Dynamic characteristics of visual evoked potentials in the dog. I. Cortical and subcortical potentials evoked by sine wave modulated light
ABSTRACT 1. 1. Potentials evoked by sinusoidally modulated light (SML) were recorded from the lateral geniculate nucleus and occipital cortex of unanaesthetized dogs. The evoked potentials were analysed by discrete Fourier analysis. 2. 2. The harmonic components of SML evoked potentials were described by frequency response functions. The range of linear and non-linear behaviour was determined. 3. 3. A linear description was only possible regarding the SML evoked potentials recorded from the posterior marginal gyrus. 4. 4. Three types of non-linearities were characterized: saturation, non-linear oscillations responsible for the generation of subharmonics and essential non-linearities. 5. 5. The essential non-linearities correspond to rectification occurring in "on" and "off" neuronal populations; they were the dominant features of SML evoked potentials in the lateral geniculate nucleus and the calcarine region of occipital cortex, but not in the posterior marginal gyrus. 6. 6. The phase functions were shown to be determined in part by a delay time. 7. 7. The relations between SML evoked potential parameters and data obtained at the unit level are discussed.
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- "Brain function of dogs has been studied in the past mainly by recording activity with electroencephalography (EEG) directly from the brain, by sedating the animals and restraining their movements, and by putting them down after the experiment. Most of the functional brain research of dogs has explored epilepsy [e.g., , although some studies have described features of the nervous system functionality, such as oscillatory EEG activity during sleep  or awake state , or visual evoked potentials to flashes of light –. However the intracranial measurements, with the need to restrain and medicate the animals, do not readily allow the study of the nervous system function during cognitive events. Hence much of the underlying neural functionality of dog cognition remains unresolved. "
ABSTRACT: Studying cognition of domestic dogs has gone through a renaissance within the last decades. However, although the behavioral studies of dogs are beginning to be common in the field of animal cognition, the neural events underlying cognition remain unknown. Here, we employed a non-invasive electroencephalography, with adhesive electrodes attached to the top of the skin, to measure brain activity of from 8 domestic dogs (Canis familiaris) while they stayed still to observe photos of dog and human faces. Spontaneous oscillatory activity of the dogs, peaking in the sensors over the parieto-occipital cortex, was suppressed statistically significantly during visual task compared with resting activity at the frequency of 15-30 Hz. Moreover, a stimulus-induced low-frequency (∼2-6 Hz) suppression locked to the stimulus onset was evident at the frontal sensors, possibly reflecting a motor rhythm guiding the exploratory eye movements. The results suggest task-related reactivity of the macroscopic oscillatory activity in the dog brain. To our knowledge, the study is the first to reveal non-invasively measured reactivity of brain electrophysiological oscillations in healthy dogs, and it has been based purely on positive operant conditional training, without the need for movement restriction or medication.PLoS ONE 05/2013; 8(5):e61818. DOI:10.1371/journal.pone.0061818 · 3.23 Impact Factor
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- "In non-human species, the ERP components have been studied less likely due to differences between human and animal research traditions. However, the event-related potential N1, one of the early ERP components peaking around 100–200 ms after visual stimulus onset, has been characterized both in human non-invasive EEG (e.g., O'Donnell et al. 1997) and in animals with intracranial EEG studies: in monkeys (e.g., Pineda et al. 1994; Woodman et al. 2007) and in dogs (Bichsel et al. 1988; Lopes da Silva et al. 1970a, b). In the current study, we employed a completely non-invasive EEG in assessing the neurocognitive correlates of the visual cognition of dogs. "
ABSTRACT: Previously, social and cognitive abilities of dogs have been studied within behavioral experiments, but the neural processing underlying the cognitive events remains to be clarified. Here, we employed completely non-invasive scalp-electroencephalography in studying the neural correlates of the visual cognition of dogs. We measured visual event-related potentials (ERPs) of eight dogs while they observed images of dog and human faces presented on a computer screen. The dogs were trained to lie still with positive operant conditioning, and they were neither mechanically restrained nor sedated during the measurements. The ERPs corresponding to early visual processing of dogs were detectable at 75-100 ms from the stimulus onset in individual dogs, and the group-level data of the 8 dogs differed significantly from zero bilaterally at around 75 ms at the most posterior sensors. Additionally, we detected differences between the responses to human and dog faces in the posterior sensors at 75-100 ms and in the anterior sensors at 350-400 ms. To our knowledge, this is the first illustration of completely non-invasively measured visual brain responses both in individual dogs and within a group-level study, using ecologically valid visual stimuli. The results of the present study validate the feasibility of non-invasive ERP measurements in studies with dogs, and the study is expected to pave the way for further neurocognitive studies in dogs.Animal Cognition 04/2013; 16(6). DOI:10.1007/s10071-013-0630-2 · 2.58 Impact Factor
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ABSTRACT: 1.1. Sinusoidally modulated light (SML) evoked potentials recorded from the posterior marginal gyrus were described as generated by a beta frequency selective system.2.2. The beta resonance is related to the dominant mode of spontaneous activity recorded from the same brain area and characterized by means of power spectra.3.3. The resonance behaviour of cortical SML evoked potentials was dependent on the state of the animal and disappeared during light Nembutal anaesthesia.4.4. A linear model including resonance was devised to account for the cortical frequency selective system. The model was tested experimentally by obtaining the system's impulse response by means of cross-correlating the input and output of the system excited with noise modulated light.5.5. The implications of beta selectivity in terms of neural pathways and networks are discussed.Résumé1.1. Les potentiels évoqués par lumière sinusoïdalement modulée (LMS) au niveau du gyrus marginal postérieur sont décrits comme produits par un système sélectif de fréquence bêta.2.2. La résonance bêta est liée au mode dominant d'activité spontanée enregistrée au niveau de la même aire cérébrale, caractérisée au moyen de spectres de puissance.3.3. Le comportement de résonnance des potentiels évoqués corticaux à la LMS dépend de l'état de l'animal et disparaît lors d'une anesthésie légère au Nembutal.4.4. Un modèle linéaire comportant la résonannce a été élaboré pour rendre compte du système sélectif de fréquence bêta corticale. Ce modèle a été testé expérimentalement en obtenant les réponses d'impulsion du système au moyen d'une cross-corrélation de l'entrée et de la sortie du système excité par une lumière modulée par un signal de bruit.5.5. Les implications de la sélectivité bêta en termes de voies et de réseaux neuroniques sont discutées.Electroencephalography and Clinical Neurophysiology 10/1970; 29(3):260-8. DOI:10.1016/0013-4694(70)90138-0