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Limbic system and memory


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limbic system and memory

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Limbic system and memory

  1. 1. LIMBIC SYSTEM AND MEMORY CSMU Anatomy Department By Caleb Tinashe Munikwa Group 214
  2. 2.  The limbic system is composed of structures in the brain that deal with Emotions(such as anger , happiness and fear) as well as Memory
  3. 3.  It supports a variety of functions including adrenaline flow, emotion, behavior, motivation, long-term memory, and olfaction. Emotional life is largely housed in the limbic system, and it has a great deal to do with the formation of memories.  The limbic system (or paleomammalian brain) is a complex set of brain structures located on both sides of the thalamus, right under the cerebrum. It’s a collection of structures from the telencephalon, diencephalon, and mesencephalon. It includes the olfactory bulbs, hippocampus, amygdala, anterior thalamic nuclei, fornix, columns of fornix, mammillary body, septum pellucidum, habenular commissure, cingulate gyrus, parahippocampal gyrus, limbic cortex, and limbic midbrain areas ass shown in the above slide.
  4. 4. MEMORY  Memory is a process in which information is encoded , stored and retrieved  Memory is a complex relationship between brain neurons  The major parts of the Limbic System involved in Memory are : Amygdala : Hippocampus : cingulate gyrus
  5. 5.  Information flows from the outside world through our sight , hearing , smelling , testing and touch sensors  Therefore memory is simply ways we store and recall things we have sensed  We store memory in areas located throughout the cortex , some data moves into short term memory and finally into long term memory
  6. 6. AMYGDALA
  7. 7. AMYGDALA Almond shaped masses of neurons on either side of the thalamus at the lower end of the hippocampus It is for emotion , arousal , storing of memory and stimulation of the hippocampus in remembering of events for future recognition
  9. 9. LONG TERM POTENTIATIONS  Connections of neurons that fire repeatedly again and again in a particular pattern, archive long term potentiation (LTP) becoming more and more sensitive  Hence creating memory and ready to fire the exact same way in the future  LTP firing makes it more easy to remember as a result of a particular strengthened pattern of firing neurons
  11. 11.  Memory is not stored in one combination of LTP but in numerous combinations of neurons like in the above picture  The mesh of neurons in the above slide might be the memory of your first kiss  It is stored in various networks, the events leading to your 1st kiss are stored in another network, the way it felt in another network , the way it smelled in another network  Hence all added up making up the memory of your first kiss
  13. 13. AMYGDALA RESPONSIBLE FOR RECOGNITION(MEMORY)LEADING TO AROUSAL & EMOTIONS  The amygdala is responsible for recognition/ distinguishing male from female and in turn feeling aroused by the opposite gender  Females have a larger amygdala than males hence are more emotional and tend to remember the finest details of events than males e.g they can link the color red to their break up memory because the first thing she saw immediately after her break up was a red car.
  14. 14.  On the same note males have smaller amygdala compared to that of the opposite gender and tend to be less emotional  Homosexuals have a larger than amygdala compared to that of heterosexuals whose memory recognizes people of the same gender as arousing.  Damage to the amygdala causes individual to have an impaired ability to interpret emotional aspect of facial expressions
  16. 16. The cingulate gyrus provides a pathway from the thalamus to the hippocampus and is responsible for associating memories of smell with pain or pleasant memories
  18. 18. HIPPOCAMPUS  Consist of two horns that curve back from the amygdala  Responsible for converting short term memories into long termed memories, works with the amygdala for storage  Damage couples to every day memory fades away ( A condition depicted in the films [ Memento and 50 1st dates ]
  20. 20. PAPEZ ’S CIRCUT  The hippocampus consolidates new memories in an event that creates temporally links among cortex neurons e.g ‘’red’’ gets stored in the visual area of the cortex and the sound of the bitten apple gets stored in the auditory area  When one remembers the new fact ‘’delicious apple’’ the new memory converges on the hippocampus , which sends them along the same path several times to strengthen the links(LTP)
  21. 21.  The information follows a pathway called the papez circuit starting at the hippocampus , circulating through more of the limbic system (to pick up any emotional associations like ‘’happy warm day’’ and spatial associations like ‘’apple orchard’’  Then to various parts of the cortex and back to the hippocampus ,making the information flow around the circuit many times strengthens the links(LTP) enough that they stabilize and no longer need the hippocampus to bring the data together therefore becoming long term memory
  23. 23. SHORT TERM MEMORY  Short term memory is the type of memory that enables you to speak back the last sentence of a conversation when someone accuses you of not listening  It stores only data that catches your attention like a police car behind you or following direction  STM is small it holds about 7 independent items at one time such as carrying numbers when calculating arithmetic
  25. 25.  Long term memory has a large capacity and contains memories that are decades old in addition to memories that arrived several minutes ago.  Memories of LTM are relatively permanent are not likely to be lost and can be divided into two Explicit and Implicit  Explicit memory measures requires a participant to remember information e.g in exam  Implicit memory measure requires the participants to perform a task without making a conscious effort to recall the past because of previous experiences e.g playing music or tennis.
  26. 26. SPATIAL MEMORY  spatial memory is the part of memory responsible for recording information about one's environment and its spatial orientation. For example, a person's spatial memory is required in order to navigate around a familiar city
  27. 27. AMNESIA
  28. 28.  Amnesia can also be caused temporarily by the use of various sedatives and hypnotic drugs. Essentially, amnesia is loss of memory. The memory can be either wholly or partially lost due to the extent of damage that was caused. There are two main types of amnesia: retrograde amnesia and anterograde amnesia. Retrograde amnesia is the inability to retrieve information that was acquired before a particular date, usually the date of an accident or operation. In some cases the memory loss can extend back decades, while in others the person may lose only a few months of memory. Anterograde amnesia is the inability to transfer new information from the short-term store into the long-term store. People with this type of amnesia cannot remember things for long periods of time. These two types are not mutually exclusive. Both can occur within a patient at one time.
  29. 29.  Storage capacity of a human brain is 2,5 petabytes {Paul Reber} of information .Equivalence of recording a TV channel continuously for 300 years. That is a lot of information that we have learned , seen ,experienced e.t.c