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Learning, the ability to recollect from the storehouse of memory, involves a complex set of processes whereby experience alters the nervous system. These changes endure and affect subsequent experience and behavior. Is learning and recollection simply the neuronal residue of experience, or do other factors play an important role in memory recall? How are significant experiences selected for later recall? How do past experiences interact with present experiences, and how do they lead to changes in behavior?

The complexity of the problem may be illustrated by examining what is involved in using a familiar telephone number. The information is obtained by looking up a telephone number in a directory. One may see many numbers that are present in the visual field, but only one is selected for use. The recollection may be indicated by speaking, dialing or pushing buttons, by writing or simply by identifying the correct sequence of numbers as the correct number. The recollected image can be discriminated from all other sequence of numbers, including other telephone numbers we are capable of recalling. The recollection that is rapidly formed is transient, but with repetition can become long lasting.

This is but one simple example of recollection. We can obtain information through watching, reading, listening, and through other sensory experiences. We learn and remember isolated experiences, complex events and reliable skills. However, recollection does not merely consist of the particular responses that are made during the course of learning experiences. We readily learn and perform skills such as language, in which responses occur in novel sequences.

Brain lesions can impair learning and retention. However, such studies are difficult to interpret since they only reveal how behavior is altered by lesion. In addition, lesion studies have not revealed in anatomical locus for the storehouse of memory. However, since neurological changes are induced during training and recollecting, many scientists assume that an anatomical locus can exist.

Studies of electrical brain activity indicate that training and recollecting alters brain wave patterns and especially hippocampal theta activity. The hippocampus is a sea-horse like structure found in the limbic system deep within temporal lobe of the brain. It is a brain structure associated with learning, mapping, and memory retrieval. Moreover, whenever we are actively visualizing, slow brain waves of 4 to 8 cycles per second are produced. These slow waves are called theta waves. The firing pattern of single brain cells and their evoked potential recordings also show characteristic changes during recollection and learning. However it has not been determined that these correlates of learning are involved in the mechanisms underlying learning and memory recall. The electrophysiological changes produced by training and by insight experiences are signs that brain cell activities are altered.

Training of laboratory animals also produces changes in brain chemistry. Studies suggest that RNA and protein synthesis are increased by training. Furthermore, in goldfish, patterns of brain protein synthesis are changed by training. Other studies suggest that learned predispositions to light can be transferred to untrained animals via brain extracts. These extracts exist as if they were hormones promoting light avoidance or dark avoidance behaviors. Memory transfer via brain extracts is highly controversial and many neuroscientists do not feel that such 'memory transfer' studies are convincing.

The ability to recall experiences can be enhanced or impaired by treatments that alter brain activity. Such treatments are most effective if administered shortly before or shortly after the experience. Effective treatments include electrical stimulation, hormones, stimulant drugs, drugs affecting RNA and/or protein synthesis, and drugs affecting neurotransmitters. The inference drawn from these results is that normal variations in our ability to recollect may be due to the modulating influence of hormones and brain chemistry. Since hormone activity and brain metabolism is cyclic, we might expect to see rhythmic fluctuations in our abilities to recollect experiences.

   
  Questions
   
  1. (a) How do changes affect subsequent experience and behavior ?
    (b) How does the writer make a comparison with dialing a telephone ?
       
  2. (a) Describe how we recollect.
    (b) What harm can brain lesions cause ?
    (c) Why do scientists assume that there is an anatomical locus ?
       
  3. (a) Describe, in your own words, a hippocampus.
    (b) Explain the experiment with gold fish.
       
  4.   For each of the following words give one word or short phrase ( not more than seven words ) which has the same meaning as it has in the passage.
      i.   interact   v.   neurological
      ii.   recollection   vi.   evoked
      iii.   discriminated   vii.   extracts
      iv.   isolated   viii.   variations
       
  5. In less than 160 words, summarize how learning and recollection takes place.
       
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  Answers
       
  1. (a) A complicated system is involved in the learning process and it causes changes in the nervous system. The changes stay and effect later learning.
    (b) From the selection of numbers we choose one set from a directory. This number is then dialed or punched. This is done by a recollection of the numbers from the book. The image of the numbers used differs from other sets of numbers. The selection can be forgotten but will be remembered if dialed again and again.
       
  2. (a) Recollection consists of remembering information that we had gathered through the senses.
    (b) Brain lesions can interfere with learning and recollecting.
    (c) They do so because brain changes take place when training and remembering is carried out.
       
  3. (a) A hippocampus is something within the lobe of the limbic system of the brain. It is shaped like a sea horse.
    (b) In training goldfish it was discovered that in training, patterns of brain protein synthesis are changed.
       
  4. i compare
    ii remembrance
    iii differentiated
    iv single
    v brain
    vi stirred
    vii matter
    viii differences
       
  5. Learning is the ability to remember from the data that has been gathered and stored in the brain. The problem is a complex one. Taking the use of the telephone as an example, learning is the using of the senses to absorb the number from a book. Recollection is when we are able to differentiate the set of numbers from other numbers in our memory and use it o dial. Usually the rapidly formed recollection is not remembered for long, but it can be if used repeatedly.

We obtain information, through the senses, when we learn languages and other skills and remember them when we use them. Even though many scientists believe that learning causes changes to the brain and are therefore anatomical, these studies are not final. Studies indicate that training and recollecting do alter brain wave patterns. Patterns also reveal themselves in single brain cells showing that there are changes taking place when we learn or recollect. ( 159 words )

           
 
 
 
 
 

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Comprehension 1

 

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