Avian reflex and electroencephalogram responses in different states of consciousness

DA Sandercock, A Auckburally, D Flaherty, V Sandilands, DEF McKeegan*

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n= 10)). Weevaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflexwas consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (b1 min) after respiratory arrest and brain death (isoelectric EEG). The results confirm that the nictitating membrane reflex is a conservative measure of death in poultry. Using spectral analyses of the EEG waveforms it was possible to readily distinguish between the different states of clinical consciousness. In all cases,when birds progressed froma conscious to unconscious state; total spectral power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. © 2014 Elsevier Inc. All rights reserved.
Original languageEnglish
Pages (from-to)252 - 259
Number of pages8
JournalPhysiology and Behavior
Volume133
DOIs
Publication statusFirst published - 2014

Fingerprint

electroencephalography
consciousness
reflexes
birds
anesthesia
brain
euthanasia
jaws
laying hens
neck
slaughter
poultry
death
muscles
animals

Bibliographical note

2049699

Keywords

  • Anaesthesia
  • Avian
  • Consciousness
  • Cranial reflexes
  • EEG
  • FFT power analysis

Cite this

@article{ecbc1e25c0494f558aa8c92cac5e05dd,
title = "Avian reflex and electroencephalogram responses in different states of consciousness",
abstract = "Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n= 10)). Weevaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflexwas consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (b1 min) after respiratory arrest and brain death (isoelectric EEG). The results confirm that the nictitating membrane reflex is a conservative measure of death in poultry. Using spectral analyses of the EEG waveforms it was possible to readily distinguish between the different states of clinical consciousness. In all cases,when birds progressed froma conscious to unconscious state; total spectral power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. {\circledC} 2014 Elsevier Inc. All rights reserved.",
keywords = "Anaesthesia, Avian, Consciousness, Cranial reflexes, EEG, FFT power analysis",
author = "DA Sandercock and A Auckburally and D Flaherty and V Sandilands and DEF McKeegan",
note = "2049699",
year = "2014",
doi = "10.1016/j.physbeh.2014.05.030",
language = "English",
volume = "133",
pages = "252 -- 259",
journal = "Physiology and Behavior",
issn = "0031-9384",
publisher = "Elsevier",

}

Avian reflex and electroencephalogram responses in different states of consciousness. / Sandercock, DA; Auckburally, A; Flaherty, D; Sandilands, V; McKeegan, DEF.

In: Physiology and Behavior, Vol. 133, 2014, p. 252 - 259.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Avian reflex and electroencephalogram responses in different states of consciousness

AU - Sandercock, DA

AU - Auckburally, A

AU - Flaherty, D

AU - Sandilands, V

AU - McKeegan, DEF

N1 - 2049699

PY - 2014

Y1 - 2014

N2 - Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n= 10)). Weevaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflexwas consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (b1 min) after respiratory arrest and brain death (isoelectric EEG). The results confirm that the nictitating membrane reflex is a conservative measure of death in poultry. Using spectral analyses of the EEG waveforms it was possible to readily distinguish between the different states of clinical consciousness. In all cases,when birds progressed froma conscious to unconscious state; total spectral power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. © 2014 Elsevier Inc. All rights reserved.

AB - Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n= 10)). Weevaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflexwas consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (b1 min) after respiratory arrest and brain death (isoelectric EEG). The results confirm that the nictitating membrane reflex is a conservative measure of death in poultry. Using spectral analyses of the EEG waveforms it was possible to readily distinguish between the different states of clinical consciousness. In all cases,when birds progressed froma conscious to unconscious state; total spectral power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. © 2014 Elsevier Inc. All rights reserved.

KW - Anaesthesia

KW - Avian

KW - Consciousness

KW - Cranial reflexes

KW - EEG

KW - FFT power analysis

U2 - 10.1016/j.physbeh.2014.05.030

DO - 10.1016/j.physbeh.2014.05.030

M3 - Article

VL - 133

SP - 252

EP - 259

JO - Physiology and Behavior

JF - Physiology and Behavior

SN - 0031-9384

ER -