Gérard Després

Heart rate variability as a measure of autonomic regulation of cardiac activity for assessing stress and welfare in farm animals : A review

Measurement of heart rate variability (HRV) is a non-invasive technique that can be used to investigate the functioning of the autonomic nervous system, especially the balance between sympathetic and vagal activity. It has been proven to be very useful in humans for both research and clinical studies concerned with cardiovascular diseases, diabetic autonomic dysfunction, hypertension and psychiatric and psychological disorders. Over the past decade, HRV has been used increasingly in animal research to analyse changes in sympathovagal balance related to diseases, psychological and environmental stressors or individual characteristics such as temperament and coping strategies. This paper discusses current and past HRV research in farm animals. First, it describes how cardiac activity is regulated and the relationships between HRV, sympathovagal balance and stress and animal welfare. Then it proceeds to outline the types of equipment and methodological approaches that have been adapted and developed to measure inter-beats intervals (IBI) and estimate HRV in farm animals. Finally, it discusses experiments and conclusions derived from the measurement of HRV in pigs, cattle, horses, sheep, goats and poultry. Emphasis has been placed on deriving recommendations for future research investigating HRV, including approaches for measuring and analysing IBI data. Data from earlier research demonstrate that HRV is a promising approach for evaluating stress and emotional states in animals. It has the potential to contribute much to our understanding and assessment of the underlying neurophysiological processes of stress responses and different welfare states in farm animals.

Immunohistochemical localisation of nerve growth factor-like protein in the organ of Corti of the developing rat

The presence of nerve growth factor (NGF)-like protein was investigated in the cochlea of the developing rat between birth and postnatal day 30, by the indirect immunofluorescence technique. Nerve growth factor-like protein could be detected from birth up to day 8. The immunostaining was localised within the hair mainly above their nuclei. No NGF-like immunoreactivity was observed in spiral ganglion cells. The data suggest that NGF acts as a neurotrophic factor, especially for efferent endings in the developing cochlea.

Immunohistochemical localization of nerve growth factor receptor in the cochlea and in the brainstem of the perinatal rat

Nerve growth factor receptor (NGF-R) localization was studied immunohistochemically in the cochlea and in the brainstem of the perinatal rat, using a specific monoclonal antibody directed against the rat NGF-R. In the cochlea, NGF-R immunoreactivity is positive during the whole perinatal period studied, and is located at the hair cell level, in fibers that reach the organ of Corti, in the intraganglionic spiral bundle and in some small bundles of fibers in the auditory nerve. In the brainstem, NGF-R is detected in auditory structures such as the ventral cochlear nucleus, the superior olivary complex, the nuclei of the trapezoid body and the trapezoid body. Many auditory structures labelled by the NGF-R antibody are implicated in the efferent cochlear innervation. These results suggest that NGF could be implicated in interactions between auditory receptors and efferent innervation of the developing cochlea. This coincides with findings on the immunohistochemical localization of NGF-like protein in the organ of Corti of the developing rat. Moreover, these observations could be related to an early prenatal development of auditory efferent innervation.

Neurotrophins and the development of cochlear innervation

The rapid progress in the past few years concerning neurotrophic factor research, has greatly stimulated advances in developmental neurobiology of hearing. We have summarized evidence that neurotrophins are expressed by auditory sensory epithelia during the time at which ganglion cells with neurotrophin receptors send their processes to these epithelia. Recent findings have led to the identification of BDNF and NT3 as responsible substances. Since no NGF mRNA nor the NGF high affinity receptor component trkA mRNA were detectable during the development of cochlear structures, this factor is not likely to be an important neurotrophin at this level. By their biological activity, neurotrophins could be responsible for chemotrophic, differentiation, survival, and maintenance functions at the afferent as well as at the efferent level of the inner ear development.

Distribution of Cytoskeletal Proteins (Neurofilaments, Peripherin and MAP-tau) in the Cochlea of the Human Fetus

We report here an immunohistochemical study of the distribution of intermediate filaments (neurofilament, peripherin) and a microtubule-associated protein, tau, in the human fetal cochlea at 27 weeks of gestation. Neurofilament immunoreactivity (160 and 200 KDa) was localized in afferent and efferent fibers of the cochlear innervation and restricted to a few small spiral ganglion neurons. Peripherin immunoreactivity was specifically distributed in some small ganglion neurons and in their central and peripheral extensions, particularly in fibers reaching the lower part of the outer hair cells. Double immuno-labelling studies with these neurofilaments and peripherin antibodies show that only small neuron cell bodies were stained. Morpholometrical data indicate that immunostained neurons could be related to the Type II neuron population in the spiral ganglion. Tau protein was localized in intraganglionic spiral bundle fibers and in fibers that reach the lower part of hair cells. These observations suggest that neurofilament and peripherin antibodies stain a particular population of human spiral ganglion neurons with Type II characteristics. Moreover, the specificity of peripherin labelling in Type II cells and their processes suggest that peripherin could be used as a probe for the developmental study of this system in the human cochlea. On the other hand, tau antibody appeared as a marker for efferent fibers during development and could give information on the ontogenesis of efferent innervation.

Measuring happiness: from fluctuating happiness to authentic-durable happiness.

On the basis of the theoretical distinction between self-centeredness and selflessness (Dambrun and Ricard, 2011), the main goal of this research was to develop two new scales assessing distinct dimensions of happiness. By trying to maximize pleasures and to avoid displeasures, we propose that a self-centered functioning induces a fluctuating happiness in which phases of pleasure and displeasure alternate repeatedly (i.e., Fluctuating Happiness). In contrast, a selfless psychological functioning postulates the existence of a state of durable plenitude that is less dependent upon circumstances but rather is related to a person’s inner resources and abilities to deal with whatever comes his way in life (i.e., Authentic–Durable Happiness). Using various samples (n = 735), we developed a 10-item Scale measuring Subjective Fluctuating Happiness (SFHS) and a 13-item scale assessing Subjective Authentic–Durable Happiness (SA–DHS). Results indicated high internal consistencies, satisfactory test–retest validities, and adequate convergent and discriminant validities with various constructs including a biological marker of stress (salivary cortisol). Consistent with our theoretical framework, while self-enhancement values were related only to fluctuating happiness, self-transcendence values were related only to authentic–durable happiness. Support for the distinction between contentment and inner-peace, two related markers of authentic happiness, also was found.

Basic FGF-like protein in the lower stato-acoustic system of the neonatal and adult rat.

Basic fibroblast growth factor (bFGF)-like localization was studied immunohistochemically in the lower auditory tract of neonatal and adult rats. During the neonatal period, bFGF-like immunoreactivity is present in the cytoplasm of inner hair cells, spiral ganglion cells, Scarpas ganglion cells, in auditory brain stem nuclei and in vestibular nuclei. At the adult stage, bFGF-like protein is widely distributed in the auditory brain stem but was not found in the cochlea. These results suggest that bFGF could be implicated in the development as well as in the neuronal maintenance and plasticity of the auditory system.