Understanding Psychology (10th Ed)

 
Module 20 
The Foundations of Memory 
219
spatial memories (see Figure 8; Maguire, Woollett, & Spiers, 2006; Spiers & Maguire, 
2007; Woollett & Maguire, 2009). 
The amygdala , another part of the limbic system, also plays an important role 
in memory. The amygdala is especially involved with memories involving emo-
tion. For example, if you are frightened by a large Doberman, you’re likely to 
remember the event vividly—an outcome related to the functioning of the amyg-
dala. Encountering the Doberman or any large dog in the future is likely to reac-
tivate the amygdala and bring back the unpleasant memory (Hamann, 2001; 
Buchanan & Adolphs, 2004; Talmi et al., 2008).
 Memory at the Level of Neurons.
Although it is clear that the hippocampus and 
amygdala play a central role in memory formation, how is the transformation of 
information into a memory refl ected at the level of neurons? 
One answer is long-term potentiation , which shows that certain neural pathways 
become easily excited while a new response is being learned. At the same time, the 
Neuroscience in Your Life: 
Experience,
Memory, and the Brain
FIGURE 8 
Illustrating how experience can shape how our brain processes memories, these 
fMRI scans show how the number of years spent driving a taxi relates to the size of particular 
areas of the hippocampus as participants become spatial and navigational memory experts. 
In (a) we see areas of the posterior (back) hippocampus that increase in activity (in yellow) 
with the number of years spent driving a taxi. We also see the relationship illustrated 
graphically in the graph to the right of the fi gure. In contrast, in (b) we see areas of the 
anterior (front) hippocampus that show reduced activity (also in yellow) after many years of 
driving a taxi and the relationship portrayed graphically. The changes in the areas activated 
during memory tasks show how practice can shape the brain and how this allows us to 
develop specialized skills such as memory for spatial locations. 
(Source: Maguire et al., 2006.)
Posterior hippocampus (HC)
(a)
Posterior HC grey matter volume
Y
ears experience taxi driving
0
⫺
.1
0.0
.1
10
20
30
Anterior hippocampus (HC)
(b)
Anterior HC grey matter volume
0
⫺
.1
0.0
.1
10
20
30
Y
ears experience taxi driving
feL82795_ch07_206-239.indd Page 219 8/17/10 9:27 PM user-f464
feL82795_ch07_206-239.indd Page 219 8/17/10 9:27 PM user-f464

---

220
number of synapses between neurons increase as the dendrites branch out to receive 
messages. These changes refl ect a process called consolidation , in which memories 
become fi xed and stable in long-term memory. Long-term memories take some time 
to stabilize; this explains why events and other stimuli are not suddenly fi xed in 
memory. Instead, consolidation may continue for days and even years (McGaugh, 
2003; Meeter & Murre, 2004; Kawashima, Izaki, & Grace, 2006). 
Because a stimulus may contain different sensory aspects, visual, auditory, and 
other areas of the brain may be simultaneously processing information about that stim-
ulus. Information storage appears to be linked to the sites where this processing occurs, 
and it is therefore located in the particular areas that initially processed the information 
in terms of its visual, auditory, and other sensory stimuli. For this reason, memory traces 
are distributed throughout the brain. For example, when you recall a beautiful beach 
sunset, your recollection draws on memory stores located in visual areas of the brain 
(the view of the sunset), auditory areas (the sounds of the ocean), and tactile areas (the 
feel of the wind) (Desimone, 1992; Brewer et al., 1998; Squire, Clark, & Bayley, 2004). 
In short, the physical stuff of memory—the engram—is produced by a complex of 
biochemical and neural processes. Scientists are just beginning to understand how the