Memory plasticity

1. Memory

PLASTICITY
• Plasticity refers to the brain’s ability to
change as a result of experience.
• Plasticity occurs by changing the pattern
of synaptic connectivity between
neurons.
• Although the whole brain may make
contributions to learning and memory,
different regions contribute in different
ways:
1. some regions may be specialized for
learning and remembering words,
2. some regions specialized for learning
and remembering visual objects,
3. some regions may be especially
important for recollecting episodes from
one’s life.

2. Memory

SHORT-TERM AND WORKING
MEMORY
• Short-term memory (STM) is a
memory for information currently
held “in mind” (it has limited
capacity).
• Long-term memory (LTM) refers
to information that is stored; it
need not be presently accessed
or even consciously accessible.
• Long-term store is considered to
have essentially unlimited
capacity within the inherent
confounds of the brain.

3. Memory

SHORT-TERM AND WORKING
MEMORY
The concept of working memory
• Working memory - the ability to
plan and sequence an adaptive
behavior utilizing on-line or
actively stored and processed
information from both the
external and internal
environments.
• Working memory emphasizes a
wider role in cognition
(reasoning, comprehension,
etc.), whereas short-term
memory is often taken to imply a
more passive retention of
material.

4. Memory

SHORT-TERM AND WORKING
MEMORY
The concept of working memory
• The prefrontal cortex is playing a
crucial role in working memory.
• The main storage site of
information is not within the
prefrontal cortex themselves but in
the posterior cortex.
• The function of the prefrontal cortex
is to keep this information active
and/or manipulate the active
information according to current
goals.

5. Memory

DIFFERENT TYPES OF LONG-TERM
MEMORY
• Procedural memory - retention of a
learned skill (mental, perceptual, or
motor) acquired after practice.
• Procedural memory refers to
memory for skills (such as riding a
bike).
• It is not consciously accessible (in
the sense that the contents of the
memory are not amenable to verbal
report)
• The basal ganglia are important for
procedural memory

6. Memory

DIFFERENT TYPES OF LONG-TERM
MEMORY
Semantic memory is conceptually
based knowledge about the world,
including knowledge of people,
places, the meaning of objects and
words (It is culturally shared
knowledge).
Episodic (autobiographical
memory) memory refers to memory
of specific events in one’s own life.

7. Memory

DIFFERENT TYPES OF MEMORY

8. Memory

Brain Systems That Contribute to Encoding, Consolidation and Storage,
and Retrieval
The different processing stages that are involved in memory.
1. Memories have to be created —that is, information must be
encoded into memory.
1. Memories also must be stored, or maintained over time.
2. While they are stored, they may undergo consolidation, or
strengthening.
3. Finally, for a memory to be useful we need to be able to
access it; that is, we need to be able to retrieve it.

9. Memory

Encoding
• Two major brain regions play a role in encoding: the hippocampus and
prefrontal cortex.
• The hippocampal system is activated during encoding of faces, words,
scenes, or objects
• The left hippocampus is more involved for verbal materials, such as
words, whereas the right is more involved for processing of nonverbal
materials, such as faces

10. Memory

Another region of the brain that neuroimaging studies have indicated is
robustly and reliably active at the time of acquisition of information and
encoding in various long-term memory tasks is ventrolateral prefrontal
cortex
Like the hippocampal system, lateralization of activity is observed
depending on the nature of the material being encoded (the left
prefrontal cortex for words, right prefrontal cortex for unfamiliar faces)
Activity is distributed over both left and right prefrontal cortex for
namable objects, which can be coded both verbally and spatially

11. Memory

Dorsolateral prefrontal cortex, which is important for working memory,
may also contribute to encoding.
This region may aid encoding by holding together multiple pieces of
information at the same time, which would then, in turn, enhance their
ability to be bound and associated in long-term memory.
The prefrontal cortex inhibits irrelevant information and encodes
information in such a way that it can later be easily retrieved

12. Memory

Consolidation and Storage
The hippocampus also plays a role in memory consolidation, the
process by which memories are strengthened to allow for long-term
retention.

13. Memory

Retrieval
• As with encoding, both hippocampal and prefrontal regions are involved
in the retrieval of memories.
• In addition, left parietal regions have also been implicated.