in MCI patients without TD and that the presence of TD in MCI patients is associated with loss of gray matter in the medial temporal regions, including the hippocampus. Hippocampal damage and schizophrenia Research with rats indicates that spatial memory may be adversely affected by neonatal damage to the hippocampus in a way that closely resembles schizophrenia. Schizophrenia is thought to stem from neurodevelopmental problems shortly after birth. Rats are commonly used as models of schizophrenia patients. Experimenters create lesions in the ventral hippocampal area shortly after birth, a procedure known as neonatal ventral hippocampal lesioning(NVHL). Adult rats who with NVHL show typical indicators of schizophrenia such as hypersensitivity to psychostimulants, reduced social interactions and impaired prepulse inhibition, working memory and set-shifting. Similar to schizophrenia, impaired rats fail to use environmental context in spatial learning tasks such as showing difficulty completing the radial arm maze and the Moris water maze. GPS (Global Positioning System) Recent research on spatial memory and wayfinding in an article by Ishikawa et al. in 2008 revealed that using a GPS moving map device reduces an individual's navigation abilities when compared to other participants who were using maps or had previous experience on the route with a guide. GPS moving map devices are frequently set up to allow the user to only see a small detailed close-up of a particular segment of the map which is constantly updated. In comparison, maps usually allow the user to see the same view of the entire route from departure to arrival. Other research has shown that individuals who use GPS travel more slowly overall compared to map users who are faster. GPS users stop more frequently and for a longer period of time whereas map users and individuals using past experience as a guide travel on more direct routes to reach their goal. NEIL1 Endonuclease VIII-like 1 (NEIL1) is a DNA repair enzyme that is widely expressed throughout the brain. NEIL1 is a DNA glycosylase that initiates the first step in base excision repair by cleaving bases damaged by reactive oxygen species and then introducing a DNA strand break via an associated lyase reaction. This enzyme recognizes and removes oxidized DNA bases including formamidopyrimidine, thymine glycol, 5-hydroxyuracil and 5-hydroxycytosine. NEIL1 promotes short-term spatial memory retention. Mice lacking NEIL1 have impaired short-term spatial memory retention in a water maze test. Learning difficulties Nonverbal learning disability is characterized by normal verbal