Module 3 Notes - Exam notes.pdf

Chapter 9: Diencephalon GROSS ANATOMY Includes thalamus, hypothalamus, subthalamus and epithalamus Diencephalon Fornix Thalamus...

Chapter 9: Diencephalon GROSS ANATOMY Includes thalamus, hypothalamus, subthalamus and epithalamus Diencephalon Fornix Thalamus Epithalamus Anterior Commissure Optic chiasm Subthalamus Posterior FIGURE 9-1 Midsagittal section through the diencephalon. Hypothalamus Commissure Chapter 9: Diencephalon THALAMUS Large centrally located structure - sensory waystation in the brain Landmarks – central bilateral large ovoid gray mass Thalamus Inferior and Superior Colliculi View Angle from midsaggital Mid-sagittal view View Angle from posterior Thalamus Inferior and Superior Colliculi Posterior view Chapter 9: Diencephalon THALAMUS Large centrally located structure - sensory waystation in the brain Thalamus Coronal View Angle from anterior View Angle from dorsal Thalamus Horizontal Chapter 9: Diencephalon THALAMUS Large centrally located sensory waystation in the brain Thalamic White Matter Thalamic Radiations Superior Thalamic Radiation Anterior Thalamic Radiation Posterior Thalamic Radiation Inferior Thalamic Radiation Medullary Lamina Internal Medullary Lamina External Medullary Laminar Chapter 9: Diencephalon THALAMUS Large centrally located sensory waystation in the brain Thalamic White Matter Thalamic Radiations – white matter fibers (axons) from neurons in the thalamus that “radiate” outward to synapse with neurons in the cerebral cortex Superior Thalamic Radiation – axons to motor/premotor and sensory cortices Anterior Thalamic Radiation – axons to prefrontal cortex Posterior Thalamic Radiation – axons to occipital, temporal, parietal cortex Inferior Thalamic Radiation – axons to temporal cortex (auditory cortex) Superior Superior or or Posterior thalamic Central thalamic Anterior thalamic radiation radiation radiation Sup Thalamus Ant Inferior thalamic Pos radiation Frontal lobe Inf Occipital lobe Lateral view of the right cerebral hemisphere Chapter 9: Diencephalon THALAMUS Large centrally located sensory waystation in the brain Thalamic White Matter Thalamic Radiations Medullary Lamina Internal Medullary Lamina (Intralaminar) - white matter fiber tracts within the thalamus connecting neurons in different parts of the thalamus Internal medullary lamina Internal medullary lamina Chapter 9: Diencephalon THALAMUS Large centrally located sensory waystation in the brain Thalamic White Matter Thalamic Radiations Medullary Lamina External Medullary Lamina – lateral white matter fiber tract between thalamus and neurons in the reticular nucleus External medullary lamina Chapter 9: Diencephalon THALAMUS Large centrally located sensory way station in brain Major thalamic nuclei – 5 groups 1. Anterior nuclei 2. Midline and Medial nuclei 3. Lateral nuclei 4. Posterior nuclei Cross sectional view of the thalamus Chapter 9: Diencephalon THALAMUS Large centrally located sensory way station in brain Thalamic nuclei – major groups 1. Anterior nuclei - Forms the anterior tubercle – these neurons connect to the prefrontal and frontal cortex, the limbic system, the cingulate gyrus and the hypothalamus 2. Midline and Medial nuclei- Located under 3rd ventricle – these neurons connect ventrally to the hypothalamus and periaqueductal gray area (PAG) and to the bulk of the medial aspects of the frontal cortex Medial nuclei Anterior nuclei Midline nuclei Midline nuclei Chapter 9: Diencephalon THALAMUS Large centrally located sensory way station in brain Thalamic nuclei – major groups 3. Lateral nuclei Ventral Anterior [VA] & Ventral Lateral [VL] nuclei – (Thalamic Motor Nuclei) – neurons receive input from the basal ganglia & cerebellum and send info to the motor cortices (supplemental motor area and precentral gyrus) Lateral Dorsal nucleus [LD] – neurons connect to sensory association cortices Ventral Posterior nucleus [VP] - Thalamic Somatosensory Nucleus – neurons receive input from 2nd order somatosensory neurons in the medulla via the medial lemniscus and send info to the somatosensory cortex (postcentral gyrus) Lateral Dorsal (LD) Ventral To Prefrontal Cortex Anterior (VA) From Globis Pallidus (Basal Ganglia) Ventral To Supplementary and Primary Motor Cortex Lateral (VL) From Globis Pallidus and Cerebellum Ventral To Somatosensory Cortex Posterior (VP) From spinal and cranial nerve sensory tracts Chapter 9: Diencephalon THALAMUS Large centrally located sensory way station in brain Thalamic nuclei – major groups 4. Posterior nuclei Medial Geniculate Nucleus [MGN] – (Thalamic Auditory Relay) - neurons receive input from the inferior colliculus and sends info to the temporal cortex Lateral Geniculate Nucleus [LGN] – (Thalamic Visual Relay) - neurons receive input from the optic tract and sends info to the occipital cortex Pulvinar nucleus - Largest posterior group - neurons receive input from the superior colliculus and send info to the parietal and temporal cortices (posterior association cortices) To posterior association cortex Pulvinar From Superior Colliculus Medial To Primary Auditory Cortex Medial geniculate geniculate To Primary Visual Cortex From Inferior Colliculus (MGB) (MGB) From Optic Tract Chapter 9: Diencephalon THALAMUS Summary Table of Functional Divisions of Thalamic Nuclei. TABLE 9-1 Functional Divisions of Thalamic Nuclei. Chapter 9: Diencephalon HYPOTHALAMUS Bilateral centrally located brain area beneath the thalamus involved in autonomic, appetitive, and regulatory functions Landmarks – lies just below and rostral to thalamus View Angle from midsaggital Hypothalamus View Angle from anterior Hypothalamus Chapter 9: Diencephalon HYPOTHALAMUS Divisions (rostral to caudal OR anterior to posterior) Preoptic Region (purple) Medial and lateral preoptic nuclei Anterior hypothalamus (Chiasmatic or Supraoptic region) (green) Supraoptic Nucleus, Suprachiasmatic nucleus, Anterior hypothalamic nucleus, Paraventricular nucleus Central hypothalamus (Tuberal region) (blue) Ventral- and Dorso- Medial hypothalamic nuclei, Arcuate, Median Eminence Posterior hypothalamus (Mammillary Region) (red) Posterior hypothalamic nucleus, mammillary body Bilateral divisions – exist on both sides of midline Chapter 9: Diencephalon HYPOTHALAMUS Connections A number of Afferent (A) and Efferent (E) Connections inputs consistent w autonomic and regulatory functions from reticular formation in brainstem Pathways to and from the Hypothalamus. Chapter 9: Diencephalon Hypothalamus To Pituitary Signaling Perfect example of the “brain/body” relationship Hypothalamus controls release of chemical signals into the blood 2 mechanisms Posterior pituitary signaling Anterior pituitary signaling } communicate with net of blood vessels surrounding pituitary Hypothalamus/Pituitary Anatomy Anterior Pituitary Posterior Pituitary Posterior Pituitary contains endocrine cells contains pre-synaptic terminals Anterior Pituitary from cells in the hypothalamus rostral caudal rostral caudal Chapter 9: Diencephalon Hypothalamus To Pituitary Signaling Posterior pituitary signaling The Posterior lobe of the Pituitary Gland – a Neural Structure Synthesis of peptide hormones occurs in neurons located in the hypothalamus These neurons release their peptide hormones directly into the blood supply that surrounds the posterior pituitary vasopressin (ADH – Anti-Diuretic Hormone) - water retention oxytocin - uterine contractions during labor & milk letdown from mammary glands ADH neurons OT neurons ADH & Oxytocin Chapter 9: Diencephalon Hypothalamus To Pituitary Signaling Anterior pituitary signaling The Anterior lobe of the Pituitary Gland – a Neuroendocrine Structure Synthesis and release of peptide hormones occur from cells located within the anterior pituitary itself (called pituicytes) Synthesis/release from pituicytes are controlled by neurons in the hypothalamus A large variety of cells and peptides in the anterior lobe…….eg, Corticotrophs, Gonadotrophes, Corticotropin Releasing Gonadatropin Releasing CRH neurons Hormone (CRH) is Hormone (GnRH) is released from neurons released from neurons in the hypothlamus into in the hypothlamus into the blood supply the blood supply feeding feeding the anterior the anterior pituitary pituitary gland gland CRH stimulates GnRH stimulates Corticotrophs in the Gonadotrophs in the anterior pituitary to anterior pituitary to synthesize and secrete synthesize and secrete adrenocorticotropic follical stimulating hormone (ACTH) into ACTH ACTH hormone (FSH) and the blood supply leutinizing hormone (LH) into the blood supply Chapter 9: Diencephalon Hypothalamus To Pituitary Signaling Anterior pituitary signaling The Anterior lobe of the Pituitary Gland – a Neuroendocrine Structure Synthesis and release of peptide hormones occur from cells located within the anterior pituitary itself (called pituicytes) Synthesis/release from pituicytes are controlled by neurons in the hypothalamus A large variety of cells and peptides in the anterior lobe……. Corticotrophs, Gonadotrophes, Growth Hormone producing cells, Thyroid Stimulating Hormone producing cells, Prolactin producing cells F9-10 Effects of hypophyseotropic hormones on the secretion of anterior pituitary hormones. CRH, corticotropin-releasing hormone; TRH, thyrotropin-releasing hormone; GnRH, gonadotropin-releasing hormone; GRH, growth hormone-releasing hormone; GIH, growth hormone-inhibiting hormone; PRH, prolactin-releasing hormone; PIH, prolactin-inhibiting hormone. Chapter 9: Diencephalon Hypothalamus To Pituitary Signaling Anterior pituitary signaling The Anterior lobe of the Pituitary Gland – a Neuroendocrine Structure Targets of anterior pituitary hormones regulate important body functions F9-11 In women, FSH and LH act in sequence on the ovary to produce growth of the ovarian follicle, ovulation, and formation and maintenance of the corpus luteum. In men, FSH and LH control the functions of the testes. Prolactin stimulates lactation Chapter 9: Diencephalon Homeostasis and negative feedback within the Pituitary Gland Feedback from endocrine structures result in body homeostasis Negative feedback; the product acts to inhibit the release of the hormone eg., Hypothalamo-Pituitary Adrenal axis (HPA axis) -feedback loop incorporating corticotrophin-releasing hormone (CRH), ACTH, and adrenal cortical steroid (Cortisol) Cortisol (a steroid hormone) is released into the blood and feeds back and inhibits CRH and ACTH release from the hypothalamus and pituitary à turning off response! Body Chapter 9: Diencephalon Homeostasis and negative feedback within the Pituitary Gland HPA function is disrupted in depressed patients Increased cortisol secretion and levels in response to increased ATCH release enlarged pituitary and adrenals as result of hypersecretion of cortisol - due to abnormal regulation by the hypothalamus eg., increased CRF-production in hypothalamic neurons eg., increased CRF in CSF (Cortisol) Chapter 9: Diencephalon HYPOTHALAMIC FUNCTIONS Eating Lateral hypothalamus (feeding center) evokes eating Ventromedial hypothalamus (satiety center) stops eating Body Temperature Autonomic responses that cause body heat loss (vasodilation), conservation (vasoconstriction), or production (shivering) Water Balance Osmoreceptors in thirst center of hypothalamus (supraoptic region) – trigger release of vasopressin from posterior pituitary Anterior Pituitary Function Regulates secretions from endocrine glands of body controlling reproduction, sexual behavior, stress response, growth Circadian Rhythms Suprachiasmatic nucleus – body clock – keeps brain on day-night cycle Emotion Rage, fear, adversion, sexual behavior, pleasure Subject to limbic system input Chapter 9: Diencephalon SUBTHALAMUS Subthalamic nucleus - projects to basal ganglia and substantia nigra - involved in extrapyramidal motor function Sagittal Horizontal Coronal Chapter 9: Diencephalon EPITHALAMUS Habenular Trigone (Habenula) - small depressed triangular area situated above and in front of the superior colliculus - regulates neural systems connecting the forebrain and midbrain Pineal Body – lies between superior colliculi and is attached by pineal stalk Role in Rene Decartes’s philosophy (1600s). “Seat of the Soul” where all thoughts are formed Stress hormone secretion View Angle from posterior View Angle from midsaggital Habenula Pineal body Chapter 9: Diencephalon EPITHALAMUS Habenular Trigone (Habenula) - small depressed triangular area situated above and in front of the superior colliculus - regulates dopamine & serotonin neural systems connecting the forebrain and midbrain Pineal Body – lies between superior colliculi and is attached by pineal stalk Role in Rene Decartes’s philosophy (1600s). “Seat of the Soul” where all thoughts are formed Melatonin secretion (circadian rhythms), stress and sex hormone secretion Habenula Pineal body Chapter 9: Diencephalon EPITHALAMUS Habenular Trigone (Habenula) - small depressed triangular area situated above and in front of the superior colliculus - regulates dopamine & serotonin neural systems connecting the forebrain and midbrain Pineal Body – lies between superior colliculi and is attached by pineal stalk Role in Rene Decartes’s philosophy (1600s). “Seat of the Soul” where all thoughts are formed Melatonin secretion (circadian rhythms), stress and sex hormone secretion Habenula Pineal body Chapter 9: Diencephalon EPITHALAMUS Habenular Trigone (Habenula) - small depressed triangular area situated above and in front of the superior colliculus - regulates dopamine & serotonin neural systems connecting the forebrain and midbrain Pineal Body – lies between superior colliculi and is attached by pineal stalk Role in Rene Decartes’s philosophy (1600s). “Seat of the Soul” where all thoughts are formed Melatonin secretion (circadian rhythms), stress and sex hormone secretion Habenula Pineal body Chapter 9: Diencephalon EPITHALAMUS Habenular Trigone (Habenula) - small depressed triangular area situated above and in front of the superior colliculus - regulates dopamine & serotonin neural systems connecting the forebrain and midbrain Pineal Body – lies between superior colliculi and is attached by pineal stalk Role in Rene Decartes’s philosophy (1600s). “Seat of the Soul” where all thoughts are formed Melatonin secretion (circadian rhythms), stress and sex hormone secretion Habenula Pineal body Chapter 10: Cerebral Hemispheres/Telencephalon CEREBRAL GRAY MATTER - CEREBRAL CORTEX Two hemispheres divided into 6 lobes each with different functions Frontal, parietal, temporal, occipital, insular, limbic Convoluted anatomy – Cortical folds or crests (called Gyri) and deep valleys (called Sulci) anatomy increases the surface area of the cortex (~2.5sqft unfolded) 50% of cortex is hidden within sulci and fissures Multiple cortical maps Motor, somatosensory, visual Highly parcellated Different parts of cortex serve different brain functions CEREBRAL WHITE MATTER Underlying myelinated fiber tracts leading to- and from- the cerebral cortex DEEP SUBCORTICAL GRAY AREAS Underlying clusters of brain nuclei Basal ganglia Chapter 10: Cerebral Hemispheres/Telencephalon CEREBRAL CORTEX Two hemispheres divided into 6 lobes each with different functions Frontal, parietal, temporal, occipital, insular, limbic Convoluted anatomy – Cortical folds or crests (called Gyri) and deep valleys (called Sulci) anatomy increases the surface area of the cortex (~2.5sqft unfolded) 50% of cortex is hidden within sulci and fissures Frontal Parietal Frontal lobe motor cortex rostral aspect - a role in ideation and cognition Occipital Parietal lobe somatosensory cortex associative cortex Temporal Sagittal view Occipital lobe visual cortex Temporal lobe auditory cortex Insular Insular lobe mixed function cortex sensory processing, motor control, risk assessment decision-making, self awareness, emotion Limbic Limbic lobe Midsagittal view motivation, emotion, learning and memory *Only specific portion of each lobe dedicated to the above functions Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Sulci vs. Fissures: Distinction A fissure (deep sulcus) is a cleft or groove that separates one lobe from another A sulcus is a groove within a lobe and delimits gyri from one another Main Sulci and Fissures Lateral Cerebral Fissure (Sylvian Fissure) – separates temporal lobe from frontal & parietal lobes Central Sulcus (Fissure of Rolando) – separates frontal and parietal lobes Longitudinal Cerebral Fissure – separates cerebral hemispheres Circuminsular Fissure (Circular sulcus) – separates insula from frontal, parietal, and temporal lobes Parieto-occipital Fissure – medial surface of posterior cortex – separates the parietal and occipital lobes Calcarine Fissure – medial surface of occipital pole forward towards the parieto-occipital fissure Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Main Sulci and Fissures Lateral Cerebral Fissure (Sylvian Fissure) – separates temporal lobe from frontal & parietal lobes Central Sulcus (Fissure of Rolando) – separates frontal and parietal lobes Longitudinal Cerebral Fissure – separates cerebral hemispheres Circuminsular Fissure (Circular sulcus) – separates insula from frontal, parietal, and temporal lobes Parieto-occipital Fissure – medial surface of posterior cortex – separates parietal and occipital lobes Calcarine Fissure – medial surface of occipital pole forward towards parieto-occipital fissure Central Sulcus Lateral Cerebral Fissure Longitudinal Cerebral Fissure Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Main Sulci and Fissures Lateral Cerebral Fissure (Sylvian Fissure) – separates temporal lobe from frontal & parietal lobes Central Sulcus (Fissure of Rolando) – separates frontal and parietal lobes Longitudinal Cerebral Fissure – separates cerebral hemispheres Circuminsular Fissure (Circular sulcus) – separates insula from frontal, parietal, and temporal lobes Parieto-occipital Fissure – medial surface of posterior cortex – separates parietal and occipital lobes Calcarine Fissure – medial surface of occipital pole forward towards parieto-occipital fissure Central Sulcus Lateral Cerebral Fissure Circular Sulcus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Main Sulci and Fissures Lateral Cerebral Fissure (Sylvian Fissure) – separates temporal lobe from frontal & parietal lobes Central Sulcus (Fissure of Rolando) – separates frontal and parietal lobes Longitudinal Cerebral Fissure – separates cerebral hemispheres Circuminsular Fissure (Circular sulcus) – separates insula from frontal, parietal, and temporal lobes Parieto-occipital Fissure – medial surface of posterior cortex – separates parietal and occipital lobes Calcarine Fissure – medial surface of occipital pole forward towards parieto-occipital fissure Central Sulcus Lateral Cerebral Fissure Circular Sulcus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Main Sulci and Fissures Lateral Cerebral Fissure (Sylvian Fissure) – separates temporal lobe from frontal & parietal lobes Central Sulcus (Fissure of Rolando) – separates frontal and parietal lobes Longitudinal Cerebral Fissure – separates cerebral hemispheres Circuminsular Fissure (Circular sulcus) – separates insula from frontal, parietal, and temporal lobes Parieto-occipital Fissure – medial surface of posterior cortex – separates parietal and occipital lobes Calcarine Fissure – medial surface of occipital pole – a horizontal fissure in the occipital lobe that moves forward towards parieto-occipital fissure Parieto-occipital Fissure Midsagittal view Calcarine Fissure Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Corpus Callosum Large bundle of myelinated/non-myelinated fibers – mainly connecting counterparts of opposite hemisphere Crosses Longitudinal Cerebral Fissure – coordinates activity of two cerebral hemispheres Connects two cerebral hemispheres Body - arched upper surface Genu – anterior curved portion Rostrum – antero-ventral portion Splenium – thick posterior portion Body Splenium Genu Midsagittal view Rostrum Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Corpus Callosum Large bundle of myelinated/non-myelinated fibers – mainly connecting counterparts of opposite hemisphere Crosses Longitudinal Cerebral Fissure – coordinates activity of two cerebral hemispheres Connects two cerebral hemispheres Longitudinal Cerebral Fissure View Angle from Horizontal Plane Corpus Callosum View Angle from Anterior Coronal Plane Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Motor cortex – controls voluntary motor behavior Precentral gyrus (the Primary Motor Cortex) – controls motor movement Contains Pyramidal upper motor neurons in a highly conserved map Analogous to the somatotropic map that is in the postcentral gyrus Premotor Area – supplementary motor area – involved in motor ideation Rostral to Central Sulcus Separated from motor area by Precentral Sulcus Central Sulcus Precentral Sulcus Precentral Gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Frontal association areas - Judgment, abstract reasoning, creativity, socially appropriate behavior Precentral sulcus – lies anterior (rostral) to Precentral gyrus (the Primary Motor Cortex) Superior and Inferior Frontal Sulci – extend down and forward from the Precentral gyrus Divide lateral surface of frontal lobe into: Superior Frontal Gyrus, Middle Frontal Gyrus, Inferior Frontal Gyrus Prefrontal cortex – higher order association cortex Judgment, abstract reasoning, creativity, socially appropriate behavior Anterior to primary motor cortex and adjacent premotor area Central Sulcus Precentral Sulcus Superior Frontal Sulcus Precentral Gyrus Inferior Frontal Sulcus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Frontal association areas - Judgment, abstract reasoning, creativity, socially appropriate behavior Precentral sulcus – lies anterior (rostral) to Precentral gyrus (the Primary Motor Cortex) Superior and Inferior Frontal Sulci – extend down and forward from the Precentral gyrus Divide lateral surface of frontal lobe into: Superior Frontal Gyrus, Middle Frontal Gyrus, Inferior Frontal Gyrus Prefrontal cortex – higher order association cortex Judgment, abstract reasoning, creativity, socially appropriate behavior Anterior to primary motor cortex and adjacent premotor area Central Sulcus Precentral Sulcus Superior Frontal Sulcus Middle Frontal Gyrus Superior Frontal Gyrus Precentral Gyrus Inferior Frontal Sulcus Inferior Frontal Gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Frontal association areas - Judgment, abstract reasoning, creativity, socially appropriate behavior Precentral sulcus – lies anterior (rostral) to Precentral gyrus (the Primary Motor Cortex) Superior and Inferior Frontal Sulci – extend down and forward from the Precentral gyrus Divide lateral surface of frontal lobe into: Superior Frontal Gyrus, Middle Frontal Gyrus, Inferior Frontal Gyrus Prefrontal cortex – higher order association cortex Judgment, abstract reasoning, creativity, socially appropriate behavior Anterior to primary motor cortex and adjacent premotor area Superior Frontal Sulcus Middle Frontal Gyrus Superior Frontal Gyrus Inferior Frontal Gyrus Precentral Sulcus Inferior Frontal Sulcus Precentral Gyrus Central Sulcus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Frontal association areas - Judgment, abstract reasoning, creativity, socially appropriate behavior Precentral sulcus – lies anterior (rostral) to Precentral gyrus (the Primary Motor Cortex) Superior and Inferior Frontal Sulci – extend down and forward from the Precentral gyrus Divide lateral surface of frontal lobe into: Superior Frontal Gyrus, Middle Frontal Gyrus, Inferior Frontal Gyrus Prefrontal cortex – higher order association cortex Judgment, abstract reasoning, creativity, socially appropriate behavior Anterior to primary motor cortex and adjacent premotor area Superior Frontal Gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Frontal association areas - Judgment, abstract reasoning, creativity, socially appropriate behavior Precentral sulcus – lies anterior (rostral) to Precentral gyrus (the Primary Motor Cortex) Superior and Inferior Frontal Sulci – extend down and forward from the Precentral gyrus Divide lateral surface of frontal lobe into: Superior Frontal Gyrus, Middle Frontal Gyrus, Inferior Frontal Gyrus Prefrontal cortex – higher order association cortex – lies below the Inferior Frontal Gyrus Judgment, abstract reasoning, creativity, socially appropriate behavior Anterior to primary motor cortex and adjacent premotor area Central Sulcus Precentral Sulcus Superior Frontal Sulcus Middle Frontal Gyrus Superior Frontal Gyrus Precentral Gyrus Inferior Frontal Sulcus Prefrontal cortex Inferior Frontal Gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Frontal Lobe Frontal association areas - Judgment, abstract reasoning, creativity, socially appropriate behavior Cingulate gyrus – arched gyrus on medial surface of frontal cortex between the Cingulate sulcus and the corpus callosum Cingulate Cortex Midsagittal view Cingulate Superior Frontal Gyrus Gyrus Cingulate Sulcus Corpus Callosum Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Parietal Lobe From Central sulcus to Parieto-occipital fissure Postcentral gyrus (the Primary Somatosensory Cortex) behind Central sulcus and before Postcentral sulcus Intraparietal sulcus – a horizontal sulcus that may unite with Postcentral sulcus Supramarginal gyrus – anterior to the Angular gyrus Angular gyrus - near the superior edge of the temporal lobe, and immediately posterior to the Supramarginal gyrus Central Sulcus Postcentral Gyrus Postcentral Sulcus Intraparietal Sulcus Parietal Lobe Parietal-occipital Fissure Angular Gyrus Supramarginal Gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Occipital Lobe Behind parieto-occipital fissure Occipital Gyri – Primary Visual Cortex Calcarine fissure – divides occipital lobe into: Cuneus (above the fissure) Lingual gyrus (below the fissure) Both contain Striate Cortex – cortex in each gyrus on banks of fissure Central Sulcus Parietal-occipital Fissure Occipital Gyri Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Occipital Lobe Behind the Parieto-occipital fissure Occipital Gyri – Primary Visual Cortex Calcarine Sulcus – divides occipital lobe into: Cuneus (below the Parieto-occipital fissure and above the Calcarine Sulcus) Lingual gyrus (below the Calcarine Sulcus) Midsagittal view Parieto-occipital Fissure Cuneus Calcarine Sulcus Lingual gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Temporal Lobe Below the Lateral fissure extends to Parieto-occipital fissure Superior Temporal Gyrus Middle Temporal Gyrus Inferior Temporal Gyrus Superior Temporal Sulci Inferior (or Middle) Temporal Sulci Central Sulcus Lateral Cerebral Fissure Superior Temporal Gyrus Temporal Lobe Middle Temporal Gyrus Inferior Temporal Gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Temporal Lobe Below the Lateral fissure extends to Parieto-occipital fissure Superior Temporal Gyrus Middle Temporal Gyrus Inferior Temporal Gyrus Superior Temporal Sulcus – separate Superior and Middle Temporal Gyri Inferior (or Middle) Temporal Sulcus – long sulcus extending on lower surface of temporal lobe from temporal pole to occipital lobe – separates Middle and Inferior Temporal Gyri Central Sulcus Lateral Cerebral Fissure Superior Temporal Gyrus Temporal Lobe Middle Temporal Gyrus Superior Temporal Sulcus Inferior Temporal Gyrus Inferior Temporal Sulcus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Temporal Lobe Below the Lateral fissure extends to Parieto-occipital fissure Hippocampal fissure – medial aspect of temporal lobe from the splenium of the corpus callosum (posterior) to to the uncas Parahippocampal gyrus – above hippocampal fissure Uncas – inward curved most medial portion of temporal lobe Midsagittal view Splenium of the Corpus Callosum Hippocampal fissure Uncus Parahippocampal gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Temporal Lobe Below the Lateral fissure extends to Parieto-occipital fissure Hippocampal fissure – medial aspect of temporal lobe from the splenium of the corpus callosum (posterior) to to the uncas Parahippocampal gyrus – above hippocampal fissure Uncas – inward curved most medial portion of temporal lobe Pole of Temporal Cortex Uncus Parahippocampal gyrus Hippocampal fissure Ventral view Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Temporal Lobe Below the Lateral fissure extends to Parieto-occipital fissure Hippocampal fissure – medial aspect of temporal lobe from the splenium of the corpus callosum (posterior) to to the uncas Parahippocampal gyrus – above hippocampal fissure Uncas – inward curved most medial portion of temporal lobe Coronal view Hippocampal fissure Parahippocampal gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Insular Lobe Sunken portion of the cortex at the bottom of a deep fold within the Lateral Cerebral Fissure Insula Insula Lateral Cerebral fissure Insula Coronal view Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES SUMMARY OF CORTICAL AREAS Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES SUMMARY OF CORTICAL AREAS Parietal-occipital fissure Angular gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES SUMMARY OF CORTICAL AREAS Precentral Gyrus Central Sulcus Postcentral Gyrus Precentral Sulcus Superior Frontal Gyrus Postcentral Sulcus Superior Frontal Sulcus Supramarginal Gyrus Middle Frontal Gyrus Intraparietal Sulcus Inferior Frontal Sulcus Angular Gyrus Inferior Frontal Gyrus Parieto-occipital Opercularis Fissure Triangularis Orbitalis Occipital Gyri Lateral Cerebral Fissure Superior Temporal Gyrus Middle Temporal Gyrus Inferior Temporal Gyrus Inferior Temporal Sulcus Superior Temporal Sulcus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Cingulate Cortex Limbic System Cortical components Ring of cortex between diencephalon & lateral neocortex Phylogenetically oldest cortex à called the archicortex v Cingulate gyrus v Parahippocampal gyrus Parahippocampal gyrus v Hippocampal formation Parahippocampal gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Basal forebrain and Septum Nuclei that lie deep within the cerebral hemispheres Basal forebrain nuclei Nucleus basalis, substantia innominata, nucleus accumbens Septal nuclei (Septum) – more dorsally located nuclei Septum Nucleus basalis Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Basal forebrain and Septum Nuclei that lie deep within the cerebral hemispheres Basal forebrain nuclei Nucleus basalis, substantia innominata, nucleus accumbens Septal nuclei (Septum) – more dorsally located nuclei Septum Nucleus accumbens Nucleus basalis Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Subcortical White matter Transverse (Commissural) fibers - Interconnect cerebral hemispheres Corpus callosum - connects cortex to cortex Anterior commissure Anterior commissure – - connects olfactory bulbs and temporal lobes Hippocampal commissure (Commissure of fornix) - connects two hippocampi Corpus callosum Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Subcortical White matter Transverse (Commissural) fibers - Interconnect cerebral hemispheres Corpus callosum - connects cortex to cortex Anterior commissure – - connects olfactory bulbs and temporal lobes Hippocampal commissure (Commissure of fornix) - connects two hippocampi Fornix fornix Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Subcortical White matter Projection fibers Connect cerebral cortex w lower brain structures or the spinal cord Afferent projections – axon fibers connecting lower brain structures to cortex Optic radiation – axons fibers projecting from thalamus to visual cortex Acoustic radiation – axons fibers projecting from thalamus to auditory cortex Efferent projections – axons fibers connecting cortex to lower brain structures or spinal cord Pyramidal tracts – axons of large corticospinal tract that projects from upper motor neurons in the motor cortex to lower motor neurons in the spinal cord Optic radiation Acoustic radiation Corticospinal Tract Occipital lobes Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Subcortical White matter Association fibers Connect portions of cerebral hemispheres on same side of brain Short association fibers – connect adjacent gyri of the cortex (called U fibers) Long association fibers – connect widely separated areas Uncinate fasciculus connects frontal lobe ßà temporal lobe Cingulum connects cingulate cortex ßà parahippocampal gyrus Arcuate fasciculus connects frontal lobe ßà temporal lobe Superior longitudinal fasciculus and Occipito-frontal fasciculus Connects frontal lobe ßà occipital lobe Inferior longitudinal fasciculus connects temporal lobe ßà occipital lobe Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Subcortical White matter Uncinate fasciculus connects frontal lobe ßà temporal lobe Cingulum connects cingulate cortex ßà parahippocampal gyrus Arcuate fasciculus connects frontal lobe ßà temporal lobe Superior longitudinal fasciculus and Occipito-frontal fasciculus Connects frontal lobe ßà occipital lobe Inferior longitudinal fasciculus connects temporal lobe ßà occipital lobe Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES Subcortical White matter Uncinate fasciculus connects frontal lobe ßà temporal lobe Superior longitudinal fasciculus and Occipito-frontal fasciculus Connects frontal lobe ßà occipital lobe Inferior longitudinal fasciculus connects temporal lobe ßà occipital lobe Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES BASAL GANGLIA Masses of gray matter (collections of cell bodies) buried deep within the cerebral hemispheres Situated around the upper and lateral portions of the thalamus Anatomically: Caudate nucleus, putamen, globus pallidus = collectively termed the corpus striatum Caudate nucleus and putamen = Striatum – major input to basal ganglia Putamen and globis pallidus = Lenticular nucleus – major output from basal ganglia Functionally: Forms an integral part of the Extrapyramidal Motor System Implicated in fine motor control and the initiation of voluntary motor movements Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES BASAL GANGLIA (Anatomy) Masses of gray matter buried deep within cerebral hemispheres Caudate nucleus - pair shaped gray area contiguous w/ putamen - tapers off to amygdala Putamen Globis pallidus Caudate nucleus, putamen, globus pallidus = corpus striatum Caudate nucleus and putamen = Striatum – major input to basal ganglia Putamen and globis pallidus = Lenticular nucleus – major output from basal ganglia Caudate Body Thalamus Caudate Head Anterior Posterior Putamen Putamen Globis pallidus Lateral Views Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES BASAL GANGLIA (Anatomy) Masses of gray matter buried deep within cerebral hemispheres Caudate nucleus - pair shaped gray area contiguous w/ putamen - tapers off to amygdala Putamen Globis pallidus Caudate nucleus, putamen, globus pallidus = collectively called the Corpus Striatum Caudate nucleus and putamen = called the Striatum – major input to basal ganglia Putamen and globis pallidus = called the Lenticular nucleus – major output from basal ganglia Caudate Head Caudate Body Caudate Body Thalamus Putamen Putamen Caudate Head Thalamus Caudate Tail Amygdala Ventricle Optic nerve Caudate Tail Amygdala Lateral Ventricle Optic nerves & Optic chiasm Para hippocampal gyrus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES BASAL GANGLIA Masses of gray matter buried deep within cerebral hemispheres Caudate nucleus - pair shaped gray area contiguous w/ putamen - tapers off to amygdala Putamen Globis pallidus Caudate Body Body Caudate Head Thalamus Caudate Head Putamen and Globis pallidus Putamen Globis pallidus Caudate nucleus Putamen Globis pallidus F10-19 Spatial relationships between basal ganglia, thalamus, and internal capsule. Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES BASAL GANGLIA Masses of gray matter buried deep within cerebral hemispheres Caudate nucleus - pair shaped gray area contiguous w/ putamen - tapers off to amygdala Putamen Globis pallidus Caudate Caudate nucleus Thalamus Putamen Putamen Globis Globis pallidus pallidus Caudate nucleus (head) Caudate Globis pallidus Putamen Putamen Thalamus F10-20 A: Frontal section through cerebral hemispheres. B: Horizontal section through cerebral hemispheres. Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES BASAL GANGLIA Connections coursing through the basal ganglia Caudate nucleus is perforated by sheets of myelinated fibers of the Internal Capsule INTERNAL CAPSULE Myelinated fibers separating putamen and globis pallidus from caudate and thalamus Dense fiber bundle that runs directly through the basal ganglia Contains corticobulbar & corticospinal (descending motor) and thalamo-cortical (ascending sensory) tracts Putamen Putamen Caudate Body Head Putamen and Globis pallidus Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES INTERNAL CAPSULE Myelinated fibers separating putamen and globis pallidus from caudate and thalamus Dense fiber bundle that runs directly through the basal ganglia Contains corticobulbar & corticospinal (descending motor) and thalamo-cortical (ascending sensory) tracts Caudatolenticular gray bridges Caudato-lenticular gray bridges View basal ganglia from coronal viewpoint (c) Coronal section Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES INTERNAL CAPSULE Myelinated fibers separating putamen and globis pallidus from caudate and thalamus Dense fiber bundle that runs directly through the basal ganglia Contains corticobulbar & corticospinal (descending motor) and thalamo-cortical (ascending sensory) tracts Internal capsule Internal capsule (a) Coronal section Caudate (b) Horizontal section Internal Capsule Thalamus Putamen Thalamus Globis pallidus F10-20 A: Frontal section through cerebral hemispheres. B: Horizontal section through cerebral hemispheres. Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES INTERNAL CAPSULE Myelinated fibers separating putamen and globis pallidus from caudate and thalamus Dense fiber bundle that runs directly through the basal ganglia Corticobulbar and Corticospinal tracts (descending motor tracts) [purple] Thalamo-cortical tracts (ascending sensory tracts) [light blue, green] tracts Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES INTERNAL CAPSULE Myelinated fibers separating putamen and globis pallidus from caudate and thalamus Dense fiber bundle that runs directly through the basal ganglia Posterior Limb Corticobulbar and Corticospinal (descending motor) tracts Thalamo-cortical (ascending sensory) tracts Highly organized – the descending motor fibers of the Corticobulbar and Corticospinal tracts of the Face, Arm, and Leg (F, A, L) run in front of the ascending sensory fibers of the Thalamo- coritical tract for the face, arm, and leg (f, a, l). Posterior limb Internal Capsule Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES INTERNAL CAPSULE Myelinated fibers separating putamen and globis pallidus from caudate and thalamus Dense fiber bundle that runs directly through the basal ganglia Anterior Limb Cortico-thalamic and Fronto-pontine (descending) tracts Thalamo-cortical (ascending) tracts Highly organized – the ascending fibers of the Thalamo-cortical tract (red) run sandwiched in between descending fibers of the Cortico-thalamic and Fronto-pontine tracts (green) Anterior limb Internal Capsule Chapter 10: Cerebral Hemispheres/Telencephalon ANATOMY OF CEREBRAL HEMISPHERES CLAUSTRUM, EXTERNAL CAPSULE & EXTREME CAPSULE Claustrum – thin layer of gray matter beneath insular cortex Separated from putamen by the External Capsule (thin white matter sheet) and from the insular cortex by the Extreme Capsule (thin white matter sheet) Caudate External Capsule Extreme Capsule Internal Capsule Thalamus Claustrum Putamen Globis pallidus Chapter 10: Cerebral Hemispheres/Telencephalon MENINGES AND THE BLOOD-BRAIN BARRIER Brain & spinal cord enveloped by membranes – insulate and protect it from mechanical disturbances, eg, impact with inner surface of skull Closest to the CNS is the pia mater, and then the arachnoid membranes separated by blood vessels and CSF Beneath the bone is a tough leathery membrane (dura mater)