Such tasks demand the filling of the missing parts on the basis of input pattern stored in our memory. Let us take an example from the real life situation. We have multiple parking places for bicycles in the academic area. Even if you are asked later where your bicycle is you respond correctly because of input cues that trigger completion of the full encoded memory. In terms of brain representation, hippocampal system facilitates such pattern completions. There are lateral connections within the layer CA3 that enables spreading of partial activity to fill in the missing pieces.

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Experiments on laboratory rats have been largely performed on different types of mazes where the rats have to go for way-finding. An example of one such experiment is given below. Outcome of these studies endorse correlation between level of acetylcholinesterase enzyme (ACHE) in the brain and the ability to solve spatial problems. Rats trained and tested on more difficult problems had higher acetylcholinesterase in the cortex compared to those trained on easier tasks. Other experience-induced changes have also been reported. Studies have reported increase in the thickness of cortex, size of neurons nuclei, size of synaptic area and branching of dendrites (up to 25%) due to experience.