© 2016 Pearson Education, Inc.

12.2 Cerebral Hemispheres (cont.)
Cerebral White Matter Second of the three basic regions of cerebral hemispheres Responsible for communication between cerebral areas, and between cortex and lower CNS Consists of myelinated fibers bundled into large tracts Classified according to direction they run: Association, commissural, and projection fibers © 2016 Pearson Education, Inc.

Cerebral White Matter (cont.)
Association fibers: horizontal running fibers that connect different parts of same hemisphere Commissural fibers: horizontal fibers that connect gray matter of two hemispheres Projection fibers: vertical fibers that connect hemispheres with lower brain or spinal cord Internal capsule: projection fibers on each side of brain stem form compact band Passes between thalamus and some of basal nuclei Corona radiata: projection fibers that radiate through cerebral white matter to cortex © 2016 Pearson Education, Inc.

Figure 12.9a White fiber tracts of the cerebral hemispheres.
Superior Association fibers (within hemisphere) Longitudinal fissure Commissural fibers (between hemispheres) Lateral ventricle • Corpus callosum Basal nuclei Projection fibers (cerebral cortex to or from lower area) • Caudate • Putamen • Globus pallidus • Corona radiata • Internal capsule Thalamus Gray matter Third ventricle White matter Pons Decussation (cross-over) of pyramids Medulla oblongata Frontal section © 2016 Pearson Education, Inc.

Figure 12.9b White fiber tracts of the cerebral hemispheres.
Gray matter Association fibers Commissural fibers • Corpus callosum Projection fibers • Corona radiata • Internal capsule Parasagittal section and dissection © 2016 Pearson Education, Inc.

Basal Nuclei (Ganglia)
Third of the three basic regions of cerebrum Each hemisphere’s basal nuclei include a: Caudate nucleus Putamen Globus pallidus Caudate nucleus + putamen = striatum Closely associated with subthalamic nuclei (diencephalon) and substantia nigra (midbrain) © 2016 Pearson Education, Inc.

Caudate nucleus Striatum Thalamus Putamen Tail of caudate nucleus
Figure 12.10a Basal nuclei. Caudate nucleus Striatum Thalamus Putamen Tail of caudate nucleus © 2016 Pearson Education, Inc.

Basal Nuclei (Ganglia) (cont.)
Functions of basal nuclei are thought to: Influence muscle movements Play role in cognition and emotion Regulate intensity of slow or stereotyped movements Filter out incorrect/inappropriate responses Inhibit antagonistic/unnecessary movements Parkinson’s disease and Huntington’s disease are disorders of the basal nuclei © 2016 Pearson Education, Inc.

Head of caudate nucleus
Figure 12.10b Basal nuclei. Anterior Cerebral cortex Cerebral white matter Corpus callosum Anterior horn of lateral ventricle Head of caudate nucleus Putamen Globus pallidus Thalamus Tail of caudate nucleus Third ventricle Inferior horn of lateral ventricle Posterior © 2016 Pearson Education, Inc.

12.3 The Diencephalon Consists of three paired gray-matter structures:
Thalamus Hypothalamus Epithalamus All three enclose third ventricle © 2016 Pearson Education, Inc.

Figure 12.11a Midsagittal section of the brain.
Cerebral hemisphere Septum pellucidum Interthalamic adhesion (intermediate mass of thalamus) Corpus callosum Fornix Choroid plexus Thalamus (encloses third ventricle) Interventricular foramen Posterior commissure Epithalamus Anterior commissure Pineal gland Corpora quadrigemina Hypothalamus Midbrain Optic chiasma Cerebral aqueduct Pituitary gland Arbor vitae (of cerebellum) Mammillary body Fourth ventricle Pons Choroid plexus Cerebellum Medulla oblongata Spinal cord © 2016 Pearson Education, Inc.

Thalamus Bilateral egg-shaped nuclei that form superolateral walls of third ventricle Makes up 80% of diencephalon Bilateral nuclei connected by interthalamic adhesion (intermediate mass) Contains several nuclei, named for location Nuclei project and receive fibers from cerebral cortex © 2016 Pearson Education, Inc.

Figure 12.12a Selected structures of the diencephalon.
Medial dorsal nucleus Lateral dorsal nucleus Lateral posterior nucleus Pulvinar Anterior nuclei Medial geniculate body Reticular nucleus Lateral geniculate body Ventral postero- lateral Ventral anterior Ventral lateral Ventral nuclei The main thalamic nuclei. (The reticular nuclei that “cap” the thalamus laterally are depicted as curving translucent structures.) © 2016 Pearson Education, Inc.

Thalamus (cont.) Main thalamic function is to act as relay station for information coming into cortex Sorts, edits, and relays ascending input such as: Impulses from hypothalamus for regulating emotion and visceral function Impulses from cerebellum and basal nuclei to help direct motor cortices Impulses for memory or sensory integration Overall, it acts to mediate sensation, motor activities, cortical arousal, learning, and memory © 2016 Pearson Education, Inc.

Hypothalamus Located below thalamus
Forms cap over brain stem and forms inferolateral walls of third ventricle Contains many important nuclei such as: Mammillary bodies: paired anterior nuclei that act as olfactory relay stations Infundibulum: stalk that connects to pituitary gland © 2016 Pearson Education, Inc.

Figure 12.12b Selected structures of the diencephalon.
Paraventricular nucleus Anterior commissure Fornix Dorsomedial nucleus Preoptic nucleus Posterior hypothalamic nucleus Anterior hypothalamic nucleus Lateral hypothalamic area Supraoptic nucleus Suprachiasmatic nucleus Ventromedial nucleus Optic chiasma Arcuate nucleus Mammillary body Infundibulum (stalk of the pituitary gland) Pituitary gland The main hypothalamic nuclei. © 2016 Pearson Education, Inc.

Hypothalamus (cont.) The hypothalamus is the main visceral control and regulating center that is vital to homeostasis Chief homeostasis controls: Controls autonomic nervous system Examples: blood pressure, rate and force of heartbeat, digestive tract motility, pupil size Initiates physical responses to emotions Part of limbic system: perceives pleasure, fear, rage, biological rhythms, and drives (sex drive) © 2016 Pearson Education, Inc.

Hypothalamus (cont.) The hypothalamus also:
Regulates body temperature: sweating or shivering Regulates hunger and satiety in response to nutrient blood levels or hormones Regulates water balance and thirst Regulates sleep-wake cycles Suprachiasmatic nucleus of thalamus sets our biological clock © 2016 Pearson Education, Inc.

Hypothalamus (cont.) Controls endocrine system functions such as:
Secretions of anterior pituitary gland Production of posterior pituitary hormones © 2016 Pearson Education, Inc.

Clinical – Homeostatic Imbalance 12.4
Hypothalamic disturbances cause a number of disorders such as: Severe body wasting Obesity Sleep disturbances Dehydration Emotional imbalances Implicated in failure to thrive: delay in growth or development Occurs when child is deprived of a warm, nurturing relationship © 2016 Pearson Education, Inc.

Epithalamus Most dorsal portion of diencephalon
Forms roof of third ventricle Contains pineal gland (body) Extends from posterior border Secretes melatonin that helps regulate sleep-wake cycle © 2016 Pearson Education, Inc.

Figure 12.11b Midsagittal section of the brain (continued).
Corpus callosum Fornix Lateral ventricle Thalamus Posterior commissure Epithalamus Third ventricle Pineal gland Corpora quadrigemina Anterior commissure Midbrain Cerebral aqueduct Hypothalamus Arbor vitae Optic chiasma Fourth ventricle Cerebellum Mammillary body Pons Medulla oblongata © 2016 Pearson Education, Inc.

Oculomotor nerve (III) Crus cerebri of cerebral peduncles (midbrain)
Figure 12.13a Three views of the brain stem (green) and the diencephalon (purple). Thalamus Diencephalon Hypothalamus Midbrain View (a) View (c) Pons Brain stem Medulla oblongata View (b) Optic chiasma Diencephalon Optic nerve (II) • Thalamus Optic tract • Hypothalamus Mammillary body Oculomotor nerve (III) Crus cerebri of cerebral peduncles (midbrain) Trochlear nerve (IV) Trigeminal nerve (V) Middle cerebellar peduncle Pons Abducens nerve (VI) Facial nerve (VII) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Pyramid Hypoglossal nerve (XII) Ventral root of first cervical nerve Vagus nerve (X) Decussation of pyramids Accessory nerve (XI) Spinal cord Ventral view © 2016 Pearson Education, Inc.

Crus cerebri of cerebral peduncles (midbrain) Trochlear nerve (IV)
Figure 12.13b Three views of the brain stem (green) and the diencephalon (purple). Thalamus Diencephalon Hypothalamus Midbrain View (a) View (c) Pons Brain stem Medulla oblongata View (b) Optic tract Thalamus Infundibulum Superior colliculus Pituitary gland Inferior colliculus Crus cerebri of cerebral peduncles (midbrain) Trochlear nerve (IV) Trigeminal nerve (V) Superior cerebellar peduncle Pons Middle cerebellar peduncle Facial nerve (VII) Inferior cerebellar peduncle Abducens nerve (VI) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Olive Hypoglossal nerve (XII) Vagus nerve (X) Accessory nerve (XI) Left lateral view © 2016 Pearson Education, Inc.

• Superior cerebellar peduncle
Figure 12.13c Three views of the brain stem (green) and the diencephalon (purple). Thalamus Diencephalon Hypothalamus Midbrain View (a) View (c) Pons Brain stem Medulla oblongata View (b) Thalamus Midbrain Corpora quadrigemina of tectum Diencephalon • Superior colliculus • Inferior colliculus • Trochlear nerve (IV) Pineal gland • Superior cerebellar peduncle Floor of fourth ventricle Pons • Middle cerebellar peduncle Facial nerve (VII) Medulla oblongata • Inferior cerebellar peduncle Choroid plexus (fourth ventricle) • Vestibulocochlear nerve (VIII) • Glossopharyngeal nerve (IX) Dorsal median sulcus • Vagus nerve (X) Dorsal root of first cervical nerve • Accessory nerve (XI) Dorsal view © 2016 Pearson Education, Inc.

12.4 Brain Stem Consists of three regions: midbrain, pons, medulla oblongata Similar in structure to spinal cord but contains nuclei embedded in white matter Controls automatic behaviors necessary for survival Contains fiber tracts connecting higher and lower neural centers Nuclei are associated with 10 of the 12 pairs of cranial nerves © 2016 Pearson Education, Inc.

Frontal lobe Olfactory bulb (synapse point of cranial nerve I)
Figure Inferior view of the brain, showing the three parts of the brain stem: midbrain, pons, and medulla oblongata. Frontal lobe Olfactory bulb (synapse point of cranial nerve I) Optic chiasma Optic nerve (II) Optic tract Mammillary body Midbrain Pons Temporal lobe Medulla oblongata Cerebellum Spinal cord © 2016 Pearson Education, Inc.

Midbrain Located between diencephalon and pons
Cerebral peduncles: two ventral bulges that contain pyramidal motor tracts Form pillars that hold up cerebrum Cerebral aqueduct: channel running through midbrain that connects third and fourth ventricles © 2016 Pearson Education, Inc.

Midbrain (cont.) Periaqueductal gray matter: nuclei that play a role in pain suppression and fight-or-flight response Also include nuclei that control cranial nerve III (oculomotor) and IV (trochlear) © 2016 Pearson Education, Inc.

Midbrain (cont.) Midbrain nuclei scattered throughout white matter include: Corpora quadrigemina: paired dorsal protrusions Superior colliculi: visual reflex centers Inferior colliculi: auditory relay centers Substantia nigra: functionally linked to basal nuclei Parkinson’s disease is degeneration of this area © 2016 Pearson Education, Inc.

Oculomotor nucleus (III) Reticular formation Medial lemniscus
Figure 12.15a Cross sections through different regions of the brain stem. Dorsal Superior colliculus Tectum Periaqueductal gray matter Cerebral aqueduct Oculomotor nucleus (III) Reticular formation Medial lemniscus Red nucleus Substantia nigra Fibers of pyramidal tract Ventral Crus cerebri of cerebral peduncle Midbrain © 2016 Pearson Education, Inc.

Pons Located between midbrain and medulla oblongata
Fourth ventricle separates pons from cerebellum Composed of conduction tracts: Longitudinal fibers connect higher brain centers and spinal cord Transversal/dorsal fibers relay impulses between motor cortex and cerebellum © 2016 Pearson Education, Inc.

Pons (cont.) Origin of cranial nerves V (trigeminal), VI (abducens), and VII (facial) Some nuclei play role in reticular formation, and some help maintain normal rhythm of breathing © 2016 Pearson Education, Inc.

Superior cerebellar peduncle Fourth ventricle Reticular formation
Figure 12.15b Cross sections through different regions of the brain stem. Superior cerebellar peduncle Fourth ventricle Reticular formation Trigeminal main sensory nucleus Trigeminal motor nucleus Middle cerebellar peduncle Pontine nuclei Trigeminal nerve (V) Fibers of pyramidal tract Medial lemniscus Pons © 2016 Pearson Education, Inc.

Medulla Oblongata Also known as medulla
Blends into spinal cord at foramen magnum Contains fourth ventricle Continuation of central canal of spinal cord Medulla and pons form ventral wall Contains choroid plexus: capillary-rich membrane that forms cerebral spinal fluid © 2016 Pearson Education, Inc.

Medulla Oblongata (cont.)
Structures of the medulla oblongata Pyramids: two ventral longitudinal ridges formed by pyramidal tracts from motor cortex Decussation of the pyramids: point where pyramidal tracts cross over to opposite side of body Olives: swellings caused by underlying inferior olivary nuclei that relay stretch information from muscles and joints to cerebellum © 2016 Pearson Education, Inc.

Cranial nerves VIII, IX, X, and XII Vestibular and cochlear nuclei: mediate responses that maintain equilibrium Nucleus cuneatus and nucleus gracilis: relay ascending sensory information from spinal cord © 2016 Pearson Education, Inc.

Hypoglossal nucleus (XII) Solitary nucleus Fourth ventricle
Figure 12.15c Cross sections through different regions of the brain stem. Hypoglossal nucleus (XII) Solitary nucleus Fourth ventricle Dorsal motor nucleus of vagus (X) Vestibular nuclei (VIII) Choroid plexus Inferior cerebellar peduncle Cochlear nuclei (VIII) Lateral nuclear group Reticular formation Medial nuclear group Nucleus ambiguus Raphe nucleus Inferior olivary nucleus Medial lemniscus Pyramid Medulla oblongata © 2016 Pearson Education, Inc.

Functions of the medulla oblongata Medulla is an autonomic reflex center Many functions overlap with hypothalamus Hypothalamus relays instructions via medulla Functional groups of medulla include: Cardiovascular center Cardiac center adjusts force and rate of heart contraction Vasomotor center adjusts blood vessel diameter for blood pressure regulation © 2016 Pearson Education, Inc.

Respiratory centers Generate respiratory rhythm Control rate and depth of breathing (with pontine centers) Various other centers regulate: Vomiting Hiccupping Swallowing Coughing Sneezing © 2016 Pearson Education, Inc.

12.5 Cerebellum 11% of brain mass Located dorsal to pons and medulla
Processes input from cortex, brain stem, and sensory receptors to provide precise, coordinated movements of skeletal muscles Also plays a major role in balance © 2016 Pearson Education, Inc.

Cerebellar Anatomy Cerebellar hemispheres connected by wormlike vermis
Folia: transversely oriented gyri Each hemisphere has three lobes Anterior, posterior, and flocculonodular Contains thin cortex of gray matter with distinctive treelike pattern of white matter called arbor vitae © 2016 Pearson Education, Inc.

Cerebellar Anatomy (cont.)
Purkinje fibers originate in cortex, synapse with cerebellum Cerebellar homunculi show sensory maps of entire body © 2016 Pearson Education, Inc.

Anterior lobe Arbor vitae Cerebellar cortex Folia Pons
Figure 12.16a Cerebellum. Anterior lobe Arbor vitae Cerebellar cortex Folia Pons Fourth ventricle Posterior lobe Choroid plexus Medulla oblongata © 2016 Pearson Education, Inc.

Anterior lobe Cerebellar cortex Arbor vitae Cerebellar peduncles
Figure 12.16b Cerebellum. Anterior lobe Cerebellar cortex Arbor vitae Cerebellar peduncles Posterior lobe • Superior • Middle Choroid plexus of fourth ventricle • Inferior Flocculonodular lobe Medulla oblongata © 2016 Pearson Education, Inc.

Anterior lobe Primary fissure Posterior lobe Horizontal fissure Vermis
Figure 12.16c Cerebellum. Anterior lobe Primary fissure Posterior lobe Horizontal fissure Vermis © 2016 Pearson Education, Inc.

Cerebellar Peduncles All fibers in cerebellum are ipsilateral—from and to the same side of body Three paired fiber tracts connect cerebellum to brain stem Superior cerebellar peduncles connect cerebellum to midbrain Middle cerebellar peduncles connect pons to cerebellum Inferior cerebellar peduncles connect medulla to cerebellum © 2016 Pearson Education, Inc.

Anterior lobe Cerebellar cortex Arbor vitae Cerebellar peduncles
Figure 12.16b Cerebellum. Anterior lobe Cerebellar cortex Arbor vitae Cerebellar peduncles Posterior lobe • Superior • Middle Choroid plexus of fourth ventricle • Inferior Flocculonodular lobe Medulla oblongata © 2016 Pearson Education, Inc.

Cerebellar Processing
Cerebellum fine-tunes motor activity as follows: 1. Receives impulses from cerebral cortex of intent to initiate voluntary muscle contraction 2. Receives signals from proprioceptors throughout body, as well as visual and equilibrium pathways that: Pathways continuously “inform” cerebellum of body’s position and momentum Cerebellar cortex calculates the best way to smoothly coordinate muscle contraction Sends “blueprint” of coordinated movement to cerebral motor cortex and brain stem nuclei © 2016 Pearson Education, Inc.

Cognitive Functions of Cerebellum
Neuroimaging suggests that cerebellum plays role in thinking, language, and emotion As it does for motor processes, it may compare actual output of higher functions with expected output and adjust accordingly © 2016 Pearson Education, Inc.

© 2016 Pearson Education, Inc.

Similar presentations

Presentation on theme: "© 2016 Pearson Education, Inc."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

© 2016 Pearson Education, Inc.

Similar presentations

Presentation on theme: "© 2016 Pearson Education, Inc."— Presentation transcript:

Similar presentations

About project

Feedback