The Brain and the Voice in Speech and Song Part 4

THE PRIMARY REVIVAL OF SOME SENSATIONS IN THE BRAIN

I have on page 77 referred to Stricker's views on the primary revival of words in the sense of movement of the lips and tongue. Mach ("a.n.a.lysis of the Sensations") says: "The supposition that the processes in the larynx during singing have had something to do with the formation of the tonal series I noticed in one of my earlier publications, but did not find it tenable. Singing is connected in too extrinsic and accidental a manner with hearing to bear out such an hypothesis. I can hear and imagine tones far beyond the range of my own voice. In listening to an orchestral performance with all the parts, or in having an hallucination of such a performance, it is impossible for me to think that my understanding of this broad and complicated sound-fabric has been effected by my _one_ larynx, which is, moreover, no very practised singer. I consider the sensations which in listening to singing are doubtless occasionally noticed in the larynx a matter of subsidiary importance, like the pictures of the keys touched which when I was more in practice sprang up immediately into my imagination on hearing a performance on the piano or organ. When I imagine music, I always distinctly hear the notes. Music can no more come into being merely through the motor sensations accompanying musical performances, than a deaf man can hear by watching the movements of players. I cannot therefore agree with Stricker on this point" (comp. Stricker, "Du langage et de la musique," Paris, 1885).

Of the motor type myself and having a fairly good untrained ear for music, I find that to memorise a melody, whether played by an instrument or by an orchestra, I must either try to sing or hum that melody in order to fix it in my memory. Every time I do this, a.s.sociation processes are being set up in the brain between the auditory centres and the centres of phonation; and when I try to revive in my silent thoughts the melody again, I do so best by humming aloud a few bars of the melody to start the revival and then continuing the revival by maintaining the resonator in the position of humming the tune, viz. with closed lips, so that the sound waves can only escape through the nose; under such circ.u.mstances the only definite conscious muscular sensation I have is from the effect of closure of the lips; the sensations from the larynx are either non-existent or quite ill-defined, although I hear mentally the tonal sensations of the melody.

No doubt by closing the lips in silent humming I am in some way concentrating attention to the sensori-motor sphere of phonation and articulation, and by reactive a.s.sociation with the auditory sphere reinforcing the tonal sensations in the mind. The vocal cords (ligaments) themselves contain very few nerve fibres; those that are seen in the deeper structures of the cords and adjacent parts mainly proceed to the mucous glands. This fact, which I have ascertained by numerous careful examinations, is in accordance with the fact that there are no conscious kinaesthetic impressions of alterations of position and tension of the vocal cords. A comparative microscopic examination of the tip of the tongue and the lips shows a remarkable difference, for these structures are beset with innumerable sensory nerves, whereby every slightest alteration of tension and minute variations in degrees of pressure of the covering skin is a.s.sociated with messages thereon to the brain. The sense of movement in articulate speech is therefore explained by this fact. There is every reason then to believe that auditory tonal images are the sole primary and essential guides to the minute alterations of tension in the muscles of the larynx necessary for the production of corresponding vocal sounds. By humming a tune we concentrate our attention and thereby limit the activity of neural processes to systems and communities of neurones employed for the perception of tonal images and their activation in motor processes; and this helps to fix the tune in the memory.

PSYCHIC MECHANISM OF THE VOICE

A musical speaking voice denotes generally a good singing voice, and it must be remembered that articulation cannot be separated from phonation in the psychic mechanism. In speaking, we are unconscious of the breath necessary for the production of the voice. Not so, however, in effective singing, the management of the breathing being of fundamental importance; and it is no exaggeration to say that only the individual who knows how to breathe knows how to sing effectually. A musical ear and sense of rhythm are innate in some individuals; in others they are not innate and can only be acquired to a variable degree of perfection by persevering efforts and practice. The most intelligent persons may never be able to sing in tune, or even time; the latter (sense of rhythm) is much more easily acquired by practice than the former (correct intonation). This is easily intelligible, for rhythmical movement appertains also to speech and other acts of human beings, e.g. walking, dancing, running, swimming, etc.; moreover, rhythmical periodicity characterises the beat of the heart and respiration.

But how does a trained singer learn to sing a song or to take part in an opera? He has to study the performances of two parts for the vocal instrument--the part written by the composer and the part written by the poet or dramatist--and in order to present an artistic rendering, the intellectual and emotional characters of each part must be blended in harmonious combination. A singer will first read the words and understand their meaning, then memorise them, so that the whole attention subsequently may be given to applying the musical part to them and employing with proper phrasing, which means more than knowing when to breathe; it means imparting expression and feeling. A clever actor or orator can, if he possess a high degree of intelligence and a fairly artistic temperament, so modulate his voice as to convey to his audience the pa.s.sions and emotions while feeling none of them himself; so many great singers who are possessed of a good musical ear, a good memory, and natural intelligence, although lacking in supreme artistic temperament and conspicuous musical ability, are nevertheless able to interpret by intonation and articulation the pa.s.sions and emotions which the composer has expressed in his music and the poet or dramatist in his words. The intelligent artist possessed of the musical ear, the sense of rhythm, and a well-formed vocal organ accomplishes this by the conscious control and management of his breathing muscles and the muscles of articulation, which by education and imitation he has brought under complete control of the will. With him visual symbols of musical notes are a.s.sociated with the visual symbols of words in the mind, and the visual symbols whether of the words or of the musical notes will serve to revive in memory the sound of the one or the other, or of both. But he produces that sound by alteration of tension in co-ordinated groups of muscles necessary for vocalisation, viz. the muscles of phonation in the larynx, the muscles of articulation in the tongue, lips, jaw, and palate, and the muscles of costal respiration. _The mind_ of the orator, actor, and dramatic singer exercises a profound influence upon the respiratory system of nerves, and thereby produces the necessary variations in the force, continuance, and volume of air required for vocal expression.

Sir Charles Bell, who discovered the respiratory system of nerves, pointed out how the lungs, from being in the lower animals merely the means of oxygenating the blood, become utilised in the act of expelling air from the body for the production of audible sounds--the elements of human voice and speech. Likewise he drew attention to the influence which powerful emotions exercise upon the organ of respiration, including the countenance, e.g. the dilated nostrils in anger. Again, "when the voice suffers interruption and falters, and the face, neck, and chest are animated by strong pa.s.sion working from within the breast, language exerts its most commanding influence."

In hemiplegia or paralysis of one half of the body, there is a difference between the two sides for ordinary automatic unconscious diaphragmatic breathing and voluntary or costal breathing. Thus in ordinary breathing the movements are increased on the paralysed side, especially in the upper part of the chest, while in voluntary breathing they are increased on the sound side. Hughlings Jackson suggested the following theory to explain these facts: "_Ordinary breathing_ is an automatic act governed by the respiratory centre in the medulla. The respiratory centre is double, each side being controlled or inhibited by higher centres on the opposite side of the brain. Voluntary costal breathing, such as is employed in singing, is of cerebral origin, and controlled by centres on the opposite side of the brain, the impulses being sent down to the respective centres for the a.s.sociated movements of the muscles of articulation, phonation, and breathing, in the same way as they are sent to the centres for the movements of the arm or leg. With voluntary breathing the respiratory centre in the medulla has nothing to do. It is in fact out of gear or inhibited for the time being, so that the impulses from the brain pa.s.s by or evade it. There are thus two sets of respiratory nerve fibres pa.s.sing from the brain--the one inhibiting or controlling to the opposite half of the respiratory centre in the medulla; the other direct, evading the respiratory centre and running the same course to the spinal centres for the respiratory movements as the ordinary motor fibres do to the centres for other movements. Both sets would be affected by the lesion (or damage) which produced the hemiplegia. The inhibitory fibres being damaged, the opposite half of the respiratory centre would be under diminished control and therefore the movements of ordinary breathing on the paralysed side would be exaggerated. The damage to the direct fibres would prevent the pa.s.sage of voluntary stimuli to the groups of respiratory muscles (as it would do to the rest of the muscles of the paralysed side), and thus the voluntary movement of respiration would be diminished--diminished only and not completely abolished as in the limbs; because according to the theory of Broadbent, in the case of such closely a.s.sociated bilateral movements the lower nervous respiratory centres of both sides would be activated from either side of the brain." This certainly applies also to the muscles of phonation, but not to the princ.i.p.al muscles of articulation, viz. the tongue and lips. It is not exactly known what part of the cerebral cortex controls the a.s.sociated movements necessary for voluntary costal (rib) respiration in singing; probably it is localised in the frontal lobe in front of that part, stimulation of which gives rise to trunk movements (_vide_ fig. 16). Whatever its situation, it must be connected by a.s.sociation fibres with the centres of phonation and articulation.

[Ill.u.s.tration: FIG. 18]

[Description: FIG. 18.--The accompanying diagram is an attempt to explain the course of innervation currents in phonation.

1. Represents the whole brain sending voluntary impulses _V_ to the regions of the brain presiding over the mechanisms of voluntary breathing and phonation. These two regions are a.s.sociated in their action by fibres of a.s.sociation _A_; moreover, the corresponding centres in the two halves of the brain are unified in their action by a.s.sociation fibres _A'_ in the great bridge connecting the two hemispheres (Corpus Callosum). On each side of the centre for phonation are represented a.s.sociation fibres _H_ which come from the centre of hearing; these fibres convey the guiding mental images of sounds and determine exactly the liberation of innervation currents from the centre of phonation to the lower centres by which the required alterations in tension of the laryngeal muscles for the production of the corresponding sounds are effected. Arrows are represented pa.s.sing from the centre of phonation to the lower centres in the medulla which preside over the muscles of the jaw, tongue, lips, and larynx. Arrows indicate also the pa.s.sage of innervation currents from the centres in the brain which preside over voluntary breathing. It will be observed that the innervation currents which proceed from the brain pa.s.s over to the opposite side of the spinal cord and are not represented as coming into relation with the respiratory centre _R_. This centre, as we have seen, acts automatically, and exercises especially its influence upon the diaphragm, which is less under the control of the will than the elevators of the ribs and the abdominal muscles.

The diagram also indicates why these actions of voluntary breathing and phonation can be initiated in either hemisphere; it is because they are always bilaterally a.s.sociated in their action; consequently both the higher centres in the brain and the lower centres in the medulla oblongata and spinal cord are united by bridges of a.s.sociation fibres, the result being that even if there is a destruction of the brain at _a-b_, still the mind and will can act through both centres, although not so efficiently.

Likewise, if there is a destruction of the fibres proceeding from the brain centres to the lower medullary and spinal centres, the will is still able to act upon the muscles of phonation and breathing of both sides of the body because of the intimate connection of the lower medullary and spinal centres by a.s.sociation fibres.]

Experiments on animals and observations on human beings show that the centres presiding over the muscles of the larynx are situated one in each hemisphere, at the lower end of the ascending frontal convolution in close a.s.sociation with that of the tongue, lips, and jaw. This is as we should expect, for they form a part of the whole cerebral mechanism which presides over the voice in speech and song. But because the muscles of the tongue, the lower face muscles, and even the muscles of the jaw do not necessarily and always work synchronously and similarly on the two sides, there is more independence in their representation in the cerebral cortex. Consequently a destruction of this region of the brain or the fibres which proceed from it to the lower executive bulbar and spinal centres is followed by paralysis of the muscles of the opposite side. Likewise stimulation with an interrupted electric current applied to this region of the brain in monkeys by suitable electrodes produces movements of the muscles of the lips, tongue, and jaw of the opposite side only. Not so, however, stimulation of the region which presides over the movements of the muscles of the larynx, for then _both_ vocal cords are drawn together and made tense as in phonation. It is therefore not surprising if removal or destruction of this portion of the brain _on one side_ does not produce paralysis of the muscles of phonation, which, always bilaterally a.s.sociated in their actions, are represented as a bilateral group in both halves of the brain.

These centres may be regarded as a part of the physiological mechanism, but the brain acts as a whole in the psychic mechanism of speech and song. From these facts it appears that there is: (1) An automatic mechanism for respiration and elemental phonation (the cry) in the medulla oblongata which can act independently of the higher centres in the brain and even without them (_vide_ p. 18). (2) A cerebral conscious voluntary mechanism which controls phonation either alone or a.s.sociated with articulation. The opening of the glottis by contraction of the abductor (posterior ring-pyramid muscles) is especially a.s.sociated with descent of the diaphragm in inspiration in ordinary breathing; whereas the voluntary breathing in singing is a.s.sociated with contraction of the adductor and tensor muscles of the vocal cords.

A perfect psychic mechanism is as necessary as the physiological mechanism for the production of perfect vocalisation, especially for dramatic singing. A person, on the one hand, may be endowed with a grand vocal organ, but be a failure as a singer on account of incorrect intonation, of uncertain rhythm or imperfect diction; on the other hand, a person only endowed with a comparatively poor vocal instrument, but knowing how to use it to the best advantage, is able to charm his audience; incapable of vigorous sound production, he makes up for lack of power by correct phrasing and emotional expression. We see then that the combination of a perfect physiological and psychological mechanism is essential for successful dramatic singing, the chief attributes of which are: (1) Control of the breath, adequate volume, sustaining power, equality in the force of expulsion of air to avoid an unpleasant vibrato, and capability of producing and sustaining loud or soft tones throughout the register. (2) Compa.s.s or range of voice of not less than two octaves with adequate control by mental perception of the sounds of the necessary variation in tension of the laryngeal muscles for correct intonation. (3) Rich quality or timbre, due partly to the construction of the resonator, but in great measure to its proper use under the control of the will. Something is lacking in a performance, however perfect the vocalisation as regards intonation and quality, if it fails to arouse enthusiasm or to stir up the feelings of an audience by the expression of pa.s.sion or sentiment through the mentality of the singer.

The general public are becoming educated in music and are beginning to realise that shouting two or three high-pitched chest notes does not const.i.tute dramatic singing--"a short _beau moment_ does not compensate for a _mauvais quart d'heure_." It would be hard to describe or define the qualities that make a voice appeal to the mult.i.tude. Different singers with a similar timbre of voice and register may sing the same song correctly in time, rhythm, and phrasing, and yet only one of them may produce that sympathetic quality necessary to awaken not only the intellectual but the affective side of the mind of the hearers. Undoubtedly the effects produced upon the mind by dramatic song largely depend upon circ.u.mstances and surroundings, also upon the a.s.sociation of ideas. Thus I was never more stirred emotionally by the human voice than upon hearing a mad Frenchman sing at my request the Ma.r.s.eillaise. Previously, when talking to him his eyes had lacked l.u.s.tre and his physiognomy was expressionless; but when this broad-chested, six foot, burly, black-bearded maniac rolled out in a magnificent full-chested baritone voice the song that has stirred the emotions and pa.s.sions of millions to their deepest depth, and aroused in some hope, in others despair, as he made the building ring with "Aux armes, citoyens, formez vos bataillons" I felt an emotional thrill down the spine and a gulp in the throat, while the heart and respirations for an instant stayed in their rhythmical course. Not only was I stirred by the effect of the sounds heard, but by the change in the personality of the singer. It awakened in my mind the scenes in the French Revolution so vividly described by Carlyle. The man's facial expression and whole personality suddenly appeared changed; he planted his foot firmly forward on the ground, striking the att.i.tude of a man carrying a musket, a flag, or a pike; his eyes gleamed with fire and the lack-l.u.s.tre expression had changed to one of delirious excitement. A pike in his hand and a red cap on his head would have completed the picture of a _sans culotte_. Dramatic song therefore that does not evoke an emotional response is _vox et praeterea nihil_.