Term Test 2 Review Questions Flashcards
Describe the role of the prefrontal cortex, premotor cortex, and primary cortex (M1) in movement
Prefrontal cortex - planning
Premotor cortex - sequence organization
Primary cortex (M1) - movement production
Discuss the organization of the primary motor cortex
Located anterior to central gyrus in the frontal lobe. M1 is organized somatotopically - different regions of the cortex are responsible for controlling different parts of the body
What are mirror neurons and why might they be important?
- Mirror neurons are neurons found in primates that respond to both the thought of a motion and performing the motions itself
- Found in several areas, including the premotor cortex and inferior parietal lobe
- Thought to play a role in motor skills, speech and social interaction
Describe the process of mental rehearsing/visualizing a motor action
- When visualizing a motor action similar parts of the brain are activated when planning movement
- May help improve performance in athletes
Explain post-stroke cortical plasticity. Explain how rehabilitation (e.g. via constraint-induced motor therapy) interacts with this plasticity
- After stroke brain undergoes process of cortical plasticity to adapt to damage caused by stroke. This involves rewiring neural connections to adapt to injury
- CIMT is a type of rehabilitation that is designed to promote the use of the affected limb and encourage the brain to rewire itself to control movement
- Done through restricting use of unaffected limb and forcing the use of the affected limb through extensive training
- Loss of sensory function, does not always result in complete loss of motor function
Identify the major motor pathways in the spinal cord
Dorsolateral Column of the SC:
- Lateral corticospinal pathway
- Rubrospinal pathway
Ventromedial Column of the SC:
- Anterior corticospinal pathway
- Vestibulospinal - balance + head-turning
- Reticulospinal - locomotion and posture
- Tectospinal - orientation to stimuli, head/neck/eye movements
Discuss the major cranial nerves and spinal nerves highlighted in class
Cranial Nerves (12) - Facial nerve (VII) + Bell’s Palsy
Spinal Nerves (31):
Cervical (C1-C8)
Thoracic (T1-T12)
Lumbar (L1-L5)
Sacral (S1-S5)
Coccygeal (1)
Discuss Bell’s Palsy and its treatment
- The facial nerve (VII) travels through a ‘tight tunnel’ (bone)
- Inflammation of the nerve can lead to it being compressed against the tunnel
- Compression impairs motor function in the face
- Most patients. recover on their own
- In severe cases corticosteroids might be recommended
- Surgery to improve passage pf nerve is possible
- Physical therapy or plastic surgery
Discuss the role of the basal ganglia in movement. Give the indirect and direct pathways. Describe the role of dopamine and dopamine receptors in these pathways.
- Involved in coordinating movement
- The direct pathway through the BG is thought to play an important role in initiating movements
- The indirect pathway through the BG is thought to play a role in inhibiting unwanted movements
- Inhibitory actions of DA are mediated by D2 receptors whereas excitatory actions are mediated by D1 receptors
Discuss Parkinson’s Disease and its treatment via different methods
- Loss of DA-projecting neurons is the defining feature of PD
- PD is a progressive disorder of the NS that affects movement
- Develops gradually, advancing over time
- PD symptoms include: cogwheel rigidity, bradykinesia, postural instability
- Potential treatment options include administering L-DOPA, MAO-B, COMT
- DBS: electrodes can be planted in the subthalamic nucleus or globus pallidus to modulate activity of these structures
Where in these pathways might the effects of deep brain stimulation (DBS) be important?
The subthalamic nucleus and globus pallidus
Give the five main stages of prenatal neurodevelopment covered in class. Describe their key features. Be able to explain each stage in three to four sentences, if asked
- Induction of neural plate
- Neuronal Proliferation
- Neuronal migration + aggregation
- Axonal growth + synapse formation
- Neuronal death + synapse elimination
Describe different theories of axonal development. How are they similar? How are they different?
Chemoaffinity Hypothesis:
Cell A releases Chem. X:
- Axon B is sensitive to Chem. X but Axon C is not
- Axon B grows towards Cell A, but Axon C does not
- Signalling is not simply point-to-point
Topographic gradient hypothesis:
Cell A releases Chem. X:
- Axon B and C are both responsive to Chem. X
- Axon B is exposed more to Chem. X
- Axon B grows toward Cell A but Axon C does not
Are cell death and synaptic elimination a “bad thing” for development?
No, cell death is normal. Many neurons are lost during development. The neurons that survive you keep for a long time. Many motor neurons in the spinal cord die.
Discuss the importance of neurotrophins for neurodevelopment
Neurotrophins are cell survival signals. There is a limited amount of NTs released, leading to competition among terminals. Different kinds include:
NGF - Nerve growth factor
BDNF - brain-derived neurotrophic growth factor
NT-3 + NT-4
Differentiate apoptosis and necrosis
Apoptosis -
‘programmed cell death’: cell’s contents are packaged for convenient disposal, less inflammation
Necrosis -
Cells break apart and spill their contents, more risk for inflammation
Identify the important role that glial cells play in development
Microglia play a role in mitigating inflammation and ‘cleaning up’ cell death mess
Describe how synaptic pruning is related to age-dependent changes in behaviour
Process by which brain eliminates unwanted or not useful connections to optimize brain function. A lot during early development and then less as we get older. Can be useful to improve cognitive tasks and problem-solving. Could also be detrimental as we age (decrease in memory performance)
Discuss the phenomenon of neurogenesis. What is it? Why is there a controversy surrounding it? What is so special about adult-born neurons?
Neurogenesis is the generation of new neurons. Controversy consists of early studies showing that adult neurogenesis was constricted to certain regions, however recent studies have showed that adult neurogenesis can contribute to brain function. Significant because it challenges the view that the brain is fixed and unchangeable.
Discuss the idea of critical and sensitive developmental periods, providing examples of each when relevant
Critical period: time interval where an experience MUST occur for proper development (e.g. vision)
Sensitive period: time interval where an experience has a relatively greater effect on development (e.g. learning to play an instrument)
Discuss neurodevelopmental disorders by reviewing their symptoms, neural features, of each when relevant
Schizophrenia:
- Cortical atrophy/gray matter loss
- Abnormal cell organization
- hypofrontality
- Alterations in DA transmission
Causes:
- Genetic + environmental
- DISC-1 gene
ASD:
- Social interaction and fixated interests, slow language development
- Synaptic pruning lower in adulthood
ADHD:
- Inattention symptoms
- Hyperactivity symptoms
- Reduced cerebral volume as well as PFC, BG, dACC + cerebellum volume
- Delay in cortical maturation
- Lower white matter volumes
Why are neurodevelopmental disorders frequently co-morbid?
Due to similarities in genetic factors or environmental factors. ‘Hits’ interact for NDD risk.
