1. PD, Dr Gérard LOQUET
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

2. Results:
Unilateral hemilabyrinthectomy induces neuronal re-growth phenomenon in
the cochlear nucleus but not in the vestibular nucleus of adult rats.
Methods:
Vibratome sectionning
Immunohistochemical tools
Posturography
Nystagmography GAP-43
Expression in
Growth Cone
References:
De Waele et al., 2000 [Abstract]
Loquet, 1996 [Diplôme d’Études Approfondies: Neurosciences]
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

3. Results:
Combined exposure to environmental agents such as solvents, alcohol or noise
induces synergistic damages to hair cells and auditory nerves of adult rats.
Methods:
Audiometry 1750ppm
Electrophysiology (inferior colliculus) Toluene
inhaled
Histology (light microcopy, SEM, TEM) (OHC3 is
missing)
References:
Campo et al., 1999 [Abstract], 2001 [Abstract]
Lataye et al., 1999 [Abstract], 2000 [Abstract], 2001 [Abstract], 2005 [Abstract]
Loquet et al., 2000 [Abstract], Loquet, 2000 [Neurosciences Thesis]
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

4. Results:
Solvents are neurotoxic in both animals and humans either directly on the
sensory receptors or indirectly on the innervating fibers.
In a preventive perspective epidemiological studies should be encouraged to
identify early indicators of sensory damages and to develop screening tools.
Methods:
Epidemiology
References:
Chouanière et al., 2001
Demange et al., 2001
Loquet , 2002 [Medical Toxicology Diploma]
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

5. Results:
The auditory function in adult rats can be successfully restored through a
cochlear implant delivering monopolar electrical stimuli to the auditory nerve
and incorporating a model of neural phenomenon of adaptation.
Such a new coding strategy may improve speech reception in noise.
Methods:
Audiometry
Electric (50μA)
Electrophysiology (ventral cochlear nucleus)
Acoustic (30dB SPL)
Histology Modified Electric
References:
Loquet et al., 2002 [Abstract], 2003 [Abstract], 2004 [Abstract]
Meyer et al., 2006 [Abstract]
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

6. Results:
Sensory hearing loss induced in infant rats by bacterial meningitis infection can
be limited with doxycycline treatment (antibiotic) but not with dexamethasone
(anti-inflammatory).
Doxycycline
Mock-infected After recovery + Recovery
Methods:
ABR measurements
Pharmacology
Histopathology
References:
Meli et al., 2006 [Abstract]
Coimbra et al., 2007 [Abstract]
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

7. Results:
Batteries of audiometric tests including pure tone and differential
thresholds, speech like sounds (syllables) can be successfully tested in non-
human primates as an animal model.
In this model location of the cochlear nucleus is feasible with powerful imaging
tools as it is done in humans with neuronavigating tools.
Methods:
Conditioning (custom designed workstation)
Histology, MRI, CT
References:
Lanz et al., 2006
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

8. Results:
The Direct Acoustic Cochlea Stimulator Partial Implant (DACS-PI) intended to
stimulate the perilymph through an actuator connected to the oval window via
an artificial stapes has been successfully implanted in 9 patients (EU clinical
trial). The results show a significant improvement in speech discrimination.
Methods:
Laser doppler interferometry
Stapedectomy
Conventional audiometric testing
References:
Häusler et al., 2008 [Abstract]
Maier et al., 2010
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory

9. Results:
Discrimination is better and faster (shorter reaction times) when multimodal
stimuli are used (visual + acoustic) as compared to unimodal stimuli (visual or
acoustic). The modulated activities simultaneously recorded from neurons in
polysensory areas of the cortex is a first step towards a better understanding of
multisensory integration and unified perception.
Methods:
Electrophysiology (custom designed workstation)
Chronic recordings in awake animals
References:
Activity in
Cappe et al., 2010 [Abstract] Premotor
Cortex
Lanz et al., 2013 (submitted for publication)
Plasticity Ototoxicity Neurotoxicity Adaptation Protection Behaviour DACS-PI Multisensory