* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Abbreviated 11-15
Sensory substitution wikipedia , lookup
Animal echolocation wikipedia , lookup
End-plate potential wikipedia , lookup
Eyeblink conditioning wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Embodied language processing wikipedia , lookup
Synaptic gating wikipedia , lookup
Neuroanatomy wikipedia , lookup
Cognitive neuroscience of music wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Optogenetics wikipedia , lookup
Central pattern generator wikipedia , lookup
Proprioception wikipedia , lookup
Evoked potential wikipedia , lookup
Sensory cue wikipedia , lookup
Development of the nervous system wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Sound localization wikipedia , lookup
Perception of infrasound wikipedia , lookup
Anatomy of the cerebellum wikipedia , lookup
Synaptogenesis wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Microneurography wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Channelrhodopsin wikipedia , lookup
Biology 463 - Neurobiology Topic 11 The Central Visual System Lange The Retinofugal Projection The retinofugal projection consists of the Optic Nerve, Optic Chiasm, and Optic Tract The Retinofugal Projection • Right and Left Visual Hemifields – Left hemifield projects to right side of brain and right to the left Visual deficits from lesions in the retinofugal projection are shown in these images. Notice the specific types of loss shown in black as compared to the intact fields Nonthalamic Targets of the Optic Tract are areas that will use visual input but not in the sense of SEEING OBJECTS. – Hypothalamus: Biological rhythms, including sleep and wakefulness – Pretectum: Size of the pupil; certain types of eye movement – Superior colliculus: Orients the eyes in response to new stimuli X X X The Lateral Geniculate Nucleus (LGN) The pathways occur in alternating layers. Contralateral = on the other side Ipsilateral = on the same side Parvocellular Cells • • • Parvocellular cells, also called P-cells, are neurons located within the parvocellular layers of the lateral geniculate nucleus (LGN) of the thalamus. "Parvus" means "small" in Latin, and the name "parvocellular" refers to the small size of the cell compared to the larger magnocellular cells. The parvocellular neurons are sensitive to color, and are more capable of discriminating fine details than their magnocellular counterparts. Parvocellular cells have greater spatial resolution, but lower temporal resolution, than the magnocellular cells. Magnocellular Cells • • • Magnocellular neurosecretory cells are large cells within the supraoptic nucleus and paraventricular nucleus of the hypothalamus. There are two types of magnocellular neurosecretory cells, oxytocinproducing cells and vasopressin-producing cells, but a small number can produce both hormones. These cells are neuroendocrine neurons, they are electrically excitable, and generate action potentials in response to afferent stimulation. The Lateral Geniculate Nucleus (LGN) Inputs Segregated by Eye and Ganglion Cell Type P type = (also known as beta or midget ganglion cells) are believed to be responsible for detecting details in vision. M type = (also known as alpha or parasol ganglion cells) are believed to be responsible for detecting motion. nonM-nonP type =are a diverse group of cell types that make up the remaining 5% of RGCs. Their roles in vision are less understood than M- and P-type ganglion cells, but it is known that some non-M, non-P type cells are involved in color vision. Anatomy of the Striate Cortex The calcarine sulcus is where the primary visual cortex is concentrated. The central visual field is located in posterior portion of the calcarine sulcus and the peripheral visual field in the anterior portion. Anatomy of the Striate Cortex Inputs to the Striate Cortex – First binocular neurons found in striate cortex - most layer III neurons are binocular (but not layer IV) END. Biology 463 - Neurobiology Topic 12 The Auditory and Vestibular Systems Lange Introduction Sensory Systems – Sense of hearing, audition • Detect sound • Perceive and interpret nuances – Sense of balance, vestibular system • Head and body location • Head and body movements The Nature of Sound Sound – Audible variations in air pressure – Sound frequency: Number of cycles per second expressed in units called hertz (Hz) – Cycle: Distance between successive compressed patches The Nature of Sound Sound – Range: 20 Hz to 20,000 Hz – Pitch: High pitch = high frequency; low frequency = low pitch – Intensity: High intensity louder than low intensity The Structure of the Auditory System The Middle Ear Components of the Middle Ear 5 – Stapedius muscle 9 – Tensor Tympani muscle The Middle Ear • Sound Force Amplification by the Ossicles – Pressure: Force by surface area – Greater pressure at oval window than tympanic membrane, moves fluids • The Attenuation Reflex – Response where onset of loud sound causes tensor tympani and stapedius muscle contraction – Function: Adapt ear to loud sounds, understand speech better The Inner Ear • • • • Anatomy of the Cochlea Perilymph: Fluid in scala vestibuli and scala tympani Endolymph: Fluid in scala media Endocochlear potential: Endolymph electric potential 80 mV more positive than perilymph The Inner Ear • Physiology of the Cochlea – Pressure at oval window, pushes perilymph into scala vestibuli, round window membrane bulges out • The Response of Basilar Membrane to Sound – Structural properties: Wider at apex, stiffness decreases from base to apex • Research: Georg von Békésy – Endolymph movement bends basilar membrane near base, wave moves towards apex Georg von Békésy - Hungarian biophysicist born in Budapest. In 1961, he was awarded the Nobel Prize in Physiology or Medicine for his research on the function of the cochlea in the mammalian hearing . The Inner Ear Travelling wave in the Basilar Membrane The Inner Ear The Organ of Corti and Associated Structures External ear Tympanic membrane Malleus, incus, stapes (ossicles) Internal ear Oval window Fluids in cochlear canals Upper and middle Lower Pressure Pinna Air External acoustic meatus Middle ear One vibration Amplitude Amplification in middle ear Spiral organ (of Corti) stimulated Time Central Auditory Processes Auditory Pathway Mechanisms of Sound Localization • Techniques for Sound Localization – Horizontal: Left-right, Vertical: Up-down • Localization of Sound in Horizontal Plane – Interaural time delay: Time taken for sound to reach from ear to ear – Interaural intensity difference: Sound at high frequency from one side of ear Mechanisms of Sound Localization Interaural time delay and interaural intensity difference Mechanisms of Sound Localization The Sensitivity of Binaural Neurons to Sound Location Mechanisms of Sound Localization Localization of Sound in Vertical Plane – Vertical sound localization based on reflections from the pinna Auditory Cortex Primary Auditory Cortex – Axons leaving MGN project to auditory cortex via internal capsule in an array – Structure of A1 and secondary auditory areas: Similar to corresponding visual cortex areas The Vestibular System • Importance of Vestibular System – Balance, equilibrium, posture, head, body, eye movement • Vestibular Labyrinth – Otolith organs gravity and tilt – Semicircular canals - head rotation – Use hair cells, like auditory system, to detect changes Figure 15.35: Structure of a macula, p. 594. Macula of saccule Macula of utricle Kinocilium Stereocilia Otoliths Otolithic membrane Hair bundle Hair cells Vestibular nerve fibers Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Supporting cells Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 15.36: The effect of gravitational pull on a macula receptor cell in the utricle, p. 595. Otolithic membrane Kinocilium Ster eocilia Depolarization Hyperpolarization Receptor potential (Hairs bent towar d kinocilium) Nerve impulses generated in vestibular fiber Increased impulse frequency Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Excitation (Hairs bent away from kinocilium) Decreased impulse frequency Inhibition Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 15.37: Location and sturcture of a crista ampullaris, p. 596. Flow of endolymph Crista ampullaris (a) Fibers of vestibular nerve Cupula (b) Turning motion Cupula Position of cupula during turn (c) Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Increased firing (d) Ampulla of left ear Ampulla of right ear Cupula at rest Position of cupula during turn Fluid motion in ducts Horizontal ducts Decreased firing Afferent fibers of vestibular nerve Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. The Vestibular System Push-Pull Activation of Semicircular Canals – Three semicircular canals on one side • Helps sense all possible headrotation angles – Each paired with another on opposite side of head – Push-pull arrangement of vestibular axons: The Vestibular System The Vestibulo-Ocular Reflex (VOR) • also known as the oculocephalic reflex • a reflex eye movement that stabilizes images on the retina during head movement • Stabilization occurs by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field END. Biology 463 - Neurobiology Topic 13 The Somatic Sensory System Lange Introduction Somatic Sensation – Enables body to feel, ache, chill – Responsible for touch and pain – Somatic sensory system: Different from other systems • Receptors: Broadly distributed • Responds to many kinds of stimuli Touch • Types and layers of skin – Hairy and glabrous (hairless - e.g., palms) – Epidermis (outer) and dermis (inner) • Functions of skin – Protective – Prevents evaporation of body fluids – Provides direct contact with world • Mechanoreceptors – Most somatosensory receptors are mechanoreceptors Touch • • • • • • Mechanoreceptors Pacinian corpuscles Ruffini's endings Meissner's corpuscles Merkel's disks Krause end bulbs Touch Mechanoreceptors – Small and large receptive fields Touch Mechanoreceptors – Two-point discrimination • Receptive field density • Receptive field size Touch Primary Afferent Axons – Aa, Ab, Ad, C – C fibers mediate pain and temperature – Ab mediates touch sensations Pain Perception Primary Afferents and Spinal mechanisms – First pain and second pain – Referred pain: Angina Touch The Spinal cord – Spinal segments (30)- spinal nerves within 4 divisions of spinal cord Touch The Spinal cord – Dermatomes- 1-to-1 correspondence with segments – Shingles Touch Dorsal Column–Medial Lemniscal Pathway – Touch and proprioception Touch Homuncular Mapping Figure 12.6a-b: Lobes and fissures of the cerebral hemispheres, p. 435. Central sulcus Precentral gyrus Postcentral gyrus Parietal lobe Frontal lobe Parieto-occipital sulcus (on medial surface of hemisphere) Lateral sulcus Frontal lobe Central sulcus Occipital lobe Temporal lobe Transverse cerebral fissure Cerebellum Pons Medulla oblongata (a) Spinal cord Gyri of insula Gyrus Cortex (gray matter) Sulcus Temporal lobe (pulled down) (b) White matter Fissure (a deep sulcus) Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Wilder Penfield 1891 – 1976 Physician and Neuroscientist who mapped the brain in what became the “humunculus” Figure 12.9: Motor and sensory areas of the cerebral cortex, p. 438. Sensory Leg Motor Toes Face Genitals Lips Jaw Tongue Swallowing Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Motor cortex (precentral gyrus) Intraabdominal Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Touch Homuncular Mapping of a variety of mammals shows differences in distribution of sensory structures that relate to habitat and environmental success. Temperature Thermoreceptors – Hot and cold receptors END. Biology 463 - Neurobiology Topic 14 Spinal Control of Movement Lange Introduction Motor Programs – Motor system: Muscles and neurons that control muscles – Role: Generation of coordinated movements – Parts of motor control • Spinal cord coordinated muscle contraction • Brain motor programs in spinal cord The Somatic & Autonomic Motor Systems Types of Muscles – Smooth: digestive tract, arteries, related structures – Striated: Cardiac (heart) – skeletal (bulk of body muscle mass) Lower Motor Neurons Graded Control of Muscle Contraction by Alpha Motor Neurons – Varying firing rate of motor neurons – Recruit additional synergistic motor units Tetanus – as painted by Sir Charles Bell in 1809. Lower Motor Neurons Types of Motor Units – Red muscle fibers: Large number of mitochondria and enzymes, slow to contract, can sustain contraction – White muscle fibers: Few mitochondria, anaerobic metabolism, contract and fatigue rapidly – Fast motor units: Rapidly fatiguing white fibers – Slow motor units: Slowly fatiguing red fibers Figure 9.7a Excitation-Contraction Coupling Muscle Contraction – Alpha motor neurons release ACh – ACh produces large EPSP in muscle fiber – EPSP evokes muscle action potential – Action potential triggers Ca2+ release – Fiber contracts – Ca2+ reuptake – Fiber relaxes Spinal Control of Motor Units Sensory feedback from muscle spindles - stretch receptor Spinal Control of Motor Units The Myotatic Reflex Spinal Control of Motor Units Golgi Tendon Organs – Additional proprioceptive input - acts like strain gauge monitors muscle tension Spinal Control of Motor Units Golgi Tendon Organs – Spindles in parallel with fibers; Golgi tendon organs in series with fibers Spinal Control of Motor Units Excitatory Input – Crossed-extensor reflex: Activation of extensor muscles and inhibition of flexors on opposite side Information gleaned about nicotinic ACh receptors utilzed the electric organs of electric eels because of their high concentration of the Ach receptor. The Disease Myasthenia gravis is an autoimmune disease where the body's immune system has damaged receptors on your muscles causing long term weakness and eventual, premature death. Individual showing classic, early signs of Myasthenia gravis END. Biology 463 - Neurobiology Topic 15 Brain Control of Movement Lange George Huntington James Parkinson The Cerebellum Function: Sequence of muscle contractions Cerebellar lesions • Ataxia: Uncoordinated and inaccurate movements • Dysynergia: Decomposition of synergistic multijoint movements • Dysmetria: Overshoot or undershoot target The Planning of Movement by the Cerebral Cortex Motor Cortex – Area 4 and area 6 of the frontal lobe END.