Slide 1Main Types of ReceptorsAdaptation and ReceptorsLevels of Sensory ProcessingReceptor Fields in Cerebral CortexSomatosensory CortexAttentionDorsal Column SystemDermatomesPlasticity in Cortical MapsNociceptorsPain/Temperature ReceptorsCNS Pathways and PainHearing (Ear and its Parts)External EarMiddle EarInner EarAuditory System PathwaysTheories of Discriminating PitchDeafnessVestibular systemTasteTaste Information to BrainSmellLet’s Talk BiologyVision…aka “Oh fuck”Visual Processing…its 3:40 am…why do I care?Chemical ReactionVisual Acuity and the Fovea…WhoopWhere Signals Travel in the Brain…aka “the Hard Part”Receptive Fields in Visual System…WHY AM I AWAKE?!Hypotheses for Color VisionCortical Visual AreasSlide 34Control Mechanisms (Engineering…WTF?)Skeleton and MovementNMJProprioception and Muscle SpindlesMotor cortexesAreas of Brain + Movement =Basically all questions on exam…Parkinson’s DiseaseHuntington’s DiseaseCerebellum. Again.Psych 210Review for Exam Number 2Main Types of ReceptorsMerkel’s disc: touchMeissner’s corpuscle: touchPacinian corpuscle: vibrationRuffini’s ending: stretchFree nerve ending: pain/temperatureAdaptation and ReceptorsTonic receptors: little or no decrease in the frequency of action potentials as stimulation is maintainedPhasic receptors: display adaptation, rapidly decreasing the frequency of action potentials when the stimulus is maintainedLevels of Sensory ProcessingSpinal cord -> Brainstem ->Midbrain/Thalamus->Primary sensory cortical areas -> <- Nonprimary sensory cortical areasTrue for all sensory systems except for smellReceptor Fields in Cerebral CortexPrimary sensory cortex: for a given sensory modality (ex: vision, somatosensory, etc), the region of cortex that receives most of the info about that modality from the thalamusSecondary sensory cortex (nonprimary sensory cortex): the cortical regions receiving direct projections from primary sensory cortex for that modalityInformation is sent back and forth between these cortexes through subcortical loopsSomatosensory CortexPrimary somatosensory cortex (S1): receives touch information from opposite side of the body Secondary somatosensory cortex (S2): maps both sides of the body in registered overlayThe more sensitive the organ is to touch, the larger the portion of the somatosensory cortex is devoted to respond to itAttention**Some “visual” cells also respond to auditory or touch stimuli**-association areasPolymodal cells: several sensory modalitiesFrontal eye field: attentive visual exploration of spaceCingulate gyrus/cortex: motivational aspects of attentionPosterior parietal lobe: responsive in expecting the appearance of a stimulus (auditory or visual)Lesions in this region lead to inattention on the opposite sideDorsal Column SystemA somatosensory system that delivers most touch stimuli via the dorsal columns of spinal white matter to the brain (dorsal column nuclei in the medulla)DermatomesStrip of skin innervated by a particular spinal nerveBased on quadrupedal postureCervical=face, arms, and handsThoracic=chest, absLumbar=lower back, top of legs, top of feetSacral=butt, back of legs, bottom of feetPlasticity in Cortical MapsCortical maps change with experienceExpanded cortical representations for areas that are stimulated more often Changes may arise from production of new synapses and dendrites or loss of othersNociceptorsNociceptor: a receptor that responds to stimuli that produce tissue damage or pose the threat of damage (sense pain)Free nerve ending: axon that ends in the skin w/o any specialized cell associated with it and that detects pain and/or changes in temperaturePain/Temperature ReceptorsTRPV1: receptor that binds capsaicin to transmit burning sensation from chili peppers (normally detects sudden increase in temperature)TRPV2: detects even higher temps than TRPV1 (doesn’t respond to capsaicin) and are found on larger nerve fibersA fiber: large, myelinated axon that transmits pain info very quickly and adapts quickly (TRPV2)C fiber: small, unmyelinated axon that conducts pain info slowly and adapts slowly (TRPV1)CMR1: opens an ion channel in response to a mild temperature drop (exposure to menthol) (found on C fibers)GRP: stimulate neurons in dorsal horn to provide sensation of itch**Na+ channel relates to pain??**CNS Pathways and PainCingulate cortex: located in medial cerebral cortex, activated when experiencing painNeuropathic pain: pain caused by damage to peripheral nerves (difficult to treat) EX: phantom limb painGlutamate: most common excitatory transmitterAnterolateral/spinothalamic system: system that carries most of the pain info from body to brainPain info crosses midline in spinal cord before ascending to the brain **sensory info from one side of the body ends up in the opposite side of the brain**Hearing (Ear and its Parts)Inner ear: contains cochlea and vestibular apparatusExternal ear (pinna): the part of the ear that we readily see, including the ear canalMiddle ear: cavity between tympanic membrane and cochleaOssicles: 3 small bones (incus, malleus, stapes) that transmit sound across middle ear from tympanic membrane to the oval windowTympanic membrane->malleus->incus->stapes->oval windowExternal EarPinna modifies character of sound that reaches middle earHelps identify the direction and distance of the source of a soundCaptures, focuses, and filters soundMiddle EarTympanic membrane: also called eardrumOssicles focus the pressures from the tympanic membrane onto the smaller oval window; amplify sound pressure to produce movement in fluid of inner earTwo muscles that protect inner ear; stiffen the linkages of middle ear bones, reducing effectiveness of sounds (help us ignore self-made sounds)Tensor tympani: attached to malleusStapedius: attached to stapesInner EarCochlea: coiled, fluid-filled structure that is embedded in the temporal bone of the skullThe cochlea is a coil of three parallel canals all filled with non-compressible fluidScala vestibuli (vestibular canal)Scala media (middle canal)Scala tympani (tympanic canal)Round window: separates cochlea (scala tympani) from middle earOrgan of Corti: components that convert sounds into neural activityHair cells (stereocilia)Supporting cellsTerminations of
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