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An economical device for the microanalysis of licking
BRIEFCOMMUNICATION An Economical Device for the Microanalysis of Licking’
_. _. .-. I\;(;!‘SI IOShl. bcha\lor 1r3 $cnsral. and lickmg in particular. ha\c hccomc the foctls of intcnsivc cxatnination In jtcms primarily from the rc‘cct1 I ytk‘;ir5, ‘I 111~ intcrrst of schedule-induced polydipsia and the Jcrnonslratlon 1hcoreIlcal rcIcv3nc.c of this phenomenon to such diverse prc,ccssc5 ‘1, reward. motor control and addictive bchavioi [,3.-I/. Rcccnr worh In our laboratory has hcen clddrcsscd lo
1.(>I: Il’hl EN I’
I Ilc s~mplil~ctl
_-
_
block
.._
diagram
in
Fig.
1 illustrates
the
-
-
-
1,IC;. I Block diagram.
basic method for detecting lick duration. I‘hc tlrlnkomzter consists of 3n Ft‘l‘ op amp input stage which provides 3 variable amplitude output pulse with the stirnc’ duration as that of tongue contact. ‘I‘hc TX 1. buffer scrvcs to convert the variable amplitude output pulse IO :I st;mdard 5 V square wave. The Jiffcrcntiator con\crl$ the contacI JuraIion-dependent 5 c’ pulse IO two scpdrat? pulses. one coincidsnt with the unset of Iongus contact and the wcond coincident with rhe offset of tongue c‘c,ntact. Finally. ;I wwc shaper is provided to adjust 1111,ssparatc onset and offset channel pulses to the rcquircmcnt\ of any equipment with which the drinkomctcr is inrrrfacetl (set’ l:xamplcs of Use section). I’ulst3 I‘or C‘ounlc’r5 (the total ntinibcr ot licks:‘session) and session limifing t imcr! ian hc f:~ppcd ;I~‘ICI the
TTI.
Ruf’l‘c’r.
drinkomctsr circuit is illublruled m t:lg. 2,~. J’hcb sensilivily control rlllows for th2 adju\tnicnt 01 Ihc circuit lo animals of differing imped3nc~. Once ad.jtljtLyj. ~ltli 3 constant power source’. the circuit rcadil) accommodates IO Itlc normal range‘ 01’ anirri3ls withoul further rn;inipulation. Since the sensitlvil). control is placed 3f‘Icr lhc output of Lhc FI’I‘. change\ in ~djuslnirnl do not :ilter lhc currc’nt tlow through the animal. A\ shown in the diAgrarn (wilh 1hc 25hl resistor hctwccn the spwf ~InJ prourld) m;lxlm;ll ctrrrenl flow through the animal is O..?O p/I (short-crrcuil ‘l‘hc
550
MAC’ (;Kf:(;OK A. DRINKOMETER
C. OUTPUT
B. BUFFER .5r
DIFFERENTIATOR
AND I.lDSKI
.5r
D. WAVE SHAPER
FIG. 2. Circuit diagram of drinkometer
and associated components. A
value). This current flow is considerably smaller than that of most commercially available lickometers. Further reductions of current flow can be made by increasing the size of the resistor (or eliminating it entirely) between the spout and ground. The purpose of this resistor is to prevent the occurrence of artifactual counts due to airborne hum. As presented in the diagram, the drinkometer functions accurately in an unshielded test box. Further increases in the size of the input resistor (or its elimination) might necessitate testing in a shielded cubicle. The importance of minimizing current flow during licking has been graphically illustrated by the observation that currents of at least 1 PA (ie. 2.77 times greater than the maximal current produced by the drinkometer described here) will sustain licking in the absence of any fluid [ 21. Example
rj jl
! i
CL
i
...:~~~v'
0
&J
INTERLICK INTERVAL (msec)
B
of Use
Data collected with this drinkometer is illustrated in Fig. 3. Onset pulses were fed into a standard laboratory computer (PDP-8, Digital Corp.) to construct an interlick interval histogram (Fig. 3A). In another type of analysis each onset pulse was used to trigger a 124 msec analysis epoch during which the occurrence of the subsequent contact offset pulse was tallied. Repetition of this procedure was used to construct the lick duration histogram presented in Fig. 3B.
;
I
. _: I_-.irL.YL‘.i
0
‘.Z
65
‘.-.-
.-_
124
LICK DURATION (msec) FIG.
3. Examples of analyses of data collected with drinkometer. (A) lnterlick interval histogram. Bin width is 5 msec. (B) Lick duration histogram. Bin width is 2 msec.
REFERENCES 1. Allison, J. and N. J. CasteUan, Jr. Temporal characteristics of nutritive drinking in rats and humans. J. camp. physiol.Ps.Yc~o~. 70: 116-125,197O. 2. Slangen, J. L. and J. A. W. N. WeiJnen. The reinforcing effect of electrical stimulation of the tongue in thirsty rats. Ph.vsiol. R&au. 8: 565- 568. 1972.
3. Wayner,
M. J. Motor control functions of the lateral hype thalamus and adjunctive behavior. Physiol. Behov. 5: 1319 -1325.1970. 4. Wayner, M. J. Specificity of behavioral regulation. P!I.VSIO[. Rehav. 12: 85 l-869, 1974.
_. _. .-. I\;(;!‘SI IOShl. bcha\lor 1r3 $cnsral. and lickmg in particular. ha\c hccomc the foctls of intcnsivc cxatnination In jtcms primarily from the rc‘cct1 I ytk‘;ir5, ‘I 111~ intcrrst of schedule-induced polydipsia and the Jcrnonslratlon 1hcoreIlcal rcIcv3nc.c of this phenomenon to such diverse prc,ccssc5 ‘1, reward. motor control and addictive bchavioi [,3.-I/. Rcccnr worh In our laboratory has hcen clddrcsscd lo
1.(>I: Il’hl EN I’
I Ilc s~mplil~ctl
_-
_
block
.._
diagram
in
Fig.
1 illustrates
the
-
-
-
1,IC;. I Block diagram.
basic method for detecting lick duration. I‘hc tlrlnkomzter consists of 3n Ft‘l‘ op amp input stage which provides 3 variable amplitude output pulse with the stirnc’ duration as that of tongue contact. ‘I‘hc TX 1. buffer scrvcs to convert the variable amplitude output pulse IO :I st;mdard 5 V square wave. The Jiffcrcntiator con\crl$ the contacI JuraIion-dependent 5 c’ pulse IO two scpdrat? pulses. one coincidsnt with the unset of Iongus contact and the wcond coincident with rhe offset of tongue c‘c,ntact. Finally. ;I wwc shaper is provided to adjust 1111,ssparatc onset and offset channel pulses to the rcquircmcnt\ of any equipment with which the drinkomctcr is inrrrfacetl (set’ l:xamplcs of Use section). I’ulst3 I‘or C‘ounlc’r5 (the total ntinibcr ot licks:‘session) and session limifing t imcr! ian hc f:~ppcd ;I~‘ICI the
TTI.
Ruf’l‘c’r.
drinkomctsr circuit is illublruled m t:lg. 2,~. J’hcb sensilivily control rlllows for th2 adju\tnicnt 01 Ihc circuit lo animals of differing imped3nc~. Once ad.jtljtLyj. ~ltli 3 constant power source’. the circuit rcadil) accommodates IO Itlc normal range‘ 01’ anirri3ls withoul further rn;inipulation. Since the sensitlvil). control is placed 3f‘Icr lhc output of Lhc FI’I‘. change\ in ~djuslnirnl do not :ilter lhc currc’nt tlow through the animal. A\ shown in the diAgrarn (wilh 1hc 25hl resistor hctwccn the spwf ~InJ prourld) m;lxlm;ll ctrrrenl flow through the animal is O..?O p/I (short-crrcuil ‘l‘hc
550
MAC’ (;Kf:(;OK A. DRINKOMETER
C. OUTPUT
B. BUFFER .5r
DIFFERENTIATOR
AND I.lDSKI
.5r
D. WAVE SHAPER
FIG. 2. Circuit diagram of drinkometer
and associated components. A
value). This current flow is considerably smaller than that of most commercially available lickometers. Further reductions of current flow can be made by increasing the size of the resistor (or eliminating it entirely) between the spout and ground. The purpose of this resistor is to prevent the occurrence of artifactual counts due to airborne hum. As presented in the diagram, the drinkometer functions accurately in an unshielded test box. Further increases in the size of the input resistor (or its elimination) might necessitate testing in a shielded cubicle. The importance of minimizing current flow during licking has been graphically illustrated by the observation that currents of at least 1 PA (ie. 2.77 times greater than the maximal current produced by the drinkometer described here) will sustain licking in the absence of any fluid [ 21. Example
rj jl
! i
CL
i
...:~~~v'
0
&J
INTERLICK INTERVAL (msec)
B
of Use
Data collected with this drinkometer is illustrated in Fig. 3. Onset pulses were fed into a standard laboratory computer (PDP-8, Digital Corp.) to construct an interlick interval histogram (Fig. 3A). In another type of analysis each onset pulse was used to trigger a 124 msec analysis epoch during which the occurrence of the subsequent contact offset pulse was tallied. Repetition of this procedure was used to construct the lick duration histogram presented in Fig. 3B.
;
I
. _: I_-.irL.YL‘.i
0
‘.Z
65
‘.-.-
.-_
124
LICK DURATION (msec) FIG.
3. Examples of analyses of data collected with drinkometer. (A) lnterlick interval histogram. Bin width is 5 msec. (B) Lick duration histogram. Bin width is 2 msec.
REFERENCES 1. Allison, J. and N. J. CasteUan, Jr. Temporal characteristics of nutritive drinking in rats and humans. J. camp. physiol.Ps.Yc~o~. 70: 116-125,197O. 2. Slangen, J. L. and J. A. W. N. WeiJnen. The reinforcing effect of electrical stimulation of the tongue in thirsty rats. Ph.vsiol. R&au. 8: 565- 568. 1972.
3. Wayner,
M. J. Motor control functions of the lateral hype thalamus and adjunctive behavior. Physiol. Behov. 5: 1319 -1325.1970. 4. Wayner, M. J. Specificity of behavioral regulation. P!I.VSIO[. Rehav. 12: 85 l-869, 1974.