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Basic EEG (‘brainwaves’)
EEG records synchronous firing of pyramidal neurons
in cortex (many combined dipoles). EEG measures
combined activity of ~10 million neurons
Basic EEG (‘brainwaves’)
Limbic association cortex
A set of interconnected brain areas that
fxn in motivation, emotion, and memory
Limbic system
 Involves both cortical and subcortical
regions
 “Feeling and reacting brain” vs. thinking
brain of frontal cortex.
Fear, anger, pleasure and sexual drive
Reward and punishment centers exist
Limbic system: amygdala
Receives signals right from thalamus when
experiencing fearful stimuli (emotional stimuli)
Amygdala is associated with hippocampus,
learning.
Memory
 Short-term memory – stored for a few
minutes and can contain only a few items or
concepts (like a phone number). Items can get
‘bumped’ from STM.
 Long-term memory – lasts years or more –
generally stored in cortex. Includes factual info
about the world, and personal events.
Hippocampus
Short-term memory is converted to longterm memory using signals involving the
hippocampus
Hippocampus is an area where new neurons
can be produced.
How we remember
Newly acquired
information
Usually
permanently lost
Short-term
memory stores
Rapid retrieval
(Practice)
Inability to
retrieve
“Forgetting”
Usually only
transiently unable
to access stores
Consolidation
Long-term
memory stores
“Remembering” Searching and
readout
Slower retrieval, except for
thoroughly ingrained memories,
which are rapidly retrieved
Storage in temporal lobes, limbic system, cerebellum
Alzheimer’s disease
In Alzheimer’s disease, abnormal proteins
cause damage to neurons (amyloid beta, tau)
The hippocampus is the first to be affected
Our brain is not really a ‘swiss
army knife’
Idea that areas of the brain distinctly focus on one
sense has been discarded
There is a lot of ‘cross-talk’ between the senses (i.e.
what you see influences what you hear and so on)
Then
Now
Figure 5.28
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Cervical
cord
Thoracic
cord
Lumbar
cord
Sacral
cord
Cervical
nerves
Thoracic
nerves
Lumbar
nerves
Sacral
nerves
Coccygeal
nerve
Cauda
equina
Dermatome - a patch of skin innervated
by the same spinal nerve
Spinal
cord
Spinal
nerve
Vertebra
Meninges
layers
Nerve- a bundle of
peripheral axons.
Spinal nerves contain
afferent and efferent
fibers.
Spinal nerve
Cell body of
efferent neuron
Cell body of
afferent neuron
From
receptors
To
effectors
Interneuron
Withdrawal reflex
Thermal
pain receptor
in finger
Reflex arc
Receptor
Afferent pathway
Integrating center
Efferent pathway
Effector organs
Ascending pathway
to brain
Afferent
Pathway
Stimulus
Biceps
(flexor)
contracts
Hand
withdrawn
Efferent Pathway
Triceps
(extensor)
relaxes
Effector
organs
Response
Integrating center
(spinal cord)