Diseases & Workings of the Central Nervous System Quiz

Answer: Amyloid-beta

Amyloid-beta is meant to ensure its designated neuron remains healthy and free of pathogens. However, when amyloid-beta is 'recycled' sometimes it is not cleaved (chopped up) properly, making some of the proteins too large to be engulfed and re-used. These large proteins aggregate around the cell, and in between the synapses, eventually causing large plaques which disrupt cell-to-cell communication and can even inflame surrounding neurons - causing them to die.

This wide-spread atrophy is a leading pathology of AD.

Answer: Pyramidal cells

Pyramidal cells account for 70% of cells in the CNS, while interneurons are more local and serve to enhance or inhibit pyramidal cells. Astrocytes are similar to interneurons, and blood cells are found everywhere in the body - not just the CNS.

Answer: Frontal lobes

The temporal lobe receives auditory information, while the occipital and V1 areas receive visual. Although the frontal lobes may use sensory information to create goals and direct behaviour because of this information, this area does not receive sensory information directly.

Answer: Parkinson's disease (PD)

PD affects the substantia nigra and basal ganglia - the primary location for motor processing and is heavily connected with dopaminergic neurons.

Answer: Event-related potentials (ERP)

ERP allows for the recording of electrical brain activity that occurs at a millisecond rate. Because of the high temporal resolution, one can use ERP to measure two specific neural responses that occur close in time. The other available answers do not permit this measure at such a high temporal resolution as ERP does.

Answer: Huntington's disease (HD)

Huntington's disease is caused when the CAG repeat of the Huntingtin gene on chromosome 4 is mutated, expanding larger than 40 repeats. When this occurs, several molecular abnormalities are caused when the Huntingtin gene is transcribed into a protein; the protein is malformed because its gene is longer than normal - causing it to become toxic.

This toxicity is what leads to the degeneration of the basal ganglia and other regions like the cerebellum. This causes profound personality changes, emotional apathy and motor dysfunction.

Answer: Dreaming or hallucinating

Some research suggests that dreaming occurs when the association cortices are active but the primary cortices are not. This means that one can experience a visual or auditory episode even when one is not exposed to direct sensory input. Other research also suggests similar brain activations occur in patients who experience hallucinations, typically found in schizophrenia, where patients have overactive association cortices, possibly indicating the patient is having a dream-like experience whilst awake - i.e. a hallucination.

Answer: Dopamine; it blocks dopamine reuptake between synapses

Cocaine blocks dopamine re-uptake between synapses. Because dopamine cannot be recycled, it remains active within the post-synaptic cell - leading to more and more dopamine being included within the synaptic cleft leading to a sense of euphoria and alertness.

However, the effects of cocaine wear off within a couple of hours. After the effect has subsided, the body is temporarily left without a normal level of dopamine - leading to 'come-down' effects, such as low mood, low energy, and in extreme cases, suicidal thoughts.

Answer: Oxytocin

Dopamine is more for reward sensation and awareness. Norepinephrine and epinephrine are similar and fall under the category or 'adrenaline', meaning they are important for alertness and initiating strong behaviours. Oxytocin is important for bonding in social animals.

In cases of animals who do not bond with their mates, oxytocin is low, but in cases of animals that choose a mate for life (like humans, penguins, and voles) oxytocin is high, especially in the presence of their mate, or after birthing.

Answer: Glutamate

Glutamate is the most widely used transmitter in the CNS. GABA is similar, except it is mainly inhibitory, whereas glutamate is mainly excitatory. Dopamine and epinephrine are adrenalin-type transmitters and are used for alertness, strong action initiation, and reward sensation.