The role of the medial preoptic area in appetitive and consummatory reproductive behaviors depends on sexual experience and odor volatility in male Syrian hamsters

In Syrian hamsters (Mesocricetus auratus), the expression of reproductive behavior requires the perception and discrimination of sexual odors. The behavioral response to these odors is mediated by a network of ventral forebrain nuclei, including the medial preoptic area (MPOA). The role of MPOA in male copulatory behavior has been well-studied, but less is known about the role of MPOA in appetitive aspects of male reproductive behavior. Furthermore, many previous studies that examined the role of MPOA in reproductive behavior have used large lesions that damaged other nuclei near MPOA or fibers of passage within MPOA, making it difficult to attribute post-lesion deficits in reproductive behavior to MPOA specifically. Thus, the current study used discrete, excitotoxic lesions of MPOA to test the role of this nucleus in opposite-sex odor preference and copulatory behavior in both sexually-naïve and sexually-experienced males. Lesions of MPOA eliminated preference for volatile, opposite-sex odors in sexually-naïve, but not sexually-experienced, males. When males were allowed to contact the sexual odors, however, preference for female odors remained intact. Surprisingly, lesions of MPOA caused severe copulatory deficits only in sexually-naïve males, suggesting previous reports of copulatory deficits following MPOA lesions in sexually-experienced males were not due to damage to MPOA itself. Together, these results demonstrate that the role of MPOA in appetitive and consummatory aspects of reproductive behavior varies with the volatility of the sexual odors and the sexual experience of the male.     

A comparison of myogenic motor evoked responses to electrical and magnetic transcranial stimulation during nitrous oxide/opioid anesthesia

Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was induced with i.v. etomidate 0.3 mg/kg and sufentanil 1.5 microg/kg and was maintained with sufentanil 0.5 microg x kg(-1) x h(-1) and N2O 50% in oxygen. Muscle relaxation was kept at 25% of control with i.v. vecuronium. Electrical stimulation was accomplished with a transcranial stimulator set at maximal output (1200 V). Magnetic transcranial stimulation was accomplished with a transcranial stimulator set at maximal output (2 T). Just before skin incision, triplicate responses to single stimuli with both modes of cortical stimulation were randomly recorded from the tibialis anterior muscles. Amplitudes and latencies were compared using the Wilcoxon signed rank test. Bilateral tc-MEP responses were obtained in every patient with electrical stimulation. Magnetic stimulation evoked only unilateral responses in two patients. With electrical stimulation, the median tc-MEP amplitude was 401 microV (range 145-1145 microV), and latency was 32.8 +/- 2.3 ms. With magnetic stimulation, the tc-MEP amplitude was 287 microV (range 64-506 microV) (P < 0.05), and the latency was 34.7 +/- 2.1 ms (P < 0.05). We conclude that myogenic responses to magnetic transcranial stimulation are more sensitive to anesthetic-induced motoneural depression compared with those elicited by electrical transcranial stimulation. IMPLICATIONS: Transcranial motor evoked potentials are used to monitor spinal cord integrity intraoperatively. We compared the relative efficacy of electrical and magnetic transcranial stimuli in anesthetized patients. It seems that myogenic responses to magnetic transcranial stimulation are more sensitive to anesthetic-induced motoneural depression compared with electrical transcranial stimulation.     

Epidemiology of pyridoxine dependent seizures in the Netherlands.

BACKGROUND: Pyridoxine dependent epilepsy is a rare cause of seizures in childhood. The diagnosis is made on clinical criteria, that in many cases are never met. Therefore, epidemiological data on pyridoxine dependency are scarce. AIMS: To study the epidemiology of pyridoxine dependent epilepsy in the Netherlands, and to determine whether the diagnosis is based on the appropriate criteria. METHODS: Nationwide all departments of paediatrics (n = 113) and of paediatric or neonatal neurology (n = 17) were asked to report cases of pyridoxine dependent seizures. Birth incidences were calculated using national data on live births from 1991 to 2003. RESULTS: Response was received from 67% of paediatric departments, including all university hospitals and 94% of child neurology departments. Thirteen patients were reported. Four definite (31%), three probable (23%), and four possible cases (31%) were identified. Two cases (15%) did not meet criteria for either of these groups. The birth incidence was 1:396,000 for definite and probable cases and 1:252,000 when possible cases are included. CONCLUSIONS: Thus far, epidemiological data on pyridoxine dependent seizures were only available from the UK and Ireland. A higher incidence was found in the Netherlands, in accordance with earlier suggestions of a regional difference. The study shows that the diagnosis is often made without performance of a formal trial of withdrawal. The importance of confirming the diagnosis, concerning the consequences as for individual prognosis, the potential side effects of prolonged pyridoxine substitution, and the possibility of treating the mother in case of future pregnancies are emphasised.     

Vertebral Bodies or Discs: Which Contributes More to Human-like Lumbar Lordosis?

Background

The attainment of upright posture, with its requisite lumbar lordosis, was a major turning point in human evolution. Nonhuman primates have small lordosis angles, whereas the human spine exhibits distinct lumbar lordosis (30°–80°). We assume the lumbar spine of the pronograde ancestors of modern humans was like those of extant nonhuman primates, but which spinal components changed in the transition from small lordosis angles to large ones is not fully understood.

Questions/Purposes

We wished to determine the relative contribution of vertebral bodies and intervertebral discs to lordosis angles in extant primates and humans.

Methods

We measured the lordosis, intervertebral disc, and vertebral body angles of 100 modern humans (orthograde primates) and 56 macaques (pronograde primates) on lateral radiographs of the lumbar spine (humans–standing, macaques–side-lying).

Results

The humans exhibited larger lordosis angles (51°) and vertebral body wedging (5°) than did the macaques (15° and ?25°, respectively). The differences in wedging of the intervertebral discs, however, were much less pronounced (46° versus 40°).

Conclusions

These observations suggest the transition from pronograde to orthograde posture (ie, the lordosis angle) resulted mainly from an increase in vertebral body wedging and only in small part from the increase in wedging of the intervertebral discs.     

Clinical outcome and radiographic results after operative treatment of Scheuermann's disease

The aim of this prospective study was to evaluate radiographic findings, patient satisfaction and clinical outcome, and to report complications and instrumentation failure after operative treatment of Scheuermann's disease using a combined anterior and posterior spondylodesis. The loss of sagittal plane correction after removal of the posterior instrumentation was analysed. The indication for surgery was a thoracic kyphosis greater than 60 degrees in adolescents and adults with persistent back pain, which failed to respond to conservative treatment. Thoracic kyphosis and lumbar lordosis angles were measured by the Cobb method at preselected time points and at final follow-up. Sagittal plane alignment was measured as translation. The validated Scoliosis Research Society Instrument (SRSI) questionnaire was sent to all patients at follow-up. P-values were calculated using the Wilcoxon signed rank test (P<0.05 is significant). Between October 1987 and August 1999, 23 consecutive patients underwent operative treatment. The median follow-up was 75 months (range 25-126 months). Median preoperative thoracic kyphosis was 70 degrees (range 62 degrees-78 degrees) and median preoperative lumbar lordosis was 68 degrees (range 54 degrees-84 degrees). Immediate postoperative median thoracic kyphosis was 39 degrees (range 28 degrees-54 degrees) (P<0.05) and immediate postoperative median lumbar lordosis was 49 degrees (range 35 degrees-63 degrees) (P<0.05). These significant corrections were maintained at early follow-ups conducted 1 year and 2 years postoperatively. At final follow-up, the median thoracic kyphosis had significantly increased, to 55 degrees (range 36 degrees-65 degrees) (P<0.05 relative to immediate postoperative value), and the median lumbar lordosis had increased to 57 degrees (range 44 degrees-70 degrees) (P<0.05). The late deterioration of correction in the sagittal plane was mainly caused by removal of the posterior instrumentation, and occurred despite radiographs, bone scans and thorough intra-operative explorations demonstrating solid fusions. The median SRSI score was 83 points (range 55-106). There was no significant correlation between the radiographic outcome and the SRSI score (P>0.05). Our series showed relatively fair outcome after operative treatment in Scheuermann's disease. Therefore, the indication for surgery in patients with Scheuermann's disease can be questioned.     

Empathy and Empathy Induced Prosocial Behavior in 6- and 7-Year-Olds with Autism Spectrum Disorder

The present study aimed to assess empathy and prosocial behavior in 6–7 year old children with autism spectrum disorders (ASDs). Results showed, first, lower levels of parent- and teacher-rated cognitive empathy, and similar levels of affective empathy in children with ASD compared to typically developing (TD) children. Second, emotion recognition for basic emotions, one aspect of cognitive empathy, in a story task was adequate in ASD children, but ASD children with severe impairments in social responsiveness had difficulties in recognizing fear. Third, prosocial behavior in response to signals of distress of a peer in a computer task was similar in ASD as in TD children. In conclusion, early elementary school children with ASD show specific impairments in cognitive empathy.