Memory, Speech, and Learning PDF

MEMORY AND SPEECH LEARNING  Higher Intellectual Functions Of Brain (Memory - Learning – Language) Memory: informa pick up -Memory is the ability of the brain to store information and recall it at a late...

MEMORY AND SPEECH LEARNING  Higher Intellectual Functions Of Brain (Memory - Learning – Language) Memory: informa pick up -Memory is the ability of the brain to store information and recall it at a later time. _fif one -The storage capacity of the human brain is limited. So as: the information flows into the brain, they are classified, the most important ones (1%) are selected and stored, but all the rest are neglected and forgotten. Just 1 That Selected  4 Types Types of memory I. Sensory Memory: - Is the ability of the brain to retain sensory signals in the sensory areas of the brain for a very short interval of time following the sensory experience. -It is the initial stage of the memory processes. It can be: Just for seconds IN 6 B1e I 2 transferred into the primary or secondary memory or lost. so as 6 W II. Primary Memory: -This memory lasts from a few minutes to a few hours. - * Synaptic short-term potentiation: Multiple successive stimuli of presynaptic neuron --> Increased Ca++ concentration in presynaptic terminals ----> Increase release of transmitter ---- > facilitate synaptic transmission accumulation of catt is responsible for shorttermpotentiation Temporary memory traces. Rtm A memory trace is a newly developed pathway for signal transmission resulting from facilitation of new synapses — Creation of new circuits in the brain that keeps the memory experience. Activation of these circuits, brings the memory to one's mind. Teilns cortex memory traie inthe beging is Temporaly hippocampus 645 21 4 5 as so lil and amyglada III. Secondary Memory: www.stms engrams 41,6 said µ -Is made by formation of "memory engrams". These long- lasting memory traces formed by structural changes meee (Permanent) in synapses: a- Increased number of 11 1 1 transmitter vesicles in presynaptic terminal. b- Increased number and size of presynaptic terminals, c- Changes in sizes and conductivities of the dendrites. The memory engrams remain for long time up to several years. WS Is 2W -Formation of memory engrams requires protein synthesis NB. Antibiotics which inhibit protein synthesis, e.g. puromycin, inhibits formation of memory engrams --> preventing consolidation of memory (but does not affect primary memory) whj.ro injchangePrima  advanced stage of IV. Tertiary Memory: SendaffffIjff R Is made by the formation of "permanent engrams" So tertiary memory is considered an advanced stage of secondary memory. Consolidation Of Memory - Means the transfer of information from primary to secondary long-term memory. - This process takes from O5 minutes for minimal consolidation to 2 hours for maximal consolidation. So, if a sensory o impression is made, then followed: i i iiiiiii.is a 2 Within 5 minutes by brain concussion or electro-convulsion --> the patient can not remember the sensory impression, that is why patients with brain concussion, can not remember what happened at the time of the accident.  WWI In Consolidation Of Memory Depends On: 1)Natural tendency of the brain to rehearse the new information that catches the mind's attention: ELITE 2) Encoding Of Memory: Means classification and placing of memory items in their proper memory stores in the brain. Mechanism: my * All information go first to the hippocampus where they are sorted out. * Information is classified as important if they: a) Stimulated the reward or punishment systems, or b) Practiced or rehearsed repeatedly. if itimportant goto Important information passes from hippocampus ---- > Mammillary body of hypothalamus ---- > Basal forebrain cholinergic fibers ---- > I neocortex, amygdala and hippocampus where, they are stored. iii Iii mail.it - To recall a certain memory item, one should get access to the specific engram of this item and activate it. The thalamus may play a role in searching for the information in memory store houses. Responsible for recall -Mechanism Of Memory Trace Formation: 1- Synaptic short-term potentiation: (Temporary Memory Trace) Multiple successive stimuli of presynaptic neuron --> Increased Ca++ concentration in presynaptic terminals ----> Increase release of transmitter ---- > facilitate synaptic transmission TIF TILE 2- Long term potentiation (LTP) of synapses: (Long Temporary Memory Trace) During verbalization, the brain catches the new interest information and repeat it several times. 3- Changes in the physical properties : (Long permenent Memory Trace) of the postsynaptic membrane —> Enhanced sensitivity to the chemic transmitter.  loss ofmemory J Amnesia (Forgetfulness) I primary sw̅ a - Means inability to remember past experiences. tertiary secondary SI 2180 - There are several types of amnesia: IS 214W i.su 4 asia 1) Retrograde Amnesia : w.is 32 1I1i8S.IJW It 34 ib woi.MIL - Means inability to recall events that occurred shortly before the onset of brain malfunction without affecting memories of the remote past. be * In this condition, the transient brain malfunction erases the primary memory. 2g primary sss.jo i.I.IE aiins consolidation a www.wasotnÉIYw a 2) Anterograde Amnesia: consolidations sina.cat ish e not it Is 21 consolidations * Means inability to form new long-term memories. * The primary memory is functioning, but can not be consolidated. fesponsiblefor The memories consolidated before the onset of amnesia are retained. * Caused by lesion in hippocampus. consolidation 3) Psychogenic Or Hysterical Amnesia: * Usually follows a severe psychological stress. So, it is purely functional disorder without any organic disease. * Characteristics: meentfi imem.rs and secondary a- All the personal data are forgotten including the person's own name, b- The amnesia is not affected by key stimuli, i.e. taking the person to his former surroundings or his relatives. c- The inability to remember past events, although he can make new memories. so * Complete recovery of memory almost always occurs. 4) Alzheimer's Disease and Senile Dementia: partialnotcomplete * Caused by degeneration of the cholinergic fibers projecting from basal forebrain bundle to neocortex, hippocampus and amygdala. * Is characterized by impairment of memory and inattentiveness. It may occur at any age. In old age it is called senile dementia (found in 10 - 15% of the population above the age of 65 years IT * The anticholinesterase, eserine, produces some improvement, but it does not stop the progress of the disease.  a I d Speech and Language Definition: Understanding spoken and written words and expressing ideas into I speech and writing  Function of the dominant hemisphere (left hemisphere in It 95% of the population) Tooth  Prim. Motor area Sequens for words area in premotor Speech Broca's Hand skill Writing area area r Arcuate fasciculus Integration of T.iiiiiiimareat i i Trarts Wernicke’s area information into ideas and thoughts IieWGl.sk t.SI e Secondary Analysis Secondary Secondary visual auditory somato- and I area 2 area 3 sensory interpretation area I Sensory i Primary Primary Somato- Detection visual 2 auditory 3 sensory i area area area start here w̅ him whim is e I iI  Language-Speech Speech is the expression of ideas by spoken or written words. It represents the highest function of the cerebral cortex Lateralization Of The Speech Function In The Brain: In right-handed individuals (95%) and in some left-handed ones ---> Centers of speech in the left cerebral hemisphere (speech-dominant or categorical hemisphere). The other hemisphere (right) is dominant in other functions as recognition of faces, Steriognosis, recognition of musical themes and spatial recognition of the body (non-speech- dominant or representational hemisphere)  Speech Has Sensory and Motor Aspects: * Speech is learned basically through hearing, so if a person is born deaf, he can not develop the faculty of speech and is distinct to be dump (deaf-mutism) I. Sensory Aspect Of Speech: A) Hearing and Speech: * Hearing of the spoken words is the function of primary Auditory area. mite -Understanding the meaning of the individual words is the function of auditory association area. -This area can not understood the ideas expressed by collection of words, sentences or phrases. SI I WI a WI g a B) Reading and Speech: * Seeing the written words is the function of the primary visual area. areas. no Understanding the meaning of the individual written words is the function of visual association This can not comprehend the thoughts expressed by collection of words, i.e. sentences or phrases. It i g g  Both auditory and visual association areas feed the meaning of words to the general interpretative area or Wernicke's area. Wernick's Area (General Interpretative Area - The Language and Speech Center). * Found in the posterior part of the superior temporal gyrus. * It receives input signals from somatic, visual and auditory association areas. * In speech, Wernicke's area acts as: a) Comprehension Center: * For understanding the meanings of expressed sentences or phrases. *B Formulation of thoughts and ideas that will be expressed by speech. so L C b) Language Center: * Language is a collection of words and the way to use them. * Wernicke's area is the memory store for language. G c) Speech Center: ae IT * For choosing the suitable words to express the formulated thoughts and ideas. -Wernicke's area is very well developed in categoric hemisphere. II. Motor Aspect Of Speech: A)Word-Formation Center (Broca's Area Of Speech) WI.SI at owig W.de -Is found in the premotor area. primarymotorarea J - is connected to the Wernicke's area through the arcuate fasciculus. It stores the motor programs for different words. WILL is When stimulated ---- > Stimulation of primary motor cortex at a certain pattern to produce words by contraction laryngeal, pharyngeal, lingual and labial muscles. B) Writing Center (Exner's Center) -It is part of the area for hand skills in the premotor area. is connected to the Wernicke's area by the arcuate fasciculus. It stores the program for writing the words. When stimulated — > Stimulation of motor cortex at a certain pattern to write words using the muscles of the hand.  Speech Defects * Are divided into 2 main categories: I. Aphasia.Problem in thesensory except WVinckles area II. Dysarthria. Problem in the motor has own defect I. Aphasia - Is a speech defect which is not due to defect in vision, hearing or paralysis of speech muscles. * Types of aphasia. affected Secondary is A. Sensory Aphasia 1. Visual Aphasia (Word Blindness) PAs * Caused by lesion in the visual association area. * Patient can not understand the written words. 2- Auditory Aphasia (Word Deafness) TT s.tl to * Caused by lesion in auditory association area. at ME.am E * The patient can not understand the spoken words. se  B) Wernicke's Aphasia (general sensory aphasia)whichpart Caused by lesion in Wernicke's area or the arcuate fasciculus of speech- dominant hemisphere. a it its c a semi Lesion in Wernicke's iii area i se Ie The person is unable to comprehend thoughts or idea expressed by the written or spoken words ---- > he can not formulate thoughts or ideas to express himself ---- > he fail to select suitable words. * In this condition, the speech itself is normal and sometime the patient talks excessively (fluent aphasia). However, the speech is full of jargon and neologisms that make little sense. realanguate 811 j j g * Very rarely, when the lesion is confined to the arcuate fasciculus, it is called conduction aphasia because; Wernicke's area is disconnected from Broca's area. The patient formulates thoughts and ideas and knows what he wants to say, but can not produce the required speech  C) Motor Aphasia (Expressive Aphasia) 1) Vocal Aphasia: iii * Is due to lesion in Broca's area. * The patient knows what he wants to say and he is capable of vocalization, but he can not make his vocal system emit words, but only noises (non-fluent aphasia) Mta I 2) Writing Aphasia (Agraphia) ecoshio * Is due to lesion in the area of hand skills in the frontal lobe. * The patient knows what he wants to write and he is capable of moving the hands voluntarily, but he can not make hands write words or draw graphs to express his thoughts. 4 a 5 D) Global Aphasia * Is due to extensive lesions of the speech-dominant hemisphere involving both frontal and temporal lobes. * The aphasia is general involving both receptive and expressive functions, i.e. both language comprehension and production are lost.  II. Dysarthria - Means speech defect resulting from abnormalities in the process of articulation itself. I.WI stEI.Iiw.tw as was a I Articulation: Is the contraction of muscle of speech in a certain sequence to produce words. This is the function of motor cortex, motor nerves and muscles of speech. causes of Dysarthria 1) Lesion in the primary motor cortices of speech muscle and their connections, i.e. pyramidal tracts, cranial nerve nuclei and cranial nerves. 2) Diseases in the neuromuscular junction of speech muscle i.e. myasthenia gravis. 3) Disease in speech muscles, e.g. myopathies. 4) Disturbances in muscle tone: - Hypotonia --- > flaccid dysarthria. - Hypertonia (Parkinsonism) ---- > slow, monotonous speech I speech. 5) Incoordination (Neocerebellar lesion) ---- > Jumbled  J Learning Is the ability of the previous experience to modify the inborn reactions or to create new ones. J There are 3 types of learning: I. Non-Associative Learning His II. Associative Learning III. Insight Learning  I. Non-Associative Learning - In this form of learning, the subject learns whether to ignore or react to a certain stimulus. -This occurs through the following mechanisms. A) Habituation: - Is the gradual decrease in the response when the stimulus is frequently repeated. - e.g. a loud and unexpected sound —> several reflexes, e.g. looking toward the sound source. If this sound was insignificant, repetition of the sound — > No response. - Habituation is a stimulus specific. This explains why a j mother who sleeps through many kinds of noise wakes promptly when her baby cries. B) Sensitization: - Is potentiation of the response to a certain stimulus by coupling it to another intense or noxious stimulus. - e.g.: One normally ignores stray dogs (by habituation) but if he was bitten once or twice by stray dogs he will become more attentive to these dogs and develop the "aversion reaction" to them for long time. o - Sensitization is stimulus specific, i.e. a person who was bitten by a dog will not be afraid of donkeys. N.B. Habituation and sensitization are simple, but very important learning processes. Through them one learns to direct his attention to significant stimuli and ignore the much more numerous insignificant ones.  II. Associative Learning - In this type of learning, the subject learns about the relation of one stimulus to another. Classical Conditioning - In which the non-specific stimulus is made to produce the same response as the specific stimulus. Pavlove's Experiment: Indicated that after repeated association between the sound of the bell (conditioned stimulus - CS) and giving food (unconditioned stimulus - US) to an animal, the sound of the bell alone produces salivation. * For Conditioning To Occur: w̅ 1)The conditioned stimulus (CS) must precede the unconditioned stimulus (US). 2)If the animal is disturbed by an external stimulus after CS is applied -----> No development of CR 3) If the CS is applied repetitively without the US --- -- > CR will die out On other hand, if the conditioned reflex is reinforced from time to time by pairing the CS and US —> CR will persist indefinitely.  Ic III. Insight Learning This is the highest form of learning. It is characterized by the ability to combine previous experiences to evaluate and solve problems or achieve a desired goal. -It is the basis of studying and answering questions in examination. - It is also the basis of professional efficiency particularly in intellectual professions, e.g. scientists and physicians. It depends on: 1. Good and rich memory stores. so 2. The ability to recall proper and sufficient information at the proper time. 3. It is a combined function of the cortical association areas + the limbic system.