Neural Communication & Sensory Perception: Examining Neurons, Glial Cells, Myelin - Prof. , Study notes of Psychology

Download Neural Communication & Sensory Perception: Examining Neurons, Glial Cells, Myelin - Prof. and more Study notes Psychology in PDF only on Docsity! I. Neural Communication a. Neuron: nerve cells (100 billion connects with +10-100 thousand) b. Glial cells: support, myelin, waste-clearing i. More glial than neuron and ratio of glial to neuron dictates biological complexity ii. Resting potential: -70 MV inside axon c. Myelin Sheath: fatty tissue encasing axon d. Node of Ranvier: space between myelin sheath -> creates high sodium levels i. Ion pumps located in nodes e. Action potentials: limited in how fast things can go i. Refractory period: 1-2 milliseconds ii. All or None transmission iii. Action potential comes down, signals to vesicles to make way to edge of neuron 1. They then fuse w/ plasma membrane 2. Neurotransmitter: released to synaptic cleft 3. Hook up to receivers 4. Neurotransmitters determine speed of response b/c depends on # of synaptic gaps f. Neurotransmitters i. NT binds to receptor ii. Ion channels open iii. EPSP (excitatory postsynaptic potential) 1. Dopamine [+ions into cell] iv. IPSP (inhibitory postsynaptic potential) 1. Gabba [- ions into cell, +ions out of cell] a. Potential: message b. Opens another ion channel c. If it meets a threshold? i. Fire another AP! v. Adding of EPSPs and IPSPs: summation 1. Temporal summation: must be close in time 2. Spatial summation: must be close in area a. Resting: -70 II. Sensation and Perception a. Sensation: intake of raw info into brain (low level) b. Perception: organization and interpretation of sensory input (high level) i. Stimulus energy -> sensory receptors -> neural impulses -> brain ii. Sensation --------------------------------- perception-------------| c. Direct Realism (aka naïve realism) i. 1 to 1 relationship between physical and mental words: FALSE ii. After image: formed after focusing on image, makes you see weirdly colored pic iii. Physically diff things must be perceived as different: FALSE 1. Metamerism: matching of apparent color given diff physical characteristics iv. Physically identical things must be perceived as identical: FALSE 1. Chromatic induction: in a given context d. We perceive the world indirectly i. Filtered through sensory systems and info is tweaked e. Bottom-up processing i. Processing based on environmental stimuli 1. To build up from lower level stim to make object; not just raw characteristics f. Top-down processing i. Processing based on existing knowledge, expectations, ect. ii. Needs context III. Vision a. Eyes: primary purpose i. Direct light to form image on back of eye ii. Transform physical energy to neural energy => transduction b. Eye function i. Lens was developed over hundreds of generations ii. In time lens redirected more light to retina c. Eye spot: i. Primitive ii. Crude sensation of light d. Pinhole eyes (possibly evolved from lightspot) i. Adjustable aperture e. Lensed eyes i. Better refraction ii. Better image formation iii. Crystalline lens 1. Accommodation: adjustable focus IV. The human eye a. Cornea: transparent outer layer b. Pupil: regulates amt. of light entering eye i. Expand when see something we like or ‘catches our eyes’ ii. Expand when exposed to stimuli that were previously seen c. Retina: a. Cornea has one of highest concentrations of nocioreceptors 3. Nerve endings a. A-Nerve endings: sharp pain i. Faster b. C-Nerve endings: dull pain i. Slower 4. Fun fact: anesthesia works because it stops nocioreceptors from firing d. Tactile Activity: 2-point threshold i. Minimum distance between 2 points required to feel 2 points of pressure versus 1 point ii. Low threshold = high acuity 1. Small receptive field e. Somatosensory Cortex i. Touch center of cortex ii. Parietal lobe: map of whole body iii. Phantom Limb Syndrome 1. Phantom limbs hurt! a. Axons which used to reach end of limb end still fire b. Mirror therapy- i. Put mirror against existing limb and see how phantom limb would move iv. Haptic Tech: touch system that interfaces a machine w/ human 1. Video games w/ rumble pack Chemical Senses I. Chemical Senses? a. Type of stimulus determines sense type i. Vision -> light ii. Hearing -> vibration iii. Touch -> pressure 1. All energy 2. Smell and taste stimuli come from matter/chemicals b. Function: gatekeeping between our inner body and environment i. Brings in nutrients, keeps out toxins ii. Super tasters taste things at extreme level, so some foods are really bitter and gross to them 1. But some food is still bitter and good for you iii. Proximity to: 1. Olfaction (smell): distance 2. Gustation (taste): close/touching you II. Olfaction a. Stimuli: odorant i. Can be picked up by olfactic system, look like others but different ii. Olfactory Receptor Neuron (ORN) 1. Transduce smell 2. Location: olfactory mucus a. Amount: 40 million b. Types: 500-1000 c. Number of detectable odors: ~10,000 i. Uses combos of types to interpret smell iii. Olfactory bulb 1. Glomeruli: globes that house axons which contribute to transmission a. ORN -> mital cell synapses 2. Neutrogenesis! 3. a. When ORN die off, new neurons are produced and replace ORN 4. Links to piniform cortex, amygdala, and hippocampus iv. Smell and Memory 1. Proust Effect? a. Proust: writer who said a vivid memory was triggered by scent i. “autobiographical memory” 1. Sense of smell can more easily enhance recall of autobiographical memory b/c scent has straight shot to hippocampus ii. Studies found that visual cues led to teenage memories, smell cues to childhood memories b. Alzheimer’s: use scent to try to determine if one will develop Alzheimer’s i. An individual is asked to distinguish between smells 1. They do poorly w/out realizing they are doing poorly -> increased chance for Alzheimer’s 2. Anosmia a. Loss of odor perception i. Can be specific but generally applies to everything b. Causes: i. Congenital, infection, nerve damage c. Won’t be able to taste food as much 3. Conditioned Taste Aversion a. Discovered by John Garcia i. Radioactivity w/ rats 1. US- unconditioned stimulus 4. Primary evolutionary function of smell has to do with regulating nutrition III. Auditory Perception a. Sound: mechanical disturbance from state of equilibrium that propagates through an elastic medium i. Cannot ravel w/out material medium 1. No sound in vacuum 2. Sound is vibration that causes disturbance in medium and travels at some speed a. Air: 343 m/s b. Water: 1,500 m/s c. Solid: 5,930 m/s ii. Physical dimensions: 1. Amplitude: mag. of displacement of sound pressure wave (measured in decibels) 2. Period/cycle: time for one cycle to occur 3. Frequency: # of cycles per unit time a. Cycles per second: Hertz iii. Pure tone: rare in nature, sound w/ energy @ single frequency iv. Complex tone: sound with energy @multiple frequencies Illness (US) Nausea (UR) Food (CS) Nausea (CR)