NSCI 110 1st Edition Lecture 19Outline of Last Lecture I. Excessive amounts of glutamate overstimulates a neuron and may lead to excitotoxicitya. Increased and prolonged depolarization of membrane results in apoptosisb. Excess of cytochrome c released by mitochondriaII. There is an initial period of biological recovery followed by more psychological responsesa. Premorbid state followed by glial cell assistanceb. Eventually learning and compensatory mechanisms take overIII. There are numerous cellular mechanisms that follow the recovery perioda. Astrocytic aid involved in nerve growth factors and restoration of nutrientsb. Denervation hypersensitivityc. Synaptogenesisd. Cortical reorganizationIV. Through neuropsychological assessment the extent of brain and cognitive damage may be assesseda. Cognitive statusb. Behavioral compensationOutline of Current Lecture I. There are a variety of ways to assess degrees of wakefulnessa. Glasgow coma scale measures eye opening, motor response, verbal responseb. A person in a vegetative state may exhibit signs of wakefulness without awarenessi. Persistent vegetative stateII. Our perceptions of the visual world are based on environment, internal state, and experienceIII. Anatomy of the human eye allows photons of light to be converted into action potentialsa. Optic disk is our “blind spot”b. Light is bent when traveling from the air to the aqueous environment in the eyeCurrentLecture- Assessing levels of awareness after waking up from an unconscious stateo Glasgow coma scale measures difference indexes of wakefulness Eye opening, motor responses, verbal responses Scale from 3-15 points (E+M+V)o Vegetative state  “wakefulness without awareness”These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Long periods of wakefulness not necessarily correlated to rhythms (circadian) Eyes rove and may appear to track briefly- Sudden sounds or light may elicit orienting by the colliculi (but stillnot conscious awareness by the hypothalamus) Limbs spastic, show withdrawal to pain, grasping reflex Facial grimacing or perhaps groaning to pain Gag reflexes, chewing motions but not adequate enough for nutrition by spoon-feeding Careful observations fail to detect consistent responses indicating conscious awareness- Meaningful emotional responses are not elicited by appropriate stimuli or related to any external stimuli - No learned or consistently meaningful responses and no mimicry If this condition is for more than a month, it is said to be in a persistent vegetative stateVISION: PART ONE  SEEING FORM AND COLOR- Perception of the visual world is dependent on context, our environmental conditions, and cultureo Experience and internal state (aroused, angry, ect.) also influence visual perceptiono Not based on reality because the brain processes stimuli differently- Basic anatomy of the human eyeo Pupil Shape is dependent upon species’ evolutionary history (animals who huntin plains have more elongated/lateral pupils)o Conjuctiva Layer that is close to blood vessels Conjunctivitis (pink eye)o Extraocular muscles are controlled by cranial nerves III, IV, and VI Control movements of the eyeo Sclera  White of the eyeo Iris Muscle that regulates how much light enters the eye (regulates the size ofthe pupil) Has a texture that differs directly around the pupil vs. more distantly surrounding the pupil Color influences how much light is absorbed and reflected- People who live in lots of sunlight tend to have darker colored irises - Review functional groupings of the cranial nerves!!!o Extrinsic eye muscles allow voluntary control of gaze (CN III, IV, VI)o Intrinsic eye muscles exhibit parasympathetic and sympathetic activity CN III has parasympathetic nerve fibers that contact the circular sphincter muscle of the iris Sympathetic fibers originate in the thoracic portion of the spinal cord and contact radial muscles of the iris to cause pupil dilation- Dorsal view of the right eye (looking from the top down)o Optic nerve travels medially and meets the other optic nerve at the optic chiasm o Macula lutea is the ~6mm spot with high acuity vision Contains the fovea (no rods, almost all cones  highest visual acuity)o Optic disk is the point of exit for ganglion cell axons that make up the optic nerve No rods or cones (no visual perception here, responsible for blind spot)o Light is bent most by the fact that it is travelling from air to an aqueous substanceo Blood vessels may observed through the pupil Eye tissue comes from the brain embryologically In diabetes these blood vessels are damaged, areas of the eye are degenerated and vision is