Doc 0000022010

The image is a graphic display, not a scanned document page. It features a stylized illustration of a vault door on the left, with glowing blue accents. On the right, the text "THE BLACK VAULT" is rendered in a bold, distressed white font against a dark background. Below this title, informative text explains that the document originated from "The Black Vault," an online database of declassified government documents, specifically mentioning the MKULTRA/Mind Control Collection and a URL. There are no photographs, handwritten notes, official stamps, forms, diagrams, tables, redactions, or visual evidence of experimental procedures. , I -J ·-·---------------i ~-=-- \ I -.- .. _..-.. February 15, 1967 I Period Covered~ June 15, 1966 to January 31, 1967 I. Summary Certain key experimental findings obtained during this first phase oi the research have been combined tvith earlier obsenra::ions cited in the project propcsal to produce a model of best fit for the electrodermal system. It encompasses both a dual peripheral effector ~echanis~ and a central control system. It assigns little or no function to vascular mechanisms. It has been used to develop a ne~.; .aethcd fo:: analysis of the skin conduct&nce response which has been highly suc:essful in accomplishing sorting of qualitatively different behavi~ral states Hithout utilizing response a:nplitude as such. The new :nethod should lend itself readily to automation. II. Soecific Experimental Findings A. Periphe=al Hechanism 1. Microelectrode Observations: ~i~ potentials were simultaneously recorled from sweat pores and from areas on the palmar surface bet~.;een St>eat pores ~epidermal sites), together with-a macroscopic recording 2 from a nearby 0.3cm site (25 subjects). Pure positive waves, pure negative waves and biphasic usually obtained ~..~aves ~~ere from either microscopic site with equal frequency, although in a subjects, the epidermal showed Fredoninantly fe~ sit~s positi:ve responses t.;hile the pores produced negative or bi· phasic waves. For the population as a t-Jbole, no pattern was detect.able which allowed prediction of the particular ~·ave­ form at either type of microscopic site. One observation of interest tvas the frequent occc.sions in which the r.1icroe l£>c trodes on the st,•eat pore and epiderr.:is shot-Jed only positive t,..•aves t.;hile the macroscopic site shot>'ed pure ne~ptive waves (Fig, 1), This is attributed to the fact ) that the macroscopic site covered and ~as ~ith el~ctrodc pa~te !pproved 'lfc~~~e;;~fa :Pete _2:::...:..---- --- ------·-----· ---'-· J ) -••- .. -• .... r-- • ~ I ·------·: --;----· -- 5'.-IE t.. T POR [ -- -:- .... -:- . :=·~ + ·- ----~ ---·-. ---- ~---- - EPIDERMIS - -- -·- . -------------- - ) GROSS ----- _.,, --~-- --""""""":; .... ---··---·-·---·-------:--_/\\ ~--1_ ---~-- 2 SEC. -- --- ·------- H '":'" Fig. 1. Simultaneous microelectrode recordings from a s~;eat pore from the area between sweat pores, and from a nearby macroscopic site ~11 on the volar surface of the finger. In this the gross site shows exa~ple a negative response~ cespite the positive activity in the oicro- scopic sites. Negative is up~~ards. ) -_·_· , j ---- This page contains a typed document with handwritten annotations. There are no photographs, diagrams, or tables. Dominant handwritten elements include a date "February 15, 1967" in the upper-middle section, and a section at the bottom right containing a signed approval box labeled "Approved for Release Date 27" followed by a circled number "(150)". There are also several ink marks and a large curved line on the left margin, possibly indicating sections of interest or redactions. a s~;eat pore from the area between sweat pores, and from a nearby macroscopic site ~11 on the volar surface of the finger. In this the gross site shows exa~ple a negative response~ cespite the positive activity in the oicro- scopic sites. Negative is up~~ards. ) -_·_· , j ---- with an electrode while the microclectrode sites ~ere exposed to air and were considc!"ably drier. Hhcn dry macroscopic electrodes made of tvoven silver cloth (to .:~lLm the site to remain dry) were used, the same effect tvas obr=ained, namely prominent positive waves at the dry site, while negative waves or negative with weak positive components occurred at the wet site (Fig. 2). TI1is effect is consistent with the predictions of a hydration effect rec~~tly dis~overed at this labora:ory and investigated further under the present contract. It poi~ts out that the presence of two areas in the skin with different potentials must result in internal circuit currents. The po~ential observed at the surface is then determined by the value of the tt.;o generators and their internal resistances. If the internal resistance (which includes the stveat duct and the ho~ny layer, as well as any membranes involved) is reduced, the surface potential will move in the direction of that generator whose internal resistance is affected. Thus, when sweat overflows into the dry corneum~ it reduces the resistance of the horny layer and brings t~e surface potential closer to the potential of the epidermis t•hich is less negative than the Stveat pore. This mechanism makes it imperat:::ve to tvork with a completely hydrated preparation if this spurious effect is not to be confused with true positive potentials, such as ~ay be recorded ~ith the site immersed in dilute saline. Since the spiral duct appears to be rela:ively freely per• rneabl~ to ions as it passes through the horny layer, the corneum acts as a volume conductor when ~oist and interferes with the separation of sweat gland and oembrane effects by means of surface microelectrode recordings. To eliminate this effect and also the hydration effect described above, the skin is no~ being prepared by slicing away most of the corneum, so that the microelectrode may rest almost on the granular layer, or may be inserted directly into the exposed sweat duct at this Level. About 12 exploratory experiments have been run to de'Jelop this technique and a series t.Jith .a fixed e~peri::~ental desig~ has slicing away most of the corneum, so that the microelectrode may rest almost on the granular layer, or may be inserted directly into the exposed sweat duct at this Level. About 12 exploratory experiments have been run to de'Jelop this technique and a series t.Jith .a fixed e~peri::~ental desig~ has been initiated. Surprisingly, the potential at the surfa-:e pore is 10 to 20 mv more negative than the potential within the lumen of the duct at the granular or Halpighian layer. this may be in<licative of a diffusicn potential across the spiral duct: '~all.. Also surprising is tr_e observation of positive as well as negative and bipha-sic waves from \.Jithin the exposed lumen ai: the deeper level. Experiments entailing simultaneous microelectrode recordings from the duct and from the granular layer are in progress. These should hopefully furnish definiti~e information on the origim of the different for~s of potential response. ) ... ~- ~ 0 .··KAO •':~ -' ,'-:- ~ ·' • - ,. . ~ '---'--·-'-·--~---~----·--: _ _. ·- ~ .. : . ~ 7:-: .. : - '.! . --:--c ,. = _ : _ ~ _ : __·__,:. .,... .• : p . : ~ ~-: :. f l f - ~ . ------+_:--_·_:_·=-~--~;-~:- ·;t-~: .....: .........._. . __.._ _. --·-· - . - I ~__.:, ------t·-~-:-~ -----~- . .: --=- ~~ --~::·---~ ~~-=--.:.--~.- . ; -·- -~ -------. --- __ - : -_.._o-._. . o; _ ,•· : :- , -: . : . - - __ - _ : _ - _ ' - :. ~ ._ . --- + , - .. - , - - _ - .. . - . - ;. ~ · . . - . . . - - ~ - - - - - . ; · _ , .. . - • ; • _ · _ . - • ~ . • - - _ :..- . . ~ - . - . _ : - - . ~ - _ . . . - i . . . _ . - . _ . - . j . _ - - _ . _ - j _.. _ _ _ _ - _ :; _ . . _ . . : . - ! _ ~ , . : . . . - _ . . . . . . , .. . . . . The image displays a scientific graph with three distinct lines representing microelectrode recordings from a sweat pore, epidermis, and a gross macroscopic site. Each recording line is accompanied by a scale bar indicating voltage (2 mV) and time (2 SEC). Handwritten labels identify the different recording sites. Below the graph, a figure caption describes the experiment, noting that negative activity is displayed upwards. There are no photographs, stamps, or filled-in forms visible on this page. The page is primarily text-based, with some handwritten annotations. There are no photographs, stamps, forms, diagrams, schematics, organizational charts, or tables visible. The handwritten elements include scattered marks and symbols at the top of the page and a large bracketed symbol on the left margin. There are no obvious redactions. The text discusses experiments involving microelectrodes and skin hydration. j . _ - - _ . _ - j _.. _ _ _ _ - _ :; _ . . _ . . : . - ! _ ~ , . : . . . - _ . . . . . . , .. . . . . . . - . : . . . _ -· _ _ .. ; ... . . __ .; _ - __ - _ - _ · . - .. - l - .. · _ - ~_ · : - . - _ - __ _ -- ·-:.------- - ~- - - - "" - '; · -- - - --·-- 2 · - M -· · ... · ... I ... · .... - ....__ -- --- -·-'·----- -- -·--- - ·-·· -------· - ------~ __ _ ._ __ -.- ·------.- --.- ----- .. _. .--:,___ . · --- ·-·;-+-----"-;"' ____ ----·-:--.:--: --.· -- ... - ••' :::----: .-. :·-::.~ DRY ---:--·~-:--;-----~ ·-y-----~-~-;-r.-~~:0~ H-• -•• ....... • H; ::._:.~ ----------___ _.::...:__.:....::.....;::.....;::::;.:·c:"_=_:..;-:.:::.o.:·:.;_:..:.:,._·.,:c::.:::-::::~:" ..:·-:;··::::=-.::- - .. ;: :.-· _; - [_ :_-:;: __ ~ ~--~-¥~~-~--- :--~~- ~ ---:--.--------.- -:::: · - - - - ~ - -.-.- -:-.. -~ ...!' ... :.--:.·: .-:;..;.- '--------·- • I - I • Fig. 2. Comparison of recordit,gs from a conventional (t•e.t) site and a si~ilar dry site covered with porous silver cloth. Note greater positivity in the dry site. 3 ... .--c_ ... 2. Animal Experiments: A series of experiments tvns run on 6 cats to invcstigntc the characteristics of conductance and potential response in the footpad as a function of the pattern of electrical stimu lation of the plantar nerve. Following repetitive stimulation (e.g., 8/sec, 15 volts, 5 sec.) there is an hlitial <1ugr:1<~ntation of the conductance response to single shock stimuli. The aC~pli­ tude of this response, tested at 30-second int~rvnls, drops progressively to about 50 percent of its initial value over the course of 4 minutes following the repetitive v~lley. When it reaches this level, another repetitive volley causes an immediate doubling of the response to the standard single shock (Fig. 3). The decay then progresses as before. This phenomenon also occurs when skin potential responses are monitored. It is not due to base level effects (base level may be altered by only 5 perce~t during the repetitive volley and may fully recover by the time the first highly augment:ed (Fig. 3). The decay then progresses as before. This phenomenon also occurs when skin potential responses are monitored. It is not due to base level effects (base level may be altered by only 5 perce~t during the repetitive volley and may fully recover by the time the first highly augment:ed response is elicited). Another experimental finding in these experiments concerned the beh~vior of a second response superimposed on a preceding one. The findings of an earlier study indicated that the amplitude of a second conductance response the same as the ~as first, except for the steepest portion of the recovery slope of the first t·:ave, at point the second t<ave vias markedly t~hich attenuated. This phenomenon ~as confirmed and extended to potential response measures. The behavior of the potenti~l summation processes t·Jas almost identical to that of condu~;tance summation. In these experiments, for an unkno~n reason, attenuation of the second response on the downward slope was considerably greater than in the first series. above findings suggested numerous follow-up Th~ exper.i~ents which could help lay the basis for the calibration of electri cal chc..nges in terms of nerve activity. Hot.;ever, these ex• periments t·Jere halted when it was learned tha~ the sweat glands of the cat footpad are apocrine (G. H. Wang, The Neural Control of Sweating, 1964). This has profound irnplica:ions with regard to interpretation of measurements from tha cat footpad. It th~ renders the extrapolation of such results to human measurements highly suspect. Investigators have, however, for several decades utilized the cat fQQtpad as an experimental eccrine praparation. Consul:ation withj 1 an investigator well ex- periep·::ed in worki~with the cat!ootpad, reve-aled that there is considerable question as to the validity of t..'ang1s statement. Until this matter is cleared up however, this series of ex 1 periments is potentially irrelevant and will be suspended. 3. Plate Recordings; ~ail Soecial eff~rts were ~ade to insure thBt the pot3ntial res- I ) ,. 150 K - j f /' ' 30 SEC '. I I . ___ _J. ' I I --_j_~ __ j_____j _, ·-·- __.J-- • ---.....:."" ~ REPETETI'IE Sr 1 t·IULU:S Fig. 3. Potentiation of the skin resistance response from the cat foot· pad following a repetitive volley (V)~ ', I 4 ponscs recorded from the nail plate, previously reported, were not artifacts of potentials generated in normal skin on the opposite or lateral sides of the finger and The image displays a graph with three distinct lines, each representing a different recording. The first two lines are labeled "WET" and appear to show similar fluctuating patterns. The third line is labeled "DRY" and exhibits a different, more pronounced waveform. Scale indicators are present for voltage (2 MV and 10 MV) and time (10 Sec and 1 Sec) along the axes. Below the graph, a caption describes the figure as a comparison of recordings from conventional wet and dry sites, noting greater positivity in the dry site. There is also a handwritten annotation "-7" at the top right, and another mark, a circle, to its left. The visually present content on this page consists of text from a declassified document. There are no photographs, handwritten annotations, signatures, official stamps, forms, diagrams, schematics, organizational charts, tables, structured data, or visual evidence related to experimental procedures or facilities. The only non-textual elements are what appear to be faint horizontal lines from the original paper and a small "3" in the upper right corner. There are no redactions or obscured content. 1 t·IULU:S Fig. 3. Potentiation of the skin resistance response from the cat foot· pad following a repetitive volley (V)~ ', I 4 ponscs recorded from the nail plate, previously reported, were not artifacts of potentials generated in normal skin on the opposite or lateral sides of the finger and transmitted to the nail electrode by virtue of the volume conductor properties of the finger. A portion of the nail plate near the distal, late~al portion of the finger was cut away to expose the intact nail bed. T~vo simultaneous microelcctrode recordings were obtained from this area. The most common recordings \-Jere pure positive SPRs. tvhen one of the microelectrodes t~as pushed barely through tl:e upper;r,.o s t layer of the nail bed, the potentia 1 showed a con spicuous positive shift of the "order of 15mv and potential responses were marl<edly attenuated ac this e:..ectrode. The con trol electrode remained active (Fig. 4). In three of the four subjects thus examined, puncture caused attenuation of the response (to a word association test) to less than 5 percent of the control level; in two of these the response was essen tially abolished. Hhen the microelectrode ~vas withdra~•n and placed on the surface of the nail bed adjacent to the point of entry, activity reappeared. The fourth subject sho~•ed the positive shift with puncture but response amplitude, initially lo~. ~as not diminished. Although this evidence.added to the earlier indirect evidence_gave compelling support to the con tention that the responses did in fact originate in the surface of the nail bed, so~e doubt was cast on the supposition that the nail l::ed represents pure epidermy tissue (;:;ee of sv;eat glands) as describeti by histologist.s. . 1jreported the 1 findirg of sweat ducts a long thedistal margln of the nail \-ihich invaded the nail field (personal communication). ---··-fphoto~ graphs do show the spiral ducts entering the periPhery of the nail 'bed for a distance of 1 to 2 mm. Hhether these traversed the nail bed much further is uncertain; since nail recordings, except for those described above. are taken as close to the center of the nail bed as possible, it is thought unlikely that the potential recordings are contaminated by the products of S\~eat gland activity. However, until this factor is clearly resolved, the evidence from the nail: bed mus~ be accepted with reservations. Histological data is now being sought to settle center of the nail bed as possible, it is thought unlikely that the potential recordings are contaminated by the products of S\~eat gland activity. However, until this factor is clearly resolved, the evidence from the nail: bed mus~ be accepted with reservations. Histological data is now being sought to settle this issue. 4. A~tera~ion of SPR Waveform with Surface Solutions: An earlier study had demonstrated that total amplitude of the e~ectroderoal response, conductance or p;,cential, could be altered by the exposure of the site to various solutions. A folloiJ-up study was undertaken to determine ·.vhether the positive and negative components could be selectively altered by this procedure. The exposure of palmar sites to 1M A1Cl1 was found to potentiate the positive response by an av~rage o~ 750 percent (averase on 7 subjects). The negative respo~se was at~enuated to 54 percent o£ control, but this :::-:ay reflece the can si:npl~· celli~s effect i:::-:posed by the increase in a~?litude of the uoacw , I . Control mv] 1 Exptl t c A B Fig. 4. Simultaneous microelectrode recordings from the nail bed showfug positive responses to ~-lord associations. !n the center panel, one ::licro electrode has been pushed through the ger~inating layer and responses have disappeared. To the riaht, this electrode has been withdrawn again and replaced on the surface near the puncture. - --ELL& e ·~ i . t NaCI --J~t.---.t. .. ~'-..J~­ [zmv t 1' I t 1 ~ • ) -. AICI 3 \ •' \ ( ~, B A Fig. 5. Potentiation of the positive SPR Have by 1 H A~Cl3• Negative is up,·.·ards. ) 5 positive in the complex (Fig. 5). It is of special sig \~ave nificance the earlier study on the response ~hat conductan~e showed an average of over 6CJperccnt increase in this measure. This suggests that the conductilnce response may be associated \vith tha positive t~ave. Another agent tried \vas 5H NaCl. This had n.ot been tested for its effect on amplitude of conductance respomse, but had been sho1m to reduce resistance to 5 percent of control level. The effect on the potentia 1 response t·laveform was a conspicuous potentiation of the 11c11 wave, a negative overshoot which sometimes follows the posit;;.·'! wave. Uniphasic negative waves were unaf=ected (Fig. 6). Until the effect on the resistance response is determined, this effect cannot be fully interpreted. It is presently considered to reflect a lytic effect The image is a scanned document page containing a graph and some text. The graph displays a waveform recorded over time, with labels indicating resistance levels ("150 K", "160 K"), a time scale ("30 SEC"), and an event marker labeled "REPETETIVE STIMULUS". Below the graph, a caption reads "Fig. 3. Potentiation of the skin resistance response from the cat foot-pad following a repetitive volley (V),". There are also some faint handwritten marks and abstract shapes scattered on the page, as well as what appears to be a black ink circle near the top. The page contains typed text discussing electrodermal responses and potential research findings. There are no photographs, diagrams, stamps, or filled-in forms. There are handwritten annotations in the margins, including a squiggly line and a number "4" at the top. There are also some faint dark circular and linear marks which appear to be ink blots or smudges. response t·laveform was a conspicuous potentiation of the 11c11 wave, a negative overshoot which sometimes follows the posit;;.·'! wave. Uniphasic negative waves were unaf=ected (Fig. 6). Until the effect on the resistance response is determined, this effect cannot be fully interpreted. It is presently considered to reflect a lytic effect on an ionic bar~ier, presumably the semi-permeable merrbrane res ponsible for the positive to~ave. This membrane, according to earlier studies from this laboratory, must be accessible to surface agents. and behaves as an irr.perfectly selective cation permeable membrane. The initial phase of the response is seen as an increase in the pe·cmeability to cations, :esulting in a hyperpolarization, i.e., in a negative wave. As the breakdown of membrane resistance proceeds, the relative i~permeability ) to chlori~e is apparently lost and depolarizati~n occurs, resulting in a positive \vave. As the integrity of the ~e:;:brane is restoced, the first effect is thought to be recovery of the relative impermeability to anions. If the recovery period is prolonged, there nay be an appreciable delay before the per meability to cations is reduced to normal. During this phase, the membrane will be hyperpolarized, resulting in a second negative wave or overshoot, termed the 11c11 ~:ave. A concen trated electrolyte such as SN NaCi. is thought co loosen rc.embrane structure (to wit, the profound reduction in resistance) so that recovery is prolonged, accentuating the negati·.;e overshoot. ' The above con~ept of the rr.embrane process in the electro• dermal ~esponse also explains the effect of AlCl3. The absorption of the aluminum ion by the fixed negative charges of the membrane would c~use partial neutralization and incipient loss of selective impernu~ability to anions. Uhen the ::~e:::brane break(lcwn occurs during the response, the loss of i:.:per.:teability to anions is therefore much more marked, resu~ting in greater depolarization and a stronger positive wave. Although this explanation and that for the effect of 5M NaCl are hypothetical, they a=e consistent with a nu~ber of other ex?etimental obser vations and in part form the basis of the ne\vly formed model of ele~trodernal activity. ) ,._, . I ; ' "'\ I J, [2rnv -----+- 0.1 )" Fig. 6. Poteutia,tion of tne SPR c·wave by 5 M NaCl. Negative is up\vards. Up~or trace, 0.1 ~ ~cCl; Lower trncc, 5~ ~~Cl, 15 ~inutes • .. I ~----------·--------------------------------------------------------- --..Z::..~--~ - 6 5. Production of a Positive Potential Response by Local Ncchanical Effect: In 1921, The page displays a scientific diagram illustrating microelectrode recordings from a nail bed, showing electrical responses under different conditions labeled "Control" and "Exptl." The diagram includes handwritten labels "A," "B," and "C" beneath corresponding waveform plots, and a scale bar indicating "1 mv". A smaller scale bar labeled "t" is also present. Text at the bottom of the page describes the depicted recordings and the experimental procedure involving withdrawing and replacing an electrode. The top portion of the page contains what appear to be abstract markings or possibly remnants of original document formatting or stamps, including a circular mark and a horizontal line. J, [2rnv -----+- 0.1 )" Fig. 6. Poteutia,tion of tne SPR c·wave by 5 M NaCl. Negative is up\vards. Up~or trace, 0.1 ~ ~cCl; Lower trncc, 5~ ~~Cl, 15 ~inutes • .. I ~----------·--------------------------------------------------------- --..Z::..~--~ - 6 5. Production of a Positive Potential Response by Local Ncchanical Effect: In 1921, Ebbccke discovered that a local decrease in skin resistar.ce could be produced by pressure, electricity or heat and he interpreted this as the response of an epithelial cell layer. Several years later, Rein found that a~positive potential response could be produced by the same means. This phenomenon sub~quently drew little attention, although it was·confirmed by · - ~ It was reported to be obtained from variOus parts of the bo~but not from the palms or soles, a finding which suggests that s~~eat gl.:lnds are not involved in the process. In an effort to facilitate the investigation of the pro{:·erties of the positive response in the present research, a method was devised which would produce a fairly reproducible mechanical effect. Electrical stimulation did not appear desirable because of the numerous structures which it might activate. Pressure was thought undesirable because of the possible production of electrode artifact. The @echanical method chosen consists of taping to the volar surface of the finger a small inflatable bag. The tape is applied to the lateral sides of the finger such that inflation of the bag to 180wm Hg a stretch on exe~ts the dorsal skin under the electrode. Inflations are ~ade for 5 secon<!s at 30-second intervals and produce a square v1ave stretch. The response consists of a very rapid positive seg- ment fo~lowed by a more gradually in~reasins segment (Fig. 7). In this recording, as in all others, two sites on separate fingers are subjected to the stretch stimulus. A third site on another unstimulated finger is used to any response moni~or of reflex origin. The local responses (L) resemble the res- ponses t:o word association {H") in general form and amplitude, but are not present on the non-stimulated control finger (C). Alt:"lough the response is relatively stable, it varies t~ith the sta:e of background activity of .neural origin. In Figure 8, the enhancement of the response by negative skin potential is illustrated during the response to a sniff. This ac~ivity is typical and has been reproduced aunerous times potenti~tion on 12 S.lbjects. The local potential response (LPR) has aiso been obtained from This page contains a scientific illustration depicting electrophysiological recordings labeled as "A" and "B". Recording "A" shows two separate traces, one labeled "NaCl" with a vertical scale marker of "2mv" and a time scale marked with "t......", and another "NaCl" trace. Recording "B" shows one trace labeled "AlCl₃". The labels "A" and "B" are positioned centrally below each recording. The bottom of the page includes a caption identifying the figure as "Fig. 5. Potentiation of the positive SPR wave by 1 M AlCl₃. Negative is upwards." There are no photographs, stamps, or handwritten annotations visible on this page. of background activity of .neural origin. In Figure 8, the enhancement of the response by negative skin potential is illustrated during the response to a sniff. This ac~ivity is typical and has been reproduced aunerous times potenti~tion on 12 S.lbjects. The local potential response (LPR) has aiso been obtained from the volar surface of the finger~ despite Ehbecke's statement to the contrary, possibly because he did not use stretch. Its amplitude, however, is less thar. that from the dorsal surface. No local conductance responses were obtainable from the volar though they readily from surfac~, t~ere obtain~ble the dors1,.1:n. ) The LPR can also be produced by vascular engorgc~ent of the finger, produced by the sudden inflation of an arterial finser -- ,__. ... ..._.-- ·~ I . -~-·~""· L - \~! 'tJ L l L L t 1-----1 c Fig. 7. Conparison of local potential response (LPR) and central SPR to a word associatiQn sti~ulus. Upper trace: L =local sti~ulus (stretch); W =word association stimulus. Traces labelled L show racording from fingers fitted wi~h stretch device. Trace labelled C is a control finger which responds t9 central neural activity only. ) _____ _ ·- _/ ......,/ _ ___ ) s L L ) I2 t Mv ~ I c Fig. 8. Increase of LPR amplitude produced by backgr·:IUnd negative activity of neural origin. The negative activity has been pro~uced by having the subject sniff sharply at point "S" on the upper trace. '· ) . _, -- . - ~---=----------- 7 7 cuff. Because of the relatively large area by enco~passcd the cuff the small finger distal to it, vessels ~nd volu~c tp~ of the distal portion arc markedly engorged. Th~ resulting LPR is co~sidercd to be caused by stretching of the skin by this If prior to cuff inflation the hand is proc~ss. elev~ted to he~d le.vel to empt:y the veins, inflat:ion of the cuff produces little or no LPR. Exsanguination of the finger for 15 ~inutes, produced by rolling.a tight rubber doughnut from tip to base of the finger, potentiates the LPR by about 20 percent {14 subjects). The positive ~kin potential response of central origin (SPR) is simultaneously depressed, sometimes to less than 25 percent of control. If the positive LPR and the positive S?R are re flections of the activit:y of the same end organ, this must indicate that hypoxia exerts its effect on the nerve The image is a page of text, likely from a scientific report, with minimal visual elements. There are a few handwritten annotations at the top of the page, including what appears to be a number "5" and some scribbled lines. A small section on the left side of the page is partially obscured, indicated by a blacked-out vertical line and a curved bracket, suggesting redacted content. The text itself discusses conductance response and electrodermal activity, implying a scientific or experimental context. The positive ~kin potential response of central origin (SPR) is simultaneously depressed, sometimes to less than 25 percent of control. If the positive LPR and the positive S?R are re flections of the activit:y of the same end organ, this must indicate that hypoxia exerts its effect on the nerve endings rather than on the effector organ. Ebbecke, in fact, reported eliciting the local conductance response (LCR) from day-old cadavers. The exsanguination data suggest that the LPR is not produced by a vascular mechanism. Added evidence is seen in the fact that the LPR like the SPR is susceptible to the effects of locally applied electrolytes such