Neurophysiological techniques to assess pain in animals

Murrell, Jo; Johnson, Craig B.

doi:10.1111/j.1365-2885.2006.00758.x

Cited by 130 publications

(146 citation statements)

References 95 publications

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“…These wave forms were also accompanied by a significant increase in alpha-and beta-wave RMS values at T2 in the LPNP and HPNP animals. When interpreted alongside their respective median frequencies, these values are suggestive of post-stunning noxious stimuli (Murrell and Johnson 2006). On the contrary, the alpha and beta RMS values were significantly lower immediately after stunning at T2 in the P animals.…”

Section: Discussionmentioning

confidence: 89%

“…Briefly, the signals were subjected to fast fourier transformation (FFT), and power-density curves for each frequency band were derived on the basis of cosine bell distribution. The median frequency (F50), or the frequency below which 50% of the total EEG power lies, was derived; F50 has been previously associated with arousal and nociception in horses, dogs and pigs, as reviewed by Murrell and Johnson (2006). The root mean square (RMS) for each wave form at T1, T2 and T3 was calculated.…”

Section: Electroencephalogram Recordingsmentioning

confidence: 99%

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Changes in blood parameters and electroencephalogram of cattle as affected by different stunning and slaughter methods in cattle

et al. 2014

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Abstract. The present study aimed to provide a comparative analysis of the effects of penetrative stunning, non-penetrative stunning and post-slaughter stunning on biochemical parameters and electroencephalogram (EEG) associated with stress in heifers and steers. Ten animals were assigned to each of the following four treatment groups: (1) animals were subjected to conventional halal slaughter (a clean incision through the structures on the ventral neck at the approximate level of vertebrae C2-C3 -the trachea, oesophagus, carotid arteries and jugular veins) and post-cut penetrating mechanical stun within 10-20 s of the halal cut (U); (2) high-power non-penetrating mechanical stunning using a mushroom-headed humane killer, followed by conventional halal slaughter (HPNP); (3) low-power non-penetrating mechanical percussive stunning using a mushroom-headed humane killer, followed by conventional halal slaughter (LPNP); and (4) penetrative stunning using a captive-bolt pistol humane killer, followed by conventional halal slaughter (P). For each animal, blood samples and electroencephalogram recordings were taken before stunning, post-stunning (if applicable) and post-slaughter, and plasma concentrations of cortisol, adrenocorticotrophic hormone (ACTH), adrenaline, noradrenaline and b-endorphin were determined. Irrespective of the stunning method, except for percentage change in plasma concentrations of noradrenaline, the values of blood parameters attained before and after stunning were not significantly different. The plasma noradrenaline concentration of the HPNP animals was significantly elevated following stunning. Following slaughter, the percentage change of plasma ACTH concentration in the P animals was significantly elevated. Neither stunning method nor sampling time had a significant effect on plasma b-endorphin concentration. On the basis of the EEG results, penetrative stunning seemed to be better in maximising the possibility of post-stunning insensibility, whereas U animals appeared to demonstrate an evident increase in EEG activity which is consistent with the presence of post-slaughter noxious stimuli associated with tissue cut and injury. The U animals had consistently higher, if not the highest, RMS values than did other stunned animals. This indicates a degree of EEG changes associated with stress and pain. On the basis of EEG data, our results suggested that penetrative stunning would be the most reliable method of ensuring insensibility and minimising pain. However, at slaughter, the P animals showed a dramatic elevation in the percentage change of circulating ACTH, suggesting physiological stress response. On a cautionary note, the results are not unequivocal, and it may be that the range of analyses available to researchers at this point of time are not sufficiently specific to allow definitive conclusions to be drawn.

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Section: Discussionmentioning

confidence: 89%

Section: Electroencephalogram Recordingsmentioning

confidence: 99%

Changes in blood parameters and electroencephalogram of cattle as affected by different stunning and slaughter methods in cattle

et al. 2014

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“…The onset of isoelectric EEG signal was determined in two ways, by visual interpretation and by identification of validated spectral characteristics (PTOT less than 170mv and F50 greater than 22 Hz) as described in [32,33,47]. Two spectral variables were calculated with coded Genstat (Genstat, 14 th Edition, Rothamsted Research, UK) programs: total power (PTOT), defined as the total area under the power spectrum curve [41] and median frequency (F50), the frequency below which 50% of the EEG power resides [49]. Latency variables to unconsciousness were defined as time…”

Section: Eeg and Ecg Analysismentioning

confidence: 99%

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens

Martin

Christensen

Vizzier-Thaxton

et al. 2016

Physiology & Behavior

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A novel approach to pre-slaughter stunning of chickens has been developed in which birds are rendered unconscious by progressive hypobaric hypoxia. Termed Low Atmospheric Pressure Stunning (LAPS), this approach involves application of gradual decompression lasting 280 s according to a prescribed curve. We examined responses to LAPS by recording behaviour, electroencephalogram (EEG) and electrocardiogram (ECG) in individual male chickens, and interpreted these with regards to the welfare impact of the process. We also examined the effect of two temperature adjusted pressure curves on these responses. Broiler chickens were exposed to LAPS in 30 triplets (16 and 14 triplets assigned to each pressure curve). In each triplet, one bird was instrumented for recording of EEG and ECG while the behaviour of all three birds was observed. Birds showed a consistent sequence of behaviours during LAPS (ataxia, loss of posture, clonic convulsions and motionless) which were observed in all birds. Leg paddling, tonic convulsions, slow wing flapping, mandibulation, head shaking, open bill breathing, deep inhalation, jumping and vocalisation were observed in a proportion of birds. Spectral analysis of EEG responses at 2 s intervals throughout LAPS revealed progressive decreases in median frequency at the same time as corresponding progressive increases in total power, followed later by decreases in total power as all birds exhibited isoelectric EEG and died. There was a very pronounced increase in total power at 50-60 s into the LAPS cycle, which corresponded to dominance of the signal by high amplitude slow waves, indicating loss of consciousness.Slow wave EEG was seen early in the LAPS process, before behavioural evidence of loss of consciousness such as ataxia and loss of posture, almost certainly due to the fact that it was completely dark in the LAPS chamber. ECG recordings showed a pronounced bradycardia (starting on average 49.6 s into LAPS), often associated with arrhythmia, until around 60 s into LAPS when heart rate levelled off. There was a good correlation between behavioural, EEG and cardiac measures in relation to loss of consciousness which collectively provide a loss of consciousness estimate of around 60 s. There were some effects of temperature A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTadjusted pressure curves on behavioural latencies and ECG responses, but in general responses were consistent and very similar to those reported in previous research on controlled atmosphere stunning with inert gases. The results suggest that the process is humane (slaughter without avoidable fear, anxiety, pain, suffering and distress). In particular, the maintenance of slow wave EEG patterns in the early part of LAPS (while birds are still conscious) is strongly suggestive that LAPS is non-aversive, since we would expect this to be interrupted by pain or discomfort. Highlights A novel stunning system uses hypobaric hypoxia to render poultry unconscious  We measured electroencephalogram, electrocardiogram and...

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“…3,11 Recently, a series of experiments using a minimal anaesthesia model have documented EEG changes in different species of animals in response to a variety of noxious stimuli, including slaughter of calves by ventral neck incision. [12][13][14][15] These studies have demonstrated that the EEG can provide a reliable response to noxious stimuli under minimal anaesthesia. These EEG responses are thought to be the result of subconscious processing of pain stimuli by the cerebral cortex.…”

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confidence: 99%

“…These EEG responses are thought to be the result of subconscious processing of pain stimuli by the cerebral cortex. 13 This neurophysiological method has the advantages that it minimizes the effects on the EEG of extraneous cerebrocortical electrical activity and that it is less detrimental to the welfare of experimental animals which are anaesthetized and therefore unconscious throughout the study. 5,13 A number of derived variables have been used to indicate changes in the EEG in response to noxious stimuli.…”

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confidence: 99%

Electroencephalographic evaluation of decapitation of the anaesthetized rat

et al. 2013

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The objective of this study was to evaluate the changes in electroencephalographic (EEG) power spectrum in response to decapitation of anaesthetized rats, in order to assess the nociception or otherwise of this procedure. Ten young adult male Sprague-Dawley rats were anaesthetized with halothane in oxygen and anaesthesia was maintained at a stable concentration of halothane between 1.20% and 1.25%. The rat's head and neck were placed through the opening of a small animal guillotine so that the blade of the guillotine was positioned over the atlanto-occipial joint of the rat's neck. The EEG was recorded in a five-electrode montage, bilaterally. After recording a 15 min baseline the rat was decapitated by swiftly pressing the guillotine blade and the EEG recording was continued until the signal was isoelectric on both channels. Changes in the median frequency (F50), 95% spectral edge frequency (F95) and total power of the EEG (Ptot) were used to investigate the effects of decapitation. During the first 15 s following decapitation, there were significant increases in the F50 and F95, and a decrease in the Ptot compared with baseline values. There was a clear window of time immediately following decapitation where changes in the EEG frequency spectrum were obvious; these changes in the EEG indices of nociception could be attributed as responses generated by the rat's cerebral cortex following decapitation.Keywords rat, electroencephalogram, euthanasia, welfare, nociception Several different methods of euthanasia have been proposed for use in laboratory animals in biomedical research (e.g. injectable anaesthesia, decapitation, cervical dislocation, CO 2 asphyxiation, etc.). 1Decapitation has the advantage that it has no effect on subsequent analytical procedures.2 This is not the case with chemical methods such as a drug overdose. Despite its common use, the humaneness of decapitation of conscious animals is debatable.2-5 The question of whether brain activity continues after decapitation and, if so, for how long, has been considered essential for determining the acceptability of this procedure. These questions have been addressed in a number of studies involving different animal species including rats.2,6-10 Studies utilizing electroencephalographic (EEG) recordings have been used to map the brain following decapitation. Conversion from high voltage slow activity to low voltage fast activity (LVFA) and desynchronization, a shift in EEG activity toward high frequency, have been reported as typical EEG responses following the decapitation of conscious animals. These changes in EEG activity persist between 8 and 29 s in all species after decapitation 5 and, are followed by the onset of isoelectric EEG.Interpretation of these post-decapitation EEG changes in terms of conscious arousal and potential pain perception, and as a response to noxious stimulation, has not been simple. Other studies have demonstrated that LVFA pattern EEG activity can be seen during rapid eye movement sleep/anaesthesia and also during an...

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Neurophysiological techniques to assess pain in animals

Cited by 130 publications

References 95 publications

Changes in blood parameters and electroencephalogram of cattle as affected by different stunning and slaughter methods in cattle

Changes in blood parameters and electroencephalogram of cattle as affected by different stunning and slaughter methods in cattle

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens

Electroencephalographic evaluation of decapitation of the anaesthetized rat

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