Cerebrum - Telencephalon Animal Body Function VII PDF

11/26/24 Cerebrum - Telencephalon Animal Body Function VII Luís Resende 1 Summary Know the anatomy of the telencephalon: Cerebral hemispheres Archiocortex Pale...

11/26/24 Cerebrum - Telencephalon Animal Body Function VII Luís Resende 1 Summary Know the anatomy of the telencephalon: Cerebral hemispheres Archiocortex Paleocortex – Rhinencephalon Neocortex White mater: association fibers, commissural fibers and projection fibers For educational purposes. Egas Moniz School of Health and nov-24 Science 2 1  11/26/24 https://regionalneurological.com/wp-content/uploads/2020/03/Regional-Neurological_Brain-Science.jpeg Brain (encephalon) Functions: control the organs of the body responsible for the regulation, co-ordination and integration of the rest of the nervous system. its abilities are resembled by its morphological features. nov-24 For educa/onal purposes. Egas Moniz School of Health and Science 3 (Konig, 2020) Localization: Housed in the neurocranium Frontal bones Brain Parietal bones (encephalon) Occipital bone Temporal bones Dyce, 2018) Ethmoid bone Sphenoid bone Cranial cavity For educational purposes. Egas Moniz School of Health and nov-24 Science 4 2  11/26/24 Brain (encephalon) Can be divided anatomically and functionally Anatomic division: Rhombencephalon (hindbrain) Myelencephalon – medulla oblongata Metencephalon – pons (ventral) and cerebellum (dorsal) Mesencephalon (midbrain) Prosencephalon (forebrain) Diencephalon Telencephalon Functional division: Brainstem Cerebrum Cerebellum For educational purposes. Egas Moniz School of Health and nov-24 Science 5 Brainstea Cerebellu Cerebrum m m Myelencephalon Diencephalon Dorsal Medulla oblongata Hipotalamus Metencephalon Subtlamus Talamencephalon Arquicerebellum Epitalamus Paleocerebellum Talamus ** Neocerebellum Metatalamus Ventral Metencephalon Telencephalon Arquipalium Pons Paleopalium Neopalium Mesencephalon (midbrain) Tectum corpora quadrigeminal, Tegmentum e Cerebellar pedunculus For educational purposes. Egas Moniz School of Health and nov-24 Science 6 3  11/26/24 nov-24 For educa/onal purposes. Egas Moniz School of Health and Science 7 Anatomical orientations 8 4  11/26/24 Anatomical orientation of the brain Sagittal plane – a plane passing through the rostral to caudal axis of the brain, dividing the brain into right and left portions. sagittal section Horizontal (dorsal) plane - a plane passing through the brain at right angles to the sagittal plane, dividing the brain into dorsal and ventral portions. horizontal section Transverse plane - a plane passing Sagittal plane Horizontal (dorsal) plane Transverse plane through the brain at right angles to the sagittal and horizontal planes, dividing the brain into rostral and caudal portions. For educational purposes. Egas Moniz School of Health and nov-24 Science transverse section 9 Anatomical orientation of the brain Sagittal plane – a plane passing through the rostral to caudal axis of the brain, dividing the brain into right and left portions. sagittal section Horizontal (dorsal) plane - a plane passing through the brain at right angles to the sagittal plane, dividing the brain into dorsal and ventral portions. horizontal section Transverse plane - a plane passing through the brain at right angles to the sagittal and horizontal planes, dividing the brain into rostral and caudal portions. For educational purposes. Egas Moniz School of Health and nov-24 Science transverse section 10 5  11/26/24 Anatomical orientations of the brain The relationships between brain and body structures, or diCerent areas in the brain or body, have a set od descriptive terms: Unilateral: relating to one side of the body Bilateral: relating to both sides of the body Ipsilateral: relating to the same side of the body Contralateral: relating to the opposite side of the body nov-24 For educational purposes. Egas Moniz School of Health and Science 11 Cerebrum – Telencephalon Functions: counscious experence of sensation and iniciation of voluntary movement A Formed by two cerebral hemispheres (right and left) http://www.brainmuseum.org/specimens/lagomorpha/domesticrabbit/brain/Domesticrabbit631596clr.jpg Divided by the longitudinal fissure Each hemisphere is made of: cerebral córtex – external gray matter basal nuclei - gray matter white matter Right The surface of each hemispheres might be: A - smooth (lissencephalic) - small mammals (rodents, lagomorphs, birds, and most marsupials) B - convulated (gyrencephalic), forming gyri (ridges) Left and sulci (grooves) – in most species of veterinary interest B For educational purposes. Egas Moniz School of Health and nov-24 http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html Science 12 6  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres Each cerebral hemispheres presents: Cerebral cortex - surface grey matter Cerebral white matter - found in deeper regions Basal nuclei – deep accumulations of grey matter Lateral ventricle For educational purposes. Egas Moniz School of Health and nov-24 Science 13 Cerebrum – Telencephalon During gestation, carnivores and primates are lissencephalic until relatively late in gestation. In vertebrate animals, brain weight is http://www.brainmuseum.org/specimens/lagomorpha/domesticrabbit/brain/Domesticrabbit631596clr.jpg closely correlated with body weight: An adult sperm whale has a brain that weights five times more than a human brain However, White mater increases as a cubic function Grey matter content only increase as a square function Brains from large animals have higher white matter to grey matter ratio B For educational purposes. Egas Moniz School of Health and nov-24 http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html Science 14 7  11/26/24 Frontal pole Cerebrum – Telencephalon External anatomy Formed by two cerebral hemispheres (right and left) Right Left hemisphere Separated by the cerebral longitudinal fissure hemisphere Excepto where they are connected across the middline by: Lamina terminalis Corpus callosum Rostral comissure Caudal comissure Occipital pole Hippocampus fornix Cerebellum Separated from the cerebellum by the transverse fissure Frontal pole – rostral end of the hemisphere Occipital pole – caudal end of the hemisphere For educational purposes. Egas Moniz School of Health and nov-24 Science 15 Cerebral cortex External anatomy gyrus – outward fold (Gr. gyros circle; a circular convolution of the brain) sulcus – inward fold (L. sulcus groove) folding increases the surface area of the cerebral cortex Lateral view For educational purposes. Egas Moniz School of Health and nov-24 http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html Science 16 8  11/26/24 Cerebral cortex External anatomy gyri Frontal gyrus Prorean gyrus Precruciate gyrus Postcruciate gyrus Suprasylvian gyrus (rostral, middle, caudal) Sylvian gyrus Ectosylvian gyrus (rostral, middle, caudal) Suprasylvian gyrus Endomarginal gyrus (rostral) Marginal gyrus Ectomarginal gyrus Occipital gyrus Splenial gyrus Lateral olfactory gyrus Parahippocampal gyrus For educational purposes. Egas Moniz School of Health and nov-24 Science 17 Cerebral cortex External anatomy sulci Prorean sulcus Presylvian sulcus Cruciate sulcus Ansate sulcus Coronal sulcus Marginal sulcus Ectosylvian sulcus Suprasylvian sulcus Ectomarginal sulcus Lateral rhinal sulcus (rostral, caudal) Pseudosylvian fissure Medial rhinal sulcus Endorhinal sulcus Hippocampal sucus Splenial sulcus Suprasplenial sucus For educational purposes. Egas Moniz School of Health and nov-24 Science 18 9  11/26/24 Cerebrum – Telencephalon External anatomy Sulci present in all gyrencephalic species: Lateral rhinal sulcus – marks the separation sulci between the archipalium and the neopallium. Cruciate sulcus – in the vicinity of the cortical motor http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html área Lateral view Pseudosylvian fissure (carnivores) - in the same location as Sylvian fissure. canine cerebral hemisphere Sylvian fissure (ungulates and primates) - at the bottom of the fissure there is the insula, at the depth of which there is the claustrum. For educational purposes. Egas Moniz School of Health and nov-24 http://www.brainmuseum.org/specimens/artiodactyla/pig/brain/ Pig6clr.jpg Science 19 Cerebrum – Telencephalon External anatomy gyri and sulci Cingulate gyrus Callosal sulcus http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html Splenial sulcus The gyri arranged around the corpus callosum and the site of implantation of the brainstem are related to instinctive and emotional canine cerebral hemisphere reactions and, together with other diencephalic and mesencephalic structures, are called the Limbic System. http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html For educational purposes. Egas Moniz School of Health and nov-24 Median view Science 20 10  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres The cerebral cortex (pallium) present three regions, on the basis of evolutionary history, structure and function Archicortex (archipallium) – Hippocampus, fornix, mammilary bodies (hippothlamus) supracallosal and cingulate gyri. Allocortex - Histologically (allocortex) – present 3 layers Paleocortex (paleopallium) – associated to the rhinencephalon Isocortex Neocortex (neopallium) – the predominant part of the cerebral cortex in the mammal species - Histologically – present 6 layers For educational purposes. Egas Moniz School of Health and nov-24 Science 21 Medial rhinal Lateral rhinal sulcus sulcus (rostral) Cerebrum – Telencephalon Rhinencephalon (Gr. rhin nose, cephalon brain) Lateral rhinal sulcus Most ventral portion of the telencephalon (caudal) Phylogenetically it is the oldest portion Paleopallium and archipallium - allocortex Rhinencephalon is associated with the smell (primary olfactory function) In the lower vertebrates is developed specifically for these sense, but in our domestic species it has acquired more functions: Dyce, 2010 Is associated with memory formation and emotional behavior http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html Separated from the neocortex by the: lateral rhinal sulcus (rostral and caudal) – ventrolateral surface of the cerebral hemisphere medial rhinal sulcus – ventromedial surface For educational purposes. Egas Moniz School of Health and nov-24 Science 22 11  11/26/24 Medial rhinal sulcus Olfactory bulb Cerebrum – Telencephalon Olfactory peduncle Rhinencephalon Lateral rhinal sulcus (rostral) External anatomy Olfactory tubercle Olfactory bulb – ventral and most rostral part of the telencephalon, expanded rostral Lateral rhinal aspect of the olfactory peduncle. Olfactory sulcus (caudal) bulb neurons receive input from olfactory cells in the olfactory epithelium, and project via olfactory tract. Piriform lobe Parahippocamp Olfactory peduncle – longitudinal bulge al Gyrus on the ventral and rostral aspect of the Dyce, 2010 telencephalon extending from the http://www.cvmbs.colostate.edu/vetneuro/VCA3/vca.html olfactory bulb to the olfactory tubercule. ** the bulb and the peduncle are are hollow, containing an olfactory ventricule filled with cerebrospinal fluid. For educational purposes. Egas Moniz School of Health and nov-24 Science 23 Medial rhinal sulcus Olfactory bulb Cerebrum – Telencephalon Olfactory peduncle Rhinencephalon Lateral rhinal sulcus (rostral) External anatomy Olfactory tubercle Olfactory tubercle – ventral and rostral forebrain, forms a bulge at the caudal end of Lateral rhinal the olfactory peduncle. It is one of the relay sulcus (caudal) stations in the olfactory pathway travelling between the olfactory bulb to the piriform lobe. Piriform lobe Parahippocamp Piriform lobe – cerebral cortex on the al Gyrus ventrolateral aspect of the telencephalon. It Dyce, 2010 is the primary receiving area for olfactory stimuli and is involved in olfaction and the limbic system. It contains the amygdaloide nucleus (amygdala). ** the bulb and the peduncle are hollow, containing an olfactory ventricule filled with cerebrospinal fluid. For educational purposes. Egas Moniz School of Health and nov-24 Science 24 12  11/26/24 Medial rhinal Lateral rhinal sulcus sulcus (rostral) Cerebrum – Telencephalon 1 Rhinencephalon Lateral rhinal Can be divided into two pathways: sulcus A. OLFACTORY PATHWAY - Basal part (paleopallium) (caudal) – sensitive to olfaction - olfactory bulb, olfactory tract, lateral olfactory gyrus, and piriform lobe B. NONOLFACTORY PATHWAY – lateral olfactory and parahippocampal gyri of the piriform lobe, amygdala, septum, and hippocampal formation. Dyce, 2010 A. Septum– composed by the structures that form the medial wall of the lateral ventricle - regions of association of olfactory reflexes - B. Limbic part (archipallium) – hippocampus - reactions caused by olfactory stimuli and the vegetative phenomena that accompany these reactions 1 For educational purposes. Egas Moniz School of Health and nov-24 Science 25 Cerebrum – Telencephalon Rhinencephalon OLFACTORY PATHWAYS ➜ Important function of the rhinencephalon A. Basal part (paleopallium) – olfactory bulb (1) – sensitive to olfaction 1. Olfactory epithelium (bipolar neurons – CN I) 2. CN I pass through the cribiform plate and reach the olfactory bulb (1) 3. Olfactory peduncle (2) Olfactory peduncle is divided into: Lateral olfactory tract Medial olfactory tract Intermediate olfactory tract 1 2 Olfactory peduncles ends in the 6 1 olfactory tubercule (6) For educational purposes. Egas Moniz School of Health and nov-24 Science 26 13  11/26/24 Cerebrum – Telencephalon Rhinencephalon OLFACTORY PATHWAYS ➜ Important function of the rhinencephalon Olfactory peduncle is divided into: Lateral olfactory tract – present axons that runs caudally to the piriform lobe, lateral olfactory gyrus, amygdala, entorhinal cortex of the parahyppocampal gyrus, and hippocampus. Medial olfactory tract – present axons to the septal region Intermediate olfactory tract – present axons to the rostral commissure Rostral commissure – region that communicate with the 1 2 contralateral rhinencephalon 6 For educational purposes. Egas Moniz School of Health and nov-24 Science 27 Cerebrum – Telencephalon Rhinencephalon OLFACTORY PATHWAYS ➜ Important function of the rhinencephalon Lateral olfactory tract – present axons that runs caudally to the piriform lobe, lateral olfactory gyrus, amygdala, entorhinal cortex of the parahyppocampal Olfaction: gyrus, and hippocampus. 1. Olfactory epithelium (bipolar neurons – CN I) 2. CN I pass through the cribiform plate and reach the olfactory bulb 3. Olfactory peduncle 4. Lateral olfactory tract 5. Piriform lobe For educational purposes. Egas Moniz School of Health and nov-24 Science 28 14  11/26/24 Cerebrum – Telencephalon Rhinencephalon OLFACTORY PATHWAYS Olfaction: 1. Olfactory epithelium (bipolar neurons – CN I) 2. CN I pass through the cribiform plate and reach the olfactory bulb 3. Olfactory peduncle 4. Lateral olfactory tract 5. Piriform lobe Vomeronasal organ: 1. Olfactory epithelium (bipolar neurons – vomeronasal organ) 2. Fibers pass through the cribiform plate and reach the olfactory bulb, more specifically at the level of the accessory olfactory bulb 3. Connects with the amygdala Associated with the detection of pheromones For educational purposes. Egas Moniz School of Health and nov-24 Science 29 Cerebrum – Telencephalon Rhinencephalon NONOLFACTORY PATHWAY B. Septum– composed by the structures (grey matter) that form the medial wall of the lateral ventricle Located rostrally to the rostral commissure and ventral to the corpus callosum Septal nuclei – mediate hippocampal eWerents to the hypothalamus septal aWerents – come from the olfactory bulb and the amygdala. Stablish several connections, mainly associated with the limbic system. Connections pathways with: Hippocampus (via the fornix); Amygdala Olfactory tubercule (via medial olfactory tract) Habenula (in the epithalamus) Hypothalamus The septal region is an important reward sites of the limbic system For educational purposes. Egas Moniz School of Health and nov-24 Science 30 15  11/26/24 Cerebrum – Telencephalon Rhinencephalon NONOLFACTORY PATHWAY C. Limbic part (archipallium) – hippocampus - reactions caused by olfactory stimuli and the vegetative phenomena that accompany these reactions. Hippocampus = hippocampal formation lies deep in the parahyppocampal gyrus, forms the medial wall of the lateral ventricle (temporal horn) Principal component of the limbic system Necessary for long term memory formation and for spatial memory Hippocampus is composed by: Hippocampus proper – long and curved nuclear mass. conections to the cyngulate gyrus and the hypothalamus. Dentate gyrus – medial to the hippocampus and projects eWerents to the hyppocampus. Subiculum – Between the lateral edge of the hippocampus and the medial edge of the parahippocampal gyrus. For educational purposes. Egas Moniz School of Health and nov-24 Science 31 For educational purposes. Egas Moniz School of Health and nov-24 Science 32 16  11/26/24 Cerebrum – Telencephalon Rhinencephalon Limbic part (archiopallium) Fornix – medial aspect of the cerebral hemispheres, ventral to the corpus callosum (6). It comprises the eferente white matter of the hippocampus (from the hippocampus to the diencephalon and rhinencephalon) continuing rostrally. Crus of the fornix – rostrally directed bands of white matter that rise from the fimbria (9) on the lateral side of each hippocampus. Body of the fornix – White matter in the ventromedial aspect of the mid region of the lateral ventricles. The axons from hipocampal neurons form the rostrally-directed, paired crura of the fornix, and meet on the midline to form the body of the fornix between the lateral ventricles. Columns of the fornix (11) – Medial aspect of the rostral cerebral hemispheres, ventral to the genu of corpus callosum. The collumns originate from the body of the fornix and descend ventrally to split at the rostral commissure (2). These collumns passes into the septal area or mamillary bodies, respectively. Comissural fibres of the fornix (7) – transverse fibers connecting the left and the right fornix of the hippocampus. For educational purposes. Egas Moniz School of Health and nov-24 Science 33 Cerebrum – Telencephalon Rhinencephalon Limbic part (archipallium) – hippocampus For educational purposes. Egas Moniz School of Health and nov-24 Science 34 17  11/26/24 Cerebrum – Telencephalon Rhinencephalon Limbic part (archipallium) – hippocampus Present several connections: ATerent and eTerent pathways: Piriform lobe and parahippocampal gyrus ETerent pathways Septum region and diencephalon (via fornix) ATerent pathways Amygdala, thalamus, brainstem Amygdala (amygdaloid body) - almond shape, located within the piriform lobe. is a rhinencephalic basal nucleus located within the piriform lobe. Assigns emotional context to sensory information; one of the major components of the limbic system. significant role in modulating the visceral functions. connections with cerebrum, hippothalamus, thalamus, midbrain periaqueductal gray. For educational purposes. Egas Moniz School of Health and nov-24 Science 35 For educational purposes. Egas Moniz School of Health and nov-24 Science 36 18  11/26/24 CN I – Olfactory nerve Special visceral afferent pathways Unmyelinated axons that originate in the olfactory epithelium and pass through the cribriform plate into the cranial cavity and synapse on the olfactory bulb. Vomeronasal organ – gives rise to the vomeronasal nerve and to the terminal nerve. Evans, 2013 Vomeronasal and terminal nerve: ends in the olfactory bulb. Sometimes are referred as cranial nerve 0 (these nerves were discovered after the other nerves) Neurologic exam Evaluate the capacity to smell For educational purposes. Egas Moniz School of Health and nov-24 Science 37 Dog Humans The name olfactory “nerve” is correct as it is derived from the olfactory placode and not CNS tissue, however in humans the olfactory nerve is so diminutive as to resemble a nerve. In veterinary species, the olfactory bulb is prominent. For educational purposes. Egas Moniz School of Health and nov-24 Science 38 19  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres The cerebral cortex (pallium) present three regions, on the basis of evolutionary history, structure and function - Paleocortex (paleopallium) – associated to the rhinencephalon Allocortex - Archicortex (archipallium) – associated to the hippocampus - Histologically (allocortex) – present 3 layers - Neocortex (neopallium) – the predominant part of the cerebral cortex in the mammal species - Histologically – present 6 layers Isocortex For educational purposes. Egas Moniz School of Health and nov-24 Science 39 Cerebrum – Telencephalon Neocortex (isocortex) Neocortex (neopallium) – the predominant part of the cerebral cortex in the mammal species Cerebral hemisphere: Frontal pole (rostral end of the hemisphere) Occipital pole (caudal end of the hemisphere) The cerebral hemispheres can be dividing according to: the position of the nervous tissue in relation to the bones (not directly related to their role): Frontal lobe (1) Parietal lobe (2) Occipital lobe (3) Temporal lobe (4) Rhinencephalon (Piriforme or Olfactory lobe) (5) the function area For educational purposes. Egas Moniz School of Health and nov-24 Science 40 20  11/26/24 Cerebrum – Telencephalon Neocortex (isocortex) Neocortex (neopallium) – the predominant part of the cerebral cortex in the mammal species The cerebral hemispheres can be dividing according to: the function area There are regions in the cortex that are composed by neurons responsible for the reception and processing of nerve impulses (sensory) and others that are responsible to generate eTerent impulses (motor) to eTector cells (muscle and epithelial cells) Primary sensory areas – areas that receive aTerent impulses and are surrounded by association areas; cortical aXerents are mediated by the thalamus (except, olfactory system) Association cortex (association areas) - can have diTerent degree of complexity (e.g. in dogs, association areas constitute approximately 20% of the canine neocortex, while in human corresponds to 85%) play a central role in higher functions, including learning, memory, and behavior. For educational purposes. Egas Moniz School of Health and nov-24 Science 41 Cerebrum – Telencephalon Neocortex (isocortex) Neocortex (neopallium) – the predominant part of the cerebral cortex in the mammal species Functional Regions of Neocortex: Somatosensory area (ss1+ss2) – located at the level of the coronal sulcus. Receives tactile, proprioceptive (kinesthesic) and nociceptive (from the thalamus through the internal capsule) stimuli Gustatory (Taste) area Located near the somatosensory area that receives information from the tongue and pharynx. Insular area (ins) Located in the pseudosylvian fissure. Receives information from the viscera Olfactive area (olf) Located in the piriform lobe. Receive olfactory information Visual area (vis) Located at the level of the marginal gyrus (caudal third). Receives visual stimuli from the lateral geniculate body of the thalamus (through inner capsule) For educational purposes. Egas Moniz School of Health and nov-24 Science 42 21  11/26/24 Cerebrum – Telencephalon Neocortex (isocortex) Neocortex (neopallium) – the predominant part of the cerebral cortex in the mammal species Functional Regions of Neocortex: Auditory area (aud) Located at the level of the middle ectosylvian gyrus. Receive auditory stimuli from the medial geniculate body of the thalamus (via the internal capsule) Vestibular area (ves) Located rostral to the auditory area Prefrontal association cortex (pcf) Located at the frontal pole Association cortex – deciding behavioral/emotional responses and initiates nerve impulses to the premotor cortex and motor areas. Pre-motor cortex (pre) Active mainly in complex movements and in new learnings Motor cortex (mot) Located in the post-cruciate (appendicular muscles) and rostral suprasylvian (cervical and head muscles) gyri For educational purposes. Egas Moniz School of Health and nov-24 Science 43 Neocortex (neopallium) Cerebral hemisphere: Frontal lobe Prefrontal association cortex, Motor cortex, Premotor cortex Parietal lobe Somatosensory area Temporal lobe Auditory area, Limbic system, learning and memory Occipital lobe Visual area Rhinencephalon (Olfactory lobe) Olfactory area, limbic system, learning and memory For educational purposes. Egas Moniz School of Health and nov-24 Science 44 22  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres White matter: Association fibers: transmit nerve impulses between neurons in the same hemisphere Comissural fibers: transmit the nerve impulse from one hemisphere to the other, through the corpus callosum (in the neocortex) and the rostral commissure (in the rhinencephalon), and caudal commissure. Projection fibers: transmit the impulse that comes from the thalamus to the cerebral cortex (aTerent) or that leaves the cortex to the basal nucleus, brainstem or spinal cord (eTerent), via the internal capsule or external capsule. For educa/onal purposes. Egas Moniz School of Health nov-24 and Science 45 Cerebrum – Telencephalon Cerebral hemispheres White matter: Association fibers: transmit nerve impulses between neurons in the same hemisphere. For educational purposes. Egas Moniz School of Health and nov-24 Science 46 23  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres White matter: Association fibers: transmit nerve impulses between neurons in the same hemisphere. arcuate fibers - association axons may connect adjacent gyri. superior longitudinal fasciculus - from the occipital pole to the frontal pole. inferior longitudinal fasciculus - from the occipital pole to the ventral temporal region. uncinate fasciculus - from the ventral temporal region to the ventral frontal region. cingulum - is a band of association axons that run deep to the cingulate gyrus, connecting the paraterminal gyrus of the septum to the parahippocampal gyrus in the temporal lobe. subcallosal fasciculus - distinct in the roof of the lateral ventricle, has connections similar to the cingulum but it includes axons to the caudate nucleus. For educational purposes. Egas Moniz School of Health and nov-24 Science 47 Cerebrum – Telencephalon Cerebral hemispheres White matter: Comissural fibers or cerebral commissure: fibers that run across the midline connecting between matching areas of the right and left cerebral hemispheres. corpus callosum rostral commissure caudal commissure. For educational purposes. Egas Moniz School of Health and nov-24 Science 48 24  11/26/24 nov-24 For educational purposes. Egas Moniz School of Health and Science 49 Cerebrum – Telencephalon - cerebral hemispheres Comissural fibers: corpus callosum (in the neocortex) massive fiber bundle, interconnecting corresponding regions of the two hemispheres. genu (rounded rostral end) – interconnects frontal lobes body - interconnects other areas of the cerebral hemispheres splenium (rounded caudal end) – interconnects occipital lobes this exchange is necessary – the two cerebral cortex work as a functional unit For educational purposes. Egas Moniz School of Health and nov-24 Science 50 25  11/26/24 Cerebrum – Telencephalon - cerebral hemispheres Comissural fibers: rostral commissure, interconnects the rhinencephalic structures (olfactory bulb, piriform lobe, amygdala) in each cerebral hemisphere crosses the midline rostral to the hypothalamus about halfway of the corpus callosum and the base of the brain. For educational purposes. Egas Moniz School of Health and nov-24 Science 51 Cerebrum – Telencephalon - cerebral hemispheres Comissural fibers: caudal commissure, interconnects the nucleus of the caudal commissure, the rostral colliculi and pretectal areas on either side of the brainsteam. crosses the midline at the rostral end of the midbrain tectum and caudal of the base of the pineal gland. For educational purposes. Egas Moniz School of Health and nov-24 Science 52 26  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres White matter: Projection fibers: transmit the impulse that comes from the thalamus to the cerebral cortex (aSerent) or that leaves the cortex to the basal nucleus, brainstem or spinal cord (eSerent), via the internal capsule or external capsule. For educational purposes. Egas Moniz School of Health and nov-24 Science 53 Cerebrum – Telencephalon Cerebral hemispheres White matter: Projection fibers: internal capsule. mixture of a;erent and e;erent fibers of the cerebral cortex / interdigitated fibers that radiate in all directions only tra;ic area where all fibers to and from the cerebral cortex run area between the caudate and lentiform nuclei, and lateral to the thalamus For educational purposes. Egas Moniz School of Health and nov-24 Science 54 27  11/26/24 Cerebrum – Telencephalon Cerebral hemispheres Basal nuclei: Corresponds to gray matter that is not found in the cerebral cortex. Subcortical nuclei located in each hemisphere. Include: Caudate nucleus Regulation of the motor functions / voluntary movement. Putamen nucleus indirect feedback to the cerebral cortex Globus pallidus and indirect feedback to other subcortical motor centers (reticular formation, red nucleus of the midbrain) Lesions of the basal nuclei in dogs may result in motor deficiency detectable by specific neurologic examinations. For educational purposes. Egas Moniz School of Health and nov-24 Science 55 Cerebrum – Telencephalon Cerebral hemispheres Neostriatum: Caudate nucleus bound by medially by the thalamus and laterally by the internal capsule rostrodorsally - the floor of the 3rd ventricule rostroventrally – ends in the piriforme lobe Putamen nucleus* lateral to the internal capsule lentiform nucleus Paleostriatum: Globus pallidus** ventromedial to the putamen For educational purposes. Egas Moniz School of Health and nov-24 Science 56 28  11/26/24 Bibliography König, H.E., Liebich, H.G.(2020) Veterinary Anatomy of Domestic Animals: Textbook and Colour Atlas (7th edition) Thieme Publishing Group. ISBN 978-3132429338 Singh, B. (2018) Dyce, Sack, and Wensing's Textbook of Veterinary Anatomy (5th edition) Saunders ISBN 978-0323442640 Barone, R. (2009) Anatomie comparée des mammifères domestiques, Tome 3, Splanchnologie I. Vigot. ISBN 978-2711490462 Hermanson, J.W., de Lahunta, A., Evans, H.E. (2018) Miller and Evans’ anatomy of the dog (5th edition) Saunders ISBN 978-0323676687 International Committee on Veterinary Gross Anatomical Nomenclature (I.C.V.G.A.N.) (2017) Nomina Anatomica Veterinaria (6th ed.): World Association of Veterinary Anatomists (W.A.V.A.) Reece, W.O. & Rowe, E.W. (2017) Functional anatomy and physiology of domestic animals (5th edition), John Wiley & Sons. ISBN 9781119270850 Budras, K.D., McCarthy, P.H., Fricke, W., Richter, R. (2007) Anatomy of the Dog (5th edition) Schlutersche. ISBN 978-89993-018-4 Budras, K.D., Sack W.O., Rock, S. (2009) Antomy of the Horse (5th edition) Schlutersche. ISBN 978-3-89993-044-3 Uemura, E.E., (2015) Fundamentals of Canine Neuroanatomy and Neurophysiology. Wiley Blackwell For educational purposes. Egas Moniz School of Health and nov-24 Science 58 29