Audiology in general, and audiometric techniques in particular, have made commendable progress in the last few decades. The threshold for pure tones and speech can be accurately established and at subsequent examinations can be confirmed or compared, with a fair amount of precision. The articulation score for phonetically balanced words can be determined and so can the effect of amplification on such scores. The conductive and the cochlear component of hearing loss can be distinguished with a fair amount of reliability from what is called the "sensorineural" or the "retrocochlear component".

Quick frozen section of brain tumors, as well as the smear technique developed here at the Montreal Neurological Institute by the late Dr. W.V. Cone are extremely valuable means for arriving at a preliminary pathological diagnosis which can be relayed to the surgeon prior to the completion of an operation. We felt, however, that the fine histological distinction between benign and malignant intracranial lesions which arises in some cases could not be readily resolved by using the above techniques alone and that, perhaps, a technique could be devised to help clarify these problem cases.

Since Caton (1875) recorded electrical potential change from the exposed brain of a rabbit and, later, Berger (1929) demonstrated electrical currents produced by the living brain of man, the study of electrical activity of the cerebral cortex has become increasingly important in the understanding of brain function. However, the analysis of this activity is not an easy task, not only because of the extreme complexity of the structure of the cerebral cortex, but also because of the inadequacy of the methods conventionally used for the recording of the cortical activity.

The object of this work is to provide a morphological guide for the conduct and analysis of experiments carried out on the brain stem of the cat. In particular, the work contains a series of photomicrographic illustrations of the cat brain stem upon which are delineated the major nuclei as distinguished by the classical cytoarchitectural criteria and a set of stereotaxic coordinates referrable to modern adaptations of the Horsley-Clarke stereotaxic instrument.

Rasmussen, T.This study was conducted during the years 1960-61 when I was appointed a Hosmer Teaching Fellow in the Department of Otolaryngology, McGill University, at the Royal Victoria Hospital, Montreal. The original plan of this study was to evaluate the possible effect of some temporal lobe lesions upon vestibular function. It has been reported that a lesion of the temporal lobe may produce directional preponderance of nystagmus to the side of the lesion in response to calorie stimulation. (Fitzgerald and Hallpike 1942, and Carmichael, et al, 1954).

The mechanism of headache has been studied physiologically by the neurosurgeon, whose conclusions have sometimes proved difficult to correlate with known anatomical facts. This is because of the relative paucity of knowledge concerning intracranial sensory nerves and nerve endings so that the interpretation of physiological investigations has depended to some extent on speculation. There are at present two main groups, one which would consider the pain of headache as mediated solely or almost entirely by periarterial nerves and receptors, the other which attributes to nerves within certain special locations of dura the chief role in pain conduction. The present study has approached the problem from two aspects, the first anatomical, special interest being taken in nerve endings in dura, the second clinical, observations on dural sensitivity in man. It has become apparent that both dural vessels and sinuses as well as certain cerebral vessels are pain - sensitive, but in addition that parts of dura itself are sensitive. Furthermore complicated corpuscular nerve endings demonstrated in dura suggest that afferents other than pain fibres leave the dura. These may play a part in reflexes which control vasomotor tone or even play a part in the regulation of intracranial pressure.

Despite the advances of electrophysiology and the passage of fifty years, the conclusions of John Hughlings Jackson as regards the mechanisms involved in idiopathic epilepsy are today not only being confirmed, but are serving as a basis for farther investigation. Studies of cortical localisation of onset in various forms of epilepsy have failed to reveal a focus of onset for petit mal attacks. Major generalised convulsive seizures ("grand mal") of bilateral onset have also defied attempts at localisation at the level of the cortex.

This investigation was carried out at the instigation of Dr. W. V. Cone in the attempt to discover chronic pathological changes in oligodendroglia. Knowledge of chronic changes in the oligodendrocytes has not been greatly advanced m the past twenty years. At that time it was stated that: "Unlike astrocytes, the disappearance of myelin does not result in an increase but a decrease of the oligodendrocytes and it is quite possible that with myelin degeneration oligodendrocytes are transformed into astrocytes." (Penfield 1932).

The understanding of the functions of a certain portion of the cortex ultimately is dependent on a knowledge of the connections or interrelationships of that particular cortex. Consequently, the visual cortex and the auditory area are better understood because of the works of Poliak (1932), Talbot (1942), Talbot, Woolsey and Thompson (1946), and of Walker (1937a,1937b), of Ades and Felder (1942, 1945), Ades (1943), Woolsey and Walzl (1942), Walzl and Woolsey (1943), Tunturi (1944, 1945), Rose (1949), and Rose and Woolsey (1949).

In recent years, increasing numbers of conflicting reports (to be commented on in the section devoted to a review of the literature) have appeared in the world literature regarding the effect of chlorpromazine on epilepsy and on the seizure activity seen in the electroencephalographic tracings of epileptic patients. These have ranged, with regard to epilepsy, from one extreme position in which the drug is advocated as a therapeutically efficacious method of treatment, to the other extreme in which it is held accountable for having precipitated epileptic seizures in patients with no previous history of similar distrubance who are undergoing treatment for an unrelated illness.