Preamplifier with a second-order high-pass filtering characteristic

A new preamplifier for suppressing low-frequency interference is presented. The proposed preamplifier, with its front end being implemented by an instrumentation amplifier, enjoys the following advantages: differential high-pass filtering, high input impedance, high common--mode rejection ratio and low passive sensitivity. This circuit can be realized with commercial operational amplifiers with enough phase margin, or fabricated in a chip for practical measurement of physiological signals.

Long-term beta-blocker therapy improves autonomic nervous regulation in advanced congestive heart failure: a longitudinal heart rate variability study

BACKGROUND

beta-Blocker therapy is believed to modulate the detrimental effect of overcompensating neurohormonal activation in chronic heart failure. However, clinical doubts remain, particularly the physiologic sympathovagal balance.

METHODS

To respond to clinical concern about worsening autonomic nervous perturbation in beta-blocker therapy of advanced congestive heart failure, 15 consecutive patients were longitudinally studied to elucidate the evolution of cardiac function versus 24-hour heart rate variability (HRV) before and after 1, 3, and 6 to 9 months of atenolol-combined therapy.

RESULTS

Two patients died prematurely within 1 month. All 13 surviving patients showed improvement in New York Heart Association functional class, with decrease in left ventricular end-systolic and end-diastolic dimensions and increase in fraction shortening and ejection fraction by echocardiography after at least 3 months of atenolol use. The retarded therapeutic effect was accompanied by a general rise of total, very low, low-, and high-frequency components (9.0 +/- 0.5, 8.8 +/- 0.5, 6.2 +/- 0.6, and 6.1 +/- 0.5 vs 10.9 +/- 0.3, 10.7 +/- 0.4, 8.6 +/- 0.3, and 7.8 +/- 0.3; all P <.02) of daily HRV. This implied recovery of parasympathetic and baroreceptor function. Return of sympathovagal interaction was further supported by the suppression of Cheyne-Stokes type HRV as detected by Wigner-Ville distribution.

CONCLUSIONS

Long-term beta-blocker therapy for advanced congestive heart failure upwardly regulates the autonomic nervous interaction in synchrony with the evolution of cardiac function performance.

Slow oscillations (</=1 Hz) mediated by GABAergic interneuronal networks in rat hippocampus

Perfusion of rat brain slices with low millimole CsCl elicits slow oscillations of </=1 Hz in hippocampal CA1 pyramidal neurons. These oscillations are GABAA receptor-mediated hyperpolarizations that permit a coherent fire-pause pattern in a population of CA1 neurons. They can persist without the activation of ionotropic glutamate receptors but require adenosine-dependent inhibition of glutamate transmission. In response to external Cs+, multiple interneurons in the CA1 region display rhythmic discharges that correlate with the slow oscillations in CA1 pyramidal neurons. The interneuronal discharges arise spontaneously from the resting potential, and their rhythmicity is regulated by periodic, GABAA receptor-mediated hyperpolarizations. In addition, interneurons show periodic partial spikes and neurobiotin coupling, and applications of known gap junctional uncouplers interrupt the Cs+-induced slow rhythm in both CA1 pyramidal neurons and interneurons. We propose that these slow oscillations originate from a GABAergic interneuronal network that interacts through reciprocal inhibition and possibly gap junctional connection.

Protective agents used as additives in University of Wisconsin solution to promote protection against ischaemia-reperfusion injury in rat lung

1. An intervention to reduce ischaemia-reperfusion lung injury will be an important advance in transplant medicine. Although the mechanisms associated with producing ischaemia-reperfusion endothelial injury have not been completely elucidated, many of the injury mediators have been studied in detail. While no single pharmacological therapy is likely to be totally effective in eliminating this complex injury, we have developed a mixture of agents that are known to block pathways involved in producing ischaemia-reperfusion-associated lung vascular injury.2. The present study modified University of Wisconsin solution (UW) by adding one of the protective agents prostaglandin E1 (PGE1), dexamethasone (Dex) or dibutyryl cAMP (Bt2-cAMP), or a combination of these, to the perfusate of rat lungs exposed to 4 h of cold ischaemia followed by 1 h of reperfusion. Nine modified UW solutions were studied: (1) UW+Dex, (2) UW+PGE1, (3) UW+Bt2-cAMP, (4) UW+Dexx3, (5) UW+PGE1x3, (6) UW+Bt2-cAMPx3, (7) UW+Dex+PGE1, (8) UW+Dex+Bt2-cAMP, (9) UW+PGE1+Bt2-cAMP. These solutions were utilized in individual experiments to assess haemodynamic changes, lung weight gain, the capillary filtration coefficient (Kfc) and pathology in all lungs.3. The results indicate that lung weight gain and Kfc values were significantly lower than with UW alone in groups 1, 2 and 3, which contained only one additional protective agent. In groups 4, 5 and 6, which contain three times the concentration of each protective agent, both Kfc and lung weight gain were similar to those measured in groups 1, 2 and 3, i.e. lungs were protected but the protection was not dose dependent. In groups 7, 8 and 9, which contained two protective agents, lung weight gain and Kfc were greatly reduced compared with UW alone. Histopathological studies showed similar decreases in the injury profiles of lungs.4. Although UW contains several antioxidant protective agents such as allopurinol and glutathione, it did not provide effective protection in our ischaemia-reperfusion lung injury model. UW modified with an additive of PGE1, Dex or Bt2-cAMP attenuated ischaemia-reperfusion injury. Furthermore, UW containing two of these protective agents augmented the protection. Among the modified solutions, it appears that UW+PGE1+Bt2-cAMP protects the lungs to a greater extent than all other solutions used in our study. We suggest that preservation solutions containing PGE1-Bt2-cAMP will provide additional protective effects to organs stored for transplantation.

Time-frequency spectral analysis of heart rate variability during induction of general anaesthesia

We have examined the spectral components of heart rate variability (HRV) during induction of anaesthesia with thiopentone, tracheal intubation and subsequent inhalation of isoflurane-nitrous oxide. Commonly used spectral analysis methods such as fast Fourier transformation or autoregressive modelling require stationary data and are not suitable for the rapidly changing HRV data in this period. An advanced spectral analysis method, time-frequency analysis, which can treat non-stationary data, was used in this study. Multiple spectra were generated to demonstrate the time-related spectral components of HRV. Mid-frequency power (MF, 0.08-0.15 Hz), high-frequency power (HF, 0.15-0.5 Hz) and MF/HF ratio at baseline, after induction (before intubation), immediately after intubation and during maintenance periods were calculated and compared. MF and HF powers decreased after induction and were reduced further in the maintenance period but MF/HF ratio remained unchanged after induction. Immediately after intubation MF and HF powers did not differ significantly from the immediate pre-intubation values, but MF/HF ratio did.

Elimination of interference component in Wigner-Ville distribution for the signal with 1/f spectral characteristic

A new technique for interference-term suppression in Wigner-Ville distribution (WVD) is proposed for the signal with 1/f spectrum shape. The spectral characteristic of the signal is altered by f alpha filtering before time-frequency analysis and compensated after analysis. With the utilization of the proposed technique in smoothed pseudo Wigner-Ville distribution, an excellent suppression of interference component can be achieved.

Time-frequency distribution of heart rate variability below 0.05 Hz by Wigner-Ville spectral analysis in congestive heart failure patients

The Wigner-Ville spectral analysis was utilized to demonstrate a high-resolution time-frequency distribution of heart rate variability below 0.05 Hz. There are different time-frequency characteristics between the normal subject and the patient with severe congestive heart failure. The former consists of multiple and broad-band spectral peaks, while the latter presents unique spectral peaks. Based on Bayes theory, a classifier for the unique spectral peaks was developed. After the beneficial improvement with low-dose beta-blockers, the unique spectral peaks had disappeared or the time of occurrence was reduced in most patients.

Analog transmission line model for simulation of systemic circulation

A simple four-tube arteries-microvessels-veins system which simulates a more realistic loading for human circulation was built using transmission line network. Hemodynamic data from literature are used in the fluid-circuit analogy, and the flow leakage and viscoelastic properties of the blood vessels have been considered. The effect of veins on the input impedance spectrum was found to be negligibly small above 0.5 Hz. The predicted input impedance spectra agree reasonably well with the published measurements both in shape and magnitude. Parametric analysis shows that the changes of vascular properties in the lower body affect the first minimum, and the changes in the upper body influence the second minimum. The blood flow in and out of kidney and liver dominates the aortic impedance from 0 to 5 Hz. Decreasing capacitance (i.e., increasing arterial stiffness due to aging), reducing the lumen area, or decreasing the length of blood vessels result in an increase in the impedance modulus, and the first minimum shift to a higher frequency which agree well with experiments. In the current model, the pressure, flow waveform, and local impedance can be predicted at any location along the circulatory tree. The characteristic of arterial pulse propagation resembles published measurements.

Pulmonary edema induced by phorbol myristate acetate is attenuated by compounds that increase intracellular cAMP

We have investigated the effect of terbutaline, aminophylline and dibutyryl cyclic AMP (DBcAMP) on phorbol myristate acetate (PMA)-induced acute lung injury in isolated, blood-perfused rabbit lungs. Pulmonary arterial pressure and lung weight were measured for 30 min after a bolus injection of PMA (10 mu g/kg). In the group exposed to PMA alone, the mean pulmonary arterial pressure (PAP) increased from 16.33 + or - 1.28 to 77.30 + or - 6.40 mmHg (P <0.001), and lung weight increased by 70.69 + or - 10.94 g during the 30 min after PMA challenge (P<0.001). Pretreatment with terbutaline, aminophylline or DBcAMP prevented the increases in both PAP and lung weight (P <0.001). Each of the three drugs also prevented the increase in pulmonary vascular permeability induced by PMA: terbutaline, aminophylline, and DBcAMP all significantly reduced the pulmonary capillary filtration coefficient (KfC) as well as the albumin concentration in the lung lavage fluid after PMA exposure. Post-treatment with terbutaline 5 min after PMA administration also had a protective effect. The mechanisms responsible for these protectivp3 effects may all involve an increase in intracellular cAMP, since all three drugs increase cAMP in the lung (though by different mechanisms). Our data further indicate that the inhibition of tumor necrosis factor production may likewise play an important role in the protective effect exerted by these drugs.

Different mechanisms underlying the repolarization of narrow and wide action potentials in pyramidal cells and interneurons of cat motor cortex

Two different types of action potentials were observed among the pyramidal cells and interneurons in cat motor cortex: the narrow action potentials and the wide action potentials. These two types of action potentials had similar rising phases (528.8 +/- 77.0 vs 553.1 +/- 71.8 mV/ms for the maximal rising rate), but differed in spike duration (0.44 +/- 0.09 vs 1.40 +/- 0.39 ms) and amplitude (57.31 +/- 8.22 vs 72.52 +/- 8.31 mV), implying that the ionic currents contributing to repolarization of these action potentials are different. Here we address this issue by pharmacological manipulation and using voltage-clamp technique in slices of cat motor cortex. Raising extracellular K+ concentration (from 3 mM to 10 mM), applying a low dose of 4-aminopyridine (2-200 microM) or administering a low concentration of tetraethylammonium (0.2-1.0 mM) each not only broadened the narrow action potentials, but also increased their amplitudes. In contrast, high K+ medium or low dose of tetraethylammonium only broadened the wide action potentials, leaving their amplitudes unaffected, and 4-aminopyridine had only a slight broadening effect on the wide spikes. These results implied that K+ currents were involved in the repolarization of both types of action potentials, and that the K+ currents in the narrow action potentials seemed to activate much earlier than those in the wide spikes. This early activated K+ current may counteract the rapid sodium current, yielding the extremely brief duration and small amplitude of the narrow spikes. The sensitivity of the narrow spikes to 4-aminopyridine may not be mainly attributed to blockade of the classical A current (IA), because depolarizing the membrane potential to inactivate IA did not reproduce the effects of 4-aminopyridine. Blockade of Ca2+ influx slowed the last two-thirds repolarization of the wide action potentials. On the contrary, the narrow action potentials were not affected by Ca(2+)-current blockers, but if they were first broadened by 4-aminopyridine or tetraethylammonium, subsequent application of Ca(2+)-free medium caused further broadening, suggesting that the narrow action potentials were too brief to activate the Ca(2+)-activated potassium currents for their repolarization. Therefore, the effects of low concentrations of tetraethylammonium on the narrow spikes appeared to be mainly due to blockade of an outward current that was different from the tetraethylammonium-sensitive Ca(2+)-activated potassium current (IC). In the neurons with the narrow spikes, voltage-clamp experiments revealed two voltage-gated outward currents that were sensitive to tetraethylammonium and 4-aminopyridine, respectively. Both currents were activated rapidly following the onset of depolarizing steps. Interestingly, the tetraethylammonium-sensitive current was a transient outward current that inactivated rapidly (tau < or = 5 ms), while the 4-aminopyridine-sensitive current was relatively persistent during maintained depolarization. The 4-aminopyridine-sensitive current did not show obvious inactivation even at membrane potential of -40 mV, which completely inactivated the transient tetraethylammonium-sensitive, current. The results indicate that different potassium currents are involved in the repolarization of the narrow and wide action potentials in cat motor cortex. A novel tetraethylammonium-sensitive transient outward current and a 4-aminopyridine-sensitive outward current are responsible for the short duration and small amplitude of the narrow action potentials in the interneurons and some of the layer V pyramidal cells. These two currents are voltage-gated and Ca(2+)-independent. For the wide action potentials that characterize most pyramidal neurons, a Ca(2+)-independent tetraethylammonium-sensitive outward current and a Ca(2+)-activated potassium current are the main contributors to their repolarization.

Electrophysiological and morphological properties of pyramidal and nonpyramidal neurons in the cat motor cortex in vitro

Electrophysiological and morphological properties of the neurons in cat motor cortex were investigated using intracellular recording and staining techniques in a brain slice preparation. In response to intracellular injection of depolarizing current pulses, four distinct types of firing patterns were observed among cat neocortical neurons. Regular-spiking neurons were characterized by their repetitive firing from which conspicuous frequency adaptation was observed. Doublet-or-burst firing cells were marked with their tendency to fire 2-5 clustered spikes at the onset of depolarizing pulse. In doublet-or-burst firing neurons, but not in regular-spiking neurons, a low-threshold calcium current was revealed by single-electrode voltage clamp. Both regular-spiking and doublet-or-burst firing neurons had relatively wide action potentials. Fast-spiking neurons could fire extremely narrow action potentials at a very high frequency. Their frequency-to-intensity slope of steady-state firing was significantly higher than that of the other neurons. In contrast, narrow-spiking neurons had the smallest frequency-to-intensity slope for steady-state firing, although their action potentials were as narrow as those of the fast-spiking neurons. Both regular-spiking and doublet-or-burst firing neurons were identified as pyramidal neurons, and were found in all layers below layer I. Their apical dendrites were densely coated with dendritic spines. Narrow-spiking neurons were only recorded in layer V. They were large pyramidal cells with scare spines on their apical dendrites. Fast-spiking neurons were all nonpyramidal interneurons. Seven out of eight labelled fast-spiking cells had beaded dendrites without spines. Their axons had a large number of varicosities, and arborized extensively to form a dense plexus of terminals in the vicinity of their soma. The remaining neuron was found to be a spiny nonpyramidal neuron in layer V. These results demonstrate that, in addition to the three types of firing patterns previously identified in rodent neocortex, a group of neurons in the cat motor cortex express another type of firing behaviour which is characterized by extremely narrow action potential and very small frequency-to-intensity slope. Correlation with the morphological data shows that these neurons are large layer V pyramidal cells rather than nonpyramidal interneurons.

GABAA receptor-mediated feedback inhibition in pyramidal neurons of cat motor cortex

Feedback or recurrent inhibition is generally proposed as a basic component of circuit organization in the brain. However, there is little direct evidence for its existence in the cortex, nor for the nature of the neurotransmitters and receptors involved. Here we address this issue by analyzing the potentials following a single action potential in cat neocortical pyramidal neurons. Using 3 M KCl-filled electrodes, we observed a distinct depolarizing potential that was superimposed on the spike after-potentials in seven out of 81 recorded and the resemblance between its falling phase and the passive decay of membrane potential suggested that the depolarizing potential originated from the cell body or proximal dendrites. This potential was blocked by bicuculline methiodide (10 microM), but not by phaclofen (0.2 mM), suggesting that it was a reversed recurrent IPSP mediated by GABAA receptors.

Two mechanisms underlying the induction of long-term potentiation in motor cortex of adult cat in vitro

Long-term potentiation of synaptic transmission (LTP), as documented by the enhancement of evoked field potentials in layer III following stimulation of the underlying white matter, has been studied in slices of motor cortex from adult cats. With a 1 M NaCl-filled recording electrode, LTP was induced only in one out of eight slices. When the recording electrode in addition contained 5 mM bicuculline metiodide, LTP was obtained with a much higher rate of success (15/19), suggesting that reduction of GABAA receptor-mediated inhibition facilitated the induction of LTP in the motor cortex. Bath application of DL-2-amino-5-phosphonovaleric acid (APV, 100 microM) or Ni2+ (100 microM) significantly reduced the success rate for LTP occurrence (6/16 and 5/16, respectively); but when LTP was induced, it did not show significant change in magnitude and time course. In slices perfused with APV (100 microM) plus Ni2+ (100 microM), LTP induction was completely blocked (0/12). These results suggest that two different mechanisms may subserve LTP induction in the cat motor cortex: one is mediated by N-methyl-D-aspartate receptors and can be blocked by APV; the other may be mediated by low-threshold calcium channels and can be blocked by Ni2+.

Adult respiratory distress syndrome caused by pulmonary cryptococcosis in an immunocompetent host: a case report

The development of adult respiratory distress syndrome (ARDS) can be associated with a variety of clinical disorders. Pulmonary cryptococcosis occurring in immunocompromised patients has been reported with increasing frequency because of the rapidly rising number of immunocompromised hosts and the improvement in diagnostic techniques. But pulmonary cryptococcosis causing ARDS in immunocompetent patients has not, to present knowledge, been described. Here a rare case of pulmonary cryptococcosis is reported in an immunocompetent host who developed adult respiratory distress syndrome. The clinical course, radiologic patterns, methods of diagnosis and treatment are reviewed.

Distribution of synapses on an intracellularly labeled small pyramidal neuron in the cat motor cortex

The morphological characteristics and distribution of synapses on a small pyramidal neuron in layer III of the cat motor cortex have been studied by combining intracellular HRP staining and electron microscopic examination. The stained neuron showed spiny apical and basal dendritic profiles under the light microscope, and exhibited the morphological features of a pyramidal neuron. Ultrastructural analysis indicated that about 80% of the presynaptic terminals formed asymmetrical synapses with spines of distal apical and basal dendrites. On proximal apical dendrites, 64% of the synapses were found to make contact with spines, and 16.7% of the synapses were of symmetrical type and formed with dendritic shafts. Two types of terminal could be identified on the soma; they were alternately located and established symmetrical and asymmetrical synaptic contacts respectively. Possible functional implications are discussed.

Distribution of synapses on fast and slow pyramidal tract neurons in the cat. An electron microscopic study

Distributions of synapses on various portions of fast and slow pyramidal tract neurons (PTNs) in cat motor cortex were studied with electron microscopy. PTNs were identified by their antidromic invasion following stimulation of the medullary pyramid and were classified into fast and slow PTNs according to conduction velocities of their axons. Two fast and two slow PTNs were intracellularly labeled and, by systematic sampling, electron micrographs from various portions of these neurons were examined to compare the distributions of different types of synapses. It was found that most synapses formed on apical and basal dendrites of fast PTNs were with the dendritic shafts. In slow PTNs, while synapses on apical dendrites were mostly axospinous, about 70% of the sampled synapses on basal dendrites of slow PTNs were established with the dendritic shafts. Virtually all synapses on apical dendrites of slow PTNs belonged to asymmetrical type and most of the synapses sampled from basal dendrites of fast PTNs were also asymmetrical. On the other hand, about 29% of the synapses found on apical dendrites of fast PTNs were symmetrical and a trend was observed for this type of synapses to increase their number with increasing proximity to the cell body. Over 28% of the synapses on basal dendrites of slow PTNs were also symmetrical and seemed to be mainly distributed in layer VI. All synapses formed on the soma were symmetrical both for the fast and slow PTNs.

Multi-organ involvement in urothelial malignancies

The present study covers 1213 patients with urothelial tumours, of whom 113 have been affected by multi-organ malignancies. The disease was found to spread mostly in direction of the urine flow. Bladder was the most frequently affected organ. The incidence of pelvic cancer in China is higher than in Western countries.

Vicissitude of management of ureteral stones

Following the use of rigid ureteroscopic lithotripsy (URS) in 1984 and extracorporeal shock wave lithotripsy (ESWL) in 1987, the treatment for ureteral stones has undergone significant changes. Our experience showed that the successful rate of URS for 132 patients was 89.4% and for the upper third was rather low, percutaneous antegrade URS should be considered. 376 patients treated with ESWL in prone position with a successful rate of 96.8%. The applicability of open surgery was reduced to 17.8% in 1987 and 14.5% in 1988.

Age factor in post-nephrectomy compensatory renal growth

In a retrospective investigation we found that the endogenous creatinine clearance (Ccr) of 35 nephrectomized patients was lower than that of normal people of comparable age with two intact kidneys. The Ccr level in the post-nephrectomy patients appeared to correlate with the age of the patients at the time of nephrectomy. The average Ccr value was 99.2 ml/min in the younger group, and 54.9 ml/min in the older group. Furthermore, we also found that the measurement of the remaining kidney in the younger group was larger than that of the matched control group, but no difference was found between the measurement of the remaining kidney in the older group and that of the matched control group. Therefore, we suggest that the remaining kidney in patients over 50 years of age may be described as "a low compensatory kidney". The results from an experimental study of Wistar rats indicated that the dry and wet weights of the remaining kidneys of the younger rats which had undergone neptrectomy were 1.53 X 10(-3) g/gwt, and 5.89 X 10(-3) g/gwt respectively, vs 1.05 X 10 g/gwt and 3.82 X 10(-3) g/gwt in older ones. In tissue culture using serum of younger nephrectomized rats, the amount of 3H-TdR incorporation into the monolayer cells of renal cortex was 1,405.4 CPM, whereas it was 1,025.4 CPM by using serum of older nephrectomized rats. In addition, the cells of renal cortices from both younger and older rats had a similar response to the same serum from nephrectomized rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[The measurement of airway responsive index in normal individuals and asthmatic patients]

Measurement of airway responsiveness to nonallergenic stimuli can be used to confirm the diagnosis of asthma, document the severity of airway responsiveness, and follow changes in airway responsiveness with time in relation to treatment or exposure to occupational sensitizers. Methacholine inhalation is the preferred test for the clinical laboratory as it is more sensitive than exercise or cold air, and there are fewer side effects than with histamine. Airway responsiveness to nonspecific, pharmacologic, bronchoconstricting stimuli has been described using various methods of summarizing dose-response data. The purpone of this study was to examine a simple index of nonspecific airway responsiveness to methacholine, i.e., the slope of a straight line approximation of the dose-response curve. Twelve normal and 19 asthmatic volunteers were studied. Subjects underwent a standard methacholine challenge test, both specific airway conductance (SGaw) and forced expiratory volume of one second (FEV1) were measured. We examined the relationship between response assessed by SGaw or FEV1 and dose of methacholine in each subject. The results showed that, in most of the subjects, the decline of pulmonary function with increasing dose of methacholine almost followed a simple linear relationship. A straight line extending from the origin to the last data point obtained approximating this relationship provides a reasonable summary of each plot. This were true not only in asthmatic subjects but also in normals, and not only for FEV1 but also for SGaw. The slope of this straight line was denominate as responsive index. The summary dose-response slope effectively separated asthmatic from normal subjects without any overlapping; this was true not only when FEV1 but also for SGaw was used as the parameter of response. The responsive index was much greater among asthmatics than among normal subjects (P less than 0.001). The responsive index from the parameter of SGaw was nearly perfectively correlated with which was from FEV1 (r = 0.989, P less than 0.001). We considered that airway responsive index can be calculated not only when FEV1 but also SGaw was used as a parameter of pulmonary function response. The dose-response slope calculated in the present analysis is a summary of the overall dose-response relationship and thus differs from the slope of the latter part of the log dose-response curve. It has the advantage of providing a single, continuous, easily interpreted measure of responsiveness for all subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Thalamic projection to motor area and area 3a of the cat cerebral cortex

The distributions of thalamic neurons projecting to the motor cortex and cortical area 3a were studied in cat by means of the retrograde double-labeling technique using Nuclear Yellow (NY) and Fast Blue (FB) as tracers. Following injection of NY and FB into the motor cortex and area 3a respectively, the NY-labeled neurons were found to be mainly located in ventrolateral (VL) nucleus and FB-labeled neurons in ventro-posterolateral nucleus (VPL). However, these two kinds of neurons were intermingled with each other in the border area between VL and VPL. A small number of neurons were double-labeled by both NY and FB. They were also distributed in the border area. Some of them could often be found in centromedian and parafascicular nuclei.