Copyright © 2010 Pearson Education, Inc. Lateralization of Cortical Function Lateralization Division of labor between hemispheres Cerebral dominance Designates the hemisphere dominant for language (left hemisphere in 90% of people)

Copyright © 2010 Pearson Education, Inc. Lateralization of Cortical Function Left hemisphere Controls language, math, and logic Right hemisphere Insight, visual-spatial skills, intuition, and artistic skills Left and right hemispheres communicate via fiber tracts in the cerebral white matter

Copyright © 2010 Pearson Education, Inc. Cerebral White Matter Myelinated fibers and their tracts Responsible for communication Commissures (in corpus callosum)—connect gray matter of the two hemispheres Association fibers—connect different parts of the same hemisphere Projection fibers—(corona radiata) connect the hemispheres with lower brain or spinal cord

Copyright © 2010 Pearson Education, Inc. Figure 12.10a Corona radiata Projection fibers Longitudinal fissure Gray matter White matter Association fibers Lateral ventricle Fornix Third ventricle Thalamus Pons Medulla oblongata Decussation of pyramids Commissural fibers (corpus callosum) Internal capsule Superior Basal nuclei Caudate Putamen Globus pallidus (a) White matter tracts in brain

Copyright © 2010 Pearson Education, Inc. Figure 12.11a Fibers of corona radiata Corpus striatum (a) Projection fibers run deep to lentiform nucleus Caudate nucleus Thalamus Tail of caudate nucleus Lentiform nucleus Putamen Globus pallidus (deep to putamen) Basal Nuclei (=corpus striatum) deep nuclei in cerebral cortex connect to subs. nigra (in midbrain) & subthalamic nuclei (in diencephalon)

Copyright © 2010 Pearson Education, Inc. Figure 12.11b (1 of 2) Corpus callosum Anterior horn of lateral ventricle Caudate nucleus Putamen Lentiform nucleus (b) Globus pallidus Thalamus Tail of caudate nucleus Third ventricle Cerebral cortex Cerebral white matter Anterior Posterior Inferior horn of lateral ventricle Horizontal section through cerebrum

Copyright © 2010 Pearson Education, Inc. Figure 12.11b (2 of 2) Corpus callosum Anterior horn of lateral ventricle Caudate nucleus Lentiform nucleus (putamen, glob. pall.) (b) Thalamus Third ventricle Cerebral cortex Cerebral white matter Inferior horn of lateral ventricle Horizontal section through cerebrum

Copyright © 2010 Pearson Education, Inc. Functions of Basal Nuclei Though somewhat elusive, the following are thought to be functions of basal nuclei Influence muscular control Help regulate attention and cognition Regulate intensity of slow or stereotyped movements Inhibit antagonistic and unnecessary movements

Copyright © 2010 Pearson Education, Inc. Figure Corpus callosum Choroid plexus Thalamus (encloses third ventricle) Pineal gland (part of epithalamus) Posterior commissure Corpora quadrigemina Cerebral aqueduct Arbor vitae (of cerebellum) Fourth ventricle Choroid plexus Cerebellum Septum pellucidum Interthalamic adhesion (intermediate mass of thalamus) Interven- tricular foramen Anterior commissure Hypothalamus Optic chiasma Pituitary gland Cerebral hemisphere Mammillary body Pons Medulla oblongata Spinal cord Mid- brain Fornix Diencephalon: thalamus, hypothalamus, epithalamus

Copyright © 2010 Pearson Education, Inc. Figure 12.13a Dorsal nuclei Medial Anterior nuclear group Reticular nucleus Ventral anterior Ventral lateral Ventral postero- lateral Lateral geniculate body Medial geniculate body Pulvinar Lateral dorsal Lateral posterior (a) The main thalamic nuclei. (The reticular nuclei that “cap” the thalamus laterally are depicted as curving translucent structures.) Ventral nuclei Thalamus

Copyright © 2010 Pearson Education, Inc. Thalamus Contains multiple nuclei, named by location Receives ascending sensory information, processes it, and relays it to cerebral cortex Afferent impulses from all senses and all parts of the body Impulses from the hypothalamus for regulation of emotion and visceral function Impulses from the cerebellum and basal nuclei to help direct the motor cortices Mediates sensation, motor activities, cortical arousal, learning, and memory

Copyright © 2010 Pearson Education, Inc. Figure 12.13b Preoptic nucleus Supraoptic nucleus Supra- chiasmatic nucleus Anterior hypothalamic nucleus Dorsomedial nucleus Paraventricular nucleus Fornix Anterior commissure Posterior hypothalamic nucleus Lateral hypothalamic area Ventromedial nucleus Optic chiasma Infundibulum (stalk of the pituitary gland) Pituitary gland Mammillary body (b) The main hypothalamic nuclei. Arcuate nucleus Hypothalamus

Copyright © 2010 Pearson Education, Inc. Hypothalamus Below thalamus Multiple nuclei Autonomic control center for many visceral functions (e.g., blood pressure, rate and force of heartbeat, digestive tract motility) Center for emotional response: Involved in perception of pleasure, fear, and rage and in biological rhythms and drives Infundibulum: stalk connecting to pituitary

Copyright © 2010 Pearson Education, Inc. Hypothalamic Function Regulates body temperature, food intake, water balance, and thirst Regulates sleep and the sleep cycle Controls release of hormones by the anterior pituitary Produces posterior pituitary hormones

Copyright © 2010 Pearson Education, Inc. Epithalamus Most dorsal portion of the diencephalon; forms roof of the third ventricle Pineal gland—extends from the posterior border and secretes melatonin Melatonin—helps regulate sleep-wake cycles

Copyright © 2010 Pearson Education, Inc. Figure Corpus callosum Choroid plexus Thalamus (encloses third ventricle) Pineal gland (part of epithalamus) Posterior commissure Corpora quadrigemina Cerebral aqueduct Arbor vitae (of cerebellum) Fourth ventricle Choroid plexus Cerebellum Septum pellucidum Interthalamic adhesion (intermediate mass of thalamus) Interven- tricular foramen Anterior commissure Hypothalamus Optic chiasma Pituitary gland Cerebral hemisphere Mammillary body Pons Medulla oblongata Spinal cord Mid- brain Fornix Mid-sagittal view of brain

Copyright © 2010 Pearson Education, Inc. Brain Stem Three main parts: midbrain, pons, medulla oblongota Contains fiber tracts (ascending and descending) and embedded nuclei Controls automatic behaviors necessary for survival Associated with 10 of the 12 pairs of cranial nerves

Copyright © 2010 Pearson Education, Inc. Figure Frontal lobe Olfactory bulb (synapse point of cranial nerve I) Optic chiasma Optic nerve (II) Optic tract Mammillary body Pons Medulla oblongata Cerebellum Temporal lobe Spinal cord Midbrain Inferior view of brain, showing brain stem

Copyright © 2010 Pearson Education, Inc. Figure 12.15a Optic chiasma View (a) Optic nerve (II) Mammillary body Oculomotor nerve (III) Crus cerebri of cerebral peduncles (midbrain) Trigeminal nerve (V) Abducens nerve (VI) Facial nerve (VII) Vagus nerve (X) Accessory nerve (XI) Hypoglossal nerve (XII) Ventral root of first cervical nerve Trochlear nerve (IV) Pons Middle cerebellar peduncle Pyramid Decussation of pyramids (a) Ventral view Spinal cord Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Diencephalon Thalamus Hypothalamus Diencephalon Brainstem Thalamus Hypothalamus Midbrain Pons Medulla oblongata Brainstem, diencephalon, cranial nerve roots

Copyright © 2010 Pearson Education, Inc. Figure 12.15b View (b) Crus cerebri of cerebral peduncles (midbrain) Infundibulum Pituitary gland Trigeminal nerve (V) Abducens nerve (VI) Facial nerve (VII) Vagus nerve (X) Accessory nerve (XI) Hypoglossal nerve (XII) Pons (b) Left lateral view Glossopharyngeal nerve (IX) Diencephalon Brainstem Thalamus Hypothalamus Midbrain Pons Medulla oblongata Thalamus Superior colliculus Inferior colliculus Trochlear nerve (IV) Superior cerebellar peduncle Middle cerebellar peduncle Inferior cerebellar peduncle Vestibulocochlear nerve (VIII) Olive Brainstem, diencephalon, cranial nerve roots

Copyright © 2010 Pearson Education, Inc. Figure 12.15c View (c) Diencephalon Brainstem Thalamus Hypothalamus Midbrain Pons Medulla oblongata Pineal gland Diencephalon Anterior wall of fourth ventricle (c) Dorsal view Thalamus Dorsal root of first cervical nerve Midbrain Superior colliculus Inferior colliculus Trochlear nerve (IV) Superior cerebellar peduncle Corpora quadrigemina of tectum Medulla oblongata Inferior cerebellar peduncle Facial nerve (VII) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Vagus nerve (X) Accessory nerve (XI) Pons Middle cerebellar peduncle Dorsal median sulcus Choroid plexus (fourth ventricle) Brainstem, diencephalon, cranial nerve roots

Copyright © 2010 Pearson Education, Inc. Midbrain Located between the diencephalon and the pons Cerebral peduncles Contain pyramidal motor tracts

Copyright © 2010 Pearson Education, Inc. Midbrain Nuclei Nuclei that control cranial nerves III (oculomotor) and IV (trochlear) Corpora quadrigemina—domelike dorsal protrusions Superior colliculi—visual reflex centers Inferior colliculi—auditory relay centers Substantia nigra—functionally linked to basal nuclei Red nucleus—relay nuclei for some descending motor pathways and part of reticular formation

Copyright © 2010 Pearson Education, Inc. Figure 12.16a Dorsal Cerebral aqueduct Superior colliculus Reticular formation Crus cerebri of cerebral peduncle Ventral Fibers of pyramidal tract Substantia nigra (a) Midbrain Red nucleus Medial lemniscus Oculomotor nucleus (III) Periaqueductal gray matter Tectum Horizontal section through midbrain

Copyright © 2010 Pearson Education, Inc. Pons (“bridge”) Fibers of the pons Connect higher brain centers and the spinal cord Relay impulses between the motor cortex and the cerebellum Origin of some cranial nerves Some nuclei of the reticular formation Nuclei that help maintain normal rhythm of breathing

Copyright © 2010 Pearson Education, Inc. Figure 12.16b Reticular formation Trigeminal nerve (V) Pontine nuclei Fibers of pyramidal tract Middle cerebellar peduncle Trigeminal main sensory nucleus Trigeminal motor nucleus Superior cerebellar peduncle Medial lemniscus Fourth ventricle (b) Pons Horizontal section through pons

Copyright © 2010 Pearson Education, Inc. Medulla Oblongata Lowest part of brainstem Joins (becomes) spinal cord at foramen magnum All information passing between spinal cord and brain goes through medulla

Copyright © 2010 Pearson Education, Inc. Medulla Oblongata Pyramids—two ventral longitudinal ridges formed by pyramidal tracts (descending motor fibers, a.k.a. corticospinal tracts (cortex to spinal cord)) Decussation of the pyramids—crossover of the corticospinal tracts Some nuclei for cranial nerves Several nuclei (e.g., nucleus cuneatus and nucleus gracilis) which relay ascending sensory information

Copyright © 2010 Pearson Education, Inc. Medulla Oblongata Autonomic control areas include Solitary nucleus: receives input from pressure and chemical sensors; these inputs are used to regulate cardiovascular and respiratory systems Cardiovascular center: Generates motor outflow to regulate heart & blood vessels Respiratory: Regulate rate and depth of breathing (connects to resp. areas in pons)

Copyright © 2010 Pearson Education, Inc. Figure 12.16c Choroid plexus Fourth ventricle Pyramid Medial lemniscus Nucleus ambiguus Cochlear nuclei (VIII) Vestibular nuclear complex (VIII) Solitary nucleus Dorsal motor nucleus of vagus (X) Hypoglossal nucleus (XII) (c) Medulla oblongata Reticular formation Horizontal section through medulla oblongota

Copyright © 2010 Pearson Education, Inc. The Cerebellum 11% of brain mass Dorsal to the pons and medulla Subconsciously provides precise timing and appropriate patterns of skeletal muscle contraction

Copyright © 2010 Pearson Education, Inc. Anatomy of the Cerebellum Two hemispheres connected by vermis Folia—transversely oriented gyri Arbor vitae—distinctive treelike pattern of the cerebellar white matter

Copyright © 2010 Pearson Education, Inc. Figure 12.17b (b) Medulla oblongata Choroid plexus of fourth ventricle Arbor vitae Cerebellar cortex

Copyright © 2010 Pearson Education, Inc. Figure 12.17d (d) Anterior lobe Posterior lobe Vermis (d)

Copyright © 2010 Pearson Education, Inc. Cerebellar Processing for Motor Activity Cerebellum receives impulses from the cerebral cortex of the intent to initiate voluntary muscle contraction Signals from proprioceptors and visual and equilibrium pathways continuously “inform” the cerebellum of the body’s position and momentum Cerebellar cortex calculates the best way to smoothly coordinate a muscle contraction A “blueprint” of coordinated movement is sent to the cerebral motor cortex and to brain stem nuclei

Copyright © 2010 Pearson Education, Inc. Cognitive Function of the Cerebellum Recognizes and predicts sequences of events during complex movements Plays a role in nonmotor functions such as word association and puzzle solving