Brain Plasticity laboratory

Our understanding of the aging changes involving the cranium and its impact on the overlying soft tissues is limited. This study was designed to look at the changes that occur in the cranium with aging and to propose an additional mechanism for loss of support for overlying soft tissues. One hundred and fifty-seven white individuals (10 males and 10 females in each decade: 20-29 years, 30-39 years, 40-49 years, 50-59 years, 60-69 years, 70-79 years, 80-89 years, and 8 males and 9 females aged 90-98 years) were investigated. Computed tomographic (CT) multiplanar scans with standardized measurements of cranial thickness were performed for the frontal bone, nasion, vertex, pterion, lambda, calvarial and midfacial height, and sagittal and transverse diameter. Increasing age correlated with a decrease in sagittal diameter in both males (rp = -0.201) and females (rp = -0.055) but with an increase in transverse diameter in both males (rp = 0.233) and females (rp = 0.207). Frontal bone thickness decreased in males -1.57mm/-18.14%, whereas it increased slightly in females +0.26mm/+3.04%. At the pterion, bone thickness increased significantly in both genders. Calvarial volume decreased with increased age in both males and females: -70.2 ml/-5.35% and -61.4 ml/-5.10%, respectively. The lateral expansion of the skull may favor a skeletonized appearance of the face in elderly individuals. The computed volume of the calvaria decreased with advancing age in both genders, providing an additional element in the multifactorial model for facial soft-tissue laxity.

Abstract The main functions of primary sensory cortical areas are classically considered to be the extraction and representation of stimulus features. In contrast, higher cortical sensory association areas are thought to be responsible for combining these sensory representations with internal motivations and learnt associations. These regions generate appropriate neural responses that are maintained until a motor command is executed. Within this framework, responses of the primary sensory areas during task performance are expected to carry less information about the behavioral meaning of the stimulus than higher sensory, association, motor and frontal cortices. Here we demonstrate instead that the neuronal population responses in the early primary auditory cortex (A1) display many aspects of responses generally associated with higher-level areas. A1 activity was recorded in awake ferrets while they were either passively listening or actively discriminating two periodic click trains of different rates in a Go/No-Go paradigm. By applying population-level dimensionality reduction techniques, we found that task-engagement induced a shift in the nature of the encoding from a sensory-driven representation of the two stimuli to a behaviorally relevant representation of the two categories that specifically enhances the target stimulus. We demonstrate that this shift in encoding relies partly on a novel mechanism of change in spontaneous activity patterns upon engagement in the task. We show that this population-level representation of stimuli in A1 population activity bears strong similarities to responses in the frontal cortex, but appears earlier following stimulus presentation. Analysis of neural activity recorded in various Go/No-Go tasks, with different sounds and reinforcement paradigms, reveals that this striking population-level enhancement of target representation is a general property of task engagement. These findings indicate that primary sensory cortices play a highly flexible role in the processing of incoming stimuli and implement a crucial change in the structure of population activity in order to extract task-relevant information during behavior.

Foreign bodies in the respiratory tract are highly dangerous and need to be treated immediately and appropriately by the otolaryngologist.In our Department of Otolaryngology over the 20 years from 1981 to 2000, we treated 91 cases of tracheo-bronchial foreign bodies, an incidence of 4.6 cases per year. Two-thirds of patients were male, and 62.6% were 1 year old. Foreign bodies removed in 69.2% of patients were peanuts or other kinds of beans.Initial symptoms were typically cough, stridor and cyanosis.The pediatric department performed the initial examination of 50% of patients, and otolaryngologists initially examined only 13.2% of patients.The accord rate between the unilateral decreased lung sound, emphysema, or atelectasis and the foreign body was high (80.6%, 67.6%, 90.0%).Chest CT examination was useful to check for the presence of foreign body in the respiratory tract.It is important for the otolaryngologist to enlighten society on the possible life-threatning danger of respiratory tract foreign bodies in infants.

Inferior alveolar nerve (IAN) damage can occur in trauma, cyst enucleation, sagittal split osteotomy or third molar removal, and the consequences are a loss of sensation to the mandibular teeth, gingiva and lower lip. Because of its anatomical position in a bony canal, IAN suture is rarely evoked. The aim of this study was to demonstrate the reality of IAN regeneration by using electrophysiological and histological methods after experimental section and suture of this nerve in rabbits. Nine adult female animals were used for the experiments. Six months after section and suturing using 10.0 nylon with a conventional technique, electrical stimulation of the nerve was performed to record electrophysiological activity. Each rabbit was its own reference. In each case, an action potential was recorded after microsurgical repair and definitively suppressed by section of the nerve. Morphometric analysis showed a decrease in the number of nerve fibers in the operated nerve versus the control nerve. The histological study showed an increase in nerve fibers with a cross-sectional area of 19-36 and 37-73 micro m(2) and a decrease in the smaller fibers (2-4 and 5-7 micro m(2)). This preliminary study confirms the possibility of nerve regeneration in rabbits 6 months after section and conventional suturing.

For a long time, surgeons hesitated to extract more than 2.5 L of adipose tissue from a patient during liposculpture. Through the years, the technique has advanced, now allowing megaliposculptures to be performed so that more than 10 L can be extracted without posing any greater risk to the patient than would a conventional aesthetic liposculpture. This article traces the progressive evolution of the technique through the years, also discussing complications and the concept of megaliposculpturing. The syringe-assisted extraction of large quantities of adipose tissue without transfusion, hypovolemic shock, or any major complication opens new horizons in the symptomatic treatment of certain types of osteoarthritis of the lower extremities and of the acquired or potential complications of obesity. Large quantities of adipose tissue may safely, quickly, and efficiently be extracted. Numerous investigations in various pathological domains can now begin after this first step (megalipotherapy). Therapeutic megalipoextraction can be done either as a preliminary indication or as a treatment of the residual adiposities that occur after bariatric operations.