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Notes: Summary By using an antiserum raised against dopamine bound to bovine serum albumin, thinner dopamine-labeled nerve terminals were visualized immunohistochemically within neocortical areas, in addition to well-documented dopaminergic innervation into the prefrontal and limbic cortices.

Notes: Summary Two autopsy cases of siblings with the adult pigment (Peiffer) type of sudanophilic leukodystrophy (SLD), which demonstrated the full-blown stage (case 1) and early stage (case 2) of demyelination, were examined. Numerous brown pigments deposited in demyelinated cerebral areas were characterized histochemically and ultrastructurally as lipofuscin and ceroid. Under the electron microscope formation of blebs due to myelin splitting associated with deposition of multilamellar myeloid bodies within them was a prominent feature in the demyelinated cerebral areas of case 2 as compared with case 1. However, various features of myelin degradation such as thinning, partial or complete circumferential myelin loss, and deposition of electron-dense material on the interperiodic lines were found in both cases. Blebs occurred in all layers of myelin, and axons were compressed by these blebs or the hydropically swollen inner lips of oligodendroglias. Oligodendroglias were relatively well preserved in the demyelinated and nondemyelinated areas in case 2, although the cytoplasm was hydropic. Many spheroids were present in demyelinated areas and were irregularly distributed in both cases. The peripheral nerves in case 1 presented essentially the same changes as those in the brain, although those in case 2 were not affected. Morphometrically, the results showed that hypomyelination was not the mechanism for this pigment type of SLD. One possible cause may be an accelerated ageing of the metabolic process of myelin turnover.

Notes: Summary An autopsy case of adult-type citrullinemia in a 42-year-old male is reported. The patient neuropathologically presented mixed cerebral changes consisting of the pseudoulegyric and ischemic types of hepatocerebral disease. In common with previously reported cases of the pseudoulegyric type, the nature and localization of the cerebral changes in this case were characteristic, in that neuronal loss occurred most severely and symmetrically in the mediobasal part of the frontal and occipital lobes, gyrus cinguli, claustrum, insula and temporal lobe, and that the watershed area of the cerebral cortex, basal ganglia and Purkinje cells were only slightly affected. The importance of hypercitrullinemia was stressed in the pathogenesis of the cerebral changes evident in adulttype citrullinemia.

Notes: Abstract A new experimental technique is developed by combining a flash photolysis method with a laser-photodiode system to measure the velocity of the flow of thin liquid films. The technique is applied to the measurement of the velocity of the liquid-fuel film within the intake pipe of an internal combustion engine operated under firing condition. The results show that the velocity of the fuel film is of the order of 1/100 of the mean air velocity inside the intake pipe.

Notes: Summary We have analysed, in the awake monkey (Macaca sylvana) the functional properties of 489 neurones in the prelunate visual area (PVA, largely corresponding to V4). PVA has a coarse retinotopic organization with the lower quadrant of the visual field represented along the prelunate gyrus. The visual periphery is located medio-dorsally, the central visual field laterally near (and within?) the inferior occipital sulcus and the upper quadrant latero-ventrally. The vertical meridian runs caudally within the lunate sulcus, the horizontal meridian crosses the prelunate gyrus and continues into the superior temporal sulcus. Receptive field diameters of neurones vary between 1° and 10° with increase towards the visual periphery, but are strictly confined to the contralateral visual field. 28% of the neurones showed spectral sensitivity. About half of these cells had strong spectral opponency, the other half showed only weak opponency with broader spectral response curves. 11 cells (2%) showed striking centre/surround interactions with inhibition, disinhibition or occlusion of the two mechanisms, and different spectral response ranges of the centre and the surround, respectively. 43% of the prelunate cells were responsive to various spatial features without spectral sensitivity. We distinguished on- and off-center cells (2%), direction and movement sensitive cells (10%) and cells sensitive to gratings of parallel lines within a limited range of orientations (about 10%). A special group were cells which responded strongly to stimuli which contained many contrasts (textures without specific orientations and without regular spatial arrangements) (9%). Many of these cells were specifically responsive to variations of the internal structure of such stimuli. 3% of the cells were strongly activated in connection with behaviour: 11 neurones discharged strongly when the monkey looked attentively at a human face or when he responded with facial expressions to a threatening expression of a person. Photographs of faces were not effective. Some neurones (1%) were activated in connection with eye movement. These neurones were found in the lateral part of the prelunate gyrus. Neurones with spectral or non-spectral properties were clustered within small, irregularly shaped patches of 1–4 mm diameter. It is concluded that the prelunate visual cortex, which we consider as part of area 19, is not just a “colour area”, but represents various features of the visual environment (including colour, luminance, movement, texture and behavioral significance), and relates them — through its subcortical and cortical outputs — to behaviour. The various visual cortical areas may be seen as a cooperative of several connections between visual input and behaviour output rather than as links in a hierarchical chain of perceptual and cognitive representations.

Notes: Summary We have recorded from 661 single neurons in the foveal and parafoveal region of area 17 of the awake trained macaque monkey. The functional properties of 538 cells were investigated in detail, with flashed and moving stimuli of varying form and colour. Irrespective of their functional properties such determined, each neuron was also tested with a 2×2° square of various luminance and colour. This was done in order to get an idea how such a simple stimulus is represented by the activities of neurons in area 17. Most of the neurons showed response preference for certain aspects of visual stimuli. We have distinguished the following functional groups: 1. Sustained spectrally selective neurons (21%). These cells respond with tonic discharges to light of their optimal wavelength, and their spectral selectivity corresponded to that of opponent parvocellular cells of the lateral geniculate body. 44% of these cells were excited selectively by long, 23% by middle and 33% by short wavelength light. When slowly moving the 2×2° square of their preferred wavelength across the receptive field, discharge rate remained elevated, as long as the stimulus covered the RF and with little contour enhancement. The majority of the sustained spectrally sensitive cells responded equally well or better to large than to small (1.0°) stimuli, 17.5% were less activated and few of them completely suppressed by larger stimuli. Such cells were poorly orientation sensitive. Only three cells with weak double opponency could be identified (2.7% of this group). 2. Broadband contour (18%) and 3. Panchromatic contour cells (41%). Most neurons of these two groups were strongly activated by spots (1°) centered on their RF. They showed a short phasic response to contrast borders and most of them responded to luminance contrasts, including contrast reversal and colour contrasts equated for luminance. The broadband contour cells showed a slight wavelength preference with only weak or without any opponent suppression, the panchromatic contour neurons did not show any wavelength selectivity. Most showed orientation or direction sensitivity, but very sharp orientation selectivity was less common in spectrally biassed than in panchromatic contour cells (see Fig. 11). They responded tonically to gratings of optimal orientation and therefore may play a role also for cortical representation of textures. 22% of a restricted sample of panchromatic contour cells (or 9% of all cells) were hypercomplex. 4. Light inhibited cells. 7% of all cells were inhibited by small and large light stimuli of any wavelength centered on their receptive field, and were tonically activated by darkspots or contrasts, comparable to the light inhibited cells of the parvocellular lateral geniculate layers. 5. Neurons without consistant visual responses (11%). These neurons could not be driven by any of our visual stimuli. They were usually found in the upper cortical layers. 61 cells were tested for monocular vs. binocular input. 96% were excited from both eyes with various degrees of ocular dominance, but more binocular cells were contralaterally than ipsilaterally dominated (43 and 22%, respectively). Binocular cells showed qualitatively the same functional properties from both eyes, including spectral selectivity if there was any. Binocular summation varied between cells and was in the average 0.7, probably due to interocular inhibition. Some columnar grouping of cells with similar response properties as defined above was found in vertical penetrations, but “mixed” penetrations were common. Spectrally selective cells with the same spectral preference or light inhibited cells often were found close to each other and in the same penetration, but also often mixed with other cells excited by parvocellular input. This spatial organization is consistant with a columnar segregation of cells excited predominantly by one type of parvocellular afferents on the one hand, and contour cells with a mixed excitatory and a strong inhibitory input, on the other hand, but also indicates a considerable mixing and overlap of functional inputs into any axis perpendicular to the cortical surface. The functional organization of area 17 is compared with that of the lateral geniculate body and the prelunate visual area (V4) as investigated with the same methods and by the same laboratory.

Notes: Summary Single neuronal activity was recorded in the crown of the postcentral gyrus (areas 1 and 2) in 5 conscious monkeys. A total of 93 penetrations were made in the hand and finger region of 9 hemispheres and 827 neurons were isolated. The receptive field characteristics of neurons recorded along each of 88 penetrations which entered perpendicularly to the cortical surface were compared. The majority of neurons in this region were responsive to skin stimulation. In 54 penetrations, neurons related to different sensory submodalities were mixed. In 30, skin neurons predominated, and in 8, ‘deep’ neurons, while in the remaining 16 penetrations neurons related to different submodalities were equally mixed. In 16 penetrations, neurons responded exclusively to stimulation of skin, hair or nails. In 9 penetrations, neurons were exclusively related to joint manipulation or other types of ‘deep’ submodality. In 9 penetrations, unidentified neurons were in the majority. In each penetration, the receptive field positions varied considerably on the same finger or encompassed more than one finger. Although neurons of the same submodality, either skin or ‘deep’ tended to be set in an array, the most adequate stimulus could vary among neurons of a given array. The variability in the receptive field positions or the most adequate stimuli remained constant irrespective of the angle of the electrode penetration in the cortex. The results are compatible with the idea that vertically arranged neuronal array receive inputs of multiple sources, both thalamacortical and corticocortical, so that interactions between different inputs can readilly occur.

Notes: Summary Single neuronal activity was recorded in the crown of the postcentral gyrus (areas 1 and 2) in 5 conscious monkeys. A total of 88 penetrations entered perpendicularly to the cortical surface. Among them, 6 examples are chosen and the receptive field characteristics of constituent neurons were described in some detail. Receptive fields of neurons recorded along a particular penetration were variable in their positions, but the largest receptive field usually covered the others. Neurons with the largest receptive fields were found most frequently in the infragranular layers. Often they included inhibitory receptive fields. The inhibitory receptive fields were arranged side-by-side to the excitatory ones, rather than in a center-surround fashion. The key stimulus common to neurons in a vertical penetration was the contact of an object to the receptive field achieved during animal's active behavior to manipulate the object. We thus designated the largest receptive field as a functional surface. Our results demonstrate that a vertical array of neurons in this cortical region can be regarded as a functional assemblage which deals with a set of information concerning one of various aspects of active touch.

Notes: Abstract An approach to improve the accuracy of the incremental solutions to a nonlinear problem, through a strategy to control the size of the increment, based on stationary of an argumented energy functional, is presented. The problem of control of an optimum step size in the incremental theory is formulated for a fixed number of increments. The variables in this argumented functional are: (i) the incremental displacement vector, (ii) the scalar parameters λ i which characterize the size of each of the increments, i = 1,..., N, and (iii) a Lagrange multiplier μ which enforces the constraint that the sum of all the normalized increments, i. e., Σλi is equal to 1. The optimality condition provides us a rigorous approach which gives rise to an iterative procedure because of nonlinearity of the stationary condition. If the number of increments is not prescribed, a noniterative procedure can be obtained, where the incremental sequence is controlled adaptively with less computational effort. The extension of the proposed method to non-selfadjoint problems, where a potential energy function does not exist, is also discussed. Numerical examples demonstrate the remarkable improvement in the accuracy of the solution by optimizing the incremental sequence, as well as the effectiveness of the adaptive control procedure proposed.

Notes: Summary To investigate the means by which doxapram affects the control of ventilation, ventilatory function and P0.1 have been related to serum doxapram concentration during a 45-min infusion of doxapram hydrochloride in 7 healthy, conscious subjects under normoxic conditions. Serum doxapram concentrations increased during the infusion: 1.88, 2.48, 3.42, and 3.97 µg/ml after 5, 10, 30 and 45 min, respectively. The majority of significant changes in the measurements from the baseline were observed at 30 and 45 min: $${{\dot V}}_{{E}}$$ , VT, P0.1, P0.1/end-tidal CO2 tension, VT/Ti and blood pressure were increased, and end-tidal CO2 tension was decreased. No significant changes in Pdimax, Ti/Ttot, $${{\dot V}}_{{E}}$$ /P0.1, and P0.1/(VT/Ti) were observed. A correlation was observed between the % increases in P0.1 and $${{\dot V}}_{{E}}$$ and doxapram concentration, and between $${{\dot V}}_{{E}}$$ and P0.1. The doxapram-induced increase in $${{\dot V}}_{{E}}$$ appears to be caused by increased neural drive. It is related to the serum drug concentration in the conscious subject.