Different corticostriatal projections from two parts of the cortical masticatory area in the rabbit

The cortical masticatory area (CMA) elicits rhythmic jaw movements in response to repetitive stimulation and is involved in the control of mastication. Based on jaw movement patterns, the CMA is divided into two parts. One is the part of the CMA in which a T-pattern similar to jaw movements during food transport in natural mastication is evoked by electrical stimulation. The other is more dorsomedially located, and during chewing a C-pattern similar to jaw movements can be induced. However, it is still not known which region of the putamen receives projections from the CMA and whether projections originate from both parts of the CMA. In this study, electrophysiological and histological experiments were undertaken in rabbits to investigate projections from the CMA to the putamen. Both experiments showed that the ventral region of the putamen received projections from the CMA. The density of the projections from the CMA area inducing the T-pattern seemed to be higher than that from the area inducing the C-pattern. Furthermore, the peak latency of the evoked potentials from stimulation of the CMA area inducing the T-pattern was shorter than that from stimulation of the area inducing the C-pattern. The data obtained from the present study indicate the functional role of the ventral region of the putamen in the regulation of mastication, and further suggest that the corticostriatal pathway is involved in the transition between behavioral jaw movement patterns.     

Electrodermal Responsivity in Young Hypotensive and Hypertensive Men

Electrodermal responses were recorded during the presentation of 16 moderately intense (1000 Hz, 90dB) tones in three groups of young men: borderline hypertensives (138/79 mmHg), normotensives (112/65 mmHg), and hypotensives (104/63 mmHg). Electrodermal response habituation was measured as a decline in response over trials, number of trials to a response criterion of three successive nonresponses, and number of inversions of response amplitude (larger responses following smaller responses) in the stimulus sequence. Habituation was fastest in hypotensives. Nonspecific electrodermal responses at rest and during tone presentations were most frequent in borderline hypertensives, least frequent in the hypotensive group, with the normotensive group falling in between. There were no significant differences in electrodermal level. The rapid habituation rate in hypotensives is discussed in terms of cursory information processing associated with impulsive behaviour. The higher nonspecific electrodermal activity in borderline hypertensives is interpreted to indicate increased sympathetic nervous system activity.     

Activity of primate putamen neurons is selective to the mode of voluntary movement: visually guided,self-initiated or memory-guided

Summary The aim of this report was to investigate the neural processes of movement initiation and control in which the basal ganglia play an essential role. Single-neuron activity was recorded in the putamen of monkeys performing learned arm movements initiated in three different modes: sensorially guided, internally-timed self-initiated and memory guided. There were no significant differences in the magnitude and timing of both prime mover and supporting muscle activity between the three modes of movement. Over half of the task-related neurons showed strong activity in one of the three modes of movement initiation, but were only slightly activated in the other two modes. No clear preference for a particular movement mode was evident in the population of putamen neurons as a whole. These results are consistent with the hypothesis that there are heterogeneous groups of neurons in the putamen, and that each group of neurons participates in retrieving a different kind of information required for movement based on either external sensory events or on internally stored information.     

Control of locomotion in marine mollusc — Clione limacina. V. Photoinactivation of efferent neurons

Summary Efferent neurons in isolated pedal ganglia of the pteropodial mollusc Clione limacina were filled with Lucifer Yellow through the wing nerves. Then the ganglia were illuminated with intense blue light which resulted in the complete inactivation of these neurons. After inactivation of efferent neurons, interneurons of the pedal ganglia continued to generate the locomotor rhythm.     

Involving the patient: a prospective study on use, appreciation and effectiveness of an information system in head and neck cancer care

OBJECTIVE: To determine use, appreciation and effectiveness of an electronic health information support system in head and neck (H&N) cancer care. DESIGN: A prospective evaluation study. The evaluated system has four different functions: (1) communication amongst health care providers and between health care providers and patients, (2) information for health care providers and patients, (3) contact with fellow sufferers and (4) monitoring of discharged patients by means of electronic questionnaires. Evaluation of the system was done both objectively using automatically created log files and stored messages, and subjectively by using paper questionnaires from patients and general practitioners (GPs). SETTING: Department of Otorhinolaryngology and Head and Neck Surgery of a tertiary health care centre in the Netherlands. The system was put at patients' disposal for a period of 6 weeks following discharge from the hospital after surgery for H&N cancer, and was additional to standard care. PARTICIPANTS: Head and neck cancer patients, hospital physicians, members of a hospital-based support team, GPs, district nurses and speech therapists. MAIN OUTCOME MEASURES: Actual use of the system by patients and health care providers. Patients' appreciation for each of the system's four different functions. GPs' appreciation for the system. Capability to detect potential patient problems with the system. RESULTS: The system was used by 36 H&N cancer patients, 10 hospital physicians, 2 members of the support team, 8 GPs, 2 district nurses and 2 speech therapists. The total number of patient-sessions was 982: an average of 27.3 sessions per patient during the 6 weeks study period. In total, 456 monitoring questionnaires were completed. The support team in hospital responded with 231 actions. In 16 cases, an extra appointment was made for a patient with the hospital physician. Out of these cases, immediate action was considered necessary eight times. Patients appreciated the system highly, rating it with an average score of 8.0 on a 10-point scale. All patients used the monitoring function, and rated 'monitoring' with a mean score of 8.0 on a 10-point scale. Least used and appreciated was the 'contact with fellow sufferers' function. Only 8 out of possible 36 GPs used the system, rating it with an average of 5.6 on a 10-point scale. CONCLUSIONS: The electronic health information support system was used intensively and highly appreciated by H&N cancer patients. The system enabled the early detection of occurring health problems that required direct intervention. ICT can play an additional role in the management of patients, also in a relatively elderly and computer illiterate patient population.     

Post-Traumatic Survival of Sensory Neurons of Different Subpopulations

Immunohistochemical studies were performed to address the expression of the high-molecular-weight component of the neurofilament triplet NF200 (a marker of neurons forming A fibers) and the binding of isolectin B4 (IB4) by neurons of the L4-5 spinal ganglia after ligation or section of the sciatic nerve in rats. A total of 15% of neurons in the ganglia of intact rats expressed NF200. By 90 days after nerve ligation, the proportion of NF200+ neurons decreased two-fold; administration to these rats of the nerve regeneration stimulator xymedone increased the number of NF200+ neurons by 50.7% compared with controls (ligation, no treatment). In intact rats, 23.6% of neurons bound IB4. The proportion decreased by 2.6% 30 days after nerve ligation and to undetectable levels by 90 days; xymedone increased the proportion of surviving IB(4)+ neurons more than eight-fold. IB(4)+ neurons were more likely to enter post-traumatic apoptosis. Ligation of the nerve was followed by survival of fewer NF200+ and IB(4)+ neurons than section of the nerve, which suggests that axon lengthening is a factor maintaining neuron survival. The pyrimidine derivative xymedone increased the survival of neurons of both subpopulations, especially IB(4)+ neurons.     

Effects of task difficulty and invested mental effort on peripheral vasoconstriction

We ran two experiments to investigate whether peripheral arterial tone reflects changes in mental effort. Finger pulse wave amplitude, interpulse interval, and pulse variability in the mid- and high-frequency bands were recorded by means of a newly developed finger plethysmograph during both rest and cognitive performance. Using a modified version of the Sternberg memory task, we selectively manipulated either the difficulty of the task (Experiment 1) or the subjects' level of engagement in the task (Experiment 2). We found a significant difference in finger pulse wave amplitude between rest and task periods, suggesting that the measure reflects changes in sympathetic activity due to task engagement. In addition, our results suggest that reduced pulse wave amplitude, signaling vasoconstriction, occurs when subjects are investing effort.     

Pyramidal input to the basal ganglia in the cat

Summary In cats with mesencephalic decerebration sparing the cerebral peduncles and ablation of sensorimotor cortex, changes in firing of single neurons of caudate nucleus (CD), putamen (PU), globus pallidus (GP) and entopeduncular nucleus (EN) were studied following stimulation of the ipsilateral medullary pyramidal tract (MPT). Cells in CD and PU were not extensively influenced by impulses backfired from MPT (14.7% and 18.7%, respectively). Conversely, a larger number of GP cells (28.1%) and especially EN cells (46.9%) exhibited pronounced changes in their firing following MPT stimulation. The MPT-induced effects on CD and PU were either inhibition or excitations, the latter appearing at latencies greater than 11 ms. The responses observed in GP and EN cells were most frequently excitations, some of which appeared with latencies below 5 ms.     

Selective uptake of [3H]glutamine and [3H]glutamate into neurons and satellite cells of dorsal root ganglia in vitro

The uptake of [³H]glutamate and [³H]glutamine into rat dorsal root ganglia has been examined by autoradiography and thin-layer chromatography. [³H]glutamate was selectively accumulated by satellite glial cells and after 10 min, 53% of this had been converted to [³H]glutamine. [³H]glutamine, on the other hand, entered neuronal perikarya and 40% was converted to [³H]glutamate. It is suggested that these selective uptake processes provide supporting evidence for the existence of a neuronal-glial glutamine cycle in dorsal root ganglia. Small dark (B) cells accumulated 6 times as much [³H]glutamine as did large light (A) cells. The reasons for this marked difference in the metabolism of the two main types of dorsal root ganglion neurone are discussed.