>Aged Garlic Extract may be less effective. stick to the fresh stuff

But

https://greyduckgarlic.com/garlic-boosts-learning-and-memory.html

Garlic increases serotonin concentrations in the brain (Haider et al. 2008). High serotonin concentrations are associated with improved brain functions such as learning, memory and mood.

Aged garlic extract inhibits cortical acetylcholinesterase (AchE) while increasing glutathione (GSH) concentrations (Mukherjee and Banerjee 2013). GSH is a potent internal antioxidant that protects brain cells from free radical damage. Some treatments for Alzheimer's disease use AchE inhibition. AchE inhibition may affect executive and attentional cognitive functions (Bohnen et al. 2005).

Ethyl acetate extracts from aged garlic protects nerve cells from Aβ-induced ROS generation in vitro (Jeong et al. 2013).

Aged garlic compounds, in particular S-allyl-L-cysteine, protects neural cells from ROS. Interestingly, pretreatment of cells with garlic extract protected 80% of cells from ROS-mediated damage. It also protected pre-synaptic proteins (Ray et al. 2011). This may be beneficial in treating Alzheimer's Disease (Chauhan and Sandoval 2007, Ray et al. 2011).