CNS Myelin and Sertoli Cell Tight Junction Strands Are Absent in Osp/Claudin-11 Null Mice

Behavioural assessment of mice lacking D1A dopamine receptors

The pig model is increasingly used in the field of neuroscience because of the similarities of its brain with human. This review presents the peculiarities of the anatomy and functions of the pig brain with specific reference to its human counterpart. We propose an approximate mapping of the pig’s cortical areas since a comprehensive description of the equivalent of Brodmann’s areas is lacking. On the contrary, deep brain structures are received more consideration but a true three-dimensional (3D) atlas is still eagerly required. In the second section, we present an overview of former works describing the use of functional imaging and neuronavigation in the pig model. Recently, the pig has been increasingly used for molecular imaging studies using positron emission tomography (PET). Indeed, the large size of its brain is compatible with the limited spatial resolution of the PET scanner built to accommodate a human being. Similarly, neuronavigation is an absolute requirement to target deep brain areas in human and in pig since the surgeon cannot rely on external skull structures for zeroing the 3D reference frame. Therefore, a large body of methodological refinements has been dedicated to image guided surgery in the pig model. These refinements allow now a millimetre precision: an absolute requirement for basal nuclei targeting. In the third section, several examples of ongoing studies in our laboratory were presented to illustrate the intricacies of using the pig model. For both examples, after a brief description of the scientific context of the experiment, we present, in detail, the methodological steps required to achieve the experimental goals, which are specific to the porcine model. Finally, in the fourth section, the anatomical variations depending on the breed and age are discussed in relation with neuronavigation and brain surgery. The need for a digitized multimodality brain atlas is also highlighted.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/98DFF68C8726DB0592A8FE1E26925DBA/S1751731109004649a.pdf/div-class-title-the-pig-model-in-brain-imaging-and-neurosurgery-div.pdf

The pig model in brain imaging and neurosurgery

Loxoscelism: Old obstacles, new directions

The mouse has become a key animal model for ocular research. This situation reflects the fact that genes implicated in human retinal disorders or in mammalian retinal function may be readily manipulated in the mouse. Visual electrophysiology provides a means to examine retinal function in mutant mice, and stimulation and recording protocols have been developed that allow the activity of many classes of retinal neurons to be examined and which take into account unique features of the mouse retina. Here, we review the mouse visual electrophysiology literature, covering techniques used to record the mouse electroretinogram and visual evoked potential, and how these have been applied to characterize the functional implications of gene mutation or manipulation in the mouse retina.

Electrophysiological analysis of visual function in mutant mice.

To screen for congenital deafness, brainstem auditory-evoked potential (BAEP) testing was performed on 1031 Dalmatians from three geographically separated areas. Phenotypic marker assessment was done to determine markers possibly associated with deafness. Markers included sex, hair coat color, pigmentation of different areas of skin (eye rims, nose, and ears), presence of a patch, spot size and marking (density of spotting), sire and dam BAEP status, and presence of iris and retinal tapetal pigmentation. Combined data from all test sites showed 8.1% bilateral deafness (N = 83 dogs) and 21.6% unilateral deafness (N = 223), or an overall 29.7% incidence of hearing disorders. Significant (P less than 0.05) associations with deafness for the data from all test sites combined were seen for patch, sire and dam BAEP, iris pigment, and retinal pigment. However, results differed for several of the significant phenotypic markers when analyses were done on the data from the individual test sites; changes from significant to not significant were found. This suggested the existence of multiple populations of deafness patterns, and reinforced the precautionary conclusion that associations of phenotypic markers with deafness are not necessarily functionally significant.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.1992.tb00333.x

Brainstem auditory-evoked potential assessment of congenital deafness in Dalmatians: associations with phenotypic markers.

Recordings of averaged brain stem auditory-evoked potentials were obtained from 13 Beagle pups of both genders to document the postnatal development of the response from age 1 to 76 days. Responses were recorded between needle electrodes placed on the vertex and the ipsilateral ear, with ground at the interorbital line. Recordings were performed without sedation. Low-amplitude responses to high-intensity stimuli could be recorded from animals prior to opening of the ear canals. Peak latencies did not change after day 20 for peak I, day 30 for peaks II and III, and day 40 for peak V. As a result, the interpeak latencies between peaks I and III did not change after day 30, but continued to decrease until day 40 for peaks III-V and I-V. Peak amplitudes reached plateau values by day 20 (peak I) or day 30 (peaks II, III, and V). All of the measured latency and amplitude values had significant (P less than 0.001) linear regression lines of latency vs age and amplitude vs age. The brain stem auditory-evoked potential thresholds were mature by day 20.

Postnatal development of the brain stem auditory-evoked potential in dogs.

Flash and pattern reversal visual evoked potentials in C57BL/6J and B6CBAF1/J mice.

Hyperbaric oxygen effects on brown recluse spider (Loxosceles reclusa) envenomation in rabbits.

Vestibulotoxic and ototoxic effects often are seen after long-term, high-dose systemic treatment with gentamicin, but toxic effects after topical use have not been reported in animals, to the authors' knowledge. Vestibular and auditory effects of twice daily otic gentamicin treatment for 21 days were evaluated in 10 dogs with intact tympanic membranes and in the same 10 dogs after experimental bilateral myringotomy. Each dog served as its own control; 7 drops of gentamicin sulfate (3 mg/ml in a buffered aqueous vehicle) were placed in 1 ear, and 7 drops of vehicle were placed in the opposite ear. Treatment and control ears were reversed after myringotomy. Vestibular function was evaluated daily by neurologic examination and behavioral assessment. Auditory function was evaluated twice weekly by determination of brain stem auditory evoked potentials. Gentamicin sulfate placed in the ear of clinically normal dogs with intact or ruptured tympanic membranes, in the quantities used in this study, did not induce detectable alteration of cochlear or vestibular function. Serum gentamicin concentration after 21 days of treatment was detectable in only 2 dogs and was an order of magnitude below documented toxic concentrations.

Bruce L. Tedford

Papers

Brainstem auditory-evoked potential assessment of congenital deafness in Dalmatians: associations with phenotypic markers.

Postnatal development of the brain stem auditory-evoked potential in dogs.

Flash and pattern reversal visual evoked potentials in C57BL/6J and B6CBAF1/J mice.

Hyperbaric oxygen effects on brown recluse spider (Loxosceles reclusa) envenomation in rabbits.

Ototoxicity assessment of a gentamicin sulfate otic preparation in dogs