Posts Tagged ‘left hippocampus’

Sex Differences in Long Term Memory

September 13, 2019

This post is based on an important book by Scott D. Slotnick titled “Cognitive Neuroscience of Memory.” Remember to consult the website http://www.brainfacts.org/
to see the anatomical information referred to in this post.

Males usually perform better on navigating previously learned environment. Females usually perform better on long-term memory tasks that can depend on verbal memory such as word list recognition and recall, associative memory, and autobiographical memory. Since almost all long-term memory tasks can be performed using verbal memory strategies, females generally have better behavioral performance than males. Females have larger numbers of estrogen receptors in the hippocampus and dorsolateral prefrontal cortex. These are two of the three regions associated with long-term memory, which can increase the activity of these regions. The hippocampus and the dorsolateral prefrontal cortex are larger in females than males, relative to overall brain size. Additionally, females have relatively larger volumes of language processing cortex, which likely contributes to their superior verbal memory.

In addition, females and males often employ different cognitive strategies and have distinct patterns of brain activity while they perform the same task. An fMRI study investigated whether there were sex differences in the hippocampus during memory for object-location associations. There were 10 female and 10 male participants. During study blocks, participants viewed a video as if they were walking through a virtual environment with five colored geometric objects. During recognition blocks, an aerial view of each object was shown in a old location or a new location. Participants responded whether each was in an “old” or “new” location. Each participant also used a four-point rating scale to describe the strategy they used to learn the object locations: (1) completely verbal, (2) more verbal than pictorial, (3) more pictorial than verbal, and (4) completely pictorial.

Although there was no difference in behavioral performance between female participants and male participants, the average strategy for female participants was 2.5 and the average strategy rating for male participants was 4.0 indicating that female participants employed more verbal memory strategies and male participants employed purely spatial/non-verbal strategies. The fMRI data indicated that activity was localized to the left hippocampus in the large majority of female participants and that activity was localize to the right hippocampus in the large majority of male participants. These results are consistent with patient studies indicating the lesions in the left medial temporal lobe impair verbal memory and lesions in the right medial temporal lobe impair visual memory.