A three-electrode system for EKG recording and aversive shock

The use of three electrodes to produce digitizable EKG’s and to deliver shocks to the tail of the monkey is described. Cardiac signals are taken from a head electrode and a “ground” tail electrode. Shock is administered through a “hot” tail electrode and the “ground” tail electrode.     

A simple preparation for obtaining a reliable heart rate record in freely moving rats

A technique for recording heart rate (HR) from freely moving rats using a specially developed harness and subdermal electrodes is described. Electrodes are implanted via a hypodermic needle. Animals prepared in this way are unrestricted in their behavior and show no signs of distress. EKG signals are of high fidelity and are relatively free of electromyographic interference. These characteristics enable reliable phasic HR responses to be recorded during periods of high skeletal muscle activity such as those exhibited during aversive conditioning. Since the procedure is relatively untraumatic, electrodes may be removed and reimplanted at a later date.     

A computer-controlled cardiotachometer

A versatile display system for presenting heart rate information is described. The display has a table with 10 rows and 50 columns. This 10 by 50 matrix contains all integers from 0 to 499, so that it can display the instantaneous R-R intervals of a rat’s EKG to the nearest millisecond. At each beat 1 of 10 vertically and 1 of 50 horizontally arranged indicator lights are turned on to provide the coordinates for reading the table. Either beat-to-beat or averaged heart rate or period is displayed. Small and large changes can be easily and accurately observed on the same scale. The lights are controlled by a PDP-8/e. A listing of the assembler program is presented.     

An electrode hookup for eyelid conditioning

A method for recording eyelid CRs, using skin electrodes rather than the usual mechanical connection to the S’s eyelid, is described. Data are presented to show the comparability of the two recording systems.     

Differential pavlovian fear conditioning as a function of the qualitative nature of the UCS: Constant versus pulsating shock

Dogs were trained in a shuttlebox to perform an instrumental avoidance response to a visual signal. Then, while pharmacologically immobilized in a hammock, they received differential Pavlovian fear conditioning with two tones: one paired with a constant shock and one with a pulsating shock. During Pavlovian conditioning EKG’s were recorded. Later, in the shuttlebox, Ss received tests for the transfer of control of avoidance responding. Although no significant heart rate differences were found,Ss hurdled the barrier significantly more quickly in response to the tone previously paired with the pulsating shock than to the tone paired with the constant shock, indicating that pulsating shock results in better fear conditioning.     

A nonobtrusive heart rate telemetry system for rats

A harness for recording heart rate (HR) from unrestrained rats and an inexpensive FM transmitter for broadcasting high-resolution EKGs are described. The harness, which employs surface electrodes rather than skin pins or implanted electrodes, is especially valuable for recording HR over extended periods of time. Because it is comparatively free of noise generated by the animal’s activity, the system is applicable to a wide range of experimental conditions. Sample HRs obtained from three strains of rats while engaging in different behavioral categories are presented.     

Correlations of normality and nervousness with cardiovascular functions in pointer dogs

Methylphenidate, 0.5 mg/kg, injected intravenously, was used in 10 normal (A line) and 10 genetically nervous (E line) dogs in a blind-design experiment to aid in prediction, from cardiovascular recordings alone, of behavioral normalityversus nervousness. The prediction was 75 per cent correct, based on heart rate (HR), form of the electrocardiogram (EKG), pattern of sinus arrhythmia, and pattern of HR response to methylphenidate. Nervous dogs were found to have slower baseline HR’s, delayed return of HR to baseline after methylphenidate, greater occurrence of baseline EKG abnormalities and much greater frequency of these after methylphenidate. Degree of nervousness was found to correlate rather highly (1)negatively with baseline HR level, (2)negatively with speed of BP response, and (3)positively with frequency of some of the EKG manifestations. These data, indicative of a relative inertness of physiological functions of nervous pointer dogs compared with normal pointers, are consistent with the behavioral and some of the biochemical findings previously reported.     

Localization of electrocutaneous stimuli on the fingers and forearm: Effects of electrode configuration and body axis

Four experiments were done on the effects of electrode configuration (concentric vs. unifocal) and body axis (longitudinal vs. transverse) on localization of electrocutaneous pulse stimuli at the fingers and forearm. Subjects pointed to the apparent location of current pulses. For the transverse placement of electrodes, pulses were localized correctly, whatever the configuration and the body site might be. In addition, intrasubject variability at the forearm was smaller for the transverse axis than for the longitudinal axis. For the longitudinal placement of electrodes, pulses were localized as a function of configuration and body site. At the fingers, concentric electrodes provided precise localization but unifocal electrodes provided a great mislocalization; and intrasubject variability of localization was larger for the unifocal electrodes than for the concentric electrodes. At the forearm, whatever the configuration might be, the pulses were localized more proximally than the stimulus site; and intrasubject variability of localization did not differ between the configurations. These results are related to Boring’s anchor theory, apparent distance between two points, and the localization of other somatosensory stimuli.     

Facial expressions and vagal tone of infants of depressed and non-depressed mothers

Mothers classified as ‘depressed’, ‘non-depressed’ or ‘low scoring’ on the Beck Depression Inventory and their 3-month-old infants were videotaped during 3-minute face-to-face play interactions. Infants' facial expressions were coded using the AFFEX facial expression coding system and their EKG was recorded during the interactions to assess the relationship between cardiac measures and facial expressivity. Infants of both ‘depressed’ and ‘low scoring’ mothers showed significantly more sad and anger expressions and fewer interest expressions than infants of nondepressed mothers. Cardiac vagal tone, (quantified from the amplitude of respiratory sinus arrhythmia) was correlated with infants' joy and interest expressions and with self-comfort behaviours in the non-depressed and low scoring groups, but not in the depressed group. The results suggest that matermal depression affects infants' affective state and appearance as well as their biobehavioural emotional regulation systems.     

Estimating the spatial Nyquist of the human EEG

The discrete sampling of the brain’s electrical field at the scalp surface with individual recording sensors is subject to the same sampling error as the discrete sampling of the time series at any one sensor with analog-to-digital conversion. Unlike temporal sampling, spatial sampling is intrinsically discrete, so that the post hoc application of analog anti-aliasing filters is not possible. However, the skull acts as a low-pass spatial filter of the brain’s electrical field, attenuating the high spatial frequency information. Because of the skull’s spatial filtering, a discrete sampling of the spatial field with a reasonable number of scalp electrodes is possible. In this paper, we provide theoretical and experimental evidence that adequately sampling the human electroencephalograph (EEG) across the full surface of the head requires a minimum of 128 sensors. Further studies with each of the major EEG and event-related potential phenomena are required in order to determine the spatial frequency of these phenomena and in order to determine whether additional increases in sensor density beyond 128 channels will improve the spatial resolution of the scalp EEG.     

Cardiac cycle phase and movement and reaction times.

The EKG was recorded while Ss differentially responded to auditory or visual stimuli in a reaction time task. The EKG record was analyzed by dividing each R-R interval encompassing a stimulus presentation into 9 equal phases. Reaction times were determined as a function of the phase encompassing stimulus onset while movement times were determined for the phase in which the response was initiated. Only reaction time significantly varied with cardiac cycle, with reactions during the second phase being slower than later phases.     

The effects of atropine on viscerovisceral reactions and the electrocardiogram of the cat

In 12 chronic cats the effects of mechanical stimulation (distention) of the gallbladder on heart rate, respiratory movements and bioelectrical activity of the cerebral cortex were studied under normal conditions and after intraperitoneal administration of atropine. In the control group without atropine a decrease or an increase of heart rate and of respiratory movements occurred, depending on stimulation intensity. These changes were independent of an activated or inactivated EKG. Behavioral arousal was not seen in every cat. After administration of atropine in doses from 0.2 to 2.0 mg per kg body weight, the changes in heart rate, respiration and EKG were suppressed or completely disappeared.     

Psychophysiological adaptation: An investigation of multiple parameters

Heart rate (EKG), digital skin resistance level (SRL), and frontalis electromyography (EMG) of 20 undergraduate volunteers were monitored in three 30-min sessions to chart the course and magnitude of adaptation. As a group, 7, 13, and 13 min of adaptation were required for SRL, EMG, and EKG, respectively. High arousal levels in any of these measures at the session's outset resulted in longer adaptation times compared to low initial arousal. EMG showed the strongest variance across sessions. Females required longer adaptation periods than males in SRL and EKG. Self-reported trait anxiety levels bore little relationship to adaptation course. Methods were outlined for setting individualized adaptation periods by either the min 1 EMG level or regression equations for the initial values of each of the measures. Overall, psychophysiological adaptation proved to be an influential variable requiring experimental management to avoid confoundment with treatment effects.Portions of this research were presented at the meeting of the Southeastern Psychological Association, Washington, D.C., March 1980. We gratefully acknowledge statistical consultation given by Virginia Weymouth, Memphis State University Department of Computer Services, and Dr. Michael Lupfer.     

Auditory evoked response in chinchilla: Application to animal audiometry

In chinchilla a neural response to tone pips or the onset of pure tones can be recorded from scalp electrodes. If 64 responses are averaged by a computer the response can be recognized reliably at sound pressure levels at or near chinchilla’s usual behavioral thresholds of hearing. Detection is possible at slightly lower levels if the number of responses is increased to 500 to 1000. The response is an initiallypositive diphasic wave with latency to foot between 1.6 and 4.0 msec. It apparently arises from several structures in the brainstem but chiefly from the inferior colliculus. The technique may be useful in assessing quickly the sensitivity of the peripheral auditory mechanism in small laboratory animals.     

Relations between infants’ emerging reach‐grasp competence and event‐related desynchronization in EEG

Recent reports of similar patterns of brain electrical activity (electroencephalogram: EEG) during action execution and observation, recorded from scalp locations over motor‐related regions in infants and adults, have raised the possibility that two foundational abilities – controlling one's own intentional actions and perceiving others’ actions – may be integrally related during ontogeny. However, to our knowledge, there are no published reports of the relations between developments in motor skill (i.e. recording actual motor skill performance) and EEG during both action execution and action observation. In the present study we collected EEG from 21 9‐month‐olds who were given opportunities to reach for toys and who also observed an experimenter reach for toys. Event‐related desynchronization (ERD) was computed from the EEG during the reaching events. We assessed infants’ reaching‐grasping competence, including reach latency, errors, preshaping of the hand, and bimanual reaches, and found that desynchronization recorded in scalp electrodes over motor‐related regions during action observation was associated with action competence during execution. Infants who were more competent reachers, compared to less competent reachers, exhibited greater ERD while observing reaching‐grasping. These results provide initial evidence for an early emerging neural system integrating one's own actions with the perception of others’ actions.     

An apparatus for behavioral and physiological study of aversive conditioning in cats and kittens

An apparatus for aversive conditioning of adult cats and kittens is described. Animals are held by a cloth harness and head restraint device in a metal frame with a movable treadmill floor. They are supported in a natural standing position, with freedom to flex and move each leg and to walk or run on the treadmill. Various transducers record respiration, EKG, vocalization, leg flexion, and locomotion on the treadmill.     

Differences in brain information transmission between gifted and normal children during scientific hypothesis generation

The purpose of the present study was to investigate differences in neural information transmission between gifted and normal children involved in scientific hypothesis generation. To investigate changes in the amount of information transmission, the children’s averaged-cross mutual information (A-CMI) of EEGs was estimated during their generation of scientific hypotheses. We recorded EEG from 25 gifted and 25 age-matched normal children using 16 electrodes on each subject’s scalp. To generate hypotheses, the children were asked to observe 20 “quail eggs” that gave rise to questions. After observation, they were asked to generate a scientific hypothesis—a tentative causal explanation for the questions evoked. The results of this study revealed several distinguishing brain activities between gifted and normal children during hypothesis generation. In contrast to normal children, gifted children showed increased A-CMI values between the left temporal and central, between the left temporal and parietal, and between the left central and parietal locations while generating a hypothesis. These results suggested that gifted children more efficiently distribute the cognitive resources essential to cope with hypothesis generation.     

Concurrent measurement of heart rate and instrumental avoidance behavior in the Rhesus monkey

A graphical method has been developed for the concurrent recording of heart beats and lever responses during behavioral experiments. The EKG signal fed into any DC amplifier goes to a fixed level trigger circuit and relay driver with its own power supply. The signal from this drives any standard cumulative recorder. Lever response rates are recorded concurrently on an additional cumulative recorder using the same paper speed.     

Psychophysiological effects of noxious imagery: Prevalence and prediction

Research suggests that people who generate psychophysiological arousal in emotive imagery therapies are likely to show the largest therapeutic gains. This study investigated the frequency of occurrence and methods of predicting this imagery skill. The effects of five fearful imagery themes on 95 undergraduate volunteers were evaluated in individual sessions by psychophysiological (SRL, EKG and EMG), self-report (anxiety and clarity ratings) and behavioral (motoric expression) measures. Additionally, four questionnaires (Betts, Gordon, APQ and STAI) were administered in a group session. EKG arousal occurred in 66% of our subjects, SRL arousal in 38% and EMG arousal in 16%. Only 9% of our subjects experienced arousal in all three psychophysiological responses and 24% experienced arousal in neither. Motoric expression (overt behavioral emoting) best predicted psychophysiological arousal, self-report ratings were a distant second, and the questionnaires were worthless in this regard. Imagery-induced psychophysiological arousal appears to be a fairly common phenomena, though it eludes convenient prediction. Some training strategies were discussed, (response proposition instructions, biofeedback and motoric coaching), which could be employed with persons deficient in psychophysiological imagery skills prior to their commencing an emotive imagery therapy.     

食管癌术后心律失常相关因素分析

为了探讨影响食管癌术后心律失常的相关因素,观察了术后心律失常的发生与患者年龄（≥65岁）、性别、吸烟、术前合并症、肺功能、心电图（EKG）改变、低血钾、术后24小时失血量及手术方式的关系。结果显示,318例食管癌术后心律失常发生率为47．48％。年龄（≥65岁）、FEV1／FVC≤70%和／或MVV％≤60％、术前ECG异常、术前血钾≤4．0mmol／L、术后24小时失血≥500ml及手术方式与术后心律失常的发生相关。提示术前改善低心肺功能、纠正低血钾、减少术中出血,高龄患者和多切口手术方式者术后加强监护,可预防和减少术后心律失常发生。