Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Brain and Memory By: Pamela L. Washbourne Neurocognitive Networks Recent advances in basic and cognitive neurosciences now allow a more detailed analysis of networks Memory and Learning can be dissociated into several behavioral components: registration storage (encoding), retention and retrieval Memory can also be classified according to modality (visual and auditory) or material (verbal and nonverbal) that is being processed. Mesulam M.D.,MM.D.,M-Marsel, Marsel, (1990), “Large Scale Neurocognitive Networks and Distributed Processing for Attention, Language, and Memory” Memory”, Annual Neurology, 28, 597597-613. Cognitive Neuroscience…. …of memory is based on observations of brain damaged patients with various kinds of memory loss, experiments with healthy volunteers, studies using brain imaging techniques The fractionation of memory into component systems and subsystems has been a major theme in the cognitive neuroscience of memory for the past 10-15 years Brain imaging techniques are now providing new perspectives on various forms of memory Schater,PH.D.,Daniel (2002), “The Cognitive Neuroscience of Memory” Memory” Harvard University Conference, Neurology of Behavior. Seven Sins of Memory…. Transience: forgetting information over time Absent-mindedness: lapses in attention that produce forgetting Blocking: temporary inability to retrieve information Misattribution: confusing the source of a memory Suggestibility: incorporating misleading information into memory Bias: influence of present knowledge and beliefs on recollections of the past Persistance: unwanted memories Schater,PH.D.,Daniel (2002), “The Cognitive Neuroscience of Memory” Memory” Harvard University Conference, Neurology of Behavior. Memory Types…. Retrieval – can be declarative- the verbal report of conscious memories Procedural – the learning of a motor skill Autonomic – the visceral response associated with the experience Memory Systems….. Defined as: specific neural networks that support specific mnemonic processes Which brain regions mediate specific kinds of memory functions? Gavrielli, Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory” Memory”, Annu. Annu. Rev. Psychology, 49,8749,87-115. Evidence…. Neuroimaging studies provide evidence about the participation of medialtemporal regions in declarative memory Medial-temporal activations are observed during intentional memory retrieval and is noted to activate during encoding of memories Gavrielli, Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory” Memory”, Annu. Annu. Rev. Psychology, 49,8749,87-115. Regions…. Declarative memory is generally thought to reflect an interaction between medialtemporal/diencephalic and neocortical brain regions Medial-temporal or diencephalic lesions spare remote memories this has encouraged the view that the neocortex is the ultimate repository of consolidated long-term memory Neocortex contributes to the encoding, storage and retrieval of declarative memories Declaritive Memory… Seems to dependent on the integrity of parts of the limbic network and their interconnectivities Noted by patients with the amnesic state can acquire new motor skills although they may have no conscious knowledge of having learned the skills Of all the stages of declarative memory, registration (short-term or immediate memory) is the least dependent on the limbic system and most closely associated with vigilance and concentration *amnesic patients can have a normal concentration span Mesulam M.D.,MM.D.,M-Marsel, Marsel, (1990), “Large Scale Neurocognitive Networks and Distributed Processing for Attention, Language, and Memory” Memory”, Annual Neurology, 28, 597597-613. Declarative Memory…. Encompasses the acquisition, retention, and retreival of knowledge that can be consciously and intentionally recollected This includes memory for events (episodic memory) or facts (semantic memory) Gavrielli, Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory” Memory”, Annu. Annu. Rev. Psychology, 49,8749,87-115. Episodic memory…. Measured by direct or explicit test of memory, such as free recall, cued recall, or recognition, that refer to a prior episode Gavrielli, Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory” Memory”, Annu. Annu. Rev. Psychology, 49,8749,87-115. Intentional retrieval… A consistent by poorly understood activation occurs in right frontal cortex during intentional declarative or episodic retrieval of memory for words This activation are unexpected because they apply to verbal and nonverbal memories and because right frontal lesions have modest effect on declarative memory. One speculative interpretation is right-frontal retrieval activations reflect working memory processes that guide or evaluate the products of episodic retrieval Nondeclarative or procedural memory…. Encompass the acquisition, retention, and retrieval of knowledge expressed through experience induced changes in performance. Measured by indirect or implicit tests where no reference is made to that experience Skill learning, repetition priming, and conditioning are classes of implicit tests that often reveal procedural memory processes dissociable from declarative memory Gavrielli, Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory” Memory”, Annu. Annu. Rev. Psychology, 49,8749,87-115. Memory systems…. Nyberg and Tulving discuss memory systems as 4 major human memory systems Episodic, semantic, perceptual representation (PRS), and procedural Nyberg and Tulving, Tulving, (1996), “Classifying Human LongLong-Term Memory: Evidence from Converging Dissociations” Dissociations”, European Journal of Cognitive Psychology, 8(2), 163163-183. Dissociations ….. Nyberg & Tulving hypothesize dissociations yielded by task comparisons as partial evidence for multiple memory systems Memory processes differ with respect to rules of operation and component processes 4 kinds of dissociations…. 1. Functional dissociations: different values of independent variables 2. Developmental dissociations: stages of ontological development 3. Pharmacological dissociations: drug-induced brain states 4. Brain-damage dissociations: the presence or absence of brain damage Studies …… Many studies were reviewed and it was found to demonstrate existence of dissociations as well as contributing to the neuroanatomical localization of memory functions Localizations…. Nyberg & Tulving review suggest the two declarative systems (episodic and semantic) seem to depend on integrity of medial temporal lobe structures Frontal lobe structures have been found to be critical for both episodic and semantic memory, but different frontal regions seem to be important for the 2 systems Frontal regions in the left hemisphere are more involved in semantic and right hemisphere for episodic PET studies suggest cerebellum plays an important role in these 2 systems Occipital brain structures are critical for visual subsystem of perceptual representation Midbrain structures in procedural memory has been confirmed by several PET studies Findings…. Nyberg & Tulving concluded that the survey of exisiting dissociations can be encouraging And these studies can play an important role in shaping our ideas about classifying memories More research… There is a lot of evidence to support memory localization and systems which leads the way to studying recovery and plasticity of the brain If memory systems are in fact located in more than one place in the brain and is more of a network, why can’t the brain plasticity aid in recovery of functions? Further research is much needed and encourged with positive hypothesis agreed upon.