3. Today’s Lesson
• Explain the role of the reticular activating system in selective attention and
wakefulness; role of the thalamus in directing attention and switching sensory input on
and off
• Understand what you need to do over the mid semester break
Friday, 30 March 2012
5. The reticular activating system
Is a network of neurons extending in many directions from the reticular formation in
the brainstem to different parts of the brain and spinal cord
Functions include:
• Arousal, e.g. regulates by increasing or decreasing
• Alertness, e.g. regulates wakefulness and attention
• Selective attention, e.g. regulates what we choose to attend
to, directs specific cortical areas to focus on relevant
information
Evidence for these functions includes:
• Destroying the RAS causes a coma resembling sleep
• Electrical stimulation of RAS instantly awakens sleeping animals
Friday, 30 March 2012
6. Thalamus
Is a small structure on the top of the brain stem that filters and relays incoming
sensory information (except smell) to relevant cortical areas. Information moves from
cortical areas to lower brain structures, the spinal cord and out to the peripheral
nervous system.
Function:
• Plays a role in attention by actively filtering incoming sensory information, giving
more weight to and emphasising certain information.
• Regulates arousal through connection with the RAs.
• Closes pathways of incoming information during sleep, preventing information
from reaching the brain as it rests
Friday, 30 March 2012
7. 1. Explain the role of the reticular activating system in
humans?
2.Verie Sleapi is lying on the couch watching television. She
is feeling quite relaxed and nodding off. If you were to
examine her reticular activating system, what would you
find.
3. Outline the relationship between the reticular activating
system and the thalamus
Friday, 30 March 2012
8. Answers
1. The RAS regulates levels of attention, sleep and consciousness.
2. There would be a decreased blood flow in the RAS because there is a
lower level of activity by the neurons of the RAS. There would be less
activation of neurons.
3. The RAS controls attention and sleep and the thalamus controls
attention to stimuli. Both relate to attention.
Friday, 30 March 2012
9. The next SAC.... the timeline
First Week Back
First Lesson Back: The practice SAC - Prepare like it
is the real SAC.
Second Lesson Back: Learning from your mistakes
Second Week
SAC - Poster
Start new topic - Memory
Friday, 30 March 2012
10. What to do in the holidays
Create digital resource for the class - see wiki for info
Revise for the SAC
Get ahead with the summaries - Everyone should be at
least 1 week ahead when you get back from holidays
Revise for the exam - Start your exam preparation now.
You should revise everything we have done this term
Friday, 30 March 2012
