brain stem: reticular formation

Question 1

• very heterogeneous in its components
• anatomically it is considered the “core zone” of the brain stem
• it runs from the juncture of the medulla and the spinal cord to the midbrain/diencephalon juncture

Answer 1

core of the brain stem

Question 2

• at this point, all nuclei that are not assigned other functions are considered to be part of the RF
• ex: red nucleus was once though to be a generic part of the RF until its function was discovered
• on a schematic the RF has very unclear boundaries and is diffused

Answer 2

reitcular formation parts

Question 3

• output of the RF is ascending and descending
• not homogeneous
• reticular nucleus does not go to cortex
• small part is activating
• long axons
• large receptive field
• input from spinal cord, cortex, cerebellum, special senses

Answer 3

facts about RF

Question 4

• lateral dendrites carry info from a restricted area
• each info is weighed the same
• sends info to medial zone
• divided into 4 specific functional area

Answer 4

function of the lateral zone

Question 5

what do the 4 functional areas of the lateral zone do?

Answer 5

• 2 areas send ascending info up from spinal cord

- 2 send descending info down from cortex

Question 6

• dendrites are flat and very narrow
• run perpendicular to ascending and descending tracts
• stacked poker chips from medulla to diencephalon

Answer 6

medial zone cells

Question 7

• carry a lot of areas with each area adding info
• each input is weighed differently
• sums at hillock
• the further they have to travel the weaker the impulse, greater possibility of inhibition
• monitoring info from all ascending and descending inputs through the brain stem
• all long dendrites exit RF
• if the input is in the spinal cord then the info ascends towards the cortex
• if the info is at the cortex the the projections will descend toward the spinal cord

Answer 7

function of the medial zone