Nervous System, Neurons, and Neurotransmitters

Question 1

This neurotransmitter serves both excitatory and inhibitory functions. It contributes to movement, personality, mood, and sleep and has been identified as a contributor to several disorders. For example, a low level of it in the substantia nigra has been linked to Parkinson’s disease, while an excessive level in the caudate nucleus has been linked to Tourette’s disorder.

Answer 1

dopamine

Question 2

This dopaminergic pathway begins in the ventral tegmental area and ends in the ventral striatum (nucleus accumbens). It’s an essential part of the brain’s “reward circuit” and plays a role in the reinforcing effects of cocaine, amphetamines, nicotine, alcohol, opiates, and other substances of abuse (Adinoff, 2004). There’s evidence that the dorsolateral prefrontal cortex initiates the motivation to obtain a reward by sending signals to the ventral tegmental area and the nucleus accumbens.

Answer 2

Mesolimbic dopaminergic pathway

Question 3

This dopaminergic pathway begins in the ventral tegmental area and ends in the prefrontal cortex. It’s involved in emotion, motivation, and executive cognitive functions.

Answer 3

Mesocortical dopaminergic pathway

Question 4

This dopaminergic pathway begins in hypothalamus and ends in the pituitary gland and plays a role in hormone regulation, especially the inhibition of prolactin release.

Answer 4

Tuberoinfundibular dopaminergic pathway

Question 5

This dopaminergic pathway begins in the substantia nigra and ends in the dorsal striatum (caudate nucleus and putamen). It plays a key role in the production of purposeful movement.

Answer 5

Nigrostriatal dopaminergic pathway

Question 6

This neurotransmitter is both excitatory and inhibitory and is involved in movement, arousal, attention, and memory. With regard to movement, this causes muscles to contract. Myasthenia gravis is an autoimmune disorder that causes muscle weakness by destroying these receptors at neuromuscular junctions. With regard to memory, low levels of this in the entorhinal cortex and hippocampus have been linked to the early memory loss associated with Alzheimer’s disease.

Answer 6

Acetylcholine

Question 7

This neurotransmitter is an excitatory neurotransmitter and contributes to movement, emotions, learning, and memory. Excessive can cause cell damage and death, which is referred to as “_____-induced excitotoxicity” and is believed to contribute to a number of conditions including stroke, seizure disorders, and several neurodegenerative diseases including Huntington’s disease and Alzheimer’s disease.

Answer 7

Glutamate

Question 8

This is an excitatory neurotransmitter and is involved in arousal, attention, learning, memory, stress, and mood. According to the catecholamine hypothesis, some forms of depression are caused by a deficiency of this while mania is due to excessive levels.

Answer 8

Norepinephrine

Question 9

This neurotransmitter has an inhibitory effect and plays a role in many functions including arousal, sleep, sexual activity, mood, appetite, and pain.

Low levels of it in certain areas of the brain have been linked to depression, increased risk for suicide, bulimia nervosa, obsessive-compulsive disorder, and migraine headaches. There’s also evidence that people with anorexia nervosa have higher-than-normal brain levels of this which causes anxiety and obsessive thinking and that food restriction lowers these levels which alleviates these symptoms (e.g., Kaye, Fudge, & Paulus, 2009). Finally, higher-than-normal blood levels of this have been found in individuals with autism spectrum disorder and individuals with chronic schizophrenia who also have enlarged cerebral ventricles and/or cerebral atrophy.

Answer 9

Seratonin

Question 10

This is a primary inhibitory neurotransmitter and is involved in memory, mood, arousal, sleep, and motor control.

Low levels of this have been linked to insomnia, seizures, and anxiety, and benzodiazepines reduce anxiety and induce sleep by amplifying the effects of it. Degeneration of this and ACh cells in the basal ganglia contributes to the motor symptoms of Huntington’s disease.

Answer 10

GABA

Question 11

These neurotransmitters are inhibitory, and their effects are similar to those of opioid drugs – e.g., they contribute to feelings of pleasure and well-being and have analgesic effects. It’s believed that acupuncture may relieve pain by stimulating their release.

Answer 11

Enorphins