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CHAPtER 7 MeMory

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Why are some memories so much chemical messengers (neurotrans- more easily. Receiving neurons may grow
stronger than others? F lashbulb mitters). Experience alters the brain’s additional receptor sites. This increased
memories form when we create mental neural networks (see Chapter 3). neural efficiency, called long- term
snapshots of exciting or shocking events, To understand the power of the brain’s potentiation (LTP), enables learning and
such as our first kiss or our whereabouts memory centers, researchers Eric Kandel memory (Lynch, 2002; Whitlock et al., 2006).
when learning of a loved one’s death and James Schwartz (1982) recruited a Several lines of evidence confirm that
(Brown & Kulik, 1977; Muzzulini et al., 2020). seemingly unlikely candidate for this LTP is a physical basis for memory. For
It’s as if the brain commands, “Capture research: the California sea slug. This example, drugs that block LTP interfere
this!” In a 2006 Pew survey, 95 percent of simple animal’s nerve cells are unusu- with learning (Lynch & Staubli, 1991). Drugs
U.S. adults said they could recall exactly ally large, enabling the researchers to that mimic what happens during learn-
where they were or what they were observe how the neurons change during ing increase LTP (Harward et al., 2016). And
doing when they first heard the news learning. Using mild electric shocks, they rats given a drug that enhanced synap-
of the 9/11 terrorist attacks. With time, classically conditioned the sea slugs to tic efficiency (LTP) learned to run a maze
some errors crept in (compared with withdraw their gills when squirted with with half the usual number of mistakes
earlier reports taken right afterward). water, much as we might jump at the (Service, 1994).
Mostly, however, people’s memories of sound of a firecracker. By observing the After LTP has occurred, an electric
9/11 remained consistent over the next slugs’ neural connections before and current passing through the brain won’t
10 years (Hirst et al., 2015). after this conditioning, the researchers erase old memories. Before LTP, how-
pinpointed changes. As a slug learns, it ever, the same current can wipe out
releases more of the neurotransmitter very recent memories. This often hap-
Which do you feel is more important — your
experiences or your memories of them? serotonin into certain neurons. These pens when severely depressed people
cells’ synapses then become more effi- receive electroconvulsive therapy (ECT)
cient at transmitting signals. Experi- (see Chapter 14). Sports concussions can
Dramatic experiences remain clear in ence and learning can increase — even also wipe out recent memories. Football
our memory in part because we rehearse double — the number of synapses, even players and boxers knocked uncon-
them (Hirst & Phelps, 2016). We think about in slugs (Kandel, 2012). No wonder the brain scious typically have no memory of
them and describe them to others. Mem- area that processes spatial memory events just before the blow to the head
ories of personally important expe- grows larger in London taxi driver train- (Yarnell & Lynch, 1970). Their working mem-
riences also endure (Storm & Jobe, 2012; ees, too, as they memorize the names ory had no time to process the informa-
Talarico & Moore, 2012). Compared with non- and layout of 26,000 streets and thou- tion into long- term memory before the
Catholics, devout Catholics recalled bet- sands of popular city locations (Woollett & shutdown.
ter the resignation of Pope Benedict XVI Maguire, 2011). Recently, I [DM] did a little test of
(Curci et al., 2015). Ditto for baseball fans’ As synapses become more efficient, memory consolidation. While on an
memories of their team’s championship so do neural networks. Sending neurons operating table for a basketball- related
games (Breslin & Safer, 2011). When their now release their neurotransmitters tendon repair, I was given a face mask
team won, fans enjoyed recalling and and soon could smell the anesthesia
recounting the victory, leading to longer- gas. “So how much longer will I be
lasting memories. with you?” I asked the anesthesiologist
(knowing that our last seconds before
For an 8-minute examination falling asleep go unremembered). My
of emotion’s effect on memory, see the Video: last moment of memory was her answer:
Enhancing Memory: The Role of Emotion. “About 10 seconds.” My brain spent that
10 seconds consolidating a memory for
her 2-second answer, but could not tuck
SYNAPTIC CHANGES any further memory away before I was

LOQ 7-13 How do changes at out cold.
the synapse level affect our memory FIGURE 7.8 summarizes the brain’s
processing? two- track memory processing and stor-
age system for implicit (automatic) and
As you now think and learn about mem- renata rodrigues Pereira/Shutterstock
ory processes, your flexible brain is
changing. Activity in some brain path- flashbulb memory a clear memory of an
ways is increasing. Neural network emotionally significant moment or event.
connections are forming and strength- Not- so- sluggish synapses The much- studied long- term potentiation (LTP) an
ening. Changes are taking place at your California sea slug, Aplysia, has increased our increase in a nerve cell’s firing potential
synapses — the sites where nerve cells understanding of the neural basis of learning and after brief, rapid stimulation. LTP is a
communicate with one another using memory. neural basis for learning and memory.

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