Mechanisms of the flare reaction in human skin

The diffuse area of arteriolar vasodilation surrounding a region of recently injured human skin (axon reflex flare) is dependent upon the integrity of nerve fibers with cell bodies located in dorsal root ganglia. Evidence is presented to indicate that a vasodilator peptide similar to a kinin, neurotensin, or substance P, is implicated in the chain of biochemical events responsible for the transient shift in vascular tonus observable as the flare reaction.

Neurophysiologic and pathologic aspects of acute and chronic pain

Acute pain produced by disease or injury is the net effect of highly complex interactions of various neural systems and psychological factors. Through the interaction of the afferent systems and neocortical processes, the individual is provided perceptual information regarding location, magnitude, and spatial and temporal properties of the noxious stimulus that activates motivational tendencies toward escape or attack and permits analysis of multimodal information, past experience, and probability of outcome of different response strategies. In contrast, chronic pain is a malefic force that taxes the physical, emotional, and economic resources of the patient, his famiily, and society. Moreover, chronic pain is characterized by physiological affective and behavioral responses that are quite different than those of acute pain. The clinician must keep these differences in mind in order to provide patients with optimal relief of their pain.

[Neurophysiological data on transmission and integration of nociceptive messages (author's transl)]

In this study cutaneous nociceptive messages are followed at different levels of the CNS, from the periphery to the cortex. A brief summary is given concerning the role of the fine myelinated and unmyelinated fibres which are specifically activated by noxious stimuli. A more extensive review considers the spinal mechanisms which sustain the transmission of nociceptive messages; the electrophysiological properties of interneurones located in laminae VIII, V, and I of the dorsal horn are described in detail. At the same time, the problem of the ascending projections of those cells activated by nociceptive stimuli is discussed. Particular attention is paid to the controls acting at the spinal level: segmental controls are described first and lead to discussion of the "gate control theory"; descending inhibitory controls are then discussed and their importance emphasized. The complexity of pain mechanisms at the supra-spinal level is underlined and a brief review considers the role of various bulbar, mesencephalic and thalamic structures involved in transmission of noxious messages. Among these structures, the PO group of nuclei seem to have a particular role in pain processes. Although the importance of the cortex for final integration of nociceptive messages is discussed, a brief summary is also given of investigations into the role of somatic area SII.

Electrophysiological observations on the spinal cord of the normal and dystrophic mouse

A method of carrying out electrophysiological experiments on the mouse spinal cord is described. The conduction velocity in the spinal dorsal roots (DR) of the normal mouse was in the range 10-100 m sec-1 and in the ventral roots (VR) 50-70 m sec-1. In the dystrophic mutant (129 ReJ dy/dy) the conduction velocity for both roots was usually in the range 0.1-2.0 m sec-1. Reflexes from DR to VR were recorded in both mutant and wild type animals and it was concluded that the delays in the mutant reflex were probably due to the slower conduction velocity in the roots. Postsynaptic inhibition and presynaptic inhibition were demonstrated and records were made from Renshaw cells and intracellularly from motoneurones. Delayed activity in spinal reflex paths, probably of supraspinal origin, was more pronounced in the dystrophic mutant. It is concluded that if the dystrophic mouse mutant were to be regarded as a model for human disease then similar reflex delays should be demonstrated in human subjects with muscular dystrophy.

[NEOLOGISMS AND MOTOR APHASIA. (Afferent pathology?)]

The authors describe a case of post-traumatic aphasia in a 39-year-old man. The linguistic disturbances were marked by the unusual association of oral expression consisting mainly of neologisms, normal comprehension and almost normal written expression. A physiological interpretation based on disturbance of treatment of the sensory afferent nerves from the bucco-phonator organs is suggested to account for the neologisms in this particular form of aphasia.

Acute flexion-extension injury of the neck. Electronystagmographic study of 309 patients

Three hundred and nine patients, whose chief complaint was dizziness following a flexion-extension type of acceleration neck injury, were examined in the Neurosensory Laboratory of Temple University Health Sciences Center between 1965 and 1972. Specific attention was devoted to vestibular tests, including a search for latent and positional nystagmus, bithermal calorics, and rotatory tests. All tests were performed with the aid of electronystagmography; latent nystagmus was present in 29 percent of the patients, caloric tests were abnormal in 57 percent, and rotatory tests were abnormal in 51 percent. These findings suggest that many of these patients have a verfiable objective vestibular disturbance as a cause of dizziness, even though the neurologic examination may be normal. Furthermore, in order to detect this objective vestibular dysfunction, the patient should be tested with aid of electronystagmography since nystagmus may be inhibited by visual fixation.

[Effect of the factor "frequency of words" on temporal and structural characteristics of speech reaction in patients with motor-efferent and motor-afferent aphasia]

The effect of the factor "Frequency of the words" on the speech and the structure of the actualised verbal responses in patients with motor aphasia has been studied. It was established that the rate of the verbal associations occurence depended on the frequency of the word-stimulus and on the probable frequency of the response - stimuli with low frequency prolong the time of the actualisation, especially of the period of sound realisation. Alterations in the psycholinguistic structure of the associative responses were detected - the percentage of the syntagmatic links in both forms of motor aphasia diminished in stimuli with low frequency, which showed that the difficulties in the processes of combination increased. In repeating, reading aloud, writing to dictation with and without pronouncing low frequency words, the number of the mistakes increased and parallel to that the possibilities for their correction decreased. In words with high frequency, reverse correlation to these mentioned above have been established. The results from the study suggested that in preparing the program for the reparative education in patients with motor aphasia, we could rely not only on the "round-about ways" for the reconstruction of the impaired speech system, but also to enlarge considerably the support of its "preserved links". Such a "link" undoubtedly is the considerably preserved speech content of high frequency words.

[Effect of the hypothalamus and reticular formation on the cerebral cortex in hypoxic brain states]

In anesthetized cats and unanesthetized rabbits, the reticular formation and the posterior hypothalamus were shown to be able to reduce the resistance of cortical vessels thus increasing the blood supply of the brain cortex. This effect decreased after stimulation of the cortex and in conditions of hypoxia, hypercapnia, section of the vagus, chronic circulatory deficit in the myocardium and the brain.

[Evaluating function and disorders of taste]

In a first anatomical section the peripheral gustatory pathways, their central connections, nuclei and cortical projections are discussed. It is evident, that the gustatory fibres from the posterior part of the tongue run in the IX nerve and those from the soft palate reach the medulla oblongata via the petrosal and facial nerve. For the anterior part of the tongue there obviously exists only one gustatory pathway via the chorda tympani-facial nerve. About the further central pathways of taste fibres is much less known. In a second part the methods of taste testing with different taste solutions and the electrogustometry are described. Their practical use and the pitfalls of testing are considered. The disorders of the taste sense compose a third part. Genetic and endocrine abnormalities as well as the side effects of drugs and radiotherapy and the destruction of taste nerves may lead to gustatory deviations. The possibility of central gustatory disorders, especially the combined loss of taste and smell as a result of trauma are mentioned. A chapter dealing with the therapy of taste disorders and a short outlook on the genetic aspects of this oral sense complete this review.