55.2 Hypothalamic Control of the Autonomic Nervous System Flashcards
Which three major pathways connect the hypothalamus to the brainstem autonomic network?
Dorsal longitudinal fasciculus
Medial forebrain bundle
Mammillotegmental tract
Which pathway is shown in blue?
Medial forebrain bundle
Which pathway is shown in green?
Dorsal longitudinal fasciculus
Which pathway is shown in pink?
Mammillotegmental tract
Which is the principal pathway of the hypothalamus in the central autonomic network?
Dorsal longitudinal fasciculus
What is the origin of the DLF?
Hypothalamus, in region of PVN
Which central structures does the DLF innervate?
Periaqueductal gray
Parabrachial nucleus
Raphe nuclei
Locus coeruleus
Dorsal motor nucleus of vagus
Nucleus ambiguus
What does the DLF synapse with below the brainstem?
Autonomic nuclei (parasympathetic and sympathetic) nuclei in the spinal cord
What are the roles of the PAG?
Origin of descending autonomic fibres
Influences pain signals
What are the roles of the parabrachial nucleus?
Integration of taste/appetite signals
Regulation of breathing rate
What are the roles of the raphe nuclei?
Release of enkephalins for pain inhibition
Feedback to SCN for circadian rhythms
Thermoregulation
What are the roles of the locus coeruleus?
Principal site of NA synthesis
–> arousal, attention, memory, cognition, sleep, etc
What is the role of the dorsal motor nucleus of vagus?
Parasympathetic innervation to viscera of thorax and abdomen
–> feeding, digestion, energy/glucose metabolism
What are the roles of the nucleus ambiguus?
Motor innervation of ipsilateral muscles of soft palate, pharynx, larynx, upper eosophagus
–> Speech and swallowing
Also contains preganglionic parasympathetic neurons –> innervate heart
What are the influences of the hypothalamus on the eye?
Pupillary dilation (ventromedial part)
Pupillary constriction (lateral area)
Lacrimation (anterior nucleus)
How is the hypothalamus involved in osmotic regulation?
Controls ADH secretion
Boosts SNS linked aldosterone secretion
How is the hypothalamus involved in the cardiovascular system?
Autonomic outflows - vascular constriction/dilation, or modulation of heart rate, contractility, and AV conductance
Which two functions of the hypothalamus in the alimentary tract are highlighted in the spec?
Salivation
Peristalsis
How is the hypothalamus involved in salivation?
Receives signals (smell, taste, touch etc)
Signals to salivary centres (superior salivatory nucleus, inferior salivatory nucleus)
–> Salivary glands
How is the hypothalamus involved in peristalsis?
Stimulation of SNS by hypothalamus –> peristalsis
What are the roles of the hypothalamus for the genital system?
Induces parasympathetic erection (S2-S4 nerves) and sympathetic emission (hypogastric nerve) for ejaculation
Which higher functions is the hypothalamus involved in?
Sleep-wake cycles
Emotions
How is the hypothalamus involved in sleep-wake cycles?
Retinal inputs provide light info
SCN controls biological clock
What kind of behaviour has been exhibited when particular sites in the hypothalamus have been excited?
Aggressive behaviour
What are the neuroanatomical pathways for aggression?
Multisensory inputs processed by thalamus
Prefrontal areas can modulate aggressin
Mainly: amygdala activates hypothalamus –> activates VTA to promote learned aggressive actions, PAG controls motor execution of aggression
(CAC = core aggression circuit)
Where does the hypothalamus have neural outputs to?
Brainstem and spinal tract (amongst others)
