psychology,P~chol. 1~. ,

1916, 2S, 446.11. Lazarev, P. P., The influence of an acoustic sthnulation upon the light sensibility

of the eye,Proc. Acad. Sc. U. S. S. R .,Nr. 18 A, 1927 (Russian).12. Sherrington, C. S. , Integrative action of the nervous system , New Haven , Yale

Un iversity Press, 19 20, 8.13. Urbantschitsch, V., l]ber d en Einfluss einer Sinneserregun g an f die ilbrigen Sin-

nesempfindungen,Arch. ges. Physiol.,1888, 42.14. Whisler, R. G., Modification of the post-contraction reflex, Ab stracts of Doctors '

Dissertations, Ohio State U niversity Press, 1931, No. 7.15. Yakovlev, P. A., Visual sensations and perceptions, Moscow, 1935, 127 (Russian).16. Y akovle v, P. A., Th e influence of acoustic stimuli upon the lim its of visual fields for

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