Synaptic plasticity, memory and the hippocampus: a neural network approach to causality

• Published in: Nature reviews. Neuroscience Vol. 9; no. 1; pp. 65 - 75
• Main Authors: Bliss, Tim V. P, Neves, Guilherme, Cooke, Sam F
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2008; Nature Publishing Group
• Subjects: Academic achievement; Alzheimer's disease; Animal Genetics and Genomics; Animals; Behavioral Sciences; Biological and medical sciences; Biological Techniques; Biomedical and Life Sciences; Biomedicine; Brain-derived neurotrophic factor; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Cognition & reasoning; Cognitive ability; Dementia; Exercise; Fundamental and applied biological sciences. Psychology; General aspects. Models. Methods; Growth factors; Hippocampus (Brain); Hippocampus - physiology; Humans; Hypotheses; Information storage; Learning - physiology; Long-Term Potentiation - physiology; Memory; Memory - physiology; Models, Neurological; Multiple sclerosis; Nerve Net - physiology; Neural circuitry; Neural networks; Neurobiology; Neuronal Plasticity - physiology; Neuroplasticity; Neurosciences; Older people; opinion-2; Physical education; Physical fitness; Physiological aspects; Polymorphism; Synapses - physiology; Trends; Vertebrates: nervous system and sense organs; United States; United Kingdom; United States > US; California; Human; Theory; Memory; Central nervous system; Review; Neural network; Encephalon; Synapse; Neuron; Storage; Synaptic plasticity; Causality; Hippocampus
• ISSN: 1471-003X; 1471-0048; 1469-3178
• DOI: 10.1038/nrn2303

The hippocampus has an undisputed role in memory and has been key in discovering synaptic plasticity as the basis for learning. Bliss and colleagues provide an update on unresolved problems that surround LTP and memory, and propose strategies for finding answers that centre on new technologies. Two facts about the hippocampus have been common currency among neuroscientists for several decades. First, lesions of the hippocampus in humans prevent the acquisition of new episodic memories; second, activity-dependent synaptic plasticity is a prominent feature of hippocampal synapses. Given this background, the hypothesis that hippocampus-dependent memory is mediated, at least in part, by hippocampal synaptic plasticity has seemed as cogent in theory as it has been difficult to prove in practice. Here we argue that the recent development of transgenic molecular devices will encourage a shift from mechanistic investigations of synaptic plasticity in single neurons towards an analysis of how networks of neurons encode and represent memory, and we suggest ways in which this might be achieved. In the process, the hypothesis that synaptic plasticity is necessary and sufficient for information storage in the brain may finally be validated.