Fiber-optic endoscopic evaluation of swallowing to assess swallowing outcomes as a function of head position in a normal population.

Background: Head position practice has been shown to influence pill-swallowing ability, but the impact of head position on measures of swallowing outcomes has not yet been studied with fiber-optic endoscopic evaluation of swallowing (FEES). The primary purpose of this study was to determine whether head position impacts penetration-aspiration scale scores and/or post-swallow pharyngeal residue as assessed by FEES. Documenting the incidence of pharyngeal residue and laryngeal penetration and aspiration in a normal population was a secondary goal.

Using simple imaging markers to predict prognosis in patients with aortic valve stenosis and unacceptable high risk for operation.

Aortic valve stenosis (AS) in patients >75 years of age is a challenge for diagnosis and management of every day clinical routine. Therefore, this clinical follow-up study aims to investigate predictors of death in patients with advanced stages of AS. In a single-center study, all patients (n = 157) with primary conservatively treated severe AS (mean age 78 ± 6 years) were included.

Modeling cerebellar flocculus and paraflocculus involvement in complex predictive smooth eye pursuit in monkeys.

The role of flocculus and paraflocculus neurons in the cerebellar control of predictive eye movements was examined using two modeling techniques. The first study characterized the dependence of individual Purkinje-cell firing patterns on oculomotor output, visual input, and response timing using multilinear regression techniques. Interestingly, no dependence on visual input was detected.

Complex predictive eye pursuit in monkey: a model system for cerebellar studies of skilled movement.

Smooth pursuit eye movements provide a good model system for cerebellar studies of complex motor control in monkeys. First, the pursuit system exhibits predictive control along complex trajectories and this control improves with training. Second, the flocculus/paraflocculus region of the cerebellum appears to generate this control.

Cerebellar flocculus and ventral paraflocculus Purkinje cell activity during predictive and visually driven pursuit in monkey.

Purkinje cells in the flocculus and ventral paraflocculus were studied in tasks designed to distinguish predictive versus visually guided mechanisms of smooth pursuit. A sum-of-sines task allowed studies of complex predictive pursuit. A perturbation task examined visually driven pursuit during unpredictable right-angle changes in target direction.

Cerebellar flocculus and paraflocculus Purkinje cell activity during circular pursuit in monkey.

Responses from 69 Purkinje cells in the flocculus and paraflocculus of two rhesus monkeys were studied during smooth pursuit of targets moving along circular trajectories and compared with responses during sinusoidal pursuit and fixation. A variety of interesting responses was observed during circular pursuit. Although some neurons fired most strongly in a single preferred direction during clockwise (CW) and counterclockwise (CCW) pursuit, others had directional preferences that changed with rotation direction.

[Animal experiments for testing a hydroxyapatite ceramic coating under vacuum conditions].

Implants that were coated with hydroxyapatite ceramic (H-A.C.) under atmospheric condition in vivo often showed local areas of delamination.

Predictive smooth pursuit of complex two-dimensional trajectories demonstrated by perturbation responses in monkeys.

Two-dimensional sum-of-sines waveforms were pursued by the eye with very small phase delays compared with visual feedback delays estimated in the same monkeys. Processing delays in making smooth corrections averaged 90 msec after infrequent right-angle perturbations from a circular trajectory. These feedback delays were much larger than component phase delays during pursuit that averaged: 10 msec for sinusoids, 3 msec for circles, 20 msec for sum-of-two-sines trajectories, and 19 msec for sum-of-three-sines trajectories.

Prediction of complex two-dimensional trajectories by a cerebellar model of smooth pursuit eye movement.

A neural network model based on the anatomy and physiology of the cerebellum is presented that can generate both simple and complex predictive pursuit, while also responding in a feedback mode to visual perturbations from an ongoing trajectory. The model allows the prediction of complex movements by adding two features that are not present in other pursuit models: an array of inputs distributed over a range of physiologically justified delays, and a novel, biologically plausible learning rule that generated changes in synaptic strengths in response to retinal slip errors that arrive after long delays. To directly test the model, its output was compared with the behavior of monkeys tracking the same trajectories.

Control of remembered reaching sequences in monkey. II. Storage and preparation before movement in motor and premotor cortex.

Single-neuron responses in motor and premotor cortex were recorded during a movement-sequence delay task. On each trial the monkey viewed a randomly selected sequence of target lights arrayed in two-dimensional space, remembered the sequence during a delay period, and then generated a coordinated sequence of movements to the remembered targets. Of 307 neurons studied, 25% were tuned specifically for either the first or the second target, but not both.

Control of remembered reaching sequences in monkey. I. Activity during movement in motor and premotor cortex.

Motor and premotor cortex firing patterns from 307 single neurons were recorded while monkeys made rapid sequences of three reaching movements to remembered target buttons arrayed in two-dimensional space. A primary goal was to study and compare directionally tuned responses for each of three movement periods during 12 movement sequences that uniformly sampled the directional space in front of the monkey. The majority of neurons showed maximal responses during movements in a preferred direction with smaller increases during movements close to the preferred direction.

Predictive smooth pursuit of complex two-dimensional trajectories in monkey: component interactions.

Smooth pursuit eye movements were studied in monkeys tracking target spots that moved two-dimensionally. Complex target trajectories were created by applying either two or three sinusoids to horizontal and vertical axes in various combinations. The chance of observing predictable performance was increased by repeated training on each trajectory.

A possible inflammatory reaction in a lateral neck cyst (branchial cyst) because of odontogenic infection.

We present the case of a woman who suffered from an acutely infected diffuse mass in the right neck. This mass had grown rapidly after difficult extraction of a tooth. Histologic analysis of the excised material revealed a lateral neck cyst with a lymph node that showed signs of an acute inflammation near the cyst.

A Neural Network Model of Cortical Activity during Reaching.

Abstract A neural network model that produces many of the directional and spatial response properties that have been observed for cortical neurons in monkeys moving toward targets in space is described. These include motor cortex units with broad tuning in a single preferred direction, approximately linear variation in activity for different hold positions, and approximate invariance in preferred direction for different starting points in space. Association cortex units in the model are sometimes irregular and reminiscent of neurons observed in visually responsive brain areas such as the posterior parietal cortex.

Primate motor cortex and free arm movements to visual targets in three-dimensional space. III. Positional gradients and population coding of movement direction from various movement origins.

In one experiment, we studied the relations between the frequency of discharge of 274 single cells in the arm area of the motor cortex of the monkey and the actively maintained position of the hand in space. We found that the frequency of discharge of 63.9% of the cells studied was a multilinear function of the position of the hand in space according to the following equation (multiple linear regression): d = f + fxsx + fysy + fzsz, where d is the discharge rate of a single cell, f, fx, fy, fz are regression coefficients, and sx, sy, sz are the coordinates of the position of the hand.

Primate motor cortex and free arm movements to visual targets in three-dimensional space. II. Coding of the direction of movement by a neuronal population.

We describe a code by which a population of motor cortical neurons could determine uniquely the direction of reaching movements in three-dimensional space. The population consisted of 475 directionally tuned cells whose functional properties are described in the preceding paper (Schwartz et al., 1988).

Primate motor cortex and free arm movements to visual targets in three-dimensional space. I. Relations between single cell discharge and direction of movement.

We describe the relations between the neuronal activity in primate motor cortex and the direction of arm movement in three-dimensional (3-D) space. The electrical signs of discharge of 568 cells were recorded while monkeys made movements of equal amplitude from the same starting position to 8 visual targets in a reaction time task. The layout of the targets in 3-D space was such that the direction of the movement ranged over the whole 3-D directional continuum in approximately equal angular intervals.

Physiological study of neurons in the dorsal and posteroventral cochlear nucleus of the unanesthetized cat.

The responses of neurons in the posteroventral (PVCN) and dorsal (DCN) cochlear nucleus of the unanesthetized cat were determined for both long and short tones. These results were compared with recent studies in the barbiturate-anesthetized cat conducted in the same laboratory using similar stimuli and analysis programs. Every response pattern (poststimulus time histogram to short tones), which has been observed in previous studies using anesthetized animals, was also observed without anesthetic.

Neuronal population coding of movement direction.

Although individual neurons in the arm area of the primate motor cortex are only broadly tuned to a particular direction in three-dimensional space, the animal can very precisely control the movement of its arm. The direction of movement was found to be uniquely predicted by the action of a population of motor cortical neurons. When individual cells were represented as vectors that make weighted contributions along the axis of their preferred direction (according to changes in their activity during the movement under consideration) the resulting vector sum of all cell vectors (population vector) was in a direction congruent with the direction of movement.

Topography of binaural organization in primary auditory cortex of the cat: effects of changing interaural intensity.

Responses from neuron clusters were used to derive binaural and aural dominance maps within the 5- to 30-kHz frequency representation of the primary auditory cortical (AI) field in the barbiturate-anesthetized cat. Tone burst stimuli were presented dichotically using a calibrated and sealed acoustic delivery system to parametrically vary interaural intensity difference (IID). Neuron cluster responses were divided into three binaural interaction classes using audiovisual criteria: summation (56%), suppression (25%), and mixed (17%).

Cochlear nucleus, inferior colliculus, and medial geniculate responses during the behavioral detection of threshold-level auditory stimuli in the rabbit.

Rabbits were conditioned to respond behaviorally to auditory stimuli by pairing a white-noise conditioned stimulus (CS) with a corneal airpuff unconditioned stimulus (US). The conditioned response (CR) was movement of the nictitating membrane (NM). After the subjects were responding at better than the 90% correct level, the intensity of the auditory stimulus was reduced to behavioral threshold using a staircase procedure.

Postnatal development of the phase-locked response to low frequency tones of auditory nerve fibers in the cat.

The maturation of the auditory nerve's ability to encode temporal information in an acoustic signal was studied in young kittens, 7 to 23 days old, and in adult cats by measuring the degree to which auditory nerve fiber responses are synchronized (phase locked) to low frequency tones. The major findings include the following. In 7- to 10-day-old kittens thresholds are high (around 100 dB), and secure phase locking is observed only at frequencies below about 600 Hz.

Closed circuit television: a unique tool.

A closed circuit television station was instituted within the Children's Hospital of Winnipeg in April 1981. The station broadcasts commercial-free children's programming throughout the day with the highlight of the schedule being a 1-hour live broadcast each weekday. The personal, interactive format of the live program has made the show a unique and effective tool for reaching patients, helping individual patients accept different aspects of their care, teaching the children about the hospital, and simply boosting morale through making each child a part of the program.