Select all of the following options that identify the primary excitatory neurotransmitter responsible for mediating long-term potentiation (LTP) and synaptic plasticity in the mammalian central nervous system:

### Why this is right - **Glutamate** is identified as a modulator involved in learning and synaptic strength. - **Dopamine** is identified as a modulator involved in learning and synaptic strength. - **Acetylcholine** is identified as a modulator involved in learning and synaptic strength. ### The concept Neurotransmitters are chemical messengers used in communication between neurons. The material names glutamate, dopamine, and acetylcholine as important in modulating synaptic strength and supporting forms of learning. Endogenous opioids are discussed in relation to pain relief and pleasure, rather than in this list of learning-related modulators. ### The other options - **D. Endogenous opioids**: These chemicals contribute to pain relief and pleasure in the material; they are not included in its stated list of learning modulators. ### Terms - **Neurotransmitter**: A chemical messenger used by neurons to communicate. - **Endogenous opioids**: Naturally produced chemicals associated with pain relief and pleasure. ### Remember For the learning-related list in this material, recall glutamate, dopamine, and acetylcholine.