Download phys Learning Objectives Chapter 57 [10-31

Jimmy Kimber
LECOM – Seton Hill OMS1
Physiology Chapter 57: Cerebral Cortex, Intellectual Functions of the Brain, Learning and Memory
Learning Objectives
1. Describe the 3 types of neurons in the cortex
Granular Neurons (stellate):
- Short axons
- Function as interneurons that transmit over short distances
- Some excitatory – glutmate, some inhibitory – GABA
- High concentrations in sensory areas of cortex, and association areas
Pyramidal and Fusiform Neurons:
- Give rise to almost all output fibers from the cortex
- Pyramidal are larger and more numerous
- Pyramidal are the source of long, large nerve fibers that go to the spinal cord
2. Briefly summarize the function of each layer
Layer IV – most of the incoming specific sensory signals
Layer V – very large fibers to the brain stem and cord
Layer VI – fibers to the thalamus
Layers I, II, III – most of the intra-cortical association functions
3. What is the thalamocortical system? What are its implications regarding the relationship
between its components
The thalamocortical system is the thalamus and cortex together. The cortex operates in close
association with the thalamus and can almost be considered both anatomically and functionally
a unit with the thalamus.
Relationship: When the thalamus is damaged along with the cortex, the loss of cerebral function
is far greater than when the cortex alone is damaged because thalamic excitation is necessary
for almost all cortical activity.
4. Know the locations of the major association areas (Figure 57-4)
Jimmy Kimber
LECOM – Seton Hill OMS1
5. What is the function of primary/secondary motor, sensory areas?
Primary Sensory Areas: detect specific sensations – visual, auditory, or somatic – transmitted
directly to the brain from the peripheral sensory organs
Secondary Areas: located within a few centimeters of the primary areas, begin to analyze the
meanings of the specific sensory signals such as – interpretation of shape/texture of an object,
interpretation of color, light intensity, directions of lines and angles, and interpretations of the
meanings of sound tones and sequence of tones in the auditory signals.
6. What are association areas? List the 3 most important
Association Areas: large areas of the cerebral cortex that do not fit into the rigid categories of
primary and secondary motor and sensory areas. These receive and analyze signals
simultaneously from multiple regions of both motor and sensory cortices as well as subcortical
structures.
Most Important: parieto-occipitotemporal, prefrontal, limbic association areas
7. Where is the parieto-occipitotemporal association area? Describe its functional subunits
Location: in the large parietal and occipital cortical space bounded by the somatosensory cortex
anteriorly, visual cortex posteriorly, and the auditory cortex laterally
Subunits:
- Analysis for Spatial Coordinates of the Body: area receives visual sensory information for
posterior occipital cortex and simultaneous somatosensory information from the anterior
parietal cortex. From this information, it computes coordinates of visual, auditory, and body
surroundings
- Area for Language Comprehension: Wernicke’s area – behind the primary auditory cortex in
the posterior part of the superior gyrus of the temporal lobe.
- Reading - Area for Initial Processing of Visual Language: visual association area that feeds
visual information conveyed by words read from a book into Wernicke’s area – angular
gyrus area
- Area for naming objects: In the most lateral portions of the anterior occipital lobe and
posterior temporal lobe; names are learned through auditory input whereas physical
natures are learned through visual input
8. Differentiate between Wernicke’s and Broca’s areas
Wernicke’s Area: major area for language comprehension, located behind the primary auditory
cortex in the superior gyrus of the temporal lobe
Broca’s Area: provides neural circuitry for word formation; plans and motor patterns for
expressing individual words or short phrases are initiated and executed here.
9. What is the function of the prefrontal association area?
-
Works with motor cortex to plan complex patterns and sequences
Essential to carrying out “thought” processes
Elaboration of thoughts – stores working memories
Jimmy Kimber
LECOM – Seton Hill OMS1
10. Where is the limbic association area and what is its role?
Location: anterior pole of the temporal lobe, ventral portion of frontal lobe, and in cingulate
gyrus (deep in the longitudinal fissure)
Function: behavior, emotions, motivation
11. What is prosophenosia? What causes it?
Prosophenosia – inability to recognize faces
Cause: extensive damage on the medial undersides of both occipital lobes and along the
medioventral surfaces of the temporal lobes
12. What is the importance of Wernicke’s Area? How is it related to handedness?
Wernicke’s Area is the area of confluence of the different sensory interpretive areas: somatic,
visual, and auditory – that meet in the posterior part of the superior temporal lobe. It is
especially highly developed in the dominant side of the brain. This is the left side in almost all
right-handed people.
It is important in interpreting complicated meanings of different patterns of sensory
experiences.
13. What is the angular gyrus? Why does its destruction cause dyslexia?
Angular Gyrus – most inferior part of the posterior parietal lobe, lying immediately behind
Wernicke’s Area. It fuses with the temporal lobe.
Destruction of the Angular Gyrus with retention of Wernicke’s Area causes dyslexia because the
person will still be able to interpret auditory experiences, but the stream of visual experiences
passing into Wernicke’s area will be blocked.
14. Explain the concept of the dominant hemisphere and its reason for developing:
Dominant Hemisphere - Speech and motor control areas are usually much more highly
developed in one cerebral hemisphere than in the other.
Cause: when we are born, the left posterior temporal lobe is slightly larger than the right. So,
the mind directs thoughts to this region. Because of this, it is used to a greater extent than the
right and begins to develop at a greater rate.
15. What is the importance of the corpus callosum?
The corpus callosum provide fiber pathways for communication between the two hemispheres.
This is important because both hemispheres receive and send sensory information.
16. How does our interpretation of language change as we learn to read?
Our introduction to language is by way of hearing. This is interpreted by Wernicke’s area with
the primary and secondary hearing areas of the temporal lobe. When we begin to read, visual
Jimmy Kimber
LECOM – Seton Hill OMS1
information conveyed by written words is channed through the angular gyrus into the already
developed Wernicke’s language interpretative area of the dominant temporal lobe.
17. What are the functions of the nondominant hemisphere? Why is “dominant” a misnomer?
-
Understanding and interpreting music
Nonverbal visual experiences
Spatial relations between the person and their surroundings
Significance of body language
Intonation in people’s voices
Dominant is a misnomer because it really only refers to the language-based intellectual
functions. The “nondominant” hemisphere might actually be dominant for other types of
intelligence.
18. What are the effects of a prefrontal lobotomy?
-
Lose ability to solve complex problems
Unable to string together sequential tasks to reach complex goals
Unable to learn to do several parallel tasks simultaneously
Decreased aggressiveness, ambition
Inappropriate social responses, including loss of morals, little reticence with sex, excretion
Unable to carry through long trains of thought
Moods change rapidly from sweetness to rage
19. Which characteristics are associated with the loss of ventral parts of the frontal lobes?
Decreased aggressiveness and inappropriate social response
20. What is working memory? What abilities does it provide?
Working Memory – ability of the prefrontal areas to keep track of many bits of information
simultaneously and to cause recall of this information instantaneously as it is needed for
subsequent thoughts
Abilities: prognostication, plan for the future, delay action in response to incoming sensory
signals, consider consequences of motor actions, solve complicated
mathematical/legal/philosophical problems, correlate all avenues of information in diagnosing
rare disease, control our activities in accordance with moral laws
21. What is auditory receptive aphasia, visual receptive aphasia?
Auditory receptive aphasia (deafness) - result of destruction of portions of auditory association
area
Visual Receptive Aphasia ( dyslexia) – result of destruction of visual association areas
22. What is Wernicke’s, Global aphasia?
Jimmy Kimber
LECOM – Seton Hill OMS1
Wernicke’s Aphasia: destruction of Wernicke’s Area results in capability of understanding either
spoken or written word, but an inability to interpret the thought that is expressed
Global Aphasia: when lesion in Wernicke’s area is widespread and spreads back into angular
gyrus, down to the lower temporal lobe, and up to the sylvian fissure, the person will be
demented for language understanding and communication.
23. What are 2 stages of mentation?
-
Formation of thoughts to be expressed as well as the choice of words to be used
Motor control of vocalization and the actual act of vocalization itself
24. Which motor areas are controlled by Broca’s Area?
The skilled otor patterns for control of the larynx, lips, mouth, respiratory system, and other
accessory muscles of speech are all initiated from this area
25. Which areas of the brain are involved in articulation?
Facial and Laryngeal regions of the motor cortex activate the muscles
Cerebellum, Basal ganglia, and Sensory Cortex all help control the sequences and intensities of
muscle contraction.
26. Examine 57-8 and describe the steps involved speaking a heard/written word
Hearing to Speech: reception in primary auditory area  Wernicke’s area for interpretation 
arcuate fasciculus tract to Broca’s area  activation of motor programs in motor cortex
Reading to Speech: activation of primary visual area  angular gyrus region  Wernicke’s area,
etc.
27. What is the function of the corpus callosum? Give examples
-
-
Provides bidirectional neural connection between most of the respective cortical areas of
the two cerebral hemisphers (except for anterior temporal lobes, especially amygdala –
connected by the anterior commissure)
Make information stored in the cortex of one hemisphere available to corresponding
cortical areas of the opposite hemisphere:
o Cutting corpus callosum blocks information from Wernicke’s area to the motor
cortex on the opposite side of the brain.
Jimmy Kimber
LECOM – Seton Hill OMS1
o
o
Cutting corpus callosum prevents transfer of somatic and visual information from
the right hemisphere into Wernicke’s area in the left dominant hemisphere.
Corpus callosum sectioning causes two entirely separate conscious portions of the
brain
28. What is the holistic theory of thoughts?
Holistic Theory of Thought is a definition of thought in terms of neural activity: a thought results
from a “pattern” of stimulation of many parts of the nervous system at the same time, probably
involving most importantly the cerebral cortex, thalamus, limbic system, and upper reticular
formation of the brain stem.
29. What is consciousness?
The continuing stream of awareness of either our surroundings or our sequential thoughts
30. What are memory traces?
Memories are stored in the brain by changing the basic sensitivity of synaptic transmission
between neurons as a result of previous neural activity. The new or facilitated pathways are
memory traces. Once they are established, they can be selectively activated by the thinking
mind to reproduce memories.
31. What is positive/negative memory?
Negative Memory - the brain has capability to learn to ignore information that is of no
consequence. This is the result of inhibition of pathways for this info, and is called habituation.
Positive memory – autonomic capability of enhancing and storing memory traces for
consequences of pain or pleasure. This results from facilitation of the synaptic pathways,
memory sensitization.
32. Define short, intermediate, long-term, working, declarative, and skill memory
Short-term: lasts seconds or minutes
Intermediate Long-Term: lasts days to weeks
Long-Term: lasts years to a lifetime
Working Memory: includes mainly short-term memory used during the course of intellectual
reasoning but is terminated as each stage of the problem is resolved
Declarative: memory of details of an integrated thought (surroundings, time relationship, cause
of experience, meaning, and deductions of the experience)
Skill: motor activities of the person’s body
33. What are the proposed mechanisms for short-term memory?
-
Continual neural activity resulting from nerve signals that travel around and around a
temporary memory trace in a circuit of reverberating neurons
Presynaptic facilitation or inhibition that occurs at synapses lying on terminal nerve fibrils
immediately before they synapse with a subsequent neuron
Jimmy Kimber
LECOM – Seton Hill OMS1
34. Explain memory based on chemical changes in the snail Aplysia
When a sensory terminal is stimulated repeatedly but without stimulation of the facilitator
terminal, signal transmission at first is great but becomes less and less intense until transmission
ceases. This is habituation (negative memory). If a noxious stimulus excites the facilitator
terminal at the same time that the sensory terminal is stimulated, then the ease of transmission
instead becomes stronger; and it will remain strong for minutes, hours, days
35. What is habituation? What is its mechanism?
Habituation – type of negative memory, where sensory signals initiate less and less stimulation
without a facilitating signal.
Cause: results from progressive closure of calcium channels through the terminal membrane;
calcium needed for transmitter release
36. What is facilitation? What is its mechanism?
Facilitation – an increase in postsynaptic potential evoked by a second impulse
Mechanism:
- Stimulation of facilitator presynaptic terminal at the same time as the sensory terminal
causes serotonin release at facilitator synapse
- Serotonin activates receptors that activate adenylyl cyclase and form cAMP
- cAMP activates a protein kinase that phosphorylates potassium channels to block potassium
conductance
- lack of K+ conductance causes prolonged action potential
- prolonged action potential causes prolonged activation of calcium channels allowing great
transmitter release
ALSO: facilitation can cause long-term changes in membrane properties of the post-synaptic
neuron instead of in the presynaptic neuronal membrane
37. What structural changes are associated with development of long-term memory?
-
Increase in vesicle release sites for secretion of transmitter
Increase in number of transmitter vesicles released
Increase in number of presynaptic terminals
Changes in structures of dendritic spines that permit transmission of stronger signals
38. How do neurons change during learning?
When learning occurs, the number of neuronal connections increases based on nerve growth
factors released retrogradely from the stimulated cells.
39. What is memory consolidation? Why is it important?
Consolidation converts short-term memory to long-term memory. It is repetitive activation of
short-term memory, which causes chemical, physical, and anatomical changes in the synapses. It
involves codifying information into different classes.
Jimmy Kimber
LECOM – Seton Hill OMS1
40. How do you transfer short term memory to long term memory?
Rehearsal of the same information again and again in the mind accelerates and potentiates the
degree of transfer of short-term memory into long-term memory.
41. How are new memories codified?
New and old memories are compared for similarities and differences, and part of the storage
process is to store the information about these similarities, rather than storing new information
unprocessed. So, memories are stored in direct association with other memories of the same
type. This is necessary if one is to be able to “search” the memory.
42. What is the result of removal of the hippocampi?
Hippocampi may be removed for the treatment of severe epilepsy
Result: virtually no capability of storing verbal and symbolic types of memories (declarative
types), in long-term memory, or even in intermediate memory. Unable to establish new longterm memories of those types of information that are the basis of intelligence – anterograde
amnesia.
43. Why are the hippocampi so important in helping the brain to store new memories?
Hippocampi send important output pathways from the “reward” and “punishment” areas of the
limbic system. So, they are important in making the decision about which of our thoughts are
important enough to remember on the basis of reward/punishment.
44. What is anterograde, retrograde amnesia?
Anterograde – unable to establish new long-term memories of those types of information that
are the basis of intelligence. Caused by damage to hippocampi
Retrograde – amnesia of events in the past; most likely to lose recent memories rather than
those that occurred a long time ago (because these have been stored in wide-spread portions of
the brain). Caused by damage in thalamic areas