physiological psychology #3

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open loop movement: located in the basal ganglia, when the end of the movement doesn't need to be defined or calculated. an example of this would be throwing a baseball.
Basal Ganglia: 1) important for selection and inhibition of movements and amplitude: motor cortex excites basal ganglia --> + (excitatory) or - (inhibitory) thalamus 2) works with all regions of motor cortex 3) excites movement pattern
supplementary motor cortex: 1) sequence of movements --> memorize a piano piece 2) intention/free will
Satiety factors: 1) special mechanisms for satiety: a) delay in eating and metabolic restoration b) signals predict the restoration of energy levels --> turn on/off eating and digestive mechanisms 2) Gastric and Duodenal factors: a) distention and pain b) nutrient sensors 3) Pyloric factors: a) CCK released when fats present --> bile released --> helps to digest fats b) CCK released and closes pylorus muscle --> duodenum can only handle small amount of food at a time c) CCK levels are reported to brain via vagus nerve by pylorus --> signal inhibits feeding 4) Liver factors: injections of glucose in hepatic portal vein 5) Insulin: lets brain know if in absorptive phase 6) Leptin
2 types of extrafusal fibers: white fast-twitch fibers and red slow-twitch fibers.
extra information #2: muscles contain both muscle fibers and sensory receptors.
drawing #4: review drawing #4 "mouse and treadmill experiment"
micronutrients: vitamins and minerals.
extra information #1: all subcordical bodies are important for calculations and movements.
georgopolous experiment (1991): 1) Monkeys saw a light in 1 of 8 positions on a table (8 compass points) 2) after a moment, move a handle in direction of light --> different actions for different lights 3) different cortexes activated for different lights/movements 4) rehearsal and planning motor imagery activate motor cortex 5) monkeys trained to begin movement after 1 second delay 6) motor cortex cells showed mental rotation --> coded movement in direction of light specified, then shifted in 90 degrees in mind and executed final movement
Free radicals: can lead to the creation of diseases over time and causes damage to the body --> damage can be repairable over time
movement: this leads to better access to resources such as food, water and mates. movements are based on calculations and the motor equivalency of movement, which requires information input, is very flexible.
Onsets of Parkinson's Disease: 1) usually around age 60 or 70 a) etiology: progressive neurodegeneration b) denervation supersensitivity: symptoms don't manifest until late in progression --> 75-80% of cells killed in substantia nigra before effects seen 2) Early onset a) strong genetic component b) boxers: head injury cases --> injury to substantia nigra c) immediate onset cases: MPTP in heroin users: neurotoxin absorbed by substantia nigra --> kills cells --> catatonic state
ventral corticospinal tract: leg and trunk regions of body
Long-term storage: leftover glucose is stored as fat --> the more fat you store, the larger each fat cell gets --> the larger the fat cells, the more of the hormone leptin is released --> leptin decreases appetite and influences growth and reproductive processes (retirement account)
extra information #4: be able to work through an action and explain how all motor commands are used.
drawing #3: review drawing #3 "location of extrafusal fibers and neuromuscular junctions and how they work"
ingestive behavior: it is very complex. there are three reasons why we eat; energy, growth, body chemistry.
body chemistry: there are vitamins and minerals that your body needs that doesn't exist inside your body, therefore you need to eat to meet the bodies requirements.
energy: it replenishes and restores our body.
motor unit: either fast-twitch or slow-twitch and each fiber receives input from 1 motor neuron
slow-twitch fibers: one of the two extrafusal fibers. red in color, these fibers are aerobic, which means they require oxygen, and are slower, longer lasting contractions.
diabetes mellitus: "A sweet passing through" : 1) decreased insulin production 2) sugar not absorbed into cells or converted into glycogen --> excess sugar excreted 3) increased appetite 4) "starving in the midst of plenty"
drawing #1: review drawing #1 "location of the motor cortex"
growth: while your body grows, you need to eat to repair and regenerate new molecules.
Motor equivalence: movements learned for one set of muscles can be translated easily to another --> movements are very flexible
lateral pathways: 1) rubrospinal tract: arms --> voluntary movements (brain stem and midbrain) 2) Lateral corticospinal tract: hands and fingers --> more skilled
drawing #5: review drawing #5 "physiological controls of hunger".
frequency code/rate and recruitment: contributions to stronger muscle contractions
symptoms of a PD patient on L-Dopa therapy: 1) swaying movements --> hyperkinesia 2) dyskinesia --> bad movement
extra information #3: extrafusal fibers are the locations of neuromuscular junctions
premotor cortex: 1) movement because of arbitrary stimulus --> name said and turn head 2) mirror neurons --> empathy
Therapies for Parkinson's Disease: 1) L-Dopa and other dopamine agonists --> pass blood/brain barrier --> increase dopamine and norepinephrine a) side effects: hyperkinesia or sway b) plastic changes serve to decrease drug's effectiveness over time c) does not treat underlying cause --> loss of neurons 2) Embryonic stem cell therapy 3) Pallidotomy: lesions of globus pallidus internal --> can't inhibit thalamus 4) gene therapy: anti-oxidants reduce free radicals
fast-twitch fibers: one of the two extrafusal fibers. white in color, these fibers are anaerobic, which means they dont require oxygen, and are faster, more powerful contractions.
vilis and howe experiment (1977): 1) lever was pushed by a motor and monkeys had to place lever in same place as it started 2) monkey had to fight against motor to keep lever in same place 3) if cerebellum was temporarily lesioned, had great difficulty --> showed terminal tremors
role of antioxidants: combat free radicals in the body
primary motor cortex: 1) somatotopically organized but loosely organized around coordinated movements. 2) cognitive aspects of movements --> motor cortex is active when people mentally rehearse movements or watch someone else perform task 3) very plastic 4) cells represent goal of movements not muscle --> Kakei experiment
proprioception: "muscle sense" or sense of where muscles are in space
Behavioral compensation for PD patients: 1) arm swing: "behavioral warmup" 2) following behind 3) patterned floor: patients in hospital and walking around 4) stepping over to get something: drop keys on ground --> all used to initiate movement
Short-term storage: glucose from food is absorbed and circulates throughout the body --> insulin levels rise causing: a) decreased hunger b) glucose conversion to glycogen c) glucose access to body cells --> tell brain they have plenty of fuel (Wallet)
Leptin: 1) Hormone --> released by adipose tissue (fat) 2) long term satiety factor 3) growth and reproduction 4) obese mice were injected with this --> produced weight loss
direct pathways = disinhibition: 1) caudate nucleus is excited by motor cortex --> inhibits globus pallidus internal --> excites thalamus to disinhibit action or execute movement with amplitude of movement determined by amount of disinhibition (2 inhibitories = facilitation and disinhibition) 2) substantia nigra input is excitatory: death of SN makes it unlikely a strong movement occurs and unlikely a movement will be selected
drawing #2: review drawing #2 "anatomy of the muscle"
macronutrients: carbohydrates, fats and proteins.
extrafusal fibers: located on the outside of the muscle, these fibers contract.
Medium-term storage: glucose is stored as glycogen in the liver and muscles for use later --> after absorption, insulin levels fall causing: a) increased hunger b) glycogen conversion to glucose c) body cells can't use glucose --> body cells tell the brain they are running out of fuel (checking account)
disynaptic withdrawal reflex: this is an online abort command that comes from the skin.
indirect pathways = increased inhibition: 1) caudate nucleus is excited by motor cortex --> inhibits globus pallidus external --> excites globus pallidus internal --> inhibits thalamus --> no movement is made 2) substantia nigra input is inhibitory: a) helps selecting movements by heightening direct pathway activity and lowering indirect pathway activity b) death of substantia nigra cells increases indirect pathway activity and more movements are inhibited --> less/no control of movement
catabolism: steal protein from other tissues in body to fuel cells (rob a bank)
data from animal studies: 1) Rats a) Experiment 1: overweight lab rats fed 60% of daily intake --> rats ate all 60% at once (full of vitamins and minerals with reduced number of calories) --> rate became hungry later --> these animals lived 50 - 100% longer than controls 2) Caloric restriction diet experiment: a) used already obese rate to determine if already had an effect on health and life expectancy b) rats assigned to 3 groups: low-fat calorie restricted diet, high-fat calorie restricted diet and adlib high-fat diet --> removed group of rats that were not obese c) starting diet had an advantageous effect: rats lived approx. 1/2 year longer with ever-lean calorie restriced diet in large number of rats than normal dieted rats
rhythmic movement: movements that involve central pattern generators such as scratching an itch
prefrontal cortex: 1) planning consequences of movements --> damage leads to showering with clothes on 2) organizes movements holistically
4 types of movement: open loop movement, closed loop movement, rhythmic movement and withdraw reflexes.
central pattern generators: this involves rhythmic commands such as walking and chewing. it can be activated solely by the spinal cord and the sensory and motor neurons, there is no brain invovled.
absorptive phase: phase in which food is present within the gi tract --> 3 things happen: 1) the pancreas releases insulin, by doing this it allows glucose to get into the body cells and it causes the liver, muscles and astrocytes to convert glucose into glycogen 2) it takes the leftover glucose and convert into fats in odipose cells 3) excess glucose is excreted
symptoms of parkinson's diseasse: 1) mask-like appearance or apasia --> no control of facial muscles 2) tremors at any time 3) Bradykinesia --> slower movement or akinesia --> no movement 4) discomfort and malaise 5) failure to initiate movement
kakei experiment (1999): 1) monkeys trained to make upward movement holding a handle fist-down 2) certain cells responded to this movement 3) monkeys trained to make upward movement holding a handle fist-upward 4) same cells were active 5) conclusion: neurons represent goal of movement not muscle --> encode the goal of the movement not the muscles used to execute the movement
lateral corticospinal tract: arms and hands
ventral pathways: 1) ventral corticospinal tract: trunk balance --> primary motor cortex 2) vestibulospinal tract: vestibular nuclei --> balance system 3) reticulospinal tract: reticular formation --> locomotion 4) tectospinal tract: superior colliculus --> eyes
Social factors: 1) animals are programmed to overeat: a) fat storage b) food is environmentally-regulated c) amount you eat and portion size 2) Taste: a) contains vitamins and minerals (taste better) b) sweet and oily textures --> high in fats --> signal high energy 3) amount you eat is correlated with number of people present: more people --> eat more (longer time and higher price)
intrafusal fibers: located on the inner part of the muscle, these fibers are the sensory fibers.
cerebellum: 1) damage to this leads to terminal tremors or tremors that occur at the end of closed loop movments and it also leads to decomposition of movement 2) control of feedforward --> anticipation of feeling while performing action
monosynaptic reflex: also known as the stretch reflex, a example of this is the patellar reflex or commonly known as the hammer and knee reaction.
closed loop movement: located in the cerebellum, when the end of the movement is very important and is based on calculations. an example of this would be grasping a object.
fasting phase: phase in which food is absent within the gi tract --> 2 things happen: 1) the pancreas secretes glucagon because glucose isn't present --> tells the liver, muscles and astrocytes to convert glycogen into glucose 2) hunger sets in and the metabolism in body cells decreases
functions of insulin: 1) allows body cells to make use of blood glucose 2) tells liver to convert glucose to glycogen
Yes: Can motor neurons innervate several different extrafusal fibers?
withdrawal reflexes: automatic abort command, when you touch a hot surface with low level spinal cord circuits
innervation ratio: motor neuron vs. number of muscle fibers innervated. example would be 1:3 for finger tips and eye muscles and 1:300 for thighs and back.
3 parts of motor cortex: supplementary motor cortex, premotor cortex and prefrontal cortex. review each part.

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