Distribution of directionally selective neurons within the thalamic nuclei and striopallidal complex of the human brain

Spike activity was analyzed in the course of visual testing for directional sensitivity in 177 neuronal populations in different thalamic nuclei and the striopallidal complex in the brain of nine parkinsonian patients, diagnosed and treated using implanted intracerebral electrodes. Directionally selective neurons were discovered in the centrum medianum, the thalamic zona incerta and reticular nucleus, the caudate nucleus, and the central area of the globus pallidus. Proportions and distribution of neurons with different properties were investigated in the thalamic nuclei and striopallidal complex.Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 21, No. 5, pp. 652–660, September–October, 1989.     

Involvement of thalamic neurons and the striopallidal complex in maintaining constancy of visual perception in the human brain

Neuronal activity was investigated in different thalamic nuclei and the striopallidal complex in parkinsonian patients with long-term implantation of intracerebral electrodes in the structures concerned for diagnostic and therapeutic purposes. Directionally selective neurons were found with consistent response to presentation of visual stimuli oriented at the same angle in a variety of (spatial) head positions differing by 90°.Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 21, No. 1, pp. 93–101, January–February, 1989.     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Polarization and spectral sensitivity of single photoreceptors of the domestic cricket

The polarization and spectral sensitivity of single photoreceptors ofAcheta domesticus L. was measured. The morphological characteristics of the cricket rhabdome satisfy the conditions for a symmetrical model, for which the polarization sensitivity of a single photoreceptor is identically equal to the dichroism of a single microvillus. Characteristic curves of spectral sensitivity of all photoreceptors measured (24 cells) were similar and had two maxima: the principal at 500 nm and a secondary peak at 360 nm, characteristic of a pigment such as rhodopsin in the rods of the vertebrate retina. The mean value of polarization sensitivity measured was 2.28 ± 0.85 (mean ± standard deviation, 70 cells), suggesting the existence of slight preferential orientation of the dipole moments of the rhodopsin molecules along the axes of the microvilli.I. N. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Institute of Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 11, No. 5, pp. 483–490, September–October, 1979.     

Frequency characteristics of skate electroreceptive central neurons responding to electrical and magnetic stimulation

Responses of single neurons in the lateral lobes of the medulla to stimulation of the electroreceptive system by homogeneous sinusoidal electrical and magnetic fields were investigated in acute experiments on the skateRaja radiata. Thresholds of neuronal responses to electrical stimulation varied from 0.03 to 10 µV/cm. The optimal frequency ranges for electrical and magnetic reception were in the regions of 0.05–5 and 2–3 Hz respectively. The possible mechanisms and functional significance of frequency characteristics of central neurons are discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 16, No. 4, pp. 464–470, July–August, 1984.     

Investigation of the optimal shape of the nerve ending of the encapsulated tissue mechanoreceptor (Pacinian corpuscle)

It is shown on the basis of simple physical principles that the parameters determining the shape of the nerve ending of the Pacinian corpuscle are optimal.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Research Institute of Applied Mathematics and Cybernetics, N. I. Lobachevskii Gor'kii State University. Translated from Neirofiziologiya, Vol. 9, No. 4, pp. 423–429, July–August, 1977.     

Mechanisms of interaction between central neurons and abdominal stretch receptors in the crayfish

Mechanisms of interaction between central and receptor neurons of the crayfish (the principal inhibitory neuron — PIN — and the slow-adapting stretch receptor — SAR) when functioning under different conditions were investigated: during regular spontaneous activity of SAR, grouped discharges of PIN, and regular spontaneous activity of PIN. A close connection was found between the various parameters of the PIN and SAR responses. Adaptation of SAR to the action of adequate, regular repetitive stimulation takes place faster in the presence of stationary background activity of PIN. The appearance and disappearance of SAR spike activity are determined by the ratio between the firing rates of SAR and PIN: at the moment of changeover the neuron with the higher firing rate is predominant.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Institute of Zoology, Academy of Sciences of the Moldavian SSR, Kishinev. Translated from Neirofiziologiya, Vol. 4, No. 4, pp. 429–438, July–August, 1972.     

Cutaneous mechanism of electroreceptor temperature sensitivity of the ampullae of Lorenzini

The potential difference on the receptor epithelium of the ampullae of Lorenzini and on the skin and also spike discharges of single electroreceptor nerve fibers in response to temperature stimulation of the region of the pores of the ampullae were studied in the Black Sea skateRaja clavata. Heating the skin in the region of the pore led to the appearance of a positive potential on the skin and on the epithelium of the ampulla, and to inhibition of spike activity. The time course of the change in potential reflected the course of change of temperature; the temperature coefficient was 100–150 µV/°C. Cooling the skin was accompanied by a negative deviation of potential on the skin and in the ampullary canal and by excitation of spike activity. During cooling the temperature coefficient was 30–50 µV/°C. It is concluded that spike activity of electroreceptors reflects changes in potential on the skin due to changes in temperature. The mechanism and biological significance of the phenomena discovered are discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 13, No. 3, pp. 307–314, May–June, 1981.     

Determining neuronal response of the rabbit thermoregulatory center to thermal stimulation

A classification was made of neuronal spike activity in the dorso- and ventromedial hypothalamic nuclei. Thermosensitive neurons in which response was accompanied by change in activity pattern could be identified with 0.95 probability by means of an algorithm based on this classification.I. V. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 20, No. 3, pp. 291–301, May–June, 1988.     

Modular organization of callosal neurons in the rabbit sensomotor cortex

The density of distribution of callosal neurons in the rabbit sensomotor cortex was studied by injecting horseradish peroxidase into the symmetrical region of the cortex. The degree of inequality of distribution of labeled neurons was determined visually and by statistical analysis. Stained callosal neurons were mainly small and medium-sized pyramidal cells, located chiefly in layer III–IV, and substantially less frequently in layers V and VI. Different forms of grouping of labeled neurons were observed in layer III–IV: two cells at a time, five to eight cells arranged vertically, or in concentrations, whose width was usually 120–200µ, and separated by areas with reduced density. The results are regarded as confirmation of those drawn previously from results of electrophysiological investigations on the modular organization of callosal connections in the rabbit sensomotor cortex.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Brain Institute, Academy of Medical Sciences of the USSR, Moscow. I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 16, No. 4, pp. 451–457, July–August, 1984.     

Responses of central auditory neurons to frequency-modulated stimuli and temporal characteristics of inhibitory interaction

Responses to frequency-modulated stimuli of 118 inferior collicular neurons were compared with quantitative characteristics of the frequency — threshold curves and lateral inhibitory zones during time-varying two-tone stimulation in anesthetized albino rats. In one third of neurons high sensitivity to the direction of frequency modulation does not correspond to their spatial characteristics (the shape, width, and arrangement of the lateral inhibitory zones relative to the frequency — threshold curve). The specificity of response of these neurons to a particular direction of frequency modulation is evidently based on differences in the temporal course of inhibition evoked by high-frequency and low-frequency tones.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 7, No. 6, pp. 603–607, November–December, 1975.     

Anesthesia effect on rabbit hypothalamic neuron impulse activity

Neuronal impulse activity in the thermoregulation center in the anterior and posterior sections of the rabbit hypothalamus was studied in chronic experiments and in intravenously injected anesthetics (urethane and chloralose). Anesthesia decreased the neuronal firing rate, changed the impulse activity pattern, and decreased the number of neurons responding to skin thermal stimulation. These changes were most pronounced in the posterior hypothalamic section.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 23, No. 5, pp. 574–579, September–October, 1991.     

Comparative analysis of brain neurite-stimulating protein and nerve growth factor using a culture of chick embryo sensory neurons

A study was made of brain neurite-stimulating proteins separated from lysosomal fractions of mammalian brain tissue. This protein stimulates axonal growth in sensory neurons in organotypic spinal ganglia culture. The physicochemical properties of neurite-stimulating protein differs from nerve growth factor — the familiar neurotrophic factor. Findings showed that nerve growth factor antiserum does not block the action of this protein. Accordingly, brain neuritestimulating protein separated in highly purified form was found to be a low molecular weight protein with the properties of nerve growth promoting factor. It can also be used in the study of conditions promoting sensory neuron ontogenesis and for stimulating regenerative processes within the nervous system.I. P. Kovlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. O. O. Zhdanov State University, Leningrad. Translated from Neirofiziologiya, Vol. 20, No. 1, pp. 15–20, January–February, 1988.     

Changes produced in neuronal excitability by subthreshold depolarization as a possible mechanism of interval selective relationships within the central nervous system

A neuronal process was identified inLymnaea stagnalis nerve cells which may be viewed as one of the mechanisms underlying the interval selectivity previously described in research into the functional relationships between mammalian brain cells. This process takes the form of regularly-occurring changes in excitability resulting in a high probability (of 0.6–1) of neuronal spike response to what had previously been subthreshold depolarizing current pulses following similar subthreshold (conditioning) pulses at intervals specific to each individual neuron. It was found that the cycle of change in neuronal excitability following threshold depolarization did not arise from temporal summation of electrotonic local or postsynaptic neuronal potentials; it was an endogenous (cytoplasmic) process insensitive to transmitter (acetylcholine) application but altering irreversibly under the effects of bombesin, one of the modulator peptides.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad; Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. Translated from Neirofiziologya, Vol. 21, No. 3, pp. 291–299, May–June, 1989.     

Functional characteristics of electroreceptors of the Turkestan catfish

Acute experiments to record spike activity from single fibers of the lateral line nerve of the Turkestan catfish revealed electroreceptor formations which, in their functional characteristics, were similar to the ampullated electroreceptors of other freshwater fish (the so-called small pit organs). The threshold intensity of the uniform electric field was 1 µV/cm. A voltage drop on the skin of the fish was shown to be an effective stimulus for the electroreceptors. A spike response to a change in the magnetic field was found for the first time in electroreceptors of freshwater fish. The threshold level of magnetic induction for a velocity of rotation of the permanent magnet of 1 m/sec was 2.9 · 10^–4 T. Temperature and mechanical sensitivity of the electroreceptors was determined. The biological significance of electroreceptors of the Turkestan catfish is discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. M. I. Kalinin Andizhan Medical Institute, Ministry of Health of the Uzbek SSR. S. M. Kirov Murmansk Marine Biological Institute, Kola Branch, Academy of Sciences of the USSR, Dal'nie Zelentsy. Translated from Neirofiziologiya, Vol. 12, No. 5, pp. 508–516, September–October, 1980.     

Responses of the ampullae of Lorenzini in a uniform electric field

A linear relationship was established by analysis of discharges from electroreceptors of the ampullae of Lorenzini in a uniform electric field between the potential difference on a single ampulla and the relative change in the spike response of a single fiber. This relationship can serve as the basis for a model of activity of ampullary groups considered as functional units of the electroreceptor system.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 11, No. 2, pp. 158–166, March–April, 1979.     

Involvement of calcium-binding membrane components in neurophysiological mechanics of habituation in Helix pomatia

Dynamics of binding between calcium and hydrophobic membrane components were investigated in vivo in identified neurons ofHelix pomatia while producing habituation to tactile stimuli using a fluorescent chlortetracycline probe technique. A decline in the concentration of membrane-bound calcium (Ca _b ²⁺ ) and likewise in the intensity of electrophysiological response was found in the "command" neurons of defensive behavior when applying a train of stimuli. An increase in Ca _b ²⁺ was noted in the sensory neuron studied and in the spiracle motoneurons. It proved difficult to produce habituation in these cells fulfilling standard electrophysiological criteria. Hydrophobe-hydrophil transfer of calciumbinding molecules is thought to accompany production of habituation in nerve cells.P. K. Anokhin Institute of Normal Physiology, Academy of Medical Sciences of the USSR, Moscow. I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 21, No. 5, pp. 605–612, September–October, 1989.     

Effects of transcranial electrical stimulation of opioid brain structures on regeneration of peripheral nerves in the rat

The effects of transcranial electrical stimulation of opioid brain structures on regeneration of the rat sciatic nerve after transection and microsurgical suturing of the nerve were investigated. Electrical stimulation was found to accelerate regeneration of motor and sensory fibers of the sciatic nerve. The subject of the involvement of endogenous opioid peptides in regeneration of the peripheral nerves is discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 22, No. 1, pp. 76–79, January–February, 1990.     

Selectivity in the response of human cerebral neurons to visual stimuli at different angles of alignment

The neuronal activity of different nuclei of the thalamus and striopallidar complex was investigated in Parkinsonian patients with intracerebral electrodes chronically implanted in these structures for diagnostic and therapeutic purposes. Neuronal populations were discovered responding differently to the presentation of stimuli identical in all but angle of presentation, some of which responded solely to a single orientation and might therefore be thought of as displaying directional sensitivity. It is suggested that when motor and visual information converge within the above systems, a matching process takes place, together with an interaction relating to stability of visual perception.Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad; Institute of Information and Automotive Sciences, Academy of Sciences of the USSR, Leningrad. Translated from Neirofizologiya, Vol. 19, No. 1, pp. 3–11, January–February, 1987.     

Effects of calcium and potassium channel blockers on changes in transepithelial potential and spike responses in Lorenzi ampullary electroreceptors in Raja clavata

The effects of TEA, 4-AP, Co⁺⁺, Cd⁺⁺, Cs⁺, EDTA, and verapamil on the sensory epithelium of ampullae of Lorenzini were studied inRaja clavata (Black Sea skate). During voltage clamping, transepithelial application of TEA to the basal surface caused oscillations in transepithelial potentials in response to presentation of an excitatory stimulus, which had been suppressed by Co⁺⁺, Cd⁺⁺, and EDTA. Application of Cs⁺ was followed by complete or partial suppression of spike response adaptation. When applied to the apical epithelial surface, TEA produced an increase in spike response to stimulation and highly accelerated adaption. No substantial changes took place after apical application of Co⁺⁺, Cd⁺⁺, and verapamil. The mechanisms of these phenomena are discussed.Deceased.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 17, No. 5, pp. 652–659, September–October, 1985.