Neural control of vocalization: Respiratory and emotional influences

Previous research has shown that a region of the midbrain, the periaqueductal gray matter (PAG), is critical for vocalization. In this review, we describe the results of previous investigations in which we sought to find out how PAG neurons integrate the activity and precise timing of respiratory, laryngeal, and oral muscle activity for natural-sounding vocalization using the technique of excitatory amino acid microinjections in cats. In these studies, all surgical procedures were carried out under deep anaesthesia. In the precollicular decerebrate cat two general types of vocalization, classified as voiced and unvoiced, could be evoked by exciting neurons in the lateral part of the intermediate part of the PAG. The patterns of evoked electromyographic activity were strikingly similar to previously reported patterns of human muscle activity. Coordinated patterns of activity were evoked with just-threshold excitation leading to the conclusion that patterned muscle activity corresponding to the major categories of voiced and voiceless sound production are represented in the PAG. In a parallel series of human and animal experiments, we also determined that the speech and vocalization respiratory patterns are integrated and coordinated with afferent signals related to lung volume. These data have led to the proposal of a new hypothesis for the neural control of vocalization: that the PAG is a crucial brain site for mammalian voice production, not only in the production of emotional or involuntary sounds, but also as a generator of specific respiratory and laryngeal motor patterns essential for human speech and song     

GABAergic synaptic response and its opioidergic modulation in periaqueductal gray neurons of rats with neuropathic pain

Background  

Neuropathic pain is a chronic and intractable symptom associated with nerve injury. The periaqueductal gray (PAG) is important in the endogenous pain control system and is the main site of the opioidergic analgesia. To investigate whether neuropathic pain affects the endogenous pain control system, we examined the effect of neuropathic pain induced by sacral nerve transection on presynaptic GABA release, the kinetics of postsynaptic GABA-activated Cl^- currents, and the modulatory effect of μ-opioid receptor (MOR) activation in mechanically isolated PAG neurons with functioning synaptic boutons.     

Laryngeal Mechanisms During Human 4-kHz Vocalization Studied With CT, Videostroboscopy, and Color Doppler Imaging

The objective of this study was to investigate the underlying laryngeal mechanisms during the specific human 4-kHz vocalization. The laryngeal configuration during this vocalization was measured using high-resolution computerized tomographic scan and videostrobolaryngoscopy. The color Doppler imaging (CDI) of medical ultrasound was used to detect the vibrations of glottal and supraglottal mucosa. During the 4-kHz vocalization, the ventricular folds were adducted in the shape of a bimodal chink and the vocal folds were shaped as a "V" with an opening at the posterior glottis. In the coronal view, the laryngeal ventricles had collapsed and a divergent shaped conduit was observed at the posterior portion of the larynx. The surface mucosa vibration detected by CDI was noted over the bilateral ventricular folds and aryepiglottic folds. The vibration displacement was estimated to be on the order of 0.1mm. This vibration amplitude was too small to be detected in videostrobolaryngoscopy. The laryngeal configuration and CDI data suggested a diffuser jet with periodic vorticity bursts in the larynx producing 4 kHz voice.     

Localization of a pontine vocalization-controlling area

To find out whether there exist additional regions in the pontine brainstem, apart from the phonatory motoneuron pools involved in vocal motor control, the effects of a localized blockade of excitatory neurotransmission in the pons were studied on squirrel monkey vocalization. Vocalization was elicited by electrical stimulation of the periaqueductal gray of the midbrain. Blockade was carried out by stereotaxic injections of kynurenic acid, a nonspecific glutamate antagonist. It was found that injections made into the ventrolateral pons around the ventral nucleus of the lateral lemniscus and superior olive could block periaqueductally elicited vocalization. Injections were only effective ipsilaterally, not contralaterally to the stimulation site. The blockade was limited to one particular class of calls, all of which had in common a characteristic stereotyped frequency modulation over several kHz. It is concluded that critical processing steps of vocal motor control take place in the periolivary region.     

Laryngeal and respiratory activity during vocalization in macaque monkeys

The present study describes the laryngeal and respiratory muscle activity associated with vocalizations in macaque monkeys. During the bark vocalization, a short, aperiodic call, the cricothyroid, thyroarytenoid, rectus abdominis, and intercostals were active while the posterior cricoarytenoid and diaphragm were quiet. During the coo vocalization, a longer, clear call, the cricothyroid, thyroarytenoid, intercostals, rectus abdominis, and diaphragm were active. In one monkey, the posterior cricoarytenoid was also active during the call, while in another monkey it was not. Laryngeal muscle activity was correlated with the amplitude and duration of the coo call. Results suggest that the amplitude and duration differences between calls are determined primarily by laryngeal modification of the airflow, and that the differences in posterior cricoarytenoid activity may be due to differences in voice intensity.     

The irritable larynx syndrome

Muscular tension dysphonia, episodic laryngospasm, globus, and cough may be considered to be hyperfunctional laryngeal symptoms. Suggested etiological factors for these symptoms include gastroesophageal reflux, psychological problems, and/or dystonia. We propose a unifying hypothesis that involves neural plastic change to brainstem laryngeal control networks through which each of the above etiologies, plus central nervous system viral illness, can play a role. We suggest that controlling neurons are held in a "spasm-ready" state and that symptoms may be triggered by various stimuli. Inclusion criteria for the irritable larynx syndrome are episodic laryngospasm and/or dysphonia with or without globus or chronic cough; visible or palpable evidence of tension or tenderness in laryngeal muscles; and a definite symptom-triggering stimulus. thirty-nine patients with irritable larynx syndrome were studied. Gastroesophageal reflux was felt or proven to play a major role in a large number of the group (>90%), and about one third were deemed to have psychological causative factors. Viral illness seemed quite prevalent, with one third of patients able to relate the onset of symptoms to a viral illness that we feel might lead to central nervous system changes. Our proposed hypothesis includes a mechanism whereby acquired plastic change to central brainstem nuclei may lead to this form of hyperkinetic laryngeal dysfunction. It gives structure and reason to an array of therapy measures and suggests direction for basic research.     

Fundamental frequency and tracheal pressure during three types of vocalizations elicited from anesthetized dogs

Electrical stimulation of the midbrain was used to elicit a variety of vocalizations from six anesthetized dogs. This study was conducted to investigate the ranges of and relationships between fundamental frequency of the vocalizations (F₀) and tracheal pressure (P_t) produced during the vocalizations. The vocalizations were described according to type (growl, howl, and whine); F₀ and P_t, as well as patterns of laryngeal muscle activity, were examined for each vocalization type. Natural-sounding growl and howl vocalizations were elicited from five dogs; three dogs also produced whines. With few exceptions, F₀ was categorically different for the three vocalization types (low for growls, average for howls, very high for whines). P_t values overlapped for the three vocalization types, although, on average, howls were produced with greater P_t than growls. Patterns and degrees of laryngeal muscle activity varied across and within vocalization types, but general findings were consistent with the presumed function of most of the muscles. Laryngeal muscle activity may help explain some of the variability in the acoustic and aerodynamic data.     

Vocalization-correlated respiratory movements in the squirrel monkey

Respiratory abdominal movements associated with vocalization were recorded in awake squirrel monkeys. Several call types, such as peeping, trilling, cackling, and err-chucks, were accompanied by large vocalization-correlated respiratory movements (VCRM) that started before vocalization. During purring, in contrast, only small VCRM were recorded that started later after vocal onset. VCRM during trill calls, a vocalization type with repetitive frequency modulation, showed a modulation in the rhythm of the frequency changes. A correlation with amplitude modulation was also present, but more variable. As high frequencies need a higher lung pressure for production than low frequencies, the modulation of VCRM seems to serve to optimize the lung pressure in relation to the vocalization frequency. The modulation, furthermore, may act as a mechanism to produce different trill variants. During err-chucks and staccato peeps, which show a large amplitude modulation, a nonmodulated VCRM occurred. This indicates the existence of a laryngeal amplitude-controlling mechanism that is independent from respiration.     

Mapping of neurokinin-like immunoreactivity in the human brainstem

Background

Using an indirect immunoperoxidase technique, we have studied the distribution of immunoreactive fibers and cell bodies containing neurokinin in the adult human brainstem with no prior history of neurological or psychiatric disease.

Results

Clusters of immunoreactive cell bodies and high densities of neurokinin-immunoreactive fibers were located in the periaqueductal gray, the dorsal motor nucleus of the vagus and in the reticular formation of the medulla, pons and mesencephalon. Moreover, immunoreactive cell bodies were found in the inferior colliculus, the raphe obscurus, the nucleus prepositus hypoglossi, and in the midline of the anterior medulla oblongata. In general, immunoreactive fibers containing neurokinin were observed throughout the whole brainstem. In addition to the nuclei mentioned above, the highest densities of such immunoreactive fibers were located in the spinal trigeminal nucleus, the lateral reticular nucleus, the nucleus of the solitary tract, the superior colliculus, the substantia nigra, the nucleus ambiguus, the gracile nucleus, the cuneate nucleus, the motor hypoglossal nucleus, the medial and superior vestibular nuclei, the nucleus prepositus hypoglossi and the interpeduncular nucleus.

Conclusion

The widespread distribution of immunoreactive structures containing neurokinin in the human brainstem indicates that neurokinin might be involved in several physiological mechanisms, acting as a neurotransmitter and/or neuromodulator.     

Anatomy and cell biology of the laryngeal motor neurons: Implications for the treatment of spasmodic dysphonia

Changes in neuroanatomical pathways in the central nervous system presumably play key roles in the pathogenetic mechanism underlying spasmodic dysphonia. However, practical considerations of accessibility to clinical intervention have focused efforts on treatments based on manipulations of laryngeal motor neurons, the most peripheral extent of these pathways. This review discusses aspects of the anatomy and cell biology of the laryngeal motor neurons, which provide a basis for the understanding of current techniques for the treatment of this disorder. In addition, consideration is given to the significance of unusual morphological characteristics of the laryngeal motor neurons and to cellular processes, which may ultimately offer potential for more selective clinical strategies.     

Vocal and Laryngeal Effects of Voiced Tongue Vibration Technique According to Performance Time

Our objective is to study the vocal and laryngeal effect as well as the negative signs and sensations related to the voiced tongue vibration technique (VTVT), regarding the time of performance (from 0 to 7 minutes). Thirty adults (15 men and 15 women) with no vocal complaints nor laryngeal disorders were involved. All subjects underwent laryngostroboscopic and auditory perceptual analysis and answered about the existence of uncomfortable sensations that occurred during the exercise (1, 3, 5, and 7 minutes) and postexercise. For the auditory perceptual analysis, the female group presented better outcomes in the third minute of exercise, whereas in general the male group showed no modification because of performance time. Some men presented a significant change in the parameters involved from the fifth minute on. Men and women showed a gradual increase of undesirable sensations. It is extremely important that the performance time of the VTVT is properly prescribed to provide the expected results, without causing undue injuries to the vocal system. Therefore, we suggest this technique should be recommended for 3 and 5 minutes for women and men, respectively.     

Distinct target cell-dependent forms of short-term plasticity of the central visceral afferent synapses of the rat

Background  

The visceral afferents from various cervico-abdominal sensory receptors project to the dorsal vagal complex (DVC), which is composed of the nucleus of the solitary tract (NTS), the area postrema and the dorsal motor nucleus of the vagus nerve (DMX), via the vagus and glossopharyngeal nerves and then the solitary tract (TS) in the brainstem. While the excitatory transmission at the TS-NTS synapses shows strong frequency-dependent suppression in response to repeated stimulation of the afferents, the frequency dependence and short-term plasticity at the TS-DMX synapses, which also transmit monosynaptic information from the visceral afferents to the DVC neurons, remain largely unknown.     

Hyperosmotic stimulus induces reversible angiogenesis within the hypothalamic magnocellular nuclei of the adult rat: a potential role for neuronal vascular endothelial growth factor

Background  

In mammals, the CNS vasculature is established during the postnatal period via active angiogenesis, providing different brain regions with capillary networks of various densities that locally supply adapted metabolic support to neurons. Thereafter this vasculature remains essentially quiescent excepted for specific pathologies. In the adult rat hypothalamus, a particularly dense network of capillary vessels is associated with the supraoptic (SON) and paraventricular (PVN) nuclei containing the magnocellular neurons secreting vasopressin and oxytocin, two neurohormones involved in the control of the body fluid homoeostasis. In the seventies, it was reported that proliferation of astrocytes and endothelial cells occurs within these hypothalamic nuclei when strong metabolic activation of the vasopressinergic and oxytocinergic neurons was induced by prolonged hyperosmotic stimulation. The aim of the present study was to determine whether such proliferative response to osmotic stimulus is related to local angiogenesis and to elucidate the cellular and molecular mechanisms involved.     

R32/PAG润滑油体系的黏度和质扩散系数实验研究

本文采用光散射法对R32/PAG润滑油混合体系的动力黏度和质扩散系数进行了实验研究,温度范围从293.15~353.15 K,压力范围从0.09~1.26 MPa,共计获得16个数据点。R32/PAG体系的表面波散射特性属于过阻尼区,当温度一定时,R32/PAG混合物的黏度随着R32所占比例的升高而减小。本文黏度、质扩散系数实验数据与所获得模型的平均绝对偏差分别为1.17%、0.15%,可用于R32/PAG制冷系统的优化设计。     

The external frame function in the control of pitch, register, and singing mode: Radiographic observations of a female singer

This study investigates pitch control, register, and singing mode related movements of the laryngo-pharyngeal structures by radiographic methods. One trained female singer served as the subject. The results show that singing voice production involves complex movements in the laryngeal structures. Pitch related increase in the thyro-arytenoid distance (vocal fold length) is nonlinear, slowing down as pitch rises. Similar observations have been made earlier. At the highest pitches, a shortening of the distance can be seen, suggesting the use of alternative pitch control mechanisms. The various observations made support the existence of three registers in this trained female singing voice. Open and covered modes of singing seemed to be distinguishable on the basis of different amounts of inner and outer forces acting on the larynx. Therefore, caution must be exercised when generalizing from the results.     

傅里叶变换红外光谱用于胆囊癌细胞及其细胞核结构的基础研究

应用傅里叶变换红外光谱(FTIR)对体外培养胆囊癌细胞、细胞核进行检测,对照胆囊癌组织光谱特征,研究胆囊癌细胞株及细胞核的光谱表现;为红外光谱法诊断胆囊癌奠定细胞学基础。应用美国Nicolet(尼高力)公司5700-Ⅱ型红外光谱仪,组织标本放置于OMNIC采样器表面进行检测,记录红外光谱;体外培养胆囊癌细胞株(GBC-SD)及提取的细胞核涂于欧米采样器表面进行红外检测,记录红外光谱,得到时间轴上体外培养细胞株及细胞核的光谱图;选择特征性光谱与胆囊癌组织光谱进行比对。结果发现胆囊癌细胞株红外光谱特征与相应癌组织光谱特征存在异同。从而可得出结论：将体外培养肿瘤细胞株及提取的肿瘤细胞核,进行FTIR测定是行之有效的细胞红外光谱检测手段,能得到体外培养细胞的红外谱图;胆囊癌组织所表现的红外光谱特征具有胆囊癌细胞本身的红外光谱特征,同时也具有组织自身的复杂特点;FTIR为应用于胆囊癌的定性诊断提供了更加丰富的细胞学基础。     

雪晶成因及人工造雪分布类型探讨

从雪晶成核和生长两个方面深入探究了雪晶成因机理,讨论了影响雪晶形成过程中各种作用凼素,分析总结了人工造雪分布类型和及其相关的影响因素.对于造雪技术的进一步扩展,以及合理规划滑雪项目,具有较为重要的指导意义.     

润滑油对带膨胀机CO2跨临界循环的影响

本文对PAG、POE、PAO和AB四种润滑油特性进行了分析,结果表明PAG具有较好的综合性能.又从PAG/CO2混合物的溶解性和粘温特性证明了PAG比较适合CO2跨临界循环.最后对工质CO2夹带的微量PAG对压缩机、膨胀机、气体冷却器和蒸发器的性能影响分别进行了分析,并提出了超临界换热分析模型.结果表明润滑油虽然有助于改善压缩机、膨胀机性能,但造成了换热器性能的严重下降.     

Multifractal statistics and underlying kinetics of neuron spiking time-series

Probabilistic and multifractal properties of spiking time-series obtained in vivo from singular neurons belonging to red nucleus of the rat brain are analyzed. Lognormal and “−1” power-law probability distributions of interspike intervals are observed for healthy and for genetically depressive rats, respectively. A simple thermodynamic model is elaborated to interpret obtained results. Investigation of long-range interspike correlations (both probabilistic and multifractal) gives indications that the genetically defined depression is related to individual neurons kinetic problems rather than to the brain system disorder.     

Coordinated regulation of circadian rhythms and homeostasis by the suprachiasmatic nucleus

We have demonstrated that in rats activities of various enzymes related to gluconeogenesis and amino acid metabolism show circadian rhythms. Based on these results, we have explored the molecular mechanisms underlying circadian oscillation and phase response to light of the master clock located in the dorsomedial subdivision of the suprachiasmatic nucleus (SCN) and found various proteins closely related to phase response such as BIT/SHPS-1 and those of circadian oscillation, some of which are involved in protein-tyrosine phosphorylation.On the other hand, we have presented several lines of evidence that the ventrolateral subdivision of the SCN includes not only the control center of energy supply to the brain, but also that of homeostasis such as blood glucose, blood pressure, water balance, and body temperature. We have also shown that besides these functions, the latter subdivision is involved in the regulations of hormone secretions such as insulin, glucagon, corticosterone and vasopressin. It has been also shown by electrophysiological means that light exposure to rat eye enhances sympathetic nerve activity, whereas it depresses parasympathetic nerve activity. Thus, environmental light is implicated not only in the phase-shift through the retinohypthalamic tract (RHT), but also control of autonomic nerve activities through the RHT, It is also discussed in this review how the two divisions are interconnected and how environmental light is involved in this interconnection.