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In psychology, associative memory is defined as the ability to learn and remember the relationship between unrelated items. This would include, for example, remembering the name of someone or the aroma of a particular perfume.[1] This type of memory deals specifically with the relationship between these different objects or concepts. A normal associative memory task involves testing participants on their recall of pairs of unrelated items, such as face-name pairs.[2] Associative memory is a declarative memory structure and episodically based.[3]

ConditioningEdit

Two important processes for learning associations, and thus forming associative memories, are operant conditioning and classical conditioning. Operant conditioning refers to a type of learning where behavior is controlled by environmental factors that influence the behavior of the subject in subsequent instances of the stimuli. In contrast, classical conditioning is when a response is conditioned to an unrelated stimulus.

Location and circuitryEdit

The neuroanatomical structures that govern associative memory are found in the medial temporal lobe. The main locations are the hippocampus and its surrounding structures of the entorhinal, perirhinal, and parahippocampal cortices. Humans with large medial temporal lobe lesions have shown to have impairments in recognition memory for different types of stimuli.[4] The hippocampus has also shown to be the main location for memory consolidation, especially related to episodic memory. The inputs from these unrelated stimuli are collected in this location and the actual synaptic connections are made and strengthened.[5] Additionally, involvement from the prefrontal cortex,[6][7] frontal motor areas,[8] and the striatum has been shown in the formation of associative memories. Associative memory is not considered to be localized to a single circuit, with different types of subsets of associative memory utilizing different circuitry.[6]

Biological basisEdit

The associations made during the learning process have a biological basis that has been studied by neuroscientists for the last few decades. The convergence of the biologically important information drives the neural plasticity that is the basis of associative memory formation.[6]

Research and future workEdit

Associative memory becomes poorer in humans as they age. Additionally, it has been shown to be non-correlational with single item (non-associative) memory function.[9] Transcranial direct-current stimulation has improved performance on associative memory tasks.[2] Patients with Alzheimer's disease have been shown to be poorer in multiple forms of associative memory.[10]

Mathematical modelsEdit

Starting from Hopfield’s work,[11] mathematical modeling of memory formation and retrieval has been in the center of attention. For a long time, the ability to establish the relationship between unrelated items has been considered as an emergent feature of the nonlinear dynamics of large neural networks.[12] More recent experimental discovery of the so-called concept or grandmother cells ascribes some functions in episodic memory to single neurons.[13] Mathematical modeling of grandmother cells confirms that single neurons can indeed implement associative memory.[14] The associative property emerges in large assemblies of single neurons receiving a multidimensional synaptic input from afferent populations and synaptic plasticity obey the Hebbian rule.

ReferencesEdit

  1. ^ Suzuki, Wendy A. (February 2005). "Associative Learning and the Hippocampus". Psychological Science Agenda. American Psychological Association.
  2. ^ a b Matzen, Laura E., Michael C. Trumbo, Ryan C. Leach, and Eric D. Leshikar. "Effects of Non-invasive Brain Stimulation on Associative Memory". Brain Research 1624 (2015): 286-296.
  3. ^ Dennis, Nancy A., Indira C. Turney, Christina E. Webb, and Amy A. Overman. "The Effects of Item Familiarity on the Neural Correlates of Successful Associative Memory Encoding". Cognitive, Affective, & Behavioral Neuroscience 15.4 (2015): 889-900.
  4. ^ Ranganath, Charan, and Maureen Ritchey. "Two Cortical Systems for Memory-guided Behaviour". Nature Reviews Neuroscience 13.10 (2012): 713-26.
  5. ^ Cohen, Neal J., Jennifer Ryan, Caroline Hunt, Lorene Romine, Tracey Wszalek, and Courtney Nash. "Hippocampal System and Declarative (relational) Memory: Summarizing the Data from Functional Neuroimaging Studies". Hippocampus 9.1 (1999): 83-98.
  6. ^ a b c Fanselow, Michael S.; Poulos, Andrew M (2004-08-30). "The Neuroscience of Mammalian Associative Learning". Annual Review of Psychology. 56 (1): 207–234. doi:10.1146/annurev.psych.56.091103.070213. ISSN 0066-4308. PMID 15709934.
  7. ^ Becker, Nina, Erika J. Laukka, Grégoria Kalpouzos, Moshe Naveh-Benjamin, Lars Bäckman, and Yvonne Brehmer. "Structural Brain Correlates of Associative Memory in Older Adults". NeuroImage 118 (2015): 146-53.
  8. ^ Brasted P. J., Bussey TJ, Murray EA, Wise SP (2002). "Fornix transection impairs conditional visuomotor learning in tasks involving nonspatially differentiated responses". Journal of Neurophysiology 87: 631-633.
  9. ^ Becker, Nina, Erika J. Laukka, Grégoria Kalpouzos, Moshe Naveh-Benjamin, Lars Bäckman, and Yvonne Brehmer. "Structural Brain Correlates of Associative Memory in Older Adults". NeuroImage 118 (2015): 146-153.
  10. ^ Bastin, Christine, Mohamed Ali Bahri, Frédéric Miévis, Christian Lemaire, Fabienne Collette, Sarah Genon, Jessica Simon, Bénédicte Guillaume, Rachel A. Diana, Andrew P. Yonelinas, and Eric Salmon. "Associative Memory and Its Cerebral Correlates in Alzheimer's Disease: Evidence for Distinct Deficits of Relational and Conjunctive Memory". Neuropsychologia 63 (2014): 99-106.
  11. ^ Hopfield J.J. Neural networks and physical systems with emergent collective computational abilities. Proc Natl Acad Sci USA 79, 2554-2558 (1982)
  12. ^ Gurney K. An introduction to neural networks, Taylor & Francis, London, New York, 2014.
  13. ^ Quian Quiroga R. Concept cells: the building blocks of declarative memory functions. Nat Rev Neurosci 13, 587 (2012).
  14. ^ Gorban A.N., Makarov V.A., Tyukin I.Y. The unreasonable effectiveness of small neural ensembles in high-dimensional brain. Phys. Life. Rev. 29, 55-88 (2019).