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1.
Public Health ; 202: 1-9, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34856520

RESUMEN

OBJECTIVES: Investigate factors associated with the intention to have the COVID-19 vaccination following initiation of the UK national vaccination programme. STUDY DESIGN: An online cross-sectional survey completed by 1500 adults (13th-15th January 2021). METHODS: Linear regression analyses were used to investigate associations between intention to be vaccinated for COVID-19 and sociodemographic factors, previous influenza vaccination, attitudes and beliefs about COVID-19 and COVID-19 vaccination and vaccination in general. Participants' main reasons for likely vaccination (non-)uptake were also solicited. RESULTS: 73.5% of participants (95% CI 71.2%, 75.7%) reported being likely to be vaccinated against COVID-19, 17.3% (95% CI 15.4%, 19.3%) were unsure, and 9.3% (95% CI 7.9%, 10.8%) reported being unlikely to be vaccinated. The full regression model explained 69.8% of the variance in intention. Intention was associated with: having been/intending to be vaccinated for influenza last winter/this winter; stronger beliefs about social acceptability of a COVID-19 vaccine; the perceived need for vaccination; adequacy of information about the vaccine; and weaker beliefs that the vaccine is unsafe. Beliefs that only those at serious risk of illness should be vaccinated and that the vaccines are just a means for manufacturers to make money were negatively associated with vaccination intention. CONCLUSIONS: Most participants reported being likely to get the COVID-19 vaccination. COVID-19 vaccination attitudes and beliefs are a crucial factor underpinning vaccine intention. Continued engagement with the public with a focus on the importance and safety of vaccination is recommended.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Adulto , Estudios Transversales , Conocimientos, Actitudes y Práctica en Salud , Humanos , SARS-CoV-2 , Factores Sociodemográficos , Reino Unido , Vacunación
2.
J Public Health (Oxf) ; 39(3): 601-608, 2017 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-27412177

RESUMEN

Background: The incorporation of Human papillomavirus (HPV) testing into the English cervical screening programme has been met with fear and anxiety. Healthcare professionals need to be adequately informed about HPV to help alleviate patient concerns. The aim of this study was to evaluate the HPV training provided to practice nurses (PNs) and determine their level of HPV knowledge. Method: A web-based survey was distributed to 147 General Practice surgeries in the Leicester, Leicestershire and Rutland regions, between May and July 2015. The survey explored four broad areas; demographics/level of experience, HPV knowledge, attitudes towards the HPV vaccine and self-perceived adequacy of HPV knowledge. Results: A total of 128 surveys were completed, with 94 complete responses. Overall awareness of basic HPV facts was adequate; however, detailed, and in some cases basic, knowledge was lacking. 9.6% failed to identify that HPV can cause cervical cancer and 62.8% believed that HPV requires treatment. Not all PNs felt adequately informed about HPV and a need to improve the provision of training was identified. Conclusion: PNs play a key role in increasing public awareness of HPV and implementing cervical cancer screening. The provision of education to PNs needs to be a priority and current methods of training need to be re-evaluated.


Asunto(s)
Educación Continua en Enfermería , Conocimientos, Actitudes y Práctica en Salud , Papillomaviridae , Infecciones por Papillomavirus/diagnóstico , Infecciones por Papillomavirus/psicología , Enfermería de Atención Primaria/estadística & datos numéricos , Adulto , Estudios Transversales , Inglaterra , Femenino , Humanos , Persona de Mediana Edad , Infecciones por Papillomavirus/prevención & control , Enfermería de Atención Primaria/psicología , Encuestas y Cuestionarios , Neoplasias del Cuello Uterino/etiología , Neoplasias del Cuello Uterino/virología
3.
Cytopathology ; 27(4): 237-41, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26566859

RESUMEN

OBJECTIVE: To survey lead colposcopists to explore the extent to which patients are currently being invited to discuss the results of their invasive cervical cancer review, the reasons why this might not be happening and the clinician experience. METHODS: An online survey was sent to lead colposcopists across England. They were asked whether they offered the review to patients, if they did how they did so and what their experience was and if they did not, why not. RESULTS: There was a 68.5% (N = 122) response rate, with 53% of respondents currently offering the review meetings. Patients were predominantly invited to the review meeting face to face and clinicians' experiences were mixed with a variety of positive and negative aspects of the meetings given. For those clinicians not currently offering a review meeting, there were a variety of reasons: 25% cited a lack of awareness of the guidelines, 19% time constraints, 12% a fear of causing additional distress and 2% a fear of litigation. Open-ended responses demonstrated a considerable amount of misunderstanding about the process. CONCLUSION: Despite National Health Service Cervical Screening Programme guidelines, not all clinicians offer review meetings to patients and those who do offer them do not always offer them to all women. Patient research needs to be conducted to explore the value of the meetings further, and there is a need to do more to engage clinicians in the process.


Asunto(s)
Colposcopía/normas , Detección Precoz del Cáncer , Tamizaje Masivo , Neoplasias del Cuello Uterino/diagnóstico , Adulto , Inglaterra , Femenino , Humanos , Persona de Mediana Edad , Invasividad Neoplásica/patología , Médicos , Embarazo , Encuestas y Cuestionarios , Neoplasias del Cuello Uterino/epidemiología , Neoplasias del Cuello Uterino/patología
4.
J Obstet Gynaecol ; 36(1): 76-80, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26408400

RESUMEN

We conducted a survey to explore levels of awareness and knowledge of human papillomavirus (HPV) and cervical cancer in 170 female students and whether mode of data collection (online vs. paper) affected the results. 27% of women named HPV as a cause of cervical cancer with online respondents more likely to do so. 75% of women had heard of HPV. More online respondents had heard of HPV than paper respondents. 127 women reported having heard of HPV, with a mean knowledge score of 2.989 (standard deviation [SD] 1.599). Online respondents scored higher (3.57, SD 1.316) than paper respondents (2.688, SD 1.591). Knowledge and awareness of HPV and its link to cervical cancer appear to have increased which may be related to the HPV vaccination programme. However, there is still a considerable number of women with little to no knowledge of HPV. Online surveys may result in an inflated estimation of awareness and knowledge.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Infecciones por Papillomavirus/complicaciones , Estudiantes/psicología , Neoplasias del Cuello Uterino/virología , Adolescente , Concienciación , Recolección de Datos/métodos , Femenino , Humanos , Internet , Papel , Encuestas y Cuestionarios , Adulto Joven
5.
Cytopathology ; 24(2): 77-80, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23506198

RESUMEN

An audit of the screening history of all new cervical cancer cases has been a requirement since April 2007. While NHS cervical screening programmes (NHSCSP) guidance requires that women diagnosed with cervical cancer are offered the findings of the audit, as yet there has been no research to investigate the psychological impact that meeting to discuss the findings might have on patients. This is in spite of the fact that cytological under-call may play a role in as many as 20% of cervical cancer cases. This review draws on the literature concerning breaking bad news, discussing cancer and disclosing medical errors, in order to gain insight into both the negative and positive consequences that may accompany a cervical screening review meeting. We conclude that while patients are likely to experience some distress at disclosure, there are also likely to be positive aspects, such as greater trust and improved perception of care.


Asunto(s)
Revelación , Pacientes/psicología , Neoplasias del Cuello Uterino/psicología , Femenino , Guías como Asunto , Humanos , Tamizaje Masivo , Educación del Paciente como Asunto , Embarazo , Neoplasias del Cuello Uterino/epidemiología , Frotis Vaginal
6.
bioRxiv ; 2023 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-37034798

RESUMEN

Perception arises from activity between cortical areas, first primary cortex and then higher order cortices. This communication is served in part by transthalamic (cortico-thalamo-cortical) pathways, which ubiquitously parallel direct corticocortical pathways, but their role in sensory processing has largely remained unexplored. Here, we show that the transthalamic pathway linking somatosensory cortices propagates task-relevant information required for correct sensory decisions. Using optogenetics, we specifically inhibited the pathway at its synapse in higher order somatosensory thalamus of mice performing a texture-based discrimination task. We concurrently monitored the cellular effects of inhibition in primary or secondary cortex using two-photon calcium imaging. Inhibition severely impaired performance despite intact direct corticocortical projections, thus challenging the purely corticocentric map of perception. Interestingly, the inhibition did not reduce overall cell responsiveness to texture stimulation in somatosensory cortex, but rather disrupted the texture selectivity of cells, a discriminability that develops over task learning. This discriminability was more disrupted in the secondary than primary somatosensory cortex, emphasizing the feedforward influence of the transthalamic route. Transthalamic pathways thus appear critical in delivering performance-relevant information to higher order cortex and are critical hierarchical pathways in perceptual decision-making.

7.
Can J Ophthalmol ; 55(2): 159-166, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31712009

RESUMEN

OBJECTIVES: The aim of this study is to report a case series of atypical presentations of intracranial dysgerminoma in which the diagnosis was delayed due to clinical and radiographic findings initially suggestive of CNS inflammatory or demyelinating diseases, such as MS. METHODS: This study is a case series detailing the history, clinical presentations, radiographic and laboratory results, and management of three patients with biopsy-proven intracranial dysgerminoma. RESULTS: All three patients demonstrated hyperintense lesions on MRI that were more suggestive of demyelinating or inflammatory diseases, including lesions involving the midbrain and corpus callosum. All three patients were serum positive for oligoclonal bands and negative for both AFP and beta-hCG (these two markers are commonly seen in dysgerminoma cases). One case involved a steroid-responsive tumor whereas the other two cases either did not respond to steroids or steroids were withheld due to uncertainty of etiology. Following biopsy, all three results were consistent with dysgerminoma. CONCLUSION: Clinicians should be aware that dysgerminoma may mimic the clinical and radiographic presentations of demyelinating diseases such as MS. These lesions can cause acute visual loss or diplopia, have MRI and CSF findings that might mimic MS, and have been shown to respond to steroids. Atypical clinical (e.g., headache, dorsal midbrain syndrome, bilateral optic neuropathy) or atypical radiographic features (e.g., mass effect, hydrocephalus) should prompt consideration for repeat imaging and possible biopsy even if serum or CSF tumor markers (beta-hCG and AFP) are negative for dysgerminoma.


Asunto(s)
Neoplasias Encefálicas/diagnóstico por imagen , Enfermedades Desmielinizantes/diagnóstico por imagen , Disgerminoma/diagnóstico por imagen , Meningoencefalitis/diagnóstico por imagen , Biomarcadores de Tumor/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Enfermedades Desmielinizantes/metabolismo , Enfermedades Desmielinizantes/patología , Diagnóstico Diferencial , Disgerminoma/metabolismo , Disgerminoma/patología , Femenino , Humanos , Inmunohistoquímica , Imagen por Resonancia Magnética , Masculino , Meningoencefalitis/metabolismo , Meningoencefalitis/patología , Persona de Mediana Edad , Proteínas de Neoplasias/metabolismo , Estudios Retrospectivos , Pruebas del Campo Visual , Campos Visuales/fisiología , Adulto Joven
8.
Science ; 185(4148): 355-7, 1974 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-4599635

RESUMEN

When cats were tested for visual field perimetry, the field of vision for each eye separately was from 45 degrees contralateral to 90 degrees ipsilateral. After either bilateral occipitotemporal lesions (with a split of the tectal commissure) or bilateral area 17, 18, and 19 lesions, the cats could see with each eye only from the midline to 90 degrees ipsilateral. A cat that became nearly totally blind as a result of bilateral occipitotemporal decortication had a subsequent tectal split which enabled it to see with each eye from the midline to 90 degrees ipsilateral.


Asunto(s)
Corteza Cerebral/fisiología , Fenómenos Fisiológicos Oculares , Colículos Superiores/fisiología , Campos Visuales , Percepción Visual , Animales , Decorticación Cerebral , Lóbulo Occipital/fisiología , Orientación , Técnicas Estereotáxicas , Lóbulo Temporal/fisiología , Pruebas del Campo Visual , Vías Visuales/fisiología
9.
Science ; 186(4160): 267-9, 1974 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-4414712

RESUMEN

Monocularly deprived cats were tested for visual perinetry before and after visual cortex lesions. Such a lesion greatly enhances the deprived eye's performance and impairs that of the nondeprived eye so that the pronounced preoperative interocular asymmetry is lost postoperatively. Apparently this destruction of abnormal corticotectal pathways allows the expression of previously suppressed, normal retinotectal pathways.


Asunto(s)
Corteza Visual/fisiología , Campos Visuales , Vías Visuales/fisiología , Animales , Gatos , Decorticación Cerebral , Orientación , Colículos Superiores/fisiología , Pruebas del Campo Visual
10.
Science ; 218(4570): 389, 1982 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-7123239

RESUMEN

We injected horseradish peroxidase into single, physiologically identified, optic tract axons of X and Y cells in cats and studied their termination patterns in the lateral geniculate nucleus. All X cell axons innervate lamina A or A1 in narrow zones, and some sparsely innervate the medical interlaminar nucleus. All Y cell axons have broad terminal zones in laminae A and C (from the contralateral retina) or lamina A1 (if ipsilateral), and most innervate the medial interlaminar nucleus densely.


Asunto(s)
Vías Visuales/citología , Animales , Mapeo Encefálico , Gatos , Lateralidad Funcional , Cuerpos Geniculados/citología , Peroxidasa de Rábano Silvestre , Retina/citología
11.
Science ; 203(4387): 1353-5, 1979 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-424758

RESUMEN

In cats reared in the dark from birth until 4 months of age, the dorsal lateral geniculate nucleus contained few normal Y cells in either the binocular or monocular segments. Although most of the neurons appeared to be normal X cells unaffected by light deprivation, many cells with abnormal receptive field and response charcteristics were encountered. These effects were permanent, since 1 to 2 years of normal visual experience following initial light deprivation did not lead to any functional recovery. The sizes of cell bodies in cats reared in the dark were similar to those of normal animals, an indication that changes in geniculate cell physiology need not be related to changes in cell size.


Asunto(s)
Cuerpos Geniculados/citología , Visión Ocular , Vías Visuales/crecimiento & desarrollo , Animales , Gatos , Oscuridad , Lateralidad Funcional , Cuerpos Geniculados/crecimiento & desarrollo , Vías Visuales/citología
12.
Science ; 197(4305): 784-6, 1977 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-887922

RESUMEN

In tree shrews (Tupaia glis) reared with one eye closed, Y-cells were almost entirely absent in the binocular segment of the lateral geniculate laminae receiving input from the deprived eye. Y-cells were found in the monocular segment of these laminae, and in the binocular segment of the laminae with input from the normal eye. X-cells were present in both the deprived and normal laminae and appeared unaffected by the deprivation. A number of abnormal cells were also found, and these were located primarily in the binocular segment where Y-cells were absent.


Asunto(s)
Cuerpos Geniculados/citología , Musarañas/anatomía & histología , Vías Visuales/citología , Percepción Visual , Animales , Cuerpos Geniculados/crecimiento & desarrollo , Vías Visuales/crecimiento & desarrollo
13.
Science ; 204(4397): 1114-7, 1979 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-451559

RESUMEN

Horseradish peroxidase injected into 18 single, physiologically identified geniculate X and Y cells permitted a detailed morphological correlate to be determined for the physiological properties of each neuron. Class 1 morphological characteristics were associated with Y cells, class 3 with X cells, and class 2 structural traits were seen in both physiological types.


Asunto(s)
Cuerpos Geniculados/citología , Animales , Gatos , Cuerpos Geniculados/fisiología , Peroxidasa de Rábano Silvestre , Interneuronas/citología
14.
Neuron ; 27(3): 597-610, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11055441

RESUMEN

The thalamic relay to neocortex is dynamically gated. The inhibitory interneuron, which we have studied in the lateral geniculate nucleus, is important to this process. In addition to axonal outputs, these cells have dendritic terminals that are both presynaptic and postsynaptic. Even with action potentials blocked, activation of ionotropic and metabotropic glutamate receptors on these terminals increases their output, whereas activation of metabotropic (M2 muscarinic) but not nicotinic cholinergic receptors decreases their output. These actions can strongly affect retinogeniculate transmission.


Asunto(s)
Cicloleucina/análogos & derivados , Dendritas/fisiología , Cuerpos Geniculados/fisiología , Interneuronas/fisiología , Inhibición Neural/fisiología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Calcio/metabolismo , Gatos , Cicloleucina/farmacología , Antagonistas del GABA/farmacología , Cuerpos Geniculados/citología , Cuerpos Geniculados/efectos de los fármacos , Ácido Glutámico/metabolismo , Técnicas In Vitro , Interneuronas/citología , Interneuronas/efectos de los fármacos , Magnesio/metabolismo , Magnesio/farmacología , Agonistas Muscarínicos/farmacología , Inhibición Neural/efectos de los fármacos , Agonistas Nicotínicos/farmacología , Técnicas de Placa-Clamp , Terminales Presinápticos/efectos de los fármacos , Terminales Presinápticos/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/metabolismo , Tetrodotoxina/farmacología , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/farmacología
15.
Neuroscience ; 146(1): 463-70, 2007 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-17320295

RESUMEN

We used electron microscopy to determine the relative numbers of the three synaptic terminal types, RL (round vesicle, large terminal), RS (round vesicles, small terminal), and F (flattened vesicles), found in several representative thalamic nuclei in cats chosen as representative examples of first and higher order thalamic nuclei, where the first order nuclei relay subcortical information mainly to primary sensory cortex, and the higher order nuclei largely relay information from one cortical area to another. The nuclei sampled were the first order ventral posterior nucleus (somatosensory) and the ventral portion of the medial geniculate nucleus (auditory), and the higher order posterior nucleus (somatosensory) and the medial portion of the medial geniculate nucleus (auditory). We found that the relative percentage of synapses from RL terminals varied significantly among these nuclei, these values being higher for first order nuclei (12.6% for the ventral posterior nucleus and 8.2% for the ventral portion of the medial geniculate nucleus) than for the higher order nuclei (5.4% for the posterior nucleus, and 3.5% for the medial portion of the medial geniculate nucleus). This is consistent with a similar analysis of first and higher order nuclei for the visual system (the lateral geniculate nucleus and pulvinar, respectively). Since synapses from RL terminals represent the main information to be relayed, whereas synapses from F and RS terminals are modulatory in function, we conclude that there is relatively more modulation of the thalamic relay in the cortico-thalamo-cortical higher order pathway than in first order relays.


Asunto(s)
Vías Nerviosas/anatomía & histología , Neuronas/ultraestructura , Sinapsis/fisiología , Tálamo/citología , Animales , Gatos , Microscopía Electrónica de Transmisión/métodos , Microscopía Inmunoelectrónica/métodos , Neuronas/metabolismo , Sinapsis/ultraestructura , Ácido gamma-Aminobutírico/metabolismo
17.
Trends Neurosci ; 24(2): 122-6, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11164943

RESUMEN

All thalamic relay cells exhibit two distinct response modes--tonic and burst--that reflect the status of a voltage-dependent, intrinsic membrane conductance. Both response modes efficiently relay information to the cortex in behaving animals, but have markedly different consequences for information processing. The lateral geniculate nucleus, which is the thalamic relay of retinal information to cortex, provides a reasonable model for all of thalamus. Compared with burst mode, geniculate relay cells that are firing in tonic mode exhibit better linear summation, but have poorer detectability for visual stimuli. The switch between the response modes can be controlled by nonretinal, modulatory afferents to these cells, such as the feedback pathway from cortex. This allows the thalamus to provide a dynamic relay that affects the nature and format of information that reaches the cortex.


Asunto(s)
Potenciales de Acción/fisiología , Corteza Cerebral/fisiología , Potenciales Postsinápticos Excitadores/fisiología , Red Nerviosa/fisiología , Sinapsis/fisiología , Tálamo/fisiología , Animales , Humanos , Corteza Visual/fisiología
18.
J Neurosci ; 21(3): 1022-32, 2001 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-11157087

RESUMEN

The low-threshold spike (LTS), generated by the transient Ca(2+) current I(T), plays a pivotal role in thalamic relay cell responsiveness and thus in the nature of the thalamic relay. By injecting depolarizing current ramps at various rates to manipulate the slope of membrane depolarization (dV/dt), we found that an LTS occurred only if dV/dt exceeded a minimum value of approximately 5-12 mV/sec. We injected current ramps of variable dV/dt into relay cells that were sufficiently hyperpolarized to de-inactivate I(T) completely. Higher values of dV/dt activated an LTS. However, lower values of dV/dt eventually led to tonic firing without ever activating an LTS; apparently, the inactivation of I(T) proceeded before I(T) could be recruited. Because the maximum rate of rise of the LTS decreased with slower activating ramps of injected current, we conclude that slower ramps allow increasing inactivation of I(T) before the threshold for its activation gating is reached, and when the injected ramps have a sufficiently low dV/dt, the inactivation is severe enough to prevent activation of an LTS. In the presence of Cs(+), we found that even the lowest dV/dt that we applied led to LTS activation, apparently because Cs(+) reduced the K(+) "leak" conductance and increased neuronal input resistance. Nonetheless, under normal conditions, our data suggest that there is neither significant window current (related to the overlap of the inactivation and activation curves for I(T)), rhythmogenic properties, nor bistability properties for these neurons. Our theoretical results using a minimal model of LTS excitability in these neurons are consistent with the experimental observations and support our conclusions. We suggest that inputs activating very slow EPSPs (i.e., via metabotropic receptors) may be able to inactivate I(T) without generating sizable I(T) and a spurious burst of action potentials to cortex.


Asunto(s)
Potenciales de Acción/fisiología , Cuerpos Geniculados/fisiología , Neuronas/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Señalización del Calcio/fisiología , Gatos , Cesio/farmacología , Simulación por Computador , Estimulación Eléctrica/métodos , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , Cuerpos Geniculados/citología , Técnicas In Vitro , Lisina/análogos & derivados , Modelos Neurológicos , Neuronas/citología , Neuronas/efectos de los fármacos , Potasio/metabolismo , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Umbral Sensorial/fisiología , Tetrodotoxina/farmacología , Tálamo/citología , Tálamo/fisiología
19.
J Neurosci ; 20(10): 3909-14, 2000 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-10804230

RESUMEN

Thalamic relay cells respond in two distinct modes, burst and tonic, that depend on a voltage-dependent, low-threshold, transient Ca(2+) current (I(T)), and these modes relay different forms of information to cortex. I(T) activation evokes a low-threshold spike (LTS), producing a burst of action potentials. Modulatory inputs from cortex and brainstem are known to activate metabotropic receptors on relay cell dendrites at which the T channels underlying I(T) may be concentrated. We thus investigated the influence of activating these receptors on the LTS, using current-clamp intracellular recording in an in vitro slice preparation of the cat's lateral geniculate nucleus. We found a strong correlation between LTS amplitude and the number of action potentials evoked in the burst. We then found that activation of either metabotropic glutamate or muscarinic receptors produced a hyperpolarizing shift in the sigmoid relationship between LTS amplitude and the initial holding potential without affecting the maximum LTS amplitude or slope of the relationship. This hyperpolarizing shift in the voltage dependency of LTS amplitude is best explained by space-clamp limitations and significantly more depolarization of T channels near the dendritic location of activated receptors than at the soma. Thus, nonretinal modulatory inputs may have a stronger influence on I(T) and number of action potentials generated in a burst than previously imagined from somatic recording, because the EPSP amplitudes generated by these inputs at the dendritic location of most T channels are greater than after their electrotonic decay recorded at the soma.


Asunto(s)
Calcio/metabolismo , Dendritas/fisiología , Cuerpos Geniculados/citología , Animales , Canales de Calcio Tipo T/fisiología , Carbacol/farmacología , Gatos , Agonistas Colinérgicos/farmacología , Cicloleucina/análogos & derivados , Cicloleucina/farmacología , Dendritas/química , Electrofisiología , Cuerpos Geniculados/química , Técnicas In Vitro , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Vías Nerviosas , Fármacos Neuroprotectores/farmacología , Periodicidad , Puente/citología , Receptores de Glutamato Metabotrópico/fisiología , Receptores Muscarínicos/fisiología
20.
J Comp Neurol ; 172(2): 211-29, 1977 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-838879

RESUMEN

The visual fields of 18 cats were measured before and after various lesions. Preoperatively, all cats had identical fields. With both eyes open, they saw from 90 degrees left to 90 degrees right; with one eye, from 90 degrees ipsilateral to 45 degrees contralateral. Thus the field for nasal retina extends from 90 degrees ipsilateral through to the midline; for temporal retina, from the midline through to 45 degrees contralateral. In summary, postoperative testing led to two major conclusions. (1) Large occipito-temporal cortical lesions produce a stable field blindness, but the blindness is alleviated by a transection of the commissure of the superior colliculus (or a unilateral collicular ablation). This transection yields the same result whether it occurs in an operation before, during, or after the cortical lesion. These data confirm and extend the Sprague effect. (2) Cats made dependent upon retinotectal pathways due to cortical ablations responded much better to stimulation of nasal retina than to stimulation of temporal retina. This presumably is related to the preponderance of nasal retina as a source of the retinotectal pathway. Since even smaller cortical lesions limited to areas 17, 18, and 19 produce this nasal/temporal retinal difference, it is concluded that integrity of the geniculocortical pathways is necessary for good temporal retinal vision as determined by these methods.


Asunto(s)
Corteza Cerebral/fisiología , Retina/fisiología , Colículos Superiores/fisiología , Animales , Gatos , Quiasma Óptico/fisiología , Lóbulo Temporal/fisiología , Corteza Visual/fisiología , Campos Visuales , Vías Visuales
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