Lecture 16 Outline of Last Lecture I. TEST LAST LECTURE Outline of Current Lecture II. Categories of Action III. Different views on how action works IV. In the brain Current Lecture I. Test Last lecture II. Categories of Action a. Reflexes – responding to external stimuli (involuntary b. Rhythmic motor patterns – different from reflex because the movement is generated voluntarily, however the rest of the movement is conducted unconsciously for the most part (is usually repetitive) c. Voluntary movement – coordinated, voluntary d. Movements – a physical act that doesn’t require cognition e. Action – involves cognition i. All levels of the CNS participate in movement/action, and there are three levels of complexity: 1. Spinal cord – reflexes 2. Brain stem – eye and head movements 3. Cortex – regulated coordinated action III. Different views on how action works a. Old view – movements are organized serially in sequence b. Karl Lashley – motor sequences occur too fast for the old view to be true c. Forward models – predict the outcome of planned movements, allows us to adjust action plans as needed (based on practice and feedback) NSCS 200 1st Editiond. “our movements are ballistic” – constant feedback is not necessary e. Degrees of freedom problem – there are an infinite number of ways to solve a problem/task IV. In the brain a. Frontal lobe – i. Homunculus – primary motor cortex is somatopically organized ii. Frontal eye fold – voluntary eye movement iii. Lateral premotor cortex – movement prepared based on external contingencies iv. Medial premotor cortex – internal cues v. Prefrontal cortex – executive movement b. Subcortex i. Basal ganglia – initiating and stopping movement ii. Cerebellum – coordinating precise movements, as well as learning these movements iii. Parkinsons disease – too many inhibitions, not enough excitations (too many indirect pathways, not enough direct pathways in basal ganglia) 1. Leads to akinesia – stopping of movement 2. Can also lead to brodykinesia – slowing of movement iv. Huntingtons disease – excessive movement due to too many excitations (direct pathways) in basal
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