Final answer:
The statement is true as neurotransmitters are essential at proper concentrations for brain functions like memory and learning, but can be toxic at high levels. This is exemplified by glutamate in Alzheimer's disease, where high levels lead to neuron death via excitotoxicity. Therefore, the balance of neurotransmitters is crucial for cognitive health.
Step-by-step explanation:
The statement 'High concentrations can be toxic; involved in most aspects of normal brain function like memory and learning' is likely referring to neurotransmitters, such as glutamate. In proper concentrations, neurotransmitters are critical for brain functions such as memory, learning, and cognition. However, at high concentrations, they can indeed become toxic. This is a phenomenon known as excitotoxicity, which can occur, for example, in the case of Alzheimer's disease, where excessive amounts of certain neurotransmitters can lead to the death of neurons.
One example of such a neurotransmitter is glutamate, which at appropriate concentrations supports learning and memory but can become harmful when unregulated due to conditions such as liver impairment, leading to cognitive decline. This harmful effect is also seen in other diseases and is a crucial consideration in the field of toxicology, where the concept of endocrine disruption at low exposures to certain chemicals has highlighted the nuanced relationship between neurotransmitter concentrations and health.
Therefore, while neurotransmitters are essential for brain function and cognitive learning, their levels must be tightly regulated, as both deficiencies and excesses can impair cognitive performance and result in neurological diseases. Learning, memory, and neurotransmitters are all interconnected components of cognitive science.