Feed supplementation with Ligilactobacillus salivarius PS21603 optimises intestinal morphology and gut microbiota composition in weaned piglets.

Post-weaning diarrhoea in piglets remains an important cause of economic losses for swine producers. Feed supplementation with probiotics is one of the alternatives to antibiotics used to reduce the impact of such gastrointestinal disease. The aim of the present study was to evaluate the effect of Ligilactobacillus salivarius PS21603 supplementation on the intestinal structure and the gut microbiota composition of weaned piglets. Safety and tolerance of L. salivarius PS21603 were previously evaluated in a 28-days study using 384 weaned piglets (28 ± 2 days old and 7.5 ± 1.5 kg) divided in three treatment groups: T1: Basal diet + L. salivarius PS21603 109 cfu/day, T2: Basal diet + L. salivarius PS21603 107 cfu/day, and T3: Basal diet (control group). For the present study, 16 piglets per treatment group were randomly selected and faecal samples were collected on day 0 (weaning) and 28 of study. At the end of study, three males and three females per treatment were euthanised. Intestinal morphometric values were measured after necropsy. Faecal counts of Escherichia coli were evaluated by culture techniques, and faecal microbiota composition was assessed by high-throughput sequencing. All data were analysed and compared between treatment groups. Supplementation with L. salivarius PS21603 caused an increase in the intestine length of piglets from T1 and in the villous height:crypt ratio of piglets from T2 (P < 0.05) compared to T3 on day 28. According to the Shannon Diversity Index, microbiota diversity increased on day 28 compared to day 0, with no significant differences observed between treatments. The main changes in the relative abundance of bacteria at the phylum, family, and genus levels were observed between different sampling time points. However, piglets from T1 and T2 had lower faecal E. coli counts than T3 on day 28 (P < 0.05). Moreover, supplementation with L. salivarius PS21603 modulated gut microbiota through a more optimal composition, reducing Escherichia and increasing Bifidobacterium relative abundance in piglets from T1 (P < 0.05) from the beginning to the end of the study. Therefore, the strain L. salivarius PS21603 has shown probiotic properties to be used as feed additive in the pig industry, along with good hygiene and farm management practices, for the prevention and/or treatment of post-weaning diarrhoea in piglets.

Safety assessment and characterisation of Ligilactobacillus salivarius PS21603 as potential feed additive for swine.

The present study aimed to characterise in vitro properties of the strain Ligilactobacillus salivarius PS21603 and evaluate in vivo piglets' tolerance for its use as feed additive in swine. The ability of L. salivarius PS21603 of inhibiting enteropathogens' growth in vitro was evaluated using a co-culture assay. Low pH tolerance, bile tolerance, and resistance to osmotic changes were evaluated. The antibiotic susceptibility profile of L. salivarius PS21603 was assessed through broth microdilution method. Whole genome sequencing (WGS) was performed to exclude the presence of antibiotic resistance genes. L. salivarius PS21603 showed a high antimicrobial activity in vitro, reducing in a mean of 6.16 log cfu/ml eight different enterotoxigenic Escherichia coli strains. Moreover, L. salivarius PS21603 showed resistance to osmotic changes and was able to survive to a pH above 3.5 during 24 h and up to pH 2 at least during 2 h. In addition, WGS revealed that L. salivarius PS21603 did not harbour any resistance genes and thus there was no risk of transmissibility. Finally, an in vivo 28-days safety and tolerance study was performed. For that, 384 healthy piglets (28±2 days old and 7.5±1.5 kg, at weaning) were divided into three treatment groups receiving a different dose of L. salivarius PS21603: T1, 109 cfu/day; T2, 107 cfu/day; T3, control. Piglet's health status was daily controlled. Individual bodyweight and feed intake per pen were weekly recorded to determine performance parameters. Blood samples were collected in 16 piglets from each treatment group on days 0 and 28 for determination of cytokine profiles. L. salivarius PS21603 was safe and well tolerated by piglets, there were no differences in performance nor cytokine profile between treatment groups. In conclusion, L. salivarius PS21603 is a potential candidate for a probiotic prevention strategy against pig diarrhoea.

The effect of the number of fibers in tractography reconstruction of white matter bundles.

The study of white matter (WM) through diffusion Magnetic Resonance Imaging (dMRI) is crucial to obtain a better understanding of human brain connections and functions, at a macroscopic level. A large number of works have focused on long range brain connections, while recently, several studies have also analyzed superficial WM connectivity. In recent years, with the massive use of HCP database, and its processing with known softwares like DSI Studio and MRtrix, it is necessary to evaluate the influence of tractography parameters on the reconstruction of fiber bundles and further analyses. We study the effect of the number of fibers, for whole brain tractography, on the reconstruction of deep and superficial WM bundles based on their segmentation using multi-subject bundle atlases. For DSI Studio (deterministic algorithm), a value of 1M fibers could reconstruct most of deep white matter (DWM) bundles, while a value of 1.5M was required for superficial white matter (SWM) bundles. In the case of MRtrix (probabilistic algorithm), a value of 3M fibers was found to be suitable for the study of both kinds of fibers. Furthermore, we found the tracking of SWM bundles to be more sensitive to several parameters than DWM, for DSI Studio.

First-line mFOLFOX plus cetuximab followed by mFOLFOX plus cetuximab or single-agent cetuximab as maintenance therapy in patients with metastatic colorectal cancer: Phase II randomised MACRO2 TTD study.

BACKGROUND: This multicentre, randomised, and phase II study evaluated mFOLFOX+cetuximab followed by maintenance mFOLFOX+cetuximab or single-agent cetuximab in metastatic colorectal cancer (mCRC) patients (NCT01161316). PATIENTS AND METHODS: Previously, untreated mCRC patients (wild-type KRAS) were randomised to receive cetuximab+mFOLFOX-6 (8 cycles for 2 weeks) followed by maintenance therapy: single-agent cetuximab (Arm-A) or mFOLFOX-6 + cetuximab (Arm-B) until progression. Primary endpoint was progression-free survival (PFS) at 9 months. RESULTS: One hundred ninety-three patients (median [range] age 60 [33-74] years) were randomised (2:1): 129 Arm-A versus 64 Arm-B. PFS at 9 months (95% confidence interval) showed non-inferiority between arms (Arm-A/Arm-B: 60 [52, 69]%/72 [61, 83]%, p [non-inferiority]<0.1). There were no statistically significant differences in the PFS (Arm-A/Arm-B: 9 [95% CI 7, 10] months/10 [7,13] months, hazard ratio [HR] = 1.19 [0.80, 1.79]) or overall survival (23 [19, 28] months/27 [18, 36] months, HR = 1.24 [0.85, 1.79]) between arms. The objective response rate was also similar (48 [39, 57]%/39 [27, 52]%). The safety profile was similar between arms, and all patients experienced at least one adverse event (AE) (Arm-A/Arm-B grade ≥III AEs: 70%/68%). The most common grade ≥III AEs were as follows: neutropenia (Arm-A/Arm-B: 28%/26%), rash acneiform (15%/24%) and sensory neuropathy (2%/15%) in any group. Arm-A was associated with less grade ≥III rash and sensory neuropathy and a lower rate of serious AEs (20%/27%). CONCLUSION(S): This phase II exploratory trial with a non-inferiority design suggests that maintenance therapy with single-agent cetuximab following mFOLFOX+cetuximab induction could be a valuable option compared with mFOLFOX+cetuximab treatment continuation. We await phase III trials to confirm single-agent cetuximab as maintenance therapy in mCRC patients.

Los cultivos de leche humana 5 años después de la primera propuesta de protocolo (II): contribución a una reducción del uso de medicamentos durante la lactancia / Human milk cultures five years after the first protocol proposal (II): Contribution to a reduction in the use of drugs during lactation

La mastitis es un problema relativamente común durante la lactancia, pero la ausencia de pruebas específicas conduce a numerosos errores tanto en el diagnóstico como en el tratamiento. Por tanto, los cultivos de leche parecen una herramienta fundamental para conocer la epidemiología real de esta infección, realizar un diagnóstico correcto e instaurar el mejor tratamiento posible. En esta segunda parte se describen seis casos prácticos que ponen de manifiesto la utilidad de los cultivos de leche para un correcto diagnóstico y tratamiento de los problemas que aparecen durante la lactancia, así como su contribución a una reducción del uso de medicamentos durante esta etapa (AU)

Mastitis is a relatively common problem during lactation but the absence of specific tests frequently leads to errors both in the diagnosis and in the treatment. Consequently, milk cultures seem a key tool in order to know the actual epidemiology of this infec-tion, to get a correct diagnosis, and to prescribe the best treatment. In this part, six practical cases showing the usefulness of milk cultures for a correct diagnosis and treatment of problems arising during lactation are described. They reveal the contribution of milk cultures in reducing the use of unnecessary drugs during lactation (AU)

Carcinoma palpebral de células de Merkel. Serie de 5 casos y revisión de la literatura / Merkel cell carcinoma of the eyelid. A series of 5 cases and review of the literature

OBJETIVO: Estudio descriptivo de 5 casos clínicos de carcinoma de Merkel a nivel palpebral, destacando las características clínicas, histopatológicas, el manejo y seguimiento. Revisión de literatura asociada. MÉTODOS: Revisión retrospectiva de fichas clínicas y entrevista telefónica a 5 pacientes tratados por carcinoma de células de Merkel entre los años 2006-2013, en el Departamento de Órbita y Oculoplástica del Hospital Clínico de la Universidad de Chile. RESULTADOS: Cinco pacientes (2 hombres, 3 mujeres), de 79,2 años (rango 64-94 años), con una evolución de 10 semanas (rango 5-16 semanas), con un tamaño tumoral de 2,5 × 2 X 2,1 cm en promedio al momento de la cirugía. Descritos como una masa nodular, exofítica, sólida, de color rojizo. Sin adenopatías sospechosas ni metástasis en el primer enfrentamiento. Tipificados como T2N0M0, tras la primera cirugía con criterios oncológicos. Se observó, durante el seguimiento, 2 recurrencias en nódulo linfoide. Encontramos metástasis a distancia en un paciente. El diagnóstico histopatológico se confirmó mediante biopsia corriente más inmunohistoquímica. La estrategia quirúrgica fue con extirpación completa, control de márgenes libres y reconstrucción palpebral con colgajo de Hughes, Cutler-Beard o cierre primario. CONCLUSIONES: El diagnóstico precoz, la extirpación amplia del tumor con control de márgenes libres intraoperatorio con cirugía convencional o técnica de Mohs y una adecuada reconstrucción palpebral permiten una supervivencia en pacientes añosos portadores de este tumor a nivel palpebral. Se recomienda el estudio de ganglio centinela y biopsia en la intervención primaria, junto a una radioterapia posterior, que disminuye la recurrencia y aumentaría la supervivencia

OBJECTIVE: Presentation of 5 clinical cases of Merkel cell carcinoma of the eyelid, highlighting the clinical, histopathological, management, and monitoring features. Review of related literature. METHODS: Retrospective review of clinical records and telephone interview of the 5 patients treated for Merkel cell carcinoma between 2006 and 2013, in the Orbit and Oculoplastic Department, Clinical Hospital of the University of Chile. RESULTS: Five patients (2 men, 3 women); 79.2 years (range 64-94 years), with a mean onset of 10 weeks (range 5-16 weeks), tumour size reaching a mean of 2.5 × 2 × 2.1 cm at the time of surgery. Described as a nodular mass, exophytic, solid, reddish coloured. With no infiltrated lymph nodes or metastases in the first match. Staging as T2N0M0, after the first surgery with oncological criteria. Two lymph node recurrences detected during monitoring. Distant metastasis was found in one patient. The histopathological diagnosis was confirmed by immunohistochemical study of the biopsy. The surgical strategy was full excision, control of surgical margins in the intraoperative period, and eyelid reconstruction with Hughes flap, Cutler/Beard flap or primary closure, depending on the case. CONCLUSIONS: Early diagnosis, wide excision of the tumour with intraoperative control of clear margins with conventional or Mohs surgery, and proper eyelid reconstruction are adequate for a good survival in elderly patients with this eyelid tumour. The study of sentinel lymph node biopsy in primary intervention is recommended; with subsequent radiotherapy to decrease the recurrence and increase survival

Merkel cell carcinoma of the eyelid. A series of 5 cases and review of the literature.

OBJECTIVE: Presentation of 5 clinical cases of Merkel cell carcinoma of the eyelid, highlighting the clinical, histopathological, management, and monitoring features. Review of related literature. METHODS: Retrospective review of clinical records and telephone interview of the 5 patients treated for Merkel cell carcinoma between 2006 and 2013, in the Orbit and Oculoplastic Department, Clinical Hospital of the University of Chile. RESULTS: Five patients (2 men, 3 women); 79.2 years (range 64-94 years), with a mean onset of 10 weeks (range 5-16 weeks), tumour size reaching a mean of 2.5×2×2.1cm at the time of surgery. Described as a nodular mass, exophytic, solid, reddish coloured. With no infiltrated lymph nodes or metastases in the first match. Staging as T2N0M0, after the first surgery with oncological criteria. Two lymph node recurrences detected during monitoring. Distant metastasis was found in one patient. The histopathological diagnosis was confirmed by immunohistochemical study of the biopsy. The surgical strategy was full excision, control of surgical margins in the intraoperative period, and eyelid reconstruction with Hughes flap, Cutler/Beard flap or primary closure, depending on the case. CONCLUSIONS: Early diagnosis, wide excision of the tumour with intraoperative control of clear margins with conventional or Mohs surgery, and proper eyelid reconstruction are adequate for a good survival in elderly patients with this eyelid tumour. The study of sentinel lymph node biopsy in primary intervention is recommended; with subsequent radiotherapy to decrease the recurrence and increase survival.

Duchenne muscular dystrophy in a developing country: challenges in management and genetic counseling.

BACKGROUND AND OBJECTIVE: Multidisciplinary management of Duchenne Muscular Dystrophy (DMD) has achieved outstanding results in developed nations. We aimed to describe the status of diagnosis and management of DMD in a developing country through the experience of non-profit organizations. METHODS: A Multistate, multiple-source, population-based survey was performed from medical records of 432 patients. Data were retrospectively collected, reviewed and curated by health specialists; including clinical features, age at first symptoms, age at diagnosis, disease progression and management, family history, education, age and cause of death. RESULTS: There is a delay in noticing first symptoms and it did not diminish over the past 20 years. Less than 30% of patients obtained definite diagnosis and most of them are in physiotherapy programs but not under steroid treatment. In our study, family history does not anticipate recognition of symptoms compared to sporadic cases (p = 0.05). Approximately 93.33% of our patients attended to education programs. Mean age at death was 18.94 +/- 6.73 years and the most frequent cause was pneumonia. CONCLUSION: Delayed diagnosis of DMD in Mexico is mainly caused by the late detection of first symptoms. There is no difference in early detection of symptoms between familiar and sporadic cases. Lifespan of patients in our cohort is reduced compared to developed countries. The late diagnosis and low percentage of definite cases may affect patient management and genetic counseling and could also preclude participation of patients into novel clinical trials.

The variable phenotype in tetrasomy 18p syndrome. A propos of a subtle dysmorphic case.

The variable phenotype in tetrasomy 18p syndrome. Apropos of a subtle dysmorphic case: Tetrasomy 18 is a rare chromosomal syndrome. Its frequency is 1/40,000 newborns and more than 40 cases have been reported. In this paper we report a 25-month-old female patient referred for chromosome examination essentially because of delayed psychomotor development. The physical examination showed: microcephaly, mild generalized spasticity, arched eyebrows, horizontal palpebral fissures with unilateral convergent strabismus, bilateral epicanthic folds, small nose, well placed ears, oral cavity with high arched palate and upper vestibular frenula, tented mouth with slightly everted upper lip, hands with normal palmar creases and long fingers. All the blood tests were normal, while the magnetic resonance imaging reported mild demyelination and polymicrogyria. The karyotype was 47,XX,+i(18)(p10).ish i(18)(plO)(D18Z1+) de novo.

[Duchenne muscular dystrophy: current aspects and perspectives on treatment]. / Distrofia muscular de Duchenne: actualidad y perspectivas de tratamiento.

INTRODUCTION AND DEVELOPMENT: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease of genetic origin that affects male children. It is characterized by progressive muscle deterioration which results in the patient becoming wheelchair-dependent until death from cardio-respiratory complications. A few years ago, DMD patients' life quality and expectancy were poor and treatment options limited; valuable recommendations that significantly delay the progress of the disease and improve the patient's life quality have been brought about recently. Numerous therapeutic approaches are now in development in order to correct the DMD genetic defect at molecular level. In the mean time, a comprehensive system to maintain patients in their best possible physical condition is needed. CONCLUSIONS: Accurate detection of complications enables caregivers to determine which patients are at higher risk and to provide treatment accordingly. Nevertheless, all of these efforts are dependent on early clinical and molecular diagnosis, careful record of clinical changes and long-term follow-up of DMD patients. Furthermore, the involvement of multidisciplinary groups and the patient's family is essential in said interventions.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico.

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico / Comparación de las prevalencias de Leishmania (Leishmania) mexicana en mamíferos pequeños en cinco focos de leishmaniosis cutánea en el estado de Campeche, México

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

En la Península de Yucatán, México, la Leishmaniosis Cutánea es causada por Leishmania (L.) mexicana en 95% de los casos humanos, con una incidencia de 5.08% por cada 100,000 habitantes. El ciclo de transmisión se limita a la estación de invierno (noviembre- marzo). Un estudio de mamíferos silvestres incrimina a Ototylomys phyllotis y Peromyscus yucatanicus como reservorios primarios de L. (L.) mexicana en el foco de infección de La Libertad, Campeche. En el presente estudio, se documenta la prevalencia de infección/enfermedad causada por L. (L.) mexicana en pequeños mamíferos, durante cinco estaciones de transmisión (1994-2004) en cinco focos de CL del estado de Campeche. Los focos separados por solamente 100 km. de distancia, aún cuando tienen abundancias relativas de pequeños roedores similares, fueron significativamente diferentes en relación a la prevalencia de síntomas así como de infección. Las tasas de transmisión y las especies de reservorios parecen estar cambiando tanto en el tiempo como en el espacio, lo cual impide el establecimiento de adecuadas medidas de control de la enfermedad aún en un área endémica tan pequeña como lo es el sur de la Península de Yucatán.

HER-2-neu: ¿posible diana del carcinoma vesical? / HER-2-neu: a possible target of bladder carcinoma?

No disponible

Placas protruyentes de la aorta torácica en el ecocardiograma transesofágico: características clínicas y ecográficas / Protruding plaques of the thoracic aorta in the transesophageal echocardiography: clinical and echographic features

Transesophageal echocardiography has a better sensitivity than conventional echocardiography for the detection of protruding atheroesclerotic plaques of the thoracic aorta. Clinical histories of 308 patients subjected to transesophageal echocardiography were reviewed. Subjects with protruding aortic plaques >0,5 cm were selected. Fifteen patients had protruding aortic plaques on transesophageal echocardiography and none of these were detected with conventional echocardiography. All these patients were in sinus rhythm and had high blood pressure. Ten subjects (67 percent) had a history of ischemic cerebrovascular or peripheral artery diseases (compared to 31 percent of subjects without protruding plaques) and in 7, the plaque was the only embolic source. Six patients (40 percent), smoked and 4 (27 percent) had coronary artery disease. One patient was diabetic and one had hypercholesterolemia. In conclusion, transesophageal echocardiography allows the detection of protruding aortic plaques that are potential embolic sources in patients with vascular diseases

[A comparison and synergy in the treatment of essential arterial hypertension]. / Comparación y sinergia en el tratamiento de la hipertensión arterial esencial.

Forty patients with mild or moderate essential hypertension were studied. They received daily doses of either 240 mg verapamil or 10 mg enalapril, as well as a placebo. Total duration of trial was 24 weeks: a "washout" period of 2 weeks, a treatment period of 6 weeks with one of the two drugs, another "washout" period of 2 weeks, and another treatment period of 6 weeks with the alternate drug. Those patients with persistence of diastolic blood pressure (DBP) above 90 mmHg received simultaneously both drugs for an additional period of 8 weeks. Patients were assigned alternately to one of the groups. When each drug was given during the first treatment period, DBP was reduced below 90 mmHg in 15 of 19 patients receiving verapamil, and in 12 of 20 that received enalapril. When the drugs were given during the second treatment period, DBP became normal in 16 of 19 patients receiving enalapril, and in all the 18 patients treated with verapamil. Three patients achieved normal DBP when received simultaneously both drugs. Two patients withdrew from the trial for personal reasons and one for experimenting cough as reaction to enalapril. There were no other undesirable side effects. Laboratory tests did not show changes. Both products were similarly effective. Synergy was shown by the improvement of patients unresponsive to either drug when given singly, but responding when both were given simultaneously.

[Cilazapril, a new ACE inhibitor, in severe arterial hypertension]. / Cilazapril, un nuevo inhibidor de ECA, en la hipertensión arterial severa.

We assessed the efficacy and safety of cilazapril, alone or in combination with hydrochlorothiazide. It was an open trial, that included 14 patients with or more 114 mmHg of diastolic arterial tension. On the first stage of 25 days, the arterial tension was normalized in 5 patients with 10 mg of cilazapril and 7 patients when hydrochlorothiazide was added, 2 patients did not respond. On the second stage of 52 weeks, of the 12 patients whose diastolic arterial tension was normalized, 2 patients remained with normal arterial tension with cilazapril, 5 when hydrochlorothiazide was added and the rest 5 patients did not respond. No undesirable side effects were detected, nor abnormalities in the laboratory tests. The long-term benefit obtained on 50% of patients make evident the usefulness of cilazapril in severe arterial hypertension. Its administration once a day and the absence of side effects increase the interest of its use.

Taponamiento cardíaco hemorrágico sin rotura cardíaca en el curso de infarto del miocardio: caso clínico / Hemorrhagic cardiac tamponade without cardiac rupture during an evolving myocardial infarction: case report

Cardiac tamponade during acute myicardial infarction is a lif threatening complication that can be confounded with right ventricular infarction. The most frequent cause of this complication is cardiac rupture. We report here a patient with acute myocardial infarction that developed cardiac tamponade on day 7, after receiving late systemic thrombolysis. The diagnosis was suspected with echocardiography and confirmed with hemodynamic measurements. The tamponade was partially relieved with pericardiocentesis but afterwards required emergency surgery. No cardiac rupture was found but an hemorragic infarction. We conclude that in this case the hemorragic tamponade was probably related both to late thrombolysis and to post infarction pericarditis

Modificaciones del mecanismo de interacción visual-vestibular en el tronco cerebral inducidas por la experiencia del vuelo / Modifications of the visual-vestibular interaction induced through the flying training

La interacción visual-vestibular es la expresión funcional de la capacidad de coordinación de aferencias multimodales en el tronco cerebral. Esta interacción posibilita el control de los movimientos oculares reflejos y la percepción de movimiento, la cual es una importante función de la orientación espacial dinámica. La percepción de movimientos en el espacio es producida por la estimulación visual de la corteza occipital, con activación secundaria de los núcleos vestibulares, mediadas por vías ipsilaterales. La modulación de la frecuencia de descarga de estas neuronas así como la percepción del vector de desplazamiento, es mediada por la directa relación entre las cortezas visual y vestibular, alimentadas por la información proveniente de la vía vestíbulo-talámica y sus relaciones con la corteza vestibular parieto-temporal. La experiencia del vuelo, en seres humanos, modifica las características de esta interacción. En directa relación con las horas de vuelo, se aprecian aumentos de las respuestas vestibulares en pilotos de aviones de combate de alto rendimiento con paralela inhibición de las respuestas optokinéticas. En pilotos de helicópteros se observa el fenómeno inverso. Queda planteada la hipótesis de la existencia de un sistema funcional de transferencia y balance de información sensorial en el tronco cerebral, el cual puede relacionarse con la actividad de la formación reticular pontina paramediana, núcleo reticular del tegmento protuberancial, núcleo intersticial de Cajal y núcleo prepósito hipogloso