Fecha: jueves13 de diciembre de 2018

Hora: 15:30h

Lugar: Sala de Graus, Facultat de Psicologia, Campus Mundet

Ponente: Veronique Bohbot, PhD McGill University

Resumen:

Experience, gender and cultural modulation of the risk of Alzheimer’s disease
 
A larger hippocampus has been associated with healthy cognition in normal aging and with a reduced risk of numerous neurological and psychiatric disorders such as Alzheimer’s disease, Schizophrenia, Post-Traumatic Stress disorder and Depression. The hippocampus is implicated in spatial memory strategies used when finding one’s way in the environment, i.e. it is allocentric and involves remembering the relationship between landmarks. On the other hand, another strategy dependent on the caudate nucleus can also be used, i.e. the response strategy, which relies on making a series of stimulus-response associations (e.g. right and left turns from given positions). Measures of spontaneous navigation strategies from ages 8 to 80 yrs have shown a decrease in spatial memory strategies across the life span, along with a reduction in activity and grey matter in the hippocampus in favor of caudate nucleus dependent response strategies. Caudate nucleus dependent strategies are modulated by reward seeking behaviors such as smoking and playing action video games, stress, cultural differences, gender and age.  
 
Interestingly, those using spatial memory in old age showed increased fMRI activity and grey matter in the hippocampus, suggesting a tight relationship between structure and function maintains in aging. Furthermore, super heathy individuals with the ApoE4 genotype, using response strategies, had atrophy in the entorhinal cortex, a region known to predict conversion rates to Alzheimer’s disease. Furthermore, patients with Alzheimer’s disease have a larger caudate nucleus than controls, suggesting that the caudate nucleus may play a more active role in Alzheimer’s disease than previously thought.   
 
In order to reverse this process and stimulate the hippocampus, we spent 5 years to develop a 16-h spatial memory improvement program that promotes the use of spatial strategies in over 50 different virtual environments, varying in size and complexity. Results indicate that completion of our cognitive intervention was associated with spatial memory improvements, increases in activity and grey matter of the hippocampus. Our findings suggest that spatial memory, which involves learning the relationship between environmental landmarks, is critical to hippocampal function which in turn, may have an impact on the incidence of neurological and psychiatric disorders.
 
Support: CIHR