Separation of Declarative and Non-Declarative Memory - Essay Example

Evaluation of the evidence for the separation of declarative and non-declarative memory s Introduction The question of separation of the human memory into declarative and non declarative has undergone various discussions. A great number of investigations were held in order to identify the difference between these two types. Memory is a generic term used for identification of the complex cognitive abilities and higher mental functions, which deals with the accumulation, preservation and reproduction of knowledge and skills.Iin its different forms and shapes memory is inherent to all higher animals. In a broader sense, memory is not only the ability to reproduce images of the past, but also the opportunity to predict the future. It may vary according to the methods of perception: visual memory, memory for sounds, smell, etc.. The main goal of the given study is to evaluate the evidence for the separation of declarative and non-declarative memory and prove that such separation is necessary and scientifically proved. The representation of memory systems’ plurality has become one of the most interesting issues in psychology. This representation is based on the data obtained from the studies of patients with different brain diseases, as well as the experiments performed on healthy subjects., One of memory subtypes belongs to the separation of long term memory into declarative and non-declarative. “Memory is not a unitary faculty of the mind but is composed of multiple systems that have different operating principles and different neuroanatomy.” (Squire, 2009). Declarative memory provides remembering the objects, events, episodes. This memory maintains the images of faces, places and objects. Declarative memory is often based on the association of concurrent stimuli. It is conscious, because it implies awareness about the object or subject of the event, the image that is retrieved from the memory, while the use of non-declarative memory behavior can be carried out without the awareness of this fact. The organization of the declarative memory requires information processing in the temporal lobes of the brain and the thalamus. The structure, which is particularly important for the declarative memory is hippocampus with the basal ganglia. Non-declarative memory is the memory of the actions. It represents motor skills, perceptual strategies, conditional and instrumental reflexes. Habituation and classical conditioning are the examples of non-declarative memory acquisition. The investigation of the mechanisms of learning and memory are conducted mainly in the context of plasticity. Since plasticity has been available for investigation at cellular and molecular levels, scientists identified many mechanisms of neural plasticity, which are supposed to contribute to various forms of training. The separation of memory into declarative and non-declarative was predetermined by a number of clinical studies. According to Squire, “studies of experimental animals have suggested that declarative memory is more flexible than non-declarative memory”. (Squire, 1996). Typically, the main changes in the formation of memory are represented by the modification of synaptic connections. Squire adds that “declarative and non-declarative memory differ with respect to the flexibility of the knowledge acquired by each system” (Squire, 1996). The experiments, which study the mechanisms of long-term plasticity, show that neurophysiologic parameters "old" and "new" memory traces are indistinguishable, but qualitatively the electrical activity of neurons is the same. It is assumed that the basis for the long-term persistence of memory traces is predetermined by the long-term changes of chemo responsiveness properties of the membrane of neurons. The membrane can be seen as a double mediator in the transmission of the information: the state of the membrane determines the sensitivity to the stimulus, and the restructuring of the membrane after receiving the signal determines the strength, specificity, and the adequacy of the response. The exclusive role of membranes is the transfer and storage of information associated with cooperative structural transitions in them. These transitions can induce changes in lipids and proteins. Ortu & Vaidya (2013) state that “the traditional taxonomy that distinguishes between neural systems supporting declarative and non-declarative forms of learning may be inadequate, as experimental and theoretical work suggests that other criteria may be more useful in categorizing the role of neural structures involved in learning such as the hippocampus and the basal ganglia.—even when stimuli are presented subliminally” (Ort & Vaidya, 2013). Convincing evidence that the procedural and declarative components are required for the formation of normal speech utterances is revealed through the experiment of M. Ullmann and S. Korkin. It involved three groups of subjects: 1) suffering from Parkinsons disease; 2) Alzheimers; 3) healthy subjects. The task was to form the past tense of the verbs represented in the list. The list included regular verbs (adding «ed» to the end of the word – non-declarative knowledge) and irregular (remembering specific information - declarative knowledge). Healthy subjects (English speakers) easily coped with the task, Alzheimers patients made mistakes mostly when dealing with irregular verbs, and patients with Parkinsons syndrome - when working with the regular verbs. The authors concluded that the speech act involves two partially independent memory subsystems, one of which is related to non-declarative knowledge (grammar) and the other to a "mental dictionary" (concrete representation of words). This analysis proves the separation of memory into the declarative and non-declarative and their influence to the formation of speech. In this case, we can see that the group of healthy people revealed both types of memory: Parkinson’s patients clearly reflected the signs of declarative memory, while Alzheimer’s ones succeed in non-declarative representation.  “H.M.”, who had parts of his medial temporal lobe, hippocampus and amygdale removed in 1953 in an attempt to cure his intractable epilepsy. After the surgery, H.M. could still form new procedural memories and , but long-lasting declarative memories could no longer be formed” (Mastin, L., 2010). This example provides clear understanding that the separation of memory into declarative and non-declarative has a strong scientific background, as it describes the processes, which reveal the function of one system in comparison with the dysfunction of another due to the particular circumstances. There is another evidence of separation of long-term memory into two basic systems. Neurobiological studies identified several brain systems, which are different according to their functions. Declarative memory depends upon hippocampus, while non-declarative on the striatum of ganglia. This hypothesis was originated during the studies, which analyzed the learning skills of the objects after the damage of hippocampus. In this case the objects impaired declarative knowledge, but spared non-declarative skills. Analyzing the data obtained from the study of human brain, the scientists separated declarative and non-declarative memory, stating that they perform different functions. As Krupa, 2009 explains, “the neurobiological basis of memory supports a clear distinction between the declarative (hippocampal dependent) and non-declarative (striatal dependent) memory systems” (Krupa, 2009). As these brain systems perform different functions, the scientists analyzed them in terms of two separate areas, which interconnect with each other. For this purpose, they used the patients with different mental disorders, which helped them consider the particular type of memory in its full representation (Krupa, 2009). Conclusion The conclusion can be made that neurobiology provides the clear evidence, which identify declarative and non-declarative memory as two different brain systems. These memory systems have different operating characteristics, which are involved in the acquisition of knowledge and are the part of different brain structures. Not all physiologists adhere to the specified division, however, they can’t disprove the fact that this type of classification is essential for training. Moreover, if physiologists wouldnt define these types of memory, the psychologists dealing with problems of training could do that. The scientific studies proved the separation of memory into declarative and non-declarative by means of experimenting with patients with various mental pathologies, making the thorough neurobiological analysis of their brain functioning. References Squire, Larry R., Zola, Stuart M. (1996). Structure and function of declarative and nondeclarative memory systems. National Academy of Sciences in the United States of America. Retrieved from: http://www.pnas.org/content/93/24/13515.full Squire, Larry R. (2009). Memory and Brain Systems: 1969–2009. The Journal of Neuroscience. Retrieved from: http://www.jneurosci.org/content/29/41/12711.full Ortu, D., Vaidya, M. (2013). A neurobiology of learning beyond the declarative non-declarative distinction. Retrieved from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827554/ Haraszti, Tegze P. (2000). CMOS memory circuits. Boston: Kluwer Academic Aggleton, John P. (1992). The Amygdala : neurobiological aspects of emotion, memory, and mental dysfunction. New York: Wiley-Liss Henderson, Ernest N. (1903). A study of memory for connected trains and thought. The USA: Press of the New Era Printing Krupa, Allison K. (2009). The competitive nature of declarative and non-declarative memory systems: converging evidence from animal and brain studies. Retrieved from: http://www.studentgroups.ucla.edu/usj/the_competitive_nature_of_declarative_and_nondeclarative_memory_systems_akkrupa.pdf Mastin, L. (2010). Declarative (explicit) and procedure (implicit) memory. 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