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Home , Cerebellum, Cerebral aqueduct, Corpora quadrigemina, Dentate nucleus, Facial colliculus, Fastigial nucleus

Brain or Encephalon The content of the two lectures

• The parts of the or encephalon • The brain stem and • The or prosencephalon: the and the telencephalon PHYLOGENY AND ONTOGENY OF THE BRAIN 1. Evolution factors which contributed to development of prosencephalon, mesencephalon and rhombencephalon. 2. Differentiation of rhombencephalon into and ( and cerebellum). 3. Differentiation of prosencephalon into the diencephalon and telencephalon 4. Evolutionary conservatism of mesencephalon and its functional reduction.

Smell

Vision

Hearing The parts of the brain or encephalon: 1. or Rhombencephalon: and metencephalon (pons and cerebellum). 2. or Mesencephalon. 3. Forebrain or Prosencephalon: diencephalon (interbrain) and telencephalon. 4. Brain stem: medulla oblongata (bulbus, myelencephalon), pons and midbrain. The parts of the brain or encephalon: 1. Hindbrain or Rhombencephalon: medulla oblongata and metencephalon (pons and cerebellum). 2. Midbrain or Mesencephalon. 3. Forebrain or Prosencephalon: diencephalon and telencephalon. 4. Brain stem: medulla oblongata (bulbus), pons and midbrain. Short characteristic of the brain stem, truncus encephali

Brain stem includes (1) medulla oblongata, (2) pons and (3) midbrain Short characteristic of the brain stem, truncus encephali Brain stem involves many of the ascending and descending neural pathways, some of which extends along the whole brain stem, while others begin or end in the brain stem. Short characteristic of the brain stem, truncus encephali

The brain stem contains the abundant (nuclei), in which neural pathways begin, end or switch over. The brain stem contains nuclei of ten cranial (III-XII) Short characteristic of the brain stem, truncus encephali

The brain stem encloses the complex of heterogeneous - (Formatia reticularis), in which the specific nuclei are discriminated. Neurons of these nuclei do influence on the sensation, sensation, regulate the cardiovascular and respiratory systems.

Neurons of the reticular formation are associated with nuclei of the cranial , cerebellum, motor mechanisms of the brain stem and and, therefore, these neurons have influence to the human movements, the human body posture and skeletal . Short characteristic of the brain stem, truncus encephali

The 4th ventricle and the is situated in the brain stem

Median and lateral apertures of Cerebral aqueduct 4th ventricle Role of choroid plexuses and apertures of 4th ventricle in the circulation of the liquor External anatomy of brain stem Anterior view

Myelencephalon: anterior median fissure, sulci (anterolateral and posterolateral); pyramid, roots of the (VI, VII, VIII, IX, X, XI, XII). Pons: basilar sulcus, middle cerebellar peduncles, roots of (V).

Mesencephalon: Cerebral peduncles, posterior perforated substance, roots of cranial nerves (III, IV). External anatomy of brain stem Lateral view

Myelencephalon: sulci (anterolateral and posterolateral); pyramid, olive. Inferior cerebellar peduncles. Cuneate and gracile tubercles; roots of the cranial nerves (VI, VII, VIII, IX, X, XI, XII).

Pons: Middle cerebellar peduncles, roots of trigeminal nerve (V).

Mesencephalon: Cerebral peduncles, : superior and inferior colliculi and their brachii, roots of cranial nerves (III, IV). External anatomy of brain stem Posterior view Superior and inferior colliculi and their Corpora quadrigemina Myelencephalon: sulci brachii (posterior median and posterolateral). Inferior Cerebral peduncles cerebellar peduncles. Cuneate Sup.medulallary velum Root of (IV) and gracile tubercles; roots of the Median sulcus cranial nerves Medial eminence Pons: cerebellar peduncles. Vestibular area

Rhomboid fossa. Superior and inferior medullary velum. Median Hypoglossal trigone sulcus, medial eminence, hypoglossal Vagal trigone and vagal trigones, facial colliculus, vestibular area.

Mesencephalon: Cerebral peduncles, corpora quadrigemina seu lamina tecti: superior and inferior colliculi and their brachii, roots of cranial nerves (IV). “The most survival" external structure on the brain stem “The most survival" external structure on the brain stem

Cerebellar peduncles Roots or rootlets of the cranial nerves (V, VI, VII, VIII, IX, X, XI, XII) Roots of the cranial nerves (V, VI, VII, VIII, IX, X, XI, XII) Levels or floors of the brain stem : Anterior (ventral) - Basis Middle- Posterior (dorsal) -Tectum

Midbrain

Pons

Basis Tegmentum Tectum Myelencephalon

Caudal Middle Rostral Brain stem basis Pyramidal tract Brain stem basis Pyramidal tract and nuclei of the pons Brain stem tegmentum Gracile and cuneate fasciculi and their nuclei. Medial and its . Anterior and posterior spinocerebellar tracts. Anterolateral fasciculus (ALF) or Brain stem tegmentum Anterior and posterior spinocerebellar tracts. Inferior olivary and Brain stem tegmentum Nuclei of the cranial nerves (III-XII) Sensory Motor Motor: Sensory somatic,visceral, special

Brain stem tegmentum Nuclei of the cranial nerves (III-XII) Motor: Sensory somatic,visceral, special

Brain stem tegmentum Trapezoidal body and . Cochlear nuclei and superior olivary nuclei Tegmentum . Ventral posteromedial nucleus of the

Trigeminal lemniscus Spinothalamic fasciculus

Principal sensory trigeminal nucleus Tegmentum Medial longitudinal fasciculus

Oculomotor and trochlear nuclei

Vestibular nerve and nucleus Reticular formation (formatia reticularis) is the complex of heterogeneous neurons, which are arranges into specific nuclei and which do influence on Tegmentum the human somatic sensation, pain sensation, regulate the cardiovascular Reticular formation and respiratory systems. Slices of brain stem Slices of brain stem Myelencephalon- basis and tegmentum

Caudal (inferior) part Slices of brain stem Myelencephalon- basis and tegmentum

Middle part Slices of brain stem Myelencephalon- basis and tegmentum

Rostral (superior) part Slices of brain stem Pons- basis and tegmentum

Trapezoid body

Superior and inferior Cerebellar peduncles

Slices of brain stem Pons- basis and tegmentum

Trapezoid body Pons- basis and tegmentum

Upper pons Slices of brain stem Midbrain- basis and tegmentum Cerebral aqueduct, , crura of cerebral peduncles Slices of brain stem Midbrain- basis and tegmentum Substantia nigra – midbrain structure, which neurons control the conscious movements - determine a movement feedback and a correction of movements. Midbrain Substatia nigra – a part of system of the brain The or nucleus ruber is a structure in the rostral midbrain involved in . It is pale pink in color; the color is believed to be due to iron, which is present in the red nucleus in at least two different forms: and ferritin. It comprises a caudal magnocellular and a rostral parvocellular part. It is located in the tegmentum of the midbrain next to the substantia nigra. The red nucleus as well as the substantia nigra are subcortical Central tegmental tract centers of the extrapyramidal ..

Red nucleus Midbrain Tracts of the midbrain basis (corticospinal and corticonuclear) Cerebellum

The cerebellum (Latin for "little brain") is a major part of the hindbrain (metencephalon). The cerebellum plays an important role in , and it may also be involved in some cognitive functions such as and as well as in regulating and pleasure responses, but its movement-related functions are the most solidly established. The human cerebellum does not initiate movement, but contributes to coordination, precision, and accurate timing. The cerebellum is located in the . The , pons and medulla oblongata are in front of the cerebellum. It is separated from the overlying by a layer of leathery , the tentorium cerebelli; all of its connections with other parts of the brain travel through the cerebellar peduncles (pedunculus cerebellaris inferior, medius et superior). The cerebellum is divided into two hemispheres and it also contains a narrow midline zone (the vermis). The cerebellum is divided into two hemispheres and it also contains a narrow midline zone (the vermis). Deep nuclei of the cerebellum: fastigial, interposed: emboliform and globose, and dentate. Deep nuclei of the cerebellum: fastigial, interposed: emboliform and globose, and dentate. of cerebellum Deep nuclei of the cerebellum: fastigial, interposed: emboliform and globose, and dentate.

Anterior Posterior lobe

Flocculonodular lobe

Fastigial-Nucleus fastigii Emboliform-Nucleus embuliformis Dentate-Nucleus dentatus Globose-Nucleus globulosus Cerebellum

1) Paleocerebellum (cortex vermi + nucleus emboliformis et globulosus) or spinocerebellum – controls (monitors) and coordinates the conscious movements and the tone of skeletal muscles; 2) Archicerebellum (lobus flocculonodularis + nucleus fastigii) or vestibulocerebellum – controls the maintenance of body balance (equilibrium) and the movements of eyes and/or heads; 3) Neocerebellum (cortex + nucleus dentatus) or cerebrocerebellum – controls and modulates conscious movements, influences the activity of and evaluates a success of movements Prosencephalon or Forebrain A complex of Diencephalon and Telencephalon

Diencephalon

It is comprised of the thalamus, metathalamus, , and .

Diencephalon acts as the relay site of general and special sensory (vision, , equilibrium) information to corresponding regions (centers) of the sensory and even motor cortices; neurons of the diencephalic nuclei regulate (influence) the transmission of sensory signals, and/or . External anatomy of diencephalon

Hypothalamus: optic , , infundibulum, mammillary bodies, . External anatomy of diencephalon

Thalamus: , . Epithalamus: pineal body, habenular and . Hypothalamus: , tuber cinereum, infundibulum, mammillary bodies, pituitary gland. External anatomy of diencephalon Thalamus: pulvinar Metathalamus: medial and lateral geniculate bodies. Epithalamus: pineal body or gland, . Internal anatomy of diencephalon

Thalamus: anterior, medial, lateral parts and nuclei; Metathalamus: nuclei of geniculate bodies. Neuronal projections of thalamic and metathalamic nuclei into cerebral cortices Hypothalic nuclei Anterior, median, and posterior nuclei, mammilo-thalamic tract and fibers to Anterior and median hypothalamic nuclei and their neuronal projections into neurohypohysis Antidiuretic , ADH

Adenocorticotropic hormone, TSH

Thyroid stimulating hormone, TSH Somatotropic hormone, STH

Follicle stimulating hormone, FSH

Gonadotropic hormone, GTH

Luteinizing hormone, LH Relationship of hypothalamic nuclei with brain stem nuclei Centrifugal and centripetal nerve fibers of hypothalamic nuclei Relationship of hypothalamic nuclei with brain stem nuclei Forebrain- Telencephalon Forebrain External anatomy. Cerebral hemispheres, longitudinal cerebral fissure, . Cortex, primary sulci and gyri. Lobes of hemispheres: frontal, Forebrain parietal, occipital, temporal. Upper lateral surface of cerebral hemispheres. Forebrain Island- insula Interlobal sulci: central and lateral. Upper lateral surface of cerebral hemispheres : inferior and superior frontal, and precentral. : postcentral and superior ir intraparietal. Sulci : transversal occipital. Temporal lobe: superior and inferior temporal. Upper lateral surface of cerebral hemispheres Gyri Frontal lobe: inferior, middle, superior frontal and precentral. Parietal lobe: postcentral, superior and inferior parietal, and angular lobules. Occipital lobe: Temporal lobe: superior, middle and inferior temporal. Sulci: sulcus of corpus Inferior and medial surface of cerebral hemispheres callosum, cingulate, parieto- and occipital. Sulci Gyri Cingulate sulcus Frontal lobe: central sulcus. Sulcus of corpus callosum Parietal lobe: parieto- occipital. Occipital lobe: calcarine sulcus. Limbic lobe: cingulate gyrus, para-hippocampal and dentate gyri. . Corpus callosum: rostrum, genu, trunk, splenium. and fornix. Cytoarchitecture of Cytoarchitecture of cerebral cortex Cytoarchitecture of cerebral cortex Functional areas of cerebral hemispheres (47 areas) Functional areas of cerebral hemispheres Basal part of cerebral hemispheres. Basal nuclei or ganglia Basal part of cerebral hemispheres. Basal nuclei or ganglia Amygdala. . : head, body, tail. : and . Corpus . Basal part of cerebral hemispheres. Basal nuclei or ganglia Amygdala. Claustrum. Caudate nucleus: head, body, tail. Lentiform nucleus: putamen and globus pallidus. Corpus striatum.

Functionally, basal nuclei control movements (depress conscious movements, coordinate movement types), and are related to learning. Relationship of basal nuclei with other nuclei and cortex Pallium and (or) cortex Neural fibers in forebrain, fibrae et fasciculi Projective fibers (), Commissural (corpus callosum, anterior commissura), Associative fibers Projective fibers, Capsula interna Associative neural fibers Commissural neural fibers, Corpus callosum and anterior commissure Nerve fibers in forebrain. Fornix Nerve fibers in forebrain. Fornix Relationship of the fornix with the hippocampus Relationship of the fornix with the hippocampus Fornix and other parts of

Limbic system is comprised by the cingulate gyri, hippocampus, fornix, amygdala and mammilary bodies. These structures are interlinked by axonal interconnections and influence smell sensation, autonomic functions, some human and behavior.