Protects the Brain and its Function
From traditional medicines of China and India, turmeric has been credited with wellbeing and functionality of the most important organ—the brain. As mentioned in other parts of this article, turmeric has been a popular research topic for scientists for decades including its affect on the nervous system.
As a mighty antioxidant, curcumin protects the brain and the nervous tissue in number of ways. Studies showed that curcumin reduces oxidative stress by readily crossing the blood-brain barrier and directly engaging ROS. Human trials show similar benefits. Curcumin improved attention, memory, cognition and mood of elder participants.  Same group showed lower LDL and overall cholesterol with no side effects within blood markers. 
Improves Memory and Cognition
Neurons are specialized cells of the nervous systems that carry messages in form of electrical impulses. Neurons come in various classes (sizes) that communicate with each other and other tissues through small gaps called synapses. These synapses can be chemical or electrical based transmitting the signals (aka neurotransmission) between nerve cells, or from neurons to specific tissues (ie: organs, muscle, glands). Brain-derived neurotrophic factor (BDNF) is a transcription protein that is found in the brain and spinal chord (central nervous system). BDNF regulates production and maintenance of neurons. It also shown to form new connections in the brain by producing new nerve cells.[74,75] BDNF is located inside the synapses and modifies neural communication based on individual experiences. This is referred to neuroplasticity and is essential for skills like learning and long term memory.
Studies shown that curcumin increases BDNF levels leading to the rise of neurons and neuroplasticity (aka synaptic plasticity).[77,78] Greater BDNF concentrations via curcumin also reduce inflammation factors like COX-2 in the brain. More nerve cells and connectivity is an exciting research area which potentially can delay and/or reverse neurodegenerative diseases. 
Combats Neurological Disorders
As already mentioned, high BDNF levels are linked to healthier brain, better memory and mood, including in the elderly. The reverse is true, as low BDNF concentrations result degeneration leading to various neural conditions like Alzheimer’s disease. Alzheimer’s is the most common type of dementia, accounts for about 60 to 80 percent of all dementia cases. Neuro-inflammation and oxidative stress further contribute to progression of Alzheimer’s and other neural disorders. Curcumin is a very promising treatment, as it may reduce Alzheimer’s disease in multiple ways with no reported side effects.
One of the Alzheimer’s hallmark signs is the buildup of protein tangles/clusters called amyloid plaques (amyloid-beta-protein and tau).[71,94] Curcumin can cross the blood-brain barrier and use its mighty antioxidant powers to scavenge ROS reducing cellular damage and neuro-inflammation.[71,95,96] Studies shown that curcumin blocks production of the amyloid plaques by directly binding to them.[94-97] Also, besides reducing beta-amyloid proteins curcumin increases immune response within the brain tissue. Curcumin activates macrophages which clear away amyloid build up.
Another active compound in turmeric is turmerone that has strong potential in treating neurodegenerative conditions. Test tube and animal studies show turmerone’s ability to stimulate production of new neurons by influencing neural stem cells in the brain. Neural stem cells have ability to transform into any kind of brain cell, and potentially repair damaged or diseased neural tissue. Due to its ability to activate and proliferate (transform) brain stem cells turmerone is showing a lot of promise in treating brain diseases such as Alzheimer’s, Parkinson, brain cancer and stroke.
Depression has constant or re-occurring periods (episodes) of feeling sad and having lack of interest. Depression often accompanies other diseases and shown to have lower levels of monoamine neurotransmitters (norepindephrine, serotonin and dopamine) in the brain. Curcumin shown as a potent antidepressant agent.[79-81] Besides increasing BDNF levels, curcumin can also boost other monoamine neurotransmitters such as serotonin and dopamine (norepinephrine levels unchanged).[82,83] Randomized study of 60 patients with depression showed that curcumin was able to improve the mood on par with prescription antidepressants (Prozac), while combined treatment (curcumin + Prozac) produced even greater results after 6 weeks.
Reduces Risk of Strokes
Ischemic stroke is a condition when brain arteries become narrowed or blocked, causing severely reduced blood flow (ischemia). The stroke treatment and the unblocking of the cerebral artery produces sudden rush of blood, causing the injury inflammation to the area called ischemia reperfusion injury (IRI). Studies shown that curcumin can help reduce the damage caused by the stroke, restoring tissue and improving healing afterwards. Curcumin reduced oxidative damage during reperfusion phase. [86,87]
Taking curcumin before the stroke also reduced overall inflammation afterwards, and minimized the infarcted zone. Microglia cells are the type of macrophages and are the main form of immune defense in the central nervous system (CNS). Once activated, microglia can perform diverse tasks by becoming different versions of itself (phenotype) initiating immune responses. The M1 type microglia is the initial respondent that is able to produce pro-inflammatory proteins (cytokines) and fats (chemokines). The M2 type microglia does the opposite, releasing anti-inflammatory factors and decreasing overall inflammation. Curcumin’s antioxidant and anti-inflammatory properties shown to decrease M1 microglia and overall inflammation markers while increasing M2 microglia levels. Ability to shift microglial population from M1 to M2 makes curcumin a strong potential treatment for post stroke related injuries. Overall research shows that taking curcumin can reduce the damage caused by the stoke.
Relieves Anxiety and Stress
In the modern day we seem to be always on the go, connected through work, socialization and tech devises to the grid of stressors. Our bodies engage these challenges (regardless of size, magnitude or importance) through a stress-response, shifting from calm—parasympathetic nervous system (rest-and-digest) to, ready—sympathetic nervous system (fight-or-flight). Continuous activation of the stress-response wears and tears our systems eventually leading to physiological, psychological and emotional symptoms like fatigue, lethargy and anxiety to name a few.
Spices like turmeric can help relieve stress and anxiety, as many of such conditions share similar biochemical markers. Scientists have big hopes for curcumin when it comes of reliving stress and anxiety. Taking curcumin by itself or with other antidepressant herbs (saffron) minimizes anxiety and depression symptoms in major depressive disorder (MDD) patients. Another human study of curcumin with fenugreek dietary fiber showed significantly reduced stress, anxiety and fatigue. The curcumin/fenugreek mixture produced a potent antioxidant blend which reduced cellular damage, lipid peroxidation while increasing protective enzymes (GPx, SOD) and compounds (GSH). Curcumin was also found to improve the mood and physical symptoms in women with premenstrual syndrome (PMS), by elevating their BDNF (the brain factor).
Further, curcumin shown to increase the bioavailability of docosahexaenoic acid (DHA)—an omega-3 fatty acid essential to brain’s development and protection. Low DHA levels have been linked with neurological disorders as well as depression and anxiety. Curcumin reduces anxiety symptoms in stressed animals by increasing DHA and BDNF production while stabilizing adrenal gland (gland that mediates body’s stress response) and its hormones (like cortisol and other glucocorticoids).[77,104]
Being stressed often comes with being tired and fatigued. It is a common problem for many, as we often looking to boost energy through consuming more coffee, energy drinks or chocolate bars. However, research shows that adding cucumin to your diet can dramatically decrease fatigue and lethargy, especially in older population. Being a potent antioxidant, curcumin reduced several inflammation markers which contribute to symptoms of chronic fatigue syndrome including immobility and hyperalgesia (greater sensitivity to pain). [138,139]
Helps You Sleep
Being constantly stressed or worried elevates oxidative stress and can lead to numerous physical and psychological conditions like anxiety, restlessness and/or insomnia. The mind worries raise stress-response hormones like epinephrine, norepinephrine and cortisol creating excitation and inhibiting sleep. Turmeric has been studied for every possible human condition, including sleep deprivation. It has shown to restore antioxidant enzymes and locomotor ability in 72 hour sleep-deprived animals. Curcumin treatment reduced oxidativce stress, anxiety symptoms and believed to be involved in nitrogen oxide (NO) regulation in studied animals. NO is a gas and neurotransmitter naturally produced in the body. Higher NO levels produce numerous health benefits including better blood circulation, immunity, cognition, sex drive and sleep.[148,149]
Chronic stress makes it difficult to “wind down” and is one of the causes for insomnia. As discussed before, stress invokes immune response by raising various cytokines (inflammatory proteins). Specific cytokines have also shown to disrupt sleep. Turmeric’s powerful antioxidant and anti-inflammatory properties decrease number of cytokines (NF-kB, TNF, IL-1, IL-2, IL-8) and inflammation enzymes (COX-2, iNOS). As the result, turmeric and/or curcumin improve overall mood, reduce depression like symptoms, balance hormones leading to a calm and relaxed state.[150,151]