38464204
| Question | Answer |
| what is the function of the cerebellum in motor control | control muscle tone and coordination in both conscious and unconscious movement |
| what is the function of the basal ganglia in motor contrl | integration of sensory and motor info to aid with voluntary movement |
| what disorders are associated with basal ganglia and motor dysfunction | parkinsons and huntingtons disease |
| do the cerebellum and basal ganglia cause muscle contraction? | no they alter other pathways to help coordinate movement |
| explain the cerebellum's role in coordinating muscle movement | recives info about ongoing movement and makes any corrections needed to ensure movement is carried out properly |
| how is the cerebellum involved in motor learning | learns patterns of movement so that they can be repeated or copied e.g writing your name in a much larger font size than you normally do |
| what are the 3 anatomical components of the cerebellum | - spino-cerebellum - cerebro-cerebellum - vestibulo-cerebellum |
| what is the function of the spino-cerebellum | regulates axial muscle and posture |
| what is the function of the vestibulo cerebellum | controls balance and eye movement |
| what is the function of teh cerebrocerebellum | compares intended movements with actual ones and sends compensatory intrsuctions |
| where does the cerebrocerebellum send correctory impulses to | the primary motor cortex so that it can alter movement |
| what is the main output cell from the cerebellum | the purkinjee cell |
| what type of signals are sent by the purkinje cell to the cerebelar nucei | inhibitory impulses |
| give 2 other cells which come from the cerebellum and enter the deep cerebellaer nuceli | mossy fibres and climbing fibres |
| what does the DCN do with signals from the climbing and mossy fibres | compares their inputs |
| what is the purpose of comparing the climbing and mossy fibres at the deeep cerebellar nuclei | compares signals before and after cerebealler processing (comparing expected to reality) |
| how does the rest of the brain aid in cerebellum activity comparison | rest of brain sends the "plan" of what was supposed to happen to the cerebellum |
| what happens if the expected and reality are different | the cerebellum adjusts outputs from the descending motor pathway |
| how does the cerebellum act as a timer | it makes sure that the sequence of motor activation is correct |
| where is the basal ganglia located | below the cortex |
| what is the function of the basal ganglia | intergration of sensory and motor information from the cortex |
| give the pathway of information to and from the basal ganglia | from the cortex to the basal ganglia then back to cortex via the thalamus |
| what is the basal ganglia's role in pre-motor activity | prepares for movement |
| what is the effect of the basal ganglia on the thalamus and what is the effect of the thalamus on the cortex? | basal ganglia is inhibitory to the thalamus thalamus is excitatory to the cortex |
| what needs to happen to the thalamus to initiate movement by the cortex | the inhibition from the basal ganglia needs to be removed |
| give some structures which make up th ebasal ganglia | straiatum GPe STN SNr |
| what is the major excitatory NTM of the brain | glutamate |
| what is teh major inhibitory NTM of the brain | GABA |
| what is the effect of dopamine on the brain | is modulatory |
| is basal outflow excitatory or inhibitory | inhibitory to the thalamus |
| give the flow of activity through the basal ganglia from the cortex to the thalamus | - cortex stimulates striatum which has inhibitory effect either on SNr or on the inhibitor of the STN - the STN excites the SNr - so inputs can either excite or inhibit the inhibitor of thalamus |
| give the direct and indirect pathways through the basal ganglia | - direct goes straight from striatum to SNr and GPi - indirect goes through GPe and STN before hitting SNr and GPi |
| what does the direct and indirect pathways promote | - direct promotes movement by inhibiting the inhibitor of the thalamus - indirect inhibits the thalamus by activating its inhibitor |
| what 2 receptors do dopamine work on | excitatory D1 recepotrs on GPi and SNr inhibitory D2 receptors |
| what is the effect of dopamine on movement | facilitates smooth movement by inhibiting the GPi or the STN depending on inputs |
| how does dopamine activity cause smooth movement | suppresses unwanted movement |
| give a hypokinetic and hyperkinetic disorder associated with the basal ganglia | hypokinetic = parkinsons (despite the shakes) hyperkinetic = huntingtons |
| what causes parkinsons and huntingtons | dysregulation bewteen indirect and direct pathways of the basal ganglia |
| why is parkinsons hypokinetic | the person struggles to initiate movement |
| describe the resting state and the movement of a parkinsons patient | tremor bradykinesia rigidity (harder to initiate minor movements) |
| what is the primary pathology of parkinsosn | loss of dopamine regulation causing increased activity of the STN thus increasing inhibition of the thalamus |
| how would parkinsons be treated | - dopamine replacement drugs such as L-DOPA - dopamine agonists - drugs which reduce Dopamine breakdown |
| why is Parkinsons treatment poor and especially treatment using inhibitory of dopamine breakdown | - doesnt treat the underlying degeneration - inhibitors of breakdown assume there is any dopamine in first place |
| what is L-Dopa and why is it a bit meh | - molecule which is metabolised into dopamine - requires functioning DOPA decarboxynase - dopamine is converted to NAD which increases SYM activity |
| how can surgery be used in parkinsons | surgical lesion of the STN to stop it from exciting the SNr |
| give the symptoms of huntingtons | excessivve and uncontrollable dance like movements caused by rapid motor pattern generation |
| explain why huntingtons is herritable | is autosomal dominant disorder |
| what is the problem in the basal ganglia caused by huntingtons | loss of stimulation of STN causing overactive thalamus activity |
| what is the function of the pre and post central gyrus | pre = primary motor cortex post = sensory cortex |
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