Univerzita Karlova v Praze – 1. lékařská fakulta

Brainstem truncus encephali εγκεφαλικού στελέχους truncus encephalicus

Anatomický ústav Author: Ivo Klepáček Obor: general medicine, dentistry

IV.

III. II.

I.

CNS hierarchy

CNS phylogenesis and structure

Williams P.L. (ed): Grays Anatomy, Churchill Livingstone, New York, 1995 brain from below

ventroanterior view ventral lateral dorsal How the brainstem is formed :

dorsal view

somatic –sensory special (n. VIII., Characterization of nerve fibers-fuctionalvestibular + auditory) aspect A) Somatomotor General somatic efferent – inervate skeletal muscles B) Visceromotor General visceral efferent – innervate smooth visceral muscles, intraocular muscles, heart, salivatory glandsNc.gustatorius… somatic - sensory V VII,IX,X general (nc. V.) C) branchial motor Special visceral efferent – innervate skeletal muscles derived from branchial (pharyngeal) arches (CN V, VII, IX, X) Nc.X D) viscerosensitive General somatic afferent – conductsolitarius impulses from skin, skeletalIII,IV,VI,XII muscles spindles visceral - Somatic - sensory special (nc. gustatorius n. (general) E) sensory motor Special somatic afferent – conduct impulses fromVII.,IX.,X.) retina, taste buds auditory and vestibular apparatus F) somatosensitive General visceral afferent – conduct impulsesvisceral - sensory from general (nc. solitarius n. viscera, blood vessels X.) visceral epithelium V,VII,IX,X VII,VII,IX,X G) sensoryBranchio Special – visceral afferent – conduct impulses from taste buds, olfactory motor mucosa(special) Viscero – motor (parasympaticus) S S S G V S V G somatic –sensory special (n. VIII., V m vestibular + auditory) B S V

S G Nc.gustatorius somatic - sensory VII,IX,X general (nc. V.)

Nc.X solitarius visceral - sensory III,IV,VI,XII special (nc. somatic motor (general) gustatorius n. V,VII,IX,X VII.,IX.,X.) taste buds branchio – motor (special) visceral - sensory general (nc. solitarius n. VII,VII,IX,X viscero - motor (parasympaticus) X.) visceral epithelium Mesencephalon differentiation Pons differentiation Some levels are unified together

Thomas Willis (1621-1675), Arteria basilaris An English physician 2 aa. vertebrales → a. basilaris • a. inferior anterior cerebelli (→ a. labyrinthi) • aa. pontis • aa. mesencephalicae • a. superior cerebelli → aa. cerebri posteriores circulus arteriosus cerebri Willisi

CN nerves branches and arteries of the Willis circle

posterior cerebellar aa. superior cerebellar aa basillar a. pontine aa. posterior anterior cerebellar aa. posterior inferior cerebellar aa. veins draining brainstem WHAT is INSIDE ?

• Tectum + tegmentum nuclei • nuclei of CN nerves !!! • Substantia grisea • Reticular formation (complexes of nuclei with different size)

• Precerebellar nuclei (arcuati, Oliva, some of RF) • Tracts (pathways passing through the brainstem up and down (ascending and descending) Internal structure of the brainstem

Tectal, geniculate medial (caudal end of Dienc.) nuclei CN nerves nuclei Two rows ofof somatomotorsomatomotor

Three visceromotor ncc.

Viscerosensitive nucleus: nucleus tractus solitarii NTS with solitarius ChemicalSomatosensitive +systems special ncc. in the CNS + interstitial ncc.)

Three rows of ncc.: medial lateral rapheal + cerebellar + chemical

Precerebellar ncc.: Pontine + arcuate ncc. Oliva Cerebellar RF ncc.

Nc. ruber, interpeduncular, substantia grisea centralis (+Cajal, Darkschewitch) + chemical ncc. Brainstem layers Tegmentum - huge region passing through Tectum full brainstem. the well Tegmentum known is a part inside mesencephalon. Pars ventralis Tegmentum contains: nuclei of CN nerves NC, Reticular formation RF, substantia nigra SN, nc. ruber NR. There are ascending sensory tracts. Ventral part of the brainstem (pyramidal part) is mostly enlarged in pontine and medulla anteroposterior oblongata levels. It contais section descending motor tracts. Tectum - four collicles (corpora quadrigemina) - decodes information from senses (eye, ear).

Optic ´visual´ tectum - superior collicles - collect signals from the optic tract and somatosesory organs.

´Hearing´´ auditory part - inferior collicles (torus semicircularis) - collects signals from the audory apparatus.

Tectum asists in head movements to the sound source or helps to turn the head to the moving object. Inside tectum are fibers from the smell organ and cerebellum… • Colliculus superior – • Colliculus inferior – 3 layers of gray and 4 layers of white involved to auditory pathway - matter, are incorporated to optic brachium colliculi – corpus tract - brachium colliculi – corpus geniculatum mediale – cortex geniculatum laterale - cortex • Central nucleus (tonotopic • superficial layers react on visual organisation) and dorsal and lateral impulses, deep layers even on cortex other sensitive impulses • Aferents for dorsal cortex is from • Te-Spi, Te-RF –orientation the auditory cortex area movement, conjugate movements • for lateral from spinal cord, ncl. • Saccadic movements gracilis a cuneatus

Ncl. intersticialis (Cajali), Ncl. intersticialis rostralis

Tegmentum mesencephali • Substantia grisea Ncl. intersticialis (Cajali) centralis – Ncl. intersticialis rostralis (Vertical eyeball movements) surrounds aquaeductus – interconnecting station between vegetative pathways and stem (Eferents to MS • HK flexors are influenced • part of control cerebellum circuit) Ncl. ruber – a part of T cerebellar and motor pathways

Substantia nigra – dopamin source for striatum – (if missed – Parkinsonism develops) Division from side to side

Rhomboid fossa Following position Somatomotoric Medial line (row) XII, VI, IV, III (+EW) Lateral line (row) IX, X (ambiguus), VII, V (motorius)

Visceromotoric (parasympathetic) X (dorsal), IX (salivatory inferior), VII (salivatory superior), III (accessory EW)

Viscerosensory Solitarius (gustatorius, IX, X, tractus solitarius V,VII,IX,X)

Somatosensory + special V (spinalis RI-IV) tractus spinalis – pain, warm, Kunc tractus VII,IX,X) V (pontinus – touch, vibratory) V (mesencephalic) VIII vestibular, cochlear Division from up to down

Rhomboid fossa Following function and structure Nuclei Reticular Specific structures of CN formation in brainstem parts nerves

Medulla oblongata RF

Pontine RF

Midbrain RF

Somatic - motor nucl. (+ disturbances)

Medial line (column): XII (hemiplegia alternans inferior), VI (hemiplegia alternans media), IV, III (hemiplegia alternans superior)

Lateral line (column): Nucl ambiquus (IX, X, XI) (nucl spinalis XI), VII, V media et superior

brainstem lesion when nerve and pyramidal tract is attacked

what seen: palsy of nerves on ipsilateral side and muscles on the contralateral side Superior alternating Inferior Alternating hemiplegia (Weber's Hemiplegia Middle Alternating Syndrome) (also known as medial Hemiplegia has a few distinct medullary syndrome) - - typically constitutes symptoms: contralateral involves a “weakness of weakness of the hemiparesis of limb and the extremities extremities facial muscle accompanied accompanied by accompanied by by weakness in one or more paralysis of muscles on paralysis of the orbit in muscles that control eye the ipsilateral side of the the eye muscle on the movement on the same side. tongue (seen as a opposite side of the deviation of the tongue affected extremities. on that side on Another symptom that protrusion). appears is the loss of eye There is a lesion in the caudal movement due to damage to and medial pons involving the the oculomotor nerve fibers. abducens nerve root (controls These symptoms indicate a The upper and lower movement of the eye) and lesion in the medulla corticospinal fibers (carries involving the corticospinal extremities have increase fibers in the pyramid and weakness. motor commands from the brain to the spinal cord). the exiting hypoglossal nerve roots). contralaterally palsy of limbs intra- and extra- glossal muscles peripheral Palsy tongue is sticken out to side where lesion is (peripheral palsy) tongue is sticken out to opposite side (central palsy)

central lateral motor column (voluntary actions)  Nc. n. V. – lesion – from it portio minor (motor fibres for all of the masticatory muscles)  Nc. n. VII. – innervates mimic muscles, the platysma muscle, the posterior belly of the digastric muscle, the stylohyoid muscle, the stapedius muscle  Nc. n. IX., X. (ambigus) – contacted with RF and olivary nuclei, innervates muscles of tonsillar pillars, pharynx, larynx, oesophagus Nc V

___ motor touch ----- pain warm ______Visceral - motor nuclei – (involved with visceral spinal reflexes, gland actions)

 Nc. parasympaticus (dorsalis) n. III. (Edinger - Westphal) – innervates the ciliary ganglion, sphincter pupillae, ciliary muscle – lesion - mydriasis  Nc. dorsalis n. VII. (nc. salivatorius superior) – innervates glandula submandibularis, sublingualis, minute glands of the oral cavity)  Nc. dorsalis n. X. (nc. salivatorius inferior) – innervates the pneumogastric system, the heart, parotid gland Position of the CN VII. nuclei SoMo – ncl. n. VII, ViMo – ncl. salivatorius sup ViSe – ncl. solitarius (resp. gustatorius), mixed nerves SoSe – ncl. spinalis et pontinus n. trigemini Division of the sensory nerve nuclei Somatic sensory and special sensory nuclei (somatic: transmit pain, pull, temperature, pressure, vibrations, proprioception; special: involved in sensory pathways – auditory, vestibular, cerebellar)

Somatic Nc. spinalis n. V. – continued to the Rexed I-IV., collaterals of centripetal fibres with ganglion trigeminale Gasseri Nc. pontinus (principalis) n. V. (connected with ganglion trigeminale) Nc. mesencephalicus n. V.) - conducts proprioception from the gingiva, masticatory system

Somatic sensory

___ motor touch ----- pain warm ______Section through

that tract can stop deep and cruel pain from the nV. regions

Nc. tractus nervi trigemini Trigeminal tract nuclei Position of the CN V. SM – ncl. n. V – portio minor VM – no, spread to peripheral branches of other nerves SoSe – ncl. spinalis. n. V. – pain and termic signals Ncl. pontinus n. V. - mechanoreception Ncl. mesencephalicus n. V. – proprioception from masticatory and oculomotory muscles mechanoreception from periodontium Division of the sensory nerve nuclei Somatic sensory and special sensory nuclei (somatic: transmit pain, pull, temperature, pressure, vibrations, proprioception; special: involved in sensory pathways – auditory, vestibular, cerebellar)

Special Nc. vestibulares (medial- Schwalbe; lateral-Deiters, cranial-Bechterew, caudal- Roller) – connection with the cerebellar nuclei Nc. cochleares (caudal; cranial) – involved in the auditory pathway, connections with the corpora trapezoidea and lemniscus Division of the sensory nerve nuclei Visceral sensory nuclei (transmit visceral sensations, involved in taste reflex and in visceral reflex arches)

Nc. n. V., VII., IX., X.) – nc. solitarius surrounded by tractus solitarius: - rostral part – nc. gustatorius - caudal part – nc. commisuralis Position of the CN VIII. nuclei Ncl. vestibulares (medialis,lateralis Ncl. cochleares cranialis, caudalis) (ventralis et dorsalis) from semicircular canals – M+Cr Lemniscus lateralis utriculus + sacculus M+L+Cau Fasciculus longitudinalis medialis

How vestibular nuclei assist in balance control Central connections with vestibular system Control of emotional behavior Autonomic functions

Afferent: Taste ! Respiratory digestive systems Chemo+baroreceptors of vessels Efferent: Thalamus – 43 taste area Reticular formation – hypothalamus amygdala To motor ncc. V.,VII.,XII. Phrenicus, Position of the CN IX + X nuclei SoMo – ncl. ambiguus ViMo – ncl. salivatorius inf. (IX) + ncl. dorsalis n. vagi ViSe – ncl. solitarius (resp. gustatorius) SoSe – ncl. spinalis et pontinus n. trigemini Ncl. spinalis n. accessorii in C1-C6 Innervation of STCM and trapezius muscles using rad. spinalis a r. externus Ncl. n. hypoglossi Neurons for branchial muscles are in ncl. ambiguus; using radix cranialis Intraglossal and extraglossal and ramus internus are added to n. muscles vagus macroscopic sections Medulla spinalis

Medulla oblongata Lower section Ncl. gracilis et cuneatus (Ncl. cuneatus lateralis)

Lemniscus medialis et deccusatio Medulla oblongata Upper section

Ncl. olivaris – p.crbl. inf. climbing fibers Rytmic dyskinesis The ventral portion of the medulla oblongata contains medullary pyramids. These two ridge-like structures travel along the length of the medulla oblongata and are bordered medially by the anterior median fissure. They each have an anterolateral sulcus along their lateral borders. Also located laterally from each pyramid is a pronounced bulge known as an olive.

The medullary pyramids contain motor fibers that are known as the corticobulbar and corticospinal tracts. The corticospinal tracts are on the anterior surface of the pyramids.

These tracts condust motor signals that originated in the precentral gyrus and travelled through the internal capsule to the medulla oblongata and pyramids. Extrapyramidal tracts are those motor tracts that do not traverse the medullary pyramids. Lateral medulla oblongata syndrome Ipsilaterally Loose of thermal and pain feelings in face Contralaterally loose of thermic ang pain feelings in remaning body parts of thermal and pain feelings in face Lower Pons Varoli section

Petrovický P. a spol. Anatomie, Centrální nervový systém. Karolinum, Praha, 1995 Williams P.L. (ed): Grays Anatomy, Churchill Livingstone, New York, 1995 Pyramidal tract Distribution of white matter fasciculi inside brainstem Ponto- mesencephalic border

Ncl. pontis Fibrae pontis longitudinales Co-po, CO – Spi Fibrae pontis transversae – brachia pontis ponto-mesencephalic border

IV. ventricle mesencephalon lower section through inferior collicles mesencephalon upper Tectum

Tegmentum

Crura cerebri

cortico-pontine pathways Midbrain section through corticospinal superior pathways colliculus Mesencephalon

Williams P.L. (ed): Grays Anatomy, Churchill Livingstone, New York, Petrovický P. a spol. Anatomie, Centrální nervový systém. 1995 Karolinum, Praha, 1995 (English mutation)

Substantia grisea

centralis SGG • Afferent connection from spinal cord, nc. solitarius, limbic system, amygdala

• Efferent connection to spinal cord, RF(magnocellular part), thalamus, hypothalamus Stimulation causes analgesia, increases pressure tachycardia, support protection reractions Probably helps to increase serotonin concentration in dorsal spinal cord horn; pain to thalamus is decreased Substantia nigra SN • Compact part - dopaminergic (Tsai group) • Reticular part – GABA • Afferent connection from striatum (basal nuclei) smaller part from pallidum

• Efferent connection to striatum, amygdala + neocortex

Loose of dopamin – Parkinsonism (hypokinesis, hypertonism, tremor) Nucleus ruber NR • magnocellular part - dopaminergic (Tsai group) • parvicellular part – GABA • Afferent connection from cingular cortex (noncrossed)

• Efferent connection to lateral spina fasciculus (rubrospinal tract) to oliva inferior to RF Reticular formation

www.macalester.edu http://img132.imageshack.us Mostly produce serotonin (B1-B6) Reticular formation nuclear system and system of nervous tracts through all brainstem parts arrangement in three perpendicular strips - rapheal, medial and lateral Rapheal – middle, unpaired nuclear strip; many connections with medial row and with limbic system

Medial – paired, massive, long connections

Lateral – only in medulla oblongata and pons, small cells, connections with rapheal system, + nuclei showing characteristic nervous conections or typical mediator (cerebellar cholinergic adrenergic) raphe nccl.: linear ncc. L dorsal rapheal Rod superior central CS magnus rapheal Romg parvus rapheal Ropo medial nccl.: cuneiform Cu pedunculopontinus pePO oral pontis OPO oral caudal PC gigantocellular GC ventral and oblongatae RV superior central CS magnus rapheal Romg parvus rapheal Ropo

lateral nccl.: subcuneiform Scu parvocellular p.c. dorsal and oblongatae RF connections

Spinal cord Thalamus

Hypothalamus RF

Cerebellum RF connections

Spinal cord Thalamus

Hypothalamus RF

Cerebellum

SN Pallidum RF connections efferent connections with other CNS structures, in all cases there are collateral fibers branching to surrounding nuclei nervous impuls can be conducted to many cells and becames stronger

afferent fibers coming from medulla, sensory tracts, cranial nerves, CRBL, hypothalamus, cortex, limbic system efferent fibers - MS, CRBL, Th, HypoTh Eye movement coordination reticular formation functional centers

pneumotactic Vestibular acoustic vasomotoric expiration inspiration Functio-structural centers: Center for breathing – RF nuclei under surface of the fossa rhomboidea (rhomboid fossa), parts of expiration and inspiration + tr. RF – Spi + feedback to n. X. centrum is under control of the s.c. pneumotaxic center - pO2, pH, pCO2 vasomotoric center under tr. n X., responsible for regulation of blood press, center for heart control (acceleration or retardation of the heart beating), vomiting center

Reflexes of “resuscitation“:

swalloving reflex, sucking reflex, reflexes of salivary glands, visceromotoric reflexes

Protecting reflexes:

ef + af: fibers NC, under RF control twinking, blinking, corneal, tearing, coughing, vomiting (suffocating), iridial

Frédéric Bremer neurophysiologist 1892–1982 Encéphale isolé medulla is cut at level C1-C2, sleep and vigilance changes each other, animal reacts on sound, head skin and visual impulses. Eyes are open, tongue and ears are moveable. EEG is typical for awaken events « encéphale isolé » Cerveau isolé the brainstem is cut between colliculi superiores and colliculi inferiores. There is lost relation between telencephalon and other brain parts. animal has closed eyes, miosis, noreaction for irritation, deep sleep. EEG is typical for sleep (EEG waves are changed by high spindles) « cerveau isolé » respiration is spontaneous, tonus of muscles is increased (decerebration rigidity) Activation of CNS by RF

http://www.ott.zynet.co.uk branching of neurons in RF (rat braistem) RF - Activation role increases intensity of impulses for cortex and medullar motoneurons and vice versa Inhibitory role inhibites activity of spinal cord motoneurons

cerveau isole, encephale isole Pathways inside brainstem • pedunculi cerebellares • lemniscus medialis • tr. spino - thalamicus • crura cerebri – tr. cortico – spinalis, cortico-pontinus • Corpus trapezoideum et lemniscus lateralis • FLM, FLD (fasciculus medialis fasciculus dorsalis (Schutz)

Precerebellar nuclei nuclei inside brainstem projecting to cerebellum:

• Ncl. pontis – synapses of cortex fibers for cerebellum • Ncl. olivares – synaptic nccl. for spinal cord fibers for cerebellum

Chemical systems in the CNS Main mediators: acetylcholin, catecholamins (adrenalin, noradrenalin, dopamin), indolamins (serotonin, histamin). Peptids - substance P, enkefalin, endorfin derivatives Gas - CO, NO

Modulators - peptids, located in synaptic connections commonly with other mediators. Cholinergic system (Ch 1-6) acetylcholin – many functions, mediator for motor and vegetative (autonomic) functions, memory and training, exciting mediator, due to receptor type exerts nervous activation as well as inhibition.

Incidence: targeting neurons and interneurons located in archicortex, neocortex and RF,

Damage: loose of memory, Alzheimer disease

Monoamines catecholamines (adrenalin, noradrenalin, dopamin) (A 1 – 16) caudorostral arrangement, predominantly exciting influence containing pigment instead of adrenergic cells, indolamines (serotonin, histamin) (B1 - 9) predominantly exerting inhibition

Adrenergic system (C1 - 3) located in RF

Noradrenergic system (A 1 - 7, ) localized in RF (A1-5) and under locus coeruleus (A 6,7), throung nervous conections conveys to all CNS: significantly increases attention - cortical arousal reaction impulses for breathing and cardiovascular systems Degeneration in locus coeruleus - demention

Dopaminergic system (A 8 - 10) dopamin is necessary for extrapyramidal motor effects, (A9) - subst. nigra compacta – through nigrostriatic tracts to striatum, Disturbance in striatum – Parkinson syndrome (akinesis, tremor, rigor) due to degeneration of nigrostriatic system. Damage of the A10 system is followed with demention. (A10) - area tegmentalis ventralis – through telencephalicus medialis tract activating frontal and limbic core, amygdalar complex and brain septum Dopamin distribution is basic for reward mechanism:

gratifying cmfortable feeling following some body function as “reward“, some drugs (cannabis derivatives, opium, cocain, alcohol) support dopamin distribution; at the some time serotonin distribution is blocked - this is principle of neurobiological base for the drug dependence.

Serotoninergic system rapheal nuclei (B1 - 9) distribute its compounds to all CNS, serotonin there is predominantly inhibiting factor (due to receptor type) Great function spectrum: in medulla: systém inhibits sympathetic neurons and pain transduction; all motoneurons are activated,

exerts influence temperature regulation, sexual behavior, digestion, brain blood supply, relax (dream) regulations, serotonin decreasing is followed with endogenous depressive reactions

Reflex irritation – answer cycle in organism; the simpliest event.in CNS effectors = mostly muscles Reflexes: uncoditional (congenital) stereotypical, permanent – (sneezing, coughing, corneal, reflex extenzing limbs, patellar) Newborn - grasping Reflexes: conditional (not congenital obtained through life): Depends on experiences because of selfteaching I.P.Pavlov (dog bulb and food), develops on uncoditionalreflex if some conditional irritation is added. Monosynaptický reflex

Lingering , grip-like

Afferent (senzoric centripetal) neuron conducts impuls through one synapsis only to efferent (motor , centrifugal) neuron Polysynaptic reflex

Afferent (senzoric, centripetal) neuron conducts impuls through interneuron (two synapses) to efferent (motor, centrifugal) neuron. Česky: Korneální reflex, Rohovkový reflex English: Corneal reflex, Blink reflex

Cornea is touched - impuls is conducted through nervi cilliares a nervus ophthalmicus (V1.) to brainstem. Efferentsugnal is conducted through VII . Nerve to m. orbicularis oculi (m. orbicularis oculi)

Corneal reflex arch: Afferent: Corneal exteroreceptors, afferent n.ophtalmicus (1. branch of n.V.) efferent: n.VII. tom. orbicularis oculi. Česky: mrkací reflex English: blink reflex Blink reflex je relativně relatively simple

Afferent part: (free nervous endings in cornea, n. trigeminus, ganglion, radix and tractus spinalis n. V., Continues to interneurons of RF, next bilaterally to motor nucleus CN VII and to m. orbicularis oculi. Effect: lower eylid contracts Rohovkový reflex Česky: Faryngový reflex, Dávivý reflex English: Pharyngeal reflex, Gag reflex

Irritation (e.g. Cotton of wool) of dorsal wall of pharynx; patient at the same time pronounces „a" or „e".

Physiologic answer - elevation and constriction ofpharynx; tongue is retracted.

Vyšetření zvlášť vlevo a vpravo umožní rozlišit lézi aferentní (oboustranné snížení nebo vymizení odpovědi při dráždění jedné strany) a eferentní části (jednostranné snížení nebo vymizení odpovědi při dráždění obou stran) reflexního oblouku. Dávivý reflex Cough is repeated strong expiration – airways are cleaned Irritation - (chemical, thermal, mechanical) receptors: Mucous membrane of upper and lower airways (vagal region - pleura, spleen, outer ear, stomach, pericardium); afferent: senzitive fibers nervus vagus (nervus laryngeus superior); Cough center: medulla oblongata (n. ambiguus, n. retroambigularis), brain cortex (voluntary);

Efferent: motoric fibers nervus vagus; effectors: respirátory muscles; Pressure gradient above 10 kPa; Air flow speed 150–280 m/s (cough) Some material used from various authors:

Petrovicky: CNS, PNS (paper texts), lectures Petrovicky et al. Anatomy with topographic remarks (Czech), Vol. III.

Druga, Grim et al.: Peripheral nervous system, lectures Ten Donkelaar: Clinical neuroanatomy Moore, Dalley: Clinically oriented anatomy Agur: Grant´s Atlas of Anatomy, Grays´s Anatomy 39th ed. Larsen´s Human embryology

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