An off-line data acquisition-device for measuring ethological elements of behaviour

Physiology & Behavior, Vol. 28, pp. 743-745 Pergamon Press and Brain Research Publ., 1982. Printed in the U.S.A

An Off-Line Data Acquisition-Device for Measuring Ethological Elements of Behaviour KARL F. HAUSAMMANN

AND KEITH DIXON

Wander Research Institute, Sandoz Research Unit P.O. Box 2747, CH-3001, Berne, Switzerland R e c e i v e d 12 N o v e m b e r 1981 H A U S A M M A N N , K. F. A N D K. D I X O N . An off-line data acquisitmn-device for measuring ethological elements of

behaviour, PHYSIOL BEHAV, 28(4) 743-745, 1982.--An improved version of an apparatus for registering and recording behavioural acts and postures (elements) or categories of elements in terms of frequency of occurrence and cumulative duration as observed simultaneously on two interacting animals, is described. Since all calculations and drawings of results are done by the computer, a considerable amount of labour can be saved. Ethological elements

Frequencies

Duration

Data acquisition

E T H O L O G I C A L units of animal behaviour occur in the form of elements, i. e., movements and postures which, once accurately described, can be counted and timed. The registration and recording of both the frequency of occurrence and the cumulative duration of elements for various behavioural activities, e. g., aggression, sexual activity, etc., is therefore a common procedure in experimental work but one which amasses a large amount of data. A number of authors have described systems for the automatic recording of such data. The first one was described under the name o f PAT (Posture, Adder, Timer), in 1965 [2] and was constructed with relays and counters. Although this machine saved considerable time, it did not eliminate the recording of and calculations on the data. Somewhat later, a sophisticated method for recording the behavioural events on a domestic taperecorder for later off-line computer processing was published [3]. A third paper [1] presented a similar device, which was even cheaper and could be used in the field. Although these machines are both silent and precise, they have a certain practical drawback: the time needed by the computer to decode the information stored on the tape is as long as the recording time, providing the replay speed is not faster than the recording speed. We now describe an improved version of PAT designed to take many of these limiting factors into account. It both registers the data and transfers them onto punched tape after each observation, thus making them available for off-line computer-analysis. DESCRIPTION OF THE UNIT

Our version o f PAT, which incoporates a microprocessor, possesses two independent channels each with a 10 button keyboard. Use of the left keyboard allows the behavioural

Microprocessor

elements of one of a pair of interacting animals (in our example a resident or H O M E animal) and the fight keyboard, the elements of the partner (or INTRODUCED) animals, to be recorded.

Hardware PAT consists of 2 module cards and a 4070 Facit punch. The first card contains the micropressor 6800, the clock, and a volatile (1K RAM) as well as a none-volatile memory (2K EPROM). The second card contains the two PeripheralInterface-Adaptors (PIA) as well as enough room to take up the additionally required integrated-circuits to handle the in- and output (Fig. 1). Each keyboard has a bounceelimination circuit which ensures that an activated key causes only one interrupt-pulse. Every time that an interrupt occurs the microprocessor reads all key positions and determines which one is active. Both the event-counter of that key and the corresponding key-status-bit in the volatile memory are set to 1, all other bits of the same keyboard being cleared. This ensures that for each keyboard, only one bit at a time can be set. Each operation of the same key increases the event-counter by l, whilst the corresponding status-bit stays set at unity. This latter bit is used for the time measurement and can be cleared by pressing the appropriate STOP-key. Every 10 milliseconds a non-maskable interrupt-pulse occurs. If a status-bit is set at this time, then it indicates which time-counter has to be increased by 1. The time is therefore accumulated in 1/100 second intervals. Since the contents of the counters are not visible, a status-indicator is necessary. The CLEAR-lamp which serves this function burns when all counters are cleared and denotes that PAT is ready for operation. As long as the

C o p y r i g h t © 1982 B r a i n R e s e a r c h P u b l i c a t i o n s Inc.--0031-9384/82/040743-03503.00/0

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RESET - I/O CONFIGURATION -CLEAR H, - A N D I i BITS - CLEAR All EVENT AND TIME COUNTERS -DISABLE H-ON AND I - O N LAMPS - ENABLE C L E A R - L A M P

READ DATA AND INTERRUPT- STATUS

- CLEARALL HI BITS - DISABLE H-ON LAMP

WAIT FOR NMI-OR IRa-INTERRUPT - CLEAR ALL h BITS - DISABLE I-ON LAMP TIME CLOCK INTERRUPT ENTRY(OCCURS EVERY 10 ms ) -

- SET H , - B I T - ENABLE H-ON LAMP,DISABLE CLEAR-LAMP INCREMENT Hi EVENT COUNTER

INCREMENT TIME COUNTER H I / I f IF BIT Hi / I I IS SET

- SET h - B I T - ENABLE-ON LAMPDISABLE CLEAR-LAMP - INCREMENT Ii EVENT COUNTER

RETURN INTERRUPT

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KEY NUMBERS (D 9) | INTERNAL IMAGE OF HOME-KEYBOARD I = INTERNAL IMAGE OF INTRODUCED-KEYBOARD FUNCTION PRESSING THE HOME KEY 4 SETS BIT H4 AND CLEARS ALL OTHER 9 BITS OF THE INTERNAL IMAGE H~

-CLEAR ALL Hi-AND I I - B I T S - DISABLE H-ON AND I-ON LAMPS - INTEGER-REAL CONVERSION OF TIME- COUNTER VALUES - CHECKSUM CALCULATION - PUNCH DATA AND CHECKSUM TWICE - CLEAR ALL EVENT AND TIME COUNTERS - ENABLE CLEAR-LAMP

RETURN INTERRUPT

FIG 2. Principal block diagram of PAT-firmware with three tasks. After a RESET (power-up or manually) PAT configures itself mternaUy and waits for a interrupt-pulse Each Ume a key is pressed, the IRQ (interrupt-request) -task zs active, which controls internal key-image, event counters, lampindicators and the punch. For the purpose of time measurement the NMI (Non-Maskable-Interrupt) -task is scheduled every 10 msec

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both simultaneously. F o r reasons of brevity this latter part and that pertaining to resumption of data processing after a punch mistake, are not shown in the block-diagram. Data is punched on tape, twice in binary form including a checksum-byte. An error recognition and correction procedure in the computer is therefore possible. The eventcounters have a capacity of 16 bits. Therefore every counter can count to a maximum of 65534. For every time-counter, 32 bits are available. The totalled time with a resolution of 1/100 second is reached after 23 hours and 18 minutes. Software

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The assignment of behavioural elements or groups of elements to the keys is facultative, i. e., each key can take either one or several elements. However, for all types of experiments a basic data-input scheme is recommended. Figure 3. shows an example of a computer drawn histogram of the behavioural changes occurring in one member of a pair of drug-treated mice as assessed with PAT. A similar histogram can be drawn for the partner (see legend to Fig. 3 for details).

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FIG 3. Example of a PAT-drawn histogram showing behawoural changes in an introduced mouse following treatment with a stimulant. ELEMENTS/N = mean change in numbers of elements/mouse. SEC/N=mean change in duration (seconds) of elements/mouse. Bars above and below horizontal hne represent increases and decreases in activity compared to control. Excessive changes denoted by broken bars. NS, SIM, AGG, etc. denote symbols for behavioural categories (i.e., particular classes of elements) of social and non-social behaviour. TOTAL=Mean total frequency change in all elements. TOTAL (Soclal)=Mean total change in duration of social elements. During observation of the animals, each element is assigned to its appropriate category by operating the corresponding key on the keyboard.

time-counters on one or the other keyboards are in operation an appropriate ON-lamp lights up. By pressing the PUNCH-key, the ongoing measurement, which normally ends with the operation of both STOP-keys, is interrupted and the data output to the tape is started. Providing punch errors are absent, the counters are cleared and PAT is ready for new measurements. The ERROR-lamp only burns if a punch error is made. In this case the contents of the counters remain unchanged so that the data can be repunched after the mistake has been corrected. Ftrmware

Figure 2. shows the main working principle of PAT. Since both keyboards are independent of each other, two interrupt-pulses can occur, PAT being capable of processing

The present version of PAT enables the behaviour of animals to be described, registered and recorded in terms of element frequencies and durations, and to be depicted in graphic form. Since this and all calculations are done by the computer, the PAT affords a marked saving in labour, completely eliminating tasks previously carried out manually. The use of integrated circuits instead of relays and electromagnetic counters ensure a noiseless performance of PAT, thus reducing disturbing influences on man and animals to a minimum. The reason for using a paper-punch instead of a digitalcassette unit is that the former apparatus is cheaper. In addition, paper itself is a cheap, durable form of data storage. Because PAT registers the elements in terms of frequency of occurrence and cumulative duration, the amount of punched-tape used is small and kept to manageable proportions. A disadvantage of PAT is that if part of the tape contains a punch error, this section must be removed if it cannot be handled by the computer. It should be noted that PAT allows data to be checked after, and not during, an experiment. Our version of PAT was not intended for analysing sequences of behaviour. However, this could be realised by the implementation of other Firmware and by the addition of a suitable but more costly volatile memory. With a slight modification it is also possible to record the frequencies of shifts from one type of behaviour to another. Thus, the apparatus can be adapted for a large range of situations in which the behaviour of animals is measured.

REFERENCES 1. Dawkms R. A cheap method of recording behav]oural events for ,direct computer-access. Behaviour 40: 162-173, 1971. 2. Mackintosh, J. H. Analysing results by computer. An,m. Behav. 13: 586-587, 1965. 3. White, R. E. C. WRATS: A computer compatible system for automatically recording and transcribing behavioural data. Behaviour 40: 135-161, 1971.