[Role of vestibular and visual analyzers in changes of postural activity of patients with childhood cerebral palsy in the process of treatment with space technology]

The paper presents the findings of stabiligraphic investigations of children afflicted with the hyperkinetic child's cerebral paralysis treated with the method of graduated wearing suit ADELI. This suit is a modification of space-designated PINGUIN used to counteract the adverse effect of long-term microgravity on the skeletal muscles and the skeleton. 30 children were investigated prior to, immediately after, and in a delayed period after this treatment. A group of 11 healthy volunteers were also investigated as their control. The program of investigation included routine stabilimetry, the station test, and head rolling tests. The results demonstrate that in healthy subjects the standing pose is primarily acquired and sustained by means of the visual analyzer, whereas the CCP patients pose could attain this pose with a significantly weakened control by the visual analyzer. Application of ADELI increases the role of visual analyzer in the control of standing pose. Following the treatment, the stabilimetric indices of patients changed for the better and approached those in healthy subjects.

Intersegmental and local interneurons in the metathorax of the stick insect Carausius morosus that monitor middle leg position

1. In the stick insect, proprioceptive information from the middle leg is used to define the target for the swing movement of the adjacent rear leg ("targeting behavior"). To investigate the underlying neural circuits, intracellular recordings were made in the ganglion controlling the rear leg, the metathoracic ganglion, while systematically moving the tarsus of the middle leg. 2. Several intersegmental interneurons and one local interneuron were identified as possible contributors to the targeting behavior. The intersegmental interneurons code the position of the middle leg tarsus in a highly simplified manner: test movements of the middle leg in the dorsal, lateral, and caudal directions from the standard starting position at right angles to the thorax elicit phasic-tonic responses in three different intersegmental neurons. The response in each interneuron actually reflects the movement and position at only one joint of the middle leg: for the neurons responding primarily to movement in the caudal, dorsal, and lateral test directions, the adequate stimulus is movement at the subcoxal joint, the coxa-trochanter joint, and the femur-tibia joint, respectively. 3. The metathoracic local interneuron integrates information from ipsilateral middle and rear legs in such a way as to provide an approximate measure of the distance between the two tarsi in the longitudinal direction. It is depolarized in a phasic-tonic manner both by caudal movements of the ipsilateral middle leg and by rostral movements of the ipsilateral rear leg. The adequate stimulus in each case is the change in the angle at the subcoxal joint of the leg moved. Depolarization of this neuron activates retractor motoneurons, which is consistent with a role in terminating the swing movement. 4. Altogether the results indicate first, that the targeting behavior could be controlled by very few intersegmental channels and, second, that the nervous system encodes the position of the middle leg tarsus in terms of joint angles rather than in abstract, body-centered coordinates.

The cerebellar nodulus and ventral uvula control the torsional vestibulo-ocular reflex

1. The vestibulo-ocular reflex (VOR) was investigated in rhesus monkeys before and after surgical ablation of the cerebellar nodulus and ventral uvula. The lesion resulted in an alteration of the torsional VOR: compensatory eye movements were poor in the low frequency range and the time constant was reduced to values comparable to those of primary semicircular canal afferents. In addition, animals permanently lost their ability to generate torsional optokinetic nystagmus (OKN). 2. The effects of the lesion on the torsional VOR differed from those observed in the horizontal and vertical vestibulo-ocular systems. While the vertical VOR and OKN were unaltered, the horizontal VOR and OKN were characterized by increased time constants and smaller phase leads during low frequency head oscillations. 3. These results suggest that the cerebellar nodulus and/or ventral uvula exert a distinct and specific dynamic control on the torsional vestibulo-ocular and optokinetic reflexes. Such specific effects on the torsional system could reflect a functional segregation of the vestibulo-cerebellum in terms of the controls of torsional versus horizontal and vertical slow phase eye movements.

Brain stem integration of vocalization: role of the midbrain periaqueductal gray

1. The contribution of the midbrain periaqueductal gray (PAG) to the central regulation of vocalization was investigated by analyzing the electromyographic (EMG) changes in respiratory, laryngeal, and oral muscles evoked by microinjection of D,L-homocysteic acid (DLH) in the PAG of unanesthetized, precollicular decerebrate cats. Moderate to large (6-40 nmol) doses of DLH evoked natural-sounding vocalization as well as increases in inspiratory depth and respiratory rate. 2. Two basic types of vocalization were evoked, each associated with a distinct and characteristic pattern of respiratory, laryngeal and oral EMG changes. Type A vocalization (voiced sounds such as howl/mew/growl) was characterized by excitation of the cricothyroid (CT) and thyro-arytenoid (TA) muscles, and inhibition of the posterior crico-arytenoid (PCA) muscle, whereas type B vocalization (unvoiced hiss sounds) was characterized by excitation of the PCA and TA muscles and no significant activation of the CT muscle. In addition, stronger expiratory (external oblique, internal oblique, internal intercostal) EMG increases were associated with type A responses, and larger increases in genioglossus and digastric muscle activity were associated with type B responses. 3. Microinjections of small doses of DLH (300 pmol-3 nmol), also evoked patterned changes in muscle activity (usually without audible vocalization) that, although of lower amplitude, were identical to those evoked by injections of moderate to large DLH doses. In no such experiments (175 sites) were individual muscles activated by small dose injections of DLH into the PAG. Further, type A vocalization/muscle patterns were evoked from PAG sites caudal to those at which type B vocalization/muscle patterns were evoked. 4. Considered together these results indicate: that the PAG contains topographically separable groups of neurons that coordinate laryngeal, respiratory, and oral muscle patterns characteristic of two fundamental types of vocalization and that the underlying PAG organization takes the form of a representation of muscle patterns, rather than individual muscles. 5. The patterns of EMG activity evoked by excitation of PAG neurons were strikingly similar to previously reported patterns of EMG activity characteristic of major phonatory categories in higher species, including humans (e.g., vowel phonation, voiceless consonant phonation). These findings raise the possibility that the sound production circuitry of the PAG could well be utilized by cortical and subcortical "language structures" to coordinate basic respiratory and laryngeal motor patterns that are necessary for speech.

[Automatic regulation in the auditory analyzer and the phenomenon of accelerated growth of loudness]

Physical analysis of the ear periphery structure and the data on loudness perception have been used to develop a model of loudness measurement and self-control in the hearing analyzer. The experimental results obtained recently by different researchers are shown to confirm that the basic ideas of this model are reasonable, and the model is of considerable heuristic importance. The author provides treatment of the main hearing "paradox", that is the existence of a wide dynamic range of loudness perception for a narrow range of afferent pulsation in auricular nerve fibers. A simple explanation is found for the so-called adaptation phenomenon. The explanation of the phenomenon of loudness increase acceleration typical for many forms of neurosensory hypoacousis opens up new perspectives in the diagnostics and treatment of these diseases.

The effects of magnitude and direction of stimulus change on auditory event-related potentials elicited by deviant signal stimuli

The present study sought to identify components of the auditory event-related potential (ERP) elicited by stimuli that serve as signals for overt discriminative responses. Sokolov's view of a selective neural filter for deviant stimuli predicts that responses to deviant signal stimuli will be graded in proportion to the amount of change from the standard and independent of the direction of that change. The demonstration of a bi-directional and graded ERP response requires at least two levels of stimulus change in each direction. The present study incorporated two deviants that were lower in pitch (lowest, low) and two that were higher in pitch (high, highest) in order to evaluate the degree (linear, quadratic, etc.) of the function relating ERP response to tonal deviance. Stimulus changes on both the direction and magnitude dimensions were also varied on a trial-by-trial, rather than on a block-by-block, basis which eliminated potential confounds with block or session differences, and discriminative responses were required to both standard and deviant tones, thereby investing both categories of stimuli with signal value. The amplitude of the P3 component associated with deviant stimuli showed close correspondence to the (quadratic) function predicted from the selective filter model. A late negative slow wave (NSW) at Fz and a positive slow wave (PSW) at Pz differentiated deviant tones from the standard but did not distinguish between the deviants themselves. A fronto-central NSW observed at Fz and Cz for initial standard tones was greater than the predominantly frontal NSW elicited by the deviant tones. The topographical differences in NSW elicited by the initial standard tone and by all deviant tones suggest that different processes are reflected in the NSW response to these stimuli.

[The noise-suppression capacity of the auditory analyzer for interfering speech in one's native and in an unknown language]

Anti-noise potential of the acoustic analyzer in Russian and Armenian speech interference was studied in twenty otologically normal 17-23-year-old subject who speak only Armenian. Intelligibility parameters were measured in a free sound field with the use of two audiometers furnished with recorders and adjusted loud speakers. One of them delivered valuable speech information, the other one was disturbing. Intelligibility of valuable speech information was found higher in masking by foreign speech than by native one.

[Vestibular function and interanalyzer interaction following space flight]

This paper presents the results of pre- and post-flight vestibular examinations using single and combined vestibular, optokinetic, proprioceptive, postural tests and cerebellar coordination tests. After extended flights most crewmembers showed spontaneous, position and positional nystagmus that points to vestibular dysfunction. The methods developed by the authors helped differentiate mechanisms of post-flight vestibular dysfunctions: in Group 1 subjects spontaneous nystagmus parameters varied during all tests; in Group 2 subjects they varied only in response to active tilt tests; in Group 3 subjects they varied only in response to vestibular, optovestibular and proprioceptive stimulation; and in Group 4 subjects they varied only in response to proprioceptive optovestibular stimulation and cerebellar coordination tests. Individual patterns of the above changes are associated with different pathways of adaptation of the vestibular function that depend on the involvement of various structures and compartments of the central nervous system.

[Loudness measurement and automatic control in the acoustic analyzer]

A block diagram of a hearing system is presented in which external hair cells are used to measure the loudness level and to adjust automatically internal hair cells. This system may assure an optimal function of the basic acoustic systems responsible for sound analysis. The data presented form a theoretical foundation for an adequate physiological interpretation of the recruitment phenomenon recorded in certain forms of neurosensory hypoacusis.

[Indicators of the state of hearing and olfactory analyzers in healthy man]

This paper presents the concept of a biological norm, methods of experimental studies, and parameters of the hearing and olfactory function as derived from large-scale examinations of healthy people of different sex and age groups. On this basis parameters of the physiological norm for the hearing and olfactory function were calculated as applied to various age groups. The paper gives tables of average thresholds and limits of variations of hearing and olfactory sensitivity adapted for practical use. The tabulated data can be employed to evaluate examination results, to make early diagnosis, and to assess performance capabilities in the norm and pathology.

[The temperature analyzer, thermoregulation and the problems of thermotherapy]

The paper presents data and conceptions on physiological mechanisms of thermoregulation by temperature analyzer at various levels, the relationships between the mechanisms, interaction, influence on systemic trophic function. In view of the knowledge the effects of some novel techniques different in principle from the standard ones applied in thermotherapy are specified.

Functional organization of the medial division of the medial geniculate body of the cat: tonotopic organization, spatial distribution of response properties and cortical connections

The discharge properties of 735 single units located in the pars magnocellularis (M) of the medial division of the medial geniculate body (MGB) were studied in 23 nitrous oxide anesthetized cats in response to simple acoustic stimuli (clicks, noise and tone bursts). A systematic decrease of single unit characteristic frequencies (CF) was observed along electrode track portions crossing M from dorso-medial to ventro-lateral. These data indicate that M is tonotopically organized with an arrangement of low CF units latero-ventrally and high CF units dorso-medially. This preferential arrangement of single units as a function of their CF was consistent with the location and orientation of clusters of labeled cells in M resulting from wheat-germ agglutinin labeled with horseradish peroxidase (WGA-HRP) injections in CF defined loci in the anterior (AAF) or primary (AI) auditory cortical fields. The quality of the tonotopic arrangement was low caudally and increased in the rostral direction, indicating that this tonotopicity concerns mainly the anterior half of M. Response latencies to clicks, noise and tone bursts were on average longer in the posterior part of M than in its anterior part. Time-locking of discharges in response to repetitive acoustic pulses was more frequent anteriorly than posteriorly and the upper limiting rate of locking was on average higher rostrally (up to 200-300 Hz). In contrast, other response properties such as responsiveness to the various combinations of simple acoustic stimuli, response patterns and tuning were more randomly distributed in M, showing the whole range of response properties seen in the MGB. Data derived from several injections of WGA-HRP performed in distinct auditory cortical fields in several animals indicated that M projects to the tonotopic cortical fields (AAF, AI and PAF) as well as to the non-tonotopically organized secondary auditory cortex (AII). The contribution of M to the total thalamic input reaching each field of the auditory cortex was quantitatively more important for AAF (30%) and PAF (20%) than for AI and AII (about 10% each).

Monitors: key mechanisms and roles in the development and aging of the consciousness and self

A network of interacting neural structures, called monitors, exists in the mammalian brain in which data derived from sensory inputs and from memory stores is precisely displayed within the brain. The key function of monitors is to provide an 'ultimate monitor', proposed to be the locus that generates the phenomenon of conscious self awareness, with information that defines or maps the positions of the parts of an individual with respect to each other and with respect to external objects or events at specific times. The resolution of at least some of these monitors (e.g. some concerned with vision) is extremely great and approaches, in the case of vision, the precision with which images of external objects are projected onto the retina. This conclusion is based on the fact that an individual is able to perceive visual images with an acuity that closely approximates the fineness of resolution of the retinal image. The sensory signals that provide information about body part positions and those that provide information about the exterior are evidently integrated with each other in a suitable hierarchy of monitors so as to provide a coherent representation of self-vs.-environment. The logical 'framework' monitor for this integrated display-mapping is proposed to be that that maps the body in space and it is proposed that the locations of objects perceived through the touch sense and senses that deal with more remote items in the environment become superimposed on a map that extends or extrapolates the body space map beyond the body's physical boundaries, a learning process that occurs during development. The ultimate monitor not only receives a display of the synthetic representations derived currently through the integrative functions defined above, but also is provided with at least four other inputs from other different classes of monitors. One of these is a monitoring system that generates timing signals needed to separate inputs into a time order and to assign an order to them. It is proposed that it is awareness of these timing signals by the ultimate monitor that is the essential and indispensible input that generates the phenomenon of awareness. A second input to the monitor that is the self is a selected part of its own activities. This awareness of what the ultimate monitor is receiving, doing or planning to do in the future is the characteristic necessary for awareness of self.(ABSTRACT TRUNCATED AT 400 WORDS)

[Aids for low vision--strategic approach]

There are currently methods to rehabilitate the remaining visual function of visually impaired people. Treatment stages and tests are based on classical physiology of vision and still remain strictly experimental. Recent investigations showed that the visual system, as a whole, operates as a space frequency analyzer. There are reception to each spatial frequency. They have to be assessed with accuracy before any rehabilitation attempting to develop channels which are still functional by elective stimulation. This stimulation must have a maximum determined energetic efficiency. The study of the Fourier spectrum on two different images demonstrates this possibility and starts opening the way for specific research.

[A device for studying liminal and supraliminal indices of the state of the olfactory analyzer]

An universal device (olfactoadaptometer) permitting to carry out threshold and suprathreshold olfaction assessment in suggested. Use of odorous substances of different receptor orientation increases the possibilities of differential diagnosis of olfactory analyzer diseases. The construction of the device is simple. Units, which are in industrial production can be used for its manufacture. The olfactometer is portable, simple in attendance and self-reacting.