Chapter 17 Summary & Outline

Functional Perspectives on Memory

• The abilities to learn and remember affect all behaviors that are characteristically human. Because every animal species appears capable of some learning and memory, the ability to learn must be required for survival.

There Are Several Kinds of Memory and Learning

• Case studies of individuals with memory impairments have especially implicated hippocampal, diencephalic, and cortical systems in memory formation, storage, and retrieval.
• Declarative memory includes facts (called semantic memory) and autobiographical information (called episodic memory). Nondeclarative memory (procedural memory) is memory for perceptual and motor behaviors—acquired through skill learning, priming, and conditioning—that are demonstrated through performance. Review Figures 17.3 and 17.5, Web Activity 17.1
• Learning includes both nonassociative forms such as habituation, dishabituation, and sensitization; and associative forms such as classical conditioning (Pavlovian conditioning) and instrumental conditioning (operant conditioning). Review Box 17.1

Study questions: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15

Memory Has Temporal Stages: Short, Intermediate, and Long

• Memories are often classified by how long they last. Frequently used classifications include iconic memory, short-term memory (sometimes called working memory), intermediate-term memory, and long-term memory.
• Although the capacity of long-term memory is huge, most of what we experience is not remembered. Attention, reinforcement, and emotional responses help determine what is held in memory beyond the short term.

Study questions: 16 | 17 | 18 | 19 | 20

Successive Processes Capture, Store, and Retrieve Information in the Brain

• Recall of a past event requires three successive memory processes: encoding, consolidation, and retrieval. Review Figures 17.7 and 17.8
• Strong emotion has a powerful effect on the strength of memories. Compounds that block biochemical signals of strong emotion may be useful for blunting unwanted traumatic memory such as that characterizing posttraumatic stress disorder (PTSD). Review Box 17.2

Study questions: 21 | 22 | 23 | 24

Different Brain Regions Process Different Aspects of Memory

• The hippocampal region is required for processing but not for storage of long-term declarative memory. Long-term (permanent) memory is probably stored in the cortex. Specialized hippocampal neurons called place cells, grid cells, and border cells play a crucial role in spatial memory. Review Figures 17.9 and 17.10
• Different forms of working memory rely on diverse brain re-gions, including the hippocampus, caudate, and prefrontal cortex. Review Figures 17.14 and 17.15, Web Activity 17.2
• Encoding, consolidation and retrieval are three crucial aspects of memory; failure of any one of these can produce amnesia.
• Long-term memory has enormous capacity, but it is quite inaccurate. Memories are subject to revision during recall and reconsolidation.

Study questions: 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42

Neural Mechanisms of Memory

• Learning and forming new memories require neural changes in nearly all organisms. The near universality of neuroplasticity indicates its evolutionary importance.

Memory Storage Requires Neuronal Remodeling

• Memory storage has long been hypothesized to involve changes in neural circuits. Research since the 1960s has demonstrated both functional and structural synaptic changes related to learning. Review Figure 17.16
• Training or enriched experience in rats leads to structural changes in the cerebral cortex, including alterations in the number and size of synaptic contacts, and in the branching of dendrites. Review Figure 17.18

Study questions: 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51

Invertebrate Nervous Systems Show Plasticity

• Research on the simple nervous systems of invertebrates provides insights into fundamental properties of plasticity and learning that may be generalized to other species. Review Figure 17.20

Study questions: 52 | 53 | 54 | 55

Synaptic Plasticity Can Be Measured in Simple Hippocampal Circuits

• Long-term potentiation of neural responses is a lasting increase in amplitude of the response of neurons caused by brief high-frequency stimulation of their afferents (tetanus). Review Figure 17.21, Web Activity 17.3
• In mammalian hippocampus, some forms of LTP depend on the activation of NMDA receptors, which induces an increase in the number of postsynaptic AMPA receptors and greater neurotransmitter release. Review Figures 17.22 and 17.23, Web Activity 17.4
• Although not conclusive yet, the evidence indicates that LTP is probably a cellular mechanism of memory. Review Web Activities 17.5–17.10

Study questions: 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68

Some Simple Learning Relies on Circuits in the Mammalian Cerebellum

• Conditioning of the eye-blink response in the rabbit is crucially dependent on the cerebellum. This simple mammalian system provides a model for understanding the formation of associations in the mammalian brain. Review Figure 17.24

Study questions: 69 | 70 | 71 | 72 | 73

In the Adult Brain, Newly Born Neurons May Aid Learning

• Unlike the cortex, the hippocampus remains capable of producing new neurons throughout life. These new neurons may play a role in certain forms of hippocampus-dependent learning. Review Figure 17.25

Study question: 74

Learning and Memory Change as We Age

• Some neurochemical and neuroanatomical measures correlate with specific declines in learning and memory that occur in most elderly subjects. Some biological changes occur only in subjects who show behavioral decline.
• The incidence of memory impairments in old age can be reduced by pharmacological intervention or by adequate early environment and continuing enriched experience.

Study questions: 75 | 76 | 77 | 78 | 79 | 80