Cerebral Lobes and Cerebellum

Cerebral lobes and Cerebellum

Amalie Misund February 2020

Topics of this presentation

• Telencephalon Cerebellum • Cerebral lobes • Functional and anatomical division • Frontal lobe • Nuclei • Parietal lobe • Temporal lobe • Occipital lobe • Insular lobe • Broadmann areas • Homunculus • Diencephalon • Thalamus • Hypothalamus Cerebral lobes

Frontal lobe Frontal lobe • Prefrontal cortex • Complex cognitive behaviour • Decision making • Social behaviour • Personality expression • Inferior frontal gyrus • Broca’s area • Inferior frontal gyrus, Broadmanns area 44 • ”Broken Boca” • Inability to form words • Precentral gyrus • Primary motor cortex (Area 4) Parietal lobe Parietal lobe • Postcentral gyrus • Primary somatosensory cortex (Area 3,1,2) • Sensory association cortex Temporal lobe Temporal lobe Temporal lobe

• Auditory cortex • Primary auditory cortex • Sensory speech cortex • Wernicke’s area • Speech comprehension Occipital lobe

• Visual cortex • Primary visual cortex Insular cortex

• Lies within the lateral sulcus • Involved in homoestasis, emotions and conciousness • Autonomic control

Summary p.524 in Thieme Head, Neck & Neuroanatomy Broadmann areas • 52 cortical areas that differ histologically Lobe Area Cortex Function Frontal lobe 4 Primary motor cortex – (precentral gyrus) Initiates voluntary movement

Frontal lobe 9,10,11 Prefrontal cortex Personality, motivation, future planning, ,12 primitive reflexes Frontal lobe 44,45 Broca’s speech area – (Inferior frontal gyrus ) Motor aspect of speech Parietal lobe 3, 1,2 Primary somatosensory (Postcentral gyrus) Organized as sensory homunculus, primary involved with localization of sensation Parietal lobe 2 Vestibular cortex (Postcentral gyrus) Function is balance and equilibrium Occipital lobe 17 Primary visual cortex Function is vision

Temporal lobe 41,42 Primary auditory cortex – located in superior Function is hearing temporal gyrus Temporal lobe 22 Wernicke’s speech area – (Superior temporal gyrus) Speech comprehension

Homunculus Diencephalon

• Thalamus • Hypothalamus • Epithalamus • Subthalamus • Third ventricle Thalamus • The ”Post office” – Major relay for all sensation except olfaction • 120 nuclei – 5 high yield • Ventral posterolateral (VPL) • Ventral posteromedial (VPM) • Lateral geniculate body (LGB) • Medial geniculate body (MGB) • Ventral lateral nucleus (VL) Thalamic nuclei • Venteral PosteroLateral • Input from spinothalamic and spinobulbothalamocortical • Senses from limbs and trunk • Vibration • Pain, pressure, proprioception • Light touch • Temperature • Ventral PosteroMedial • Face sensation • Taste

• Lateral geniculate nucleus • Vision • ”Lateral = Light” • Medial Geniculate nucleus • Hearing • ”Medial = Music” • Ventral lateral nucleus • Motor Hypothalamus

• Maintains homeostasis by regulating Thirst and water balance Adenohypophysis (ant. pit.) and Neurohypophysis (post. Pit.) Hunger Autonomic nervous system Temperature Sexual urges ”TAN HATS” Nuclei Function Lesion Lateral nucleus Hunger Anorexia Stimulated by ghrelin, inhibited by Failure to thrive in infants leptin. Venteromedial nucleus Satiety Hyperphagia Stimulated by leptin. (abnormally increased appetite) Anterior nucleus Cooling Hyperthermia - Parasympathetic Posterior nucleus Heating Hypothermia - Sympathtic Suprachiasmatic nucleus Circadian rhythm Supraoptic and paraventricular Synthesize ADH and Oxytocin nuclei Preoptic nucleus Thermoregulation, sexual behaviour Subthalamus and epithalamus

• Subthalamus • Involved in control of muscle activty • Epithalamus • Pineal gland • Produces melatonin, important for sleep • Habenulae Summary Cerebellum Cerebellum

• Vermis +lateral hemispheres. • Contains a central medullary core - white matter (tree of life) • Myelinated axons and • The four cerebellar nuclei • Part of the motor system • Does not trigger concious movement Cerebellar lobes 1. Anterior lobe (spinocerebellum) • Input from stretch receptors (muscle spindles) and Golgi tendon organs via the spinocerebellar tracts. • Regulation of muscle tone. 2. Posterior lobe (Neocerebellum) • Input from neocortex via corticospontocerebellar fibers • Plays a role in coordinating voluntary motor activity 3. Floccundular lobe (vestibulocerebellum) • Recieves input from the vestibular system • Plays a role in maintenance of posture and balance

Summary Cerebellar nuclei ”Dont Eat Greasy Foods”

Nucelus Function Dentate Influences planning and programming of movements Emboliform Coordinates activity of skeletal muscles Globose Fastigal Cerebellar lesions

• May be clinically silent for some time • Symptoms • Hypotonia (decrease of muscle tone) • Disequillibrium (loss of balance) • Dyssynergia (loss of coordinated muscle activity) • Dysarthritia • Ataxia • Dysdiadochokinesia • Intention tremor • Nystagmus THANK YOU FOR YOUR ATTENTION! BEST OF LUCK ON YOUR EXAM!