Examination for Professional Practice of Psychology (EPPP) Practice Test

Which neurotransmitter is linked to both long-term potentiation and excitotoxicity in neurodegenerative disorders?

1. Serotonin

2. Acetylcholine

3. Norepinephrine

4. Glutamate

The correct answer is: Glutamate

Glutamate is recognized as the primary excitatory neurotransmitter in the central nervous system, playing a crucial role in synaptic plasticity, particularly long-term potentiation (LTP), which is essential for learning and memory. LTP strengthens the efficacy of synapses based on recent patterns of activity, a process highly dependent on glutamate signaling, particularly at the N-methyl-D-aspartate (NMDA) receptors. In the context of neurodegenerative disorders, excessive glutamate signaling can lead to excitotoxicity. This occurs when there is an overstimulation of glutamate receptors, resulting in increased calcium influx into neurons, which can lead to cellular damage or death. This mechanism has been implicated in various neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and multiple sclerosis, highlighting the dual nature of glutamate as both a facilitator of neural communication and a potential neurotoxin when dysregulated. Thus, the association of glutamate with both the processes of long-term potentiation and excitotoxicity underscores its critical role in both normal cognitive functioning and pathological conditions.