Biomedical subjects

F Gandolfo

Publications and source records attributed to F Gandolfo.

6 recordsLinked to original sources

PubMed2000

Cortical correlates of learning in monkeys adapting to a new dynamical environment.

In this paper, we describe the neural changes observed in the primary motor cortex of two monkeys while they learned a new motor skill. The monkeys had to adapt their reaching movements to external forces that interfered with the execution of their arm movements. We found a sizable population of cells that changed their tuning properties during exposure to the force field. These cells took on the properties of neurons that are involved in the control of movement. Furthermore, the cells maintained the acquired activity as the monkey readapted to the no-force condition. Recent imaging studies in humans have reported the effects of motor learning in the primary motor cortex. Our results are consistent with the findings of these studies and provide evidence for single-cell plasticity in the primary motor cortex of primates.

Adaptation, Physiological↗

PubMed1997

The motor system does not learn the dynamics of the arm by rote memorization of past experience.

The purpose of this study was to investigate the learning mechanisms underlying motor adaptation of arm movements to externally applied perturbing forces. We considered two alternative hypotheses. According to one, adaptation occurs through the learning of a mapping between the states (positions and velocities) visited by the arm and the forces experienced at those states. The alternative hypothesis is that adaptation occurs through the memorization of the temporal sequence of forces experienced along specific trajectories. The first mechanism corresponds to developing a model of the dynamics of the environment, whereas the second is a form of "rote learning." Both types of learning would lead to the recovery of the unperturbed performance. We have tested these hypotheses by examining how adaptation is transferred across different types of movements. Our results indicate that 1) adaptation to an externally applied force field occurs with different classes of movements including but not limited to reaching movements and 2) adaptation generalizes across different movements that visit the same regions of the external field. These findings are not compatible with the hypothesis of rote learning. Instead, they are consistent with the hypothesis that adaptation to changes in movement dynamics is achieved by a module that learns to reproduce the structure of the environmental field as an association between visited states and experienced forces, independent of the kinematics of the movements made during adaptation.

Adaptation, Psychological↗

PubMed1997

[The post-cholecystectomy syndrome. Evaluation of symptomatology using Tc-99m-HIDA sequential hepatic scintigraphy (cholescintigraphy)].

The authors comment the data from research on 70 patients with post cholecystectomy syndrome, using cholescintigraphy HIDA 99mTc to evaluate the relation ship between symptomatology (see classific.) and duodenogastric reflux entity. Cholescintigraphy seems to be a valid clinical means, especially for a correct indication to endoscopy.

Adult↗

PubMed1997

[Brucellosis with osteo-muscular localization. A case report of a not rare pathological condition].

Brucellosis may show itself only through its bone and muscle complications, especially in the lumbar region, such as vertebral colliquation or psoas abscess. The authors describe a case of brucellosis (56 year old male, butcher) with lumbar bone and muscle involvement. The first symptom was a persistent pain of the right lumbar region, with irradiation to the homolateral leg. At admission the patient showed a lumbar cutaneous fistula with pus-like secretion. Quick diagnosis and therapy can prevent irreparable damage, even when the symptoms are silent.

Animals↗

PubMed1996

Motor learning by field approximation.

We investigated how human subjects adapt to forces perturbing the motion of their ams. We found that this kind of learning is based on the capacity of the central nervous system (CNS) to predict and therefore to cancel externally applied perturbing forces. Our experimental results indicate: (i) that the ability of the CNS to compensate for the perturbing forces is restricted to those spatial locations where the perturbations have been experienced by the moving arm. The subjects also are able to compensate for forces experienced at neighboring workspace locations. However, adaptation decays smoothly and quickly with distance from the locations where disturbances had been sensed by the moving limb. (ii) Our experiments also how that the CNS builds an internal model of the external perturbing forces in intrinsic (muscles and / or joints) coordinates.

Adult↗

PubMedDate not supplied

Cancer of the appendix in long-standing ulcerative colitis: a case report.

Cancer of the appendix was found in a 69-year-old female patient affected by long-standing ulcerative colitis (UC). On histological examination the cancer was a typical cystadenocarcinoma of the appendix. The appendiceal mucosa not invaded by the neoplastic process was normal. Histological examination of the colorectal mucosa did not show dysplasia or cancer. These findings suggest that appendiceal cancer and UC may be unrelated diseases. A surveillance program for early detection of cancer of the appendix in patients with long-standing UC does not seem mandatory.

Aged↗