8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 1 Development of Complex Curricula for Molecular Bionics and Infobionics Programs within a consortial* framework** Consortium leader PETER PAZMANY CATHOLIC UNIVERSITY Consortium members SEMMELWEIS UNIVERSITY, DIALOG CAMPUS PUBLISHER The Project has been realised with the support of the European Union and has been co-financed by the European Social Fund *** **Molekuláris bionika és Infobionika Szakok tananyagának komplex fejlesztése konzorciumi keretben ***A projekt az Európai Unió támogatásával, az Európai Szociális Alap társfinanszírozásával valósul meg. PETER PAZMANY CATHOLIC UNIVERSITY SEMMELWEIS UNIVERSITY sote_logo.jpg dk_fejlec.gif INFOBLOKK 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 2 Peter Pazmany Catholic University Faculty of Information Technology BASICS OF NEUROBIOLOGY COCHLEAR AND VESTIBULAR SYSTEMS www.itk.ppke.hu Neurobiológia alapjai (Halló és egyensúlyozó rendszer) ZSOLT LIPOSITS Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 3 www.itk.ppke.hu CHARACTERISTICS OF THE COCHLEAR AND VESTIBULAR SYSTEMS THE AUDITORY SYSTEM ENSURES THE SENSE OF HEARING. THE SYSTEM HAS TWO MAJOR CON-STITUENTS: THE EAR WITH THE COCHLEAR APPARATUS AND THE AUDITORY NEURONAL SYSTEM SOUND CAUSES VIBRATION OF THE TYMPANIC MEMBRANE THAT IS TRANSMITTED VIA THE OTIC OSSICLES TO THE PERILYMPHATIC FLUID. IT GENERATES A SPREADING WAVE IN THE COCHLEAR DUCT FILLED WITH ENDOLYMPH THE RESULT OF THESE EVENTS IS THE ACTIVATION OF HAIR CELLS IN THE ORGAN OF CORTI. THISSIGNAL IS TRANSMITTED BY THE COCHLEAR NERVE TO COCHLEAR NUCLEI OF THE BRAINSTEM THE COCHLEAR NUCLEI PROJECT UPSTREAM AND SEND THE INFORMATION VIA BRAIN STEM AND METATHALAMIC STRUCTURES TO THE PRIMARY AUDITORY CORTEX LOCATED IN THE SUPERIOR TEMPORAL GYRUS THE VESTIBULAR SYSTEMS SENSES LINEAR ACCELERATION, DECELERATION AND ANGULAR ROTATION OF THE HEAD RECEPTORS ARE IN THE UTRICLE, SACCULE AND THE SEMICIRCULAR CANALS. THE GENERATED SIG-NALS ARE CARRIED BY THE VESTIBULAR NERVE TO ITS NUCLEI FOR PROCESSING THE SYSTEM IS INTERCONNECTED WITH MOTOR NUCLEI OF MUSCLES REGULATING THE MOVE-MENTS OF EYE. THE VESTIBULAR INFORMATION IS ALSO FORWARDED TO THE CEREBELLUM AND THE SPINAL CORD Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 4 www.itk.ppke.hu ORGANIZATION OF THE EAR THE FIGURE DEPICTS THE OUTER, MIDDLE AND INNER PARTS OF THE EAR AND SHOWS THE PROPAGATION OF SOUND-EVOKED SIGNALS FROM THE EAR DRUM TO THE COCHLEA AND THEN TOWARD THE CENTRAL NERVOUS SYSTEM THROUGH THE COCHLEAR NERVE COCHLEA COCHLEAR NERVE EAR DRUM Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 5 www.itk.ppke.hu DETAILS OF SIGNAL PROPAGATION IN THE EAR Picture2.png SOUND CAUSES VIBRATION OF THE TYMPANIC MEMBRANE WHICH IS TRANSMITTED BY A CHAIN OF TINY BONES, THE MALLEUS, INCUSAND STA-PESTO THE OVAL WINDOW OF THE COCHLEA. THE BASIS OF THE STAPES TRANSMITS THE SIG-NAL TO THE PERILYMPH, A FLUID FILLING THE SCALA VESTIBULI AND SCALA TYMPANI COM-PARTMENTS OF THE COCHLEA. THE SCALA VES-TIBULI STARTS AT THE OVAL WINDOW AND THE FLUID FILLED MEMBRANOUS TUBE WINDS AROUND THE VERTICAL AXIS OF THE COCHLEA, THEN IT TURNS DOWNHILL AND CONTINUES AS SCALA TYMPANI WHICH ENDS AT THE MEMBRA-NE COVERING THE ROUND WINDOW. SCALA TYM-PANI AND SCALA VESTIBULI SURROUND THE MEMBRANOUS TUBE COCHLEAR DUCT WHICH IS FILLED WITH ENDOLYMPH Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 6 www.itk.ppke.hu FLUID COMPARTMENTS OF THE BONY AND MEMBRANOUS LABYRINTHS NOTE THAT THE ENDOLYMPHATIC COMPARTMENT IS SURROUNDED BY THE PERILYMPHATIC FLUID SYSTEM UTRICLE SACCULE SEMICIRCULAR CANAL VESTIBULE OVAL WINDOW ROUND WINDOW COCHLEA (UNROLLED) ENDOLYMPHIN MEMBRANOUS LABYRINTH PERILYMPHIN BONY LABYRINTH COCHLEAR DUCT Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 7 www.itk.ppke.hu THE STRUCTURE OF THE CORTI ORGAN A.THE ORGAN OF CORTI IS SITUATED WITHIN THE COCHLEAR DUCT. IT IS BUILT BY SENSORY EPITHEL HAIR CELLS AND SUPPORTIVE EPITHEL CELLS. THE SENSORY CELLS PICK UP THE SIGNAL OF THE SPREADING ENDOLYMPHATIC FLUID WAVE. NEURONS OF THE COCHLEAR GANGLION CONVEY THE INFORMATION TO AUDI-TORY CENTERS OF THE BRAIN STEM.B. HISTOLOGY OF THE COCHLEA Picture3.png A B Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 8 www.itk.ppke.hu VIBRATION OF THE BASILAR MEMBRANE, HAIR CELL ACTIVATION Picture4.png Picture5.gif DEPENDING ON THE PITCH OF THE SOUND, A PARTICULAR REGION OF THE BASILAR MEMBRANE VIBRATES WITH A MAXIMAL INTENSITY. SIGNALS AT HIGH FREQUENCY GENERATE VIBRATIONS AT THE BASE OF THE MEMBRANE, WHILE SOUNDS AT LOW FREQUENCY INITIATE MOVEMENT AT THE WIDER AND LOOSER APICAL PART OF THE BASILAR MEMB- RANE. THE EVOKED MOVEMENT RES-ULTS IN BENDING OF THE HAIRS OF SENSORY EPITHEL CELLS TOWARD THE STEREOCILIUMWHICH,IN TURN,CAUSES DEPOLARIZATION AND INCRE-ASES THE RELEASE OF TRANSMITTERS FROM HAIR CELLS. THIS EVENT ACTI-VATES THE PERIPHERAL PROCESSES OF COCHLEAR GANGLION NEURONS Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 9 www.itk.ppke.hu THE AUDITORY PATHWAY Picture6.png THE CENTRAL PROCESSES OF COCHLEAR GANGLION CELLS TERMINATE IN THE DORSAL AND VENTRAL COCHLEAR NUCLEI OF THE BRAIN STEM. THE COCHLEAR NUCLEI COM-MUNICATE WITH THE SUPERIOR OLIVE FROM WHERE THE AUDITORY FIBERS ASCEND TO THE INFERIOR COLLICULUS FORMING THE LATERAL LEMNISCUS. THIS NUCLEUS RELAYS THE INFORMATION TO THE MEDIAL GENICU-LATE BODY OF THE THALAMUS. THE FINAL ACOUSTIC RADIATION REACHES THE PRIMARY AUDITORY FIELD (A1) OF THE SUPERIOR TEMPORAL GYRUS. THE AUDITORY CENTER HAS A TONOTOPIC ORGANIZATION, THE APEX OF THE COCHLEA PROJECTS TO THE ANTERIOR PART OF THE FIELD, HIGH FREQUENCY SOUNDS ARE REPRESENTED AT THE POSTERIOR POLE. BEHIND THIS REGION IS THE SENSORY SPEECH AREA OF WERNICKE Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 10 www.itk.ppke.hu THE VESTIBULAR SYSTEM THE RECEPTOR STRUCTURES OF THE VESTIBULAR SYSTEM ARE LOCATED IN THE BONY VESTIBULE AND SEMICIRCULAR CANALS OF THE INNER EAR (A, ENFRAMEDREGION). THE LINEAR ACCE-LERATIONAND DECELERATION ARE SENSED BY RECEPTORS BUILT INTO THE ENDOLYMPH-FILLED SACCULEAND UTRICLE (B). THE ANGULAR ROTATION IS MONITORED BY HAIR CELLS OF THE CRISTA AMPULLARIS, A RECEPTOR STRUCTURE PRESENT IN EACH OF THE MEMBRANOUS SEMICIRCULAR CANALS . THE SPATIAL ARRANGEMENT OF THE SEMICIRCULAR CANALS ENABLES THE DETECTION OF ANGULAR ROTATION OF THE HEAD IN ALL DIRECTIONS. THE HAIR CELLS OF THE UTRICLE AND SACCULEPOSSESS HAIRS EMBEDDED IN THE OTOLITHMEMBRANE. THE CALCIUM CONCRETIONS GIVE THE OTOLITH MEMBRANE A HIGHER SPECIFIC GRAVITY THAN THE ENDOLYMPHAND BY BENDING THE HAIRS IT CAN STIMULATE THE HAIR CELLS. IN THE SEMICIRCULAR CANALS, THE MOVEMENT OF ENDOLYMPHTRIGGERS THE HAIR CELLS AND CHANGES THEIR ACTIVITY DEPENDING ON THE DIRECTION OF THE FLOW. THE ALTERED RECEPTOR STATUS IS REPORTED BY THE VESTIBULAR NERVE ` Picture2.png A Picture7.png B Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 11 www.itk.ppke.hu THE VESTIBULAR PATHWAYS OCULOMOR NUCLEUS TROCHLEAR NUCLEUS ABDUCENS NUCLEUS MEDIAL LONGITUDINAL FASCICULUS DESCENDING PART VESTIBULOSPINAL TRACT VESTIBULOCEREBELLAR FIBERS MEDIAL LONGITUDINAL FASCICULUS ASCENDING PART SUPERIOR VESTIBULAR NUCLEUS LATERAL VESTIBULAR NUCLEUS MEDIAL VESTIBULAR NUCLEUS INFERIOR VESTIBULAR NUCLEUS Basics of Neurobiology: Cochlear and vestibular systems 8/8/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 12 www.itk.ppke.hu THE VESTIBULO-OCULAR REFLEX MOVING THE HEAD TO THE LEFT SIDE IN THE HORIZONTAL PLANE EVOKES THE CONJUGATED MOVEMENT OF THE EYE BALLS TOWARD THE RIGHT SIDE LEFT RIGHT 1 2 3 4 5 8 7 6 1. EYE BALL 2. LATERAL RECTUS 3. MEDIAL RECTUS 4. N. OCULOMOTORIUS 5. N. ABDUCENS 6. VESTIBULAR NUCLEI 7. SEMICIRCULAR CANAL 8. VESTIBULAR GANGLION