Monday, 30 March 2015
Is There an Evolutionary Continuity between Spatial Navigation and Declarative Memory?
Sometimes someone comes up with a hypothesis whose parts fit together so neatly that it seems amazing that no one has ever thought of it before. A good example is the hypothesis proposed by György Buzsáki and Edvard Moser in the January 2013 issue of the journal Nature Neuroscience, where they propose that there is an evolutionary continuity between the cognitive processes that we use to orient ourselves in space and and the mechanisms that underlie our declarative memory. (more…)
Saturday, 14 March 2015
The “Coming Out” of the Electrical Synapse
The first living organisms composed of more than one cell first appeared on Earth slightly over 3 billion years ago. Once they did, the need arose for all of the cells in each organism to co-ordinate their efforts toward a single goal: the survival of the organism as a whole. To do so, these cells began secreting molecules that, by binding to the surface of other cells, informed them about what was happening elsewhere in the organism.
That, in short, is the origin not only of the human hormonal system but also of human synapses: the connections between nerve cells. In general, when people talk about synapses, they are referring to chemical synapses, into which neurotransmitters are released by the presynaptic neuron, then migrate across a space measured in nanometres to bind to receptors on the postsynaptic neuron on the other side.