Sleep-spindles as a marker of attention and intelligence in dogs.

The sleep spindle-generating thalamo-cortical circuitry supports attention capacity in awake humans and animals, but using sleep spindles to predict differences in attention has not been tried in either. Of the more commonly examined cognitive correlates of spindle occurrence and amplitude, post-sleep recall, and general intelligence, only post-sleep recall had been studied in dogs, rats and mice. Here, we examined a sample of companion dogs (N = 58) for whom polysomnographic recordings and several cognitive tests were performed on two occasions each, with a three-month break in-between.

The "Twin Peaks" method of automated Spike-Wave detection: A two-step, two-criteria Matlab application.

Background: There are many automated spike-wave discharge detectors, but the known weaknesses of otherwise good methods and the varying working conditions of different research groups (mainly the access to hardware and software) invite further exploration into alternative approaches.

New Method: The algorithm combines two criteria, one in the time-domain and one in the frequency-domain, exploiting morphological asymmetry and the presence of harmonics, respectively. The time-domain criterion is additionally adjusted by normal modelling between the first and second iterations.

Age-related effects on a hierarchical structure of canine cognition.

The current study investigates whether there are statistically independent age-related influences on the canine cognitive structure and how individual factors moderate cognitive aging on both cross-sectional and longitudinal samples. A battery of seven tasks was administered to 129 pet dogs, on which exploratory and confirmatory factor analyses were employed to unveil the correlational structure underlying individual differences in cognitive performance. The best-fitting model featured a hierarchical structure with two first-order cognitive domains (individual problem solving, learning) and a second-order common factor.

Cognitive and sensory capacity each contribute to the canine spatial bias.

Dogs interpret cues as being about location, which human infants would relate to objects. This spatial bias could shed light on the evolution of object-centered thought, however, research needs to rule out that this is not a by-product of dogs' weaker (compared to humans) visual capacities. In this study, we used a data set in which dogs were tested in two types of learning tasks (discrimination and reversal learning) with two types of rewarded cues (location and object features).

Sleep-physiological correlates of brachycephaly in dogs.

The shape of the cranium is one of the most notable physical changes induced in domestic dogs through selective breeding and is measured using the cephalic index (CI). High CI (a ratio of skull width to skull length > 60) is characterized by a short muzzle and flat face and is referred to as brachycephaly. Brachycephalic dogs display some potentially harmful changes in neuroanatomy, and there are implications for differences in behavior, as well.

Investigating responses to object-labels in the domestic dog (Canis familiaris).

Since the dawn of comparative cognitive research, dogs were suspected to possess some capacity for responding to human spoken language. Neuroimaging studies have supported the existence of relevant mechanisms, but convincing behavioral performance is rare, with only few exceptional dogs worldwide demonstrating a lexicon of object-labels they respond to. In the present study we aimed to investigate if and how a capacity for processing verbal stimuli is expressed in dogs (N = 20), whose alleged knowledge of verbal labels is only backed-up by owner reports taken at face value, and concerning only a few words (on average 5).

Free will strikes back: Steady-state movement-related cortical potentials are modulated by cognitive control.

In psychology and neuroscience, opposition to free will has asserted that any degree of perceived self-control or choice is a mere epiphenomenon which provides no meaningful influence on action. The present research tested the validity of this conclusion by designing a paradigm in which the potential effect of self-monitoring on motor output could be investigated. Using a repetitive finger tapping task that evokes automatic patterns in participants tapping responses, we have obtained evidence that (1) participants may voluntarily reduce the predictability of their tapping patterns (2) by exercising cognitive control that (3) modulates response-locked steady-state movement-related potentials over primary and supplementary motor areas.

Shared and unique features of mammalian sleep spindles - insights from new and old animal models.

Sleep spindles are phasic events observed in mammalian non-rapid eye movement sleep. They are relevant today in the study of memory consolidation, sleep quality, mental health and ageing. We argue that our advanced understanding of their mechanisms has not exhausted the utility and need for animal model work.

Averaging sleep spindle occurrence in dogs predicts learning performance better than single measures.

Although a positive link between sleep spindle occurrence and measures of post-sleep recall (learning success) is often reported for humans and replicated across species, the test-retest reliability of the effect is sometimes questioned. The largest to date study could not confirm the association, however methods for automatic spindle detection diverge in their estimates and vary between studies. Here we report that in dogs using the same detection method across different learning tasks is associated with observing a positive association between sleep spindle density (spindles/minute) and learning success.

Human Expressions of Object Preference Affect Dogs' Perceptual Focus, but Not Their Action Choices.

Inspired by work on infants, we investigated whether dogs' behaviors are guided by human displays of preference, contrasting with the animals' own choices. In a rewarded fetching task, dogs override their own interest toward "disgusting" objects and retrieve what the owner prefers. However, in previous research, both objects were inherently neutral to the dogs and they might have chosen the owner's object because a "happy owner" predicts a positive outcome.

A Preliminary Study toward a Rapid Assessment of Age-Related Behavioral Differences in Family Dogs.

Over the last few years, several efforts have been undertaken to characterize the aging process in dogs. In the present study, we evaluate a short protocol measuring dogs' cognitive, social, and physical capacities. Our aim was to develop a feasible test battery, with minimal pre-training requirements, no complex devices, and which is set outdoors (i.

Reliability of Family Dogs' Sleep Structure Scoring Based on Manual and Automated Sleep Stage Identification.

Non-invasive polysomnography recording on dogs has been claimed to produce data comparable to those for humans regarding sleep macrostructure, EEG spectra and sleep spindles. While functional parallels have been described relating to both affective (e.g.

Possible association between spindle frequency and reversal-learning in aged family dogs.

In both humans and dogs sleep spindle occurrence between acquisition and recall of a specific memory correlate with learning performance. However, it is not known whether sleep spindle characteristics are also linked to performance beyond the span of a day, except in regard to general mental ability in humans. Such a relationship is likely, as both memory and spindle expression decline with age in both species (in dogs specifically the density and amplitude of slow spindles).

Correction: Assertive, trainable and older dogs are perceived as more dominant in multi-dog households.

[This corrects the article DOI: 10.1371/journal.pone.

Assertive, trainable and older dogs are perceived as more dominant in multi-dog households.

Social dominance is an important and widely used concept, however, different interpretations have led to ambiguity in the scientific literature and in popular science. Even though in ethology dominance is an attribute of dyadic encounters, and not a characteristic of the individual, 'dominance' has often been referred to as a personality trait in animals. Since few studies have specifically examined the link between personality traits and dominance status, we investigated this in dogs living in multi-dog households using a questionnaire, which required owners to specify whether the dog had a dominant or submissive status, and comprised items of both the features of the individual (i.

Age-related differences and sexual dimorphism in canine sleep spindles.

Non-REM bursts of activity in the sigma range (9-16 Hz) typical of sleep spindles predict learning in dogs, similar to humans and rats. Little is known, however, about the age-related changes in amplitude, density (spindles/minute) and frequency (waves/second) of canine spindles. We investigated a large sample (N = 155) of intact and neutered pet dogs of both sexes, varying in breed and age, searching for spindles in segments of non-REM sleep.

Encounters between pairs of unfamiliar dogs in a dog park.

Introduction: The aim of this study was to explore spontaneous social interactions between dyads of unfamiliar adult dogs. Although intraspecific encounters are frequent events in the life of pet dogs, the factors that might influence encounters, such as sex, dyad composition, reproductive status, age, and state of cohabitation (keeping the dogs singly or in groups), remained unexplored.

Methods: In this study, we assigned unfamiliar, non-aggressive dogs to three types of dyads defined by sex and size.

Sex, skull length, breed, and age predict how dogs look at faces of humans and conspecifics.

The gaze of other dogs and humans is informative for dogs, but it has not been explored which factors predict face-directed attention. We used image presentations of unfamiliar human and dog heads, facing the observer (portrait) or facing away (profile), and measured looking time responses. We expected dog portraits to be aversive, human portraits to attract interest, and tested dogs of different sex, skull length and breed function, which in previous work had predicted human-directed attention.

Author Correction: EEG Transients in the Sigma Range During non-REM Sleep Predict Learning in Dogs.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

EEG Transients in the Sigma Range During non-REM Sleep Predict Learning in Dogs.

Sleep spindles are phasic bursts of thalamo-cortical activity, visible in the cortex as transient oscillations in the sigma range (usually defined in humans as 12-14 or 9-16 Hz). They have been associated with sleep-dependent memory consolidation and sleep stability in humans and rodents. Occurrence, frequency, amplitude and duration of sleep spindles co-vary with age, sex and psychiatric conditions.