Bio Sci Questions & Answers Interlude #2

Why are there many antidepressants selective serotonin reuptake inhibitors (SSRI)?

Many antidepressants are selective serotonin reuptake inhibitors (SSRI) or serotonin and norepinephrine reuptake inhibitors (SNRI)

Where in the synapse do SSRI work?

SSRI and SNRI work on the presynaptic neuron

What findings would refute the monoamine hypothesis of depression?

1) A successful antidepressant (tianeptine) does not raise monoamine levels

2) Some people with depression do not have decreased levels of monoamines

3)Lesioning monoaminergic systems does not always induce or worsen depression

What is the role of dopamine in the reward circuitry?

Acts as a key neurotransmitter in the brain's reward circuitry, signaling pleasure and motivating an organism to repeat behaviors that lead to rewarding experiences by releasing a burst of dopamine when a positive stimulus is encountered

Essentially telling the brain to remember and repeat that action to achieve the reward again; this is crucial for learning and motivation.

They report reward delivery for the most part.

What are the differences seen between white and grey matter?

White matter is composed of white myelinated axons

Grey matter is composed of unmyelinated cell bodies

What does a loss of cell bodies in the prefrontal cortex
mean?

1) LESS REGULATION of the amygdala (the
emotional control center for the brain).
2) REDUCED ABILITY to regulate emotions on a
moment-by-moment basis
3) DIFFICULTY dealing with emotions
4) DIFFICULTY deciphering when it’s appropriate to
express emotions

What was the main difference found when it came to “successful” and “non-successful” criminals?

Increased prefrontal grey matter volume

What does the AMYGDALA for us?

Influences our motivation, emotional control, fear response and interpretations of nonverbal emotional expressions

What does the HYPOTHALAMUS for us?

To some extent, Regulates fear, thirst, sexual drive, sleep, and aggression

How come we can make the claim that “attack neurons in the VMHvl are sufficient to elicit aggression?

Activation of these neurons by channelrhodopsin is enough to cause aggressive behavior

What is an optogenetic tool?

A research tool that uses light-sensitive proteins to control neurons in living tissue

Halorhodopsin experiments show what?

Attack neurons in VMHvI are necessary to elicit aggression

If attack neurons are necessary what does that mean?

That aggression cannot occur without attack neurons.

What are the main differences when it comes to sufficiency versus necessity?

• If something is sufficient for a function it means it is enough to perform the function itself.

• If something is necessary for a function and cannot function without it, you cannot perform the function

Is eating a form of necessity or sufficiency?

Both: eating is necessary but it is not sufficient for survival as you also need water, oxygen, etc.

What do you need to do in order to test if something is sufficient or necessary?

• To test if something is sufficient, one would need to activate it.

• To test if something is necessary, one would need to inactivate the neuron.

___ can be used to inactivate neurons.
Inactivating neurons in the VMHvl & LOSS of
aggression shows that attack neurons are
___ to trigger aggressive behavior

Halorhodopsin; Necessary

What do we learn from raising aggressive flies?

Nature and nurture act to control aggression by influencing common genes.

What does explicit emotional processing mean?

Conscious, declarative evaluation of emotional states

What does implicit emotional processing mean?

Unconscious, automatic processing of emotional stimuli

What does sensory transduction do?

Converts various forms of energy located
outside of the body (e.g. light rays, sound
waves, mechanical forces, or chemicals)
into neural signals

Is the eye a part of the central nervous system (CNS)

Of course!

How many photons of light are required to activate a rod photoreceptor?

one.

Based on the density of photoreceptors at
different parts of your retina, how should you
look at something if you want to see it clearly in
dim lighting?

Looking at the object when it is just a small
angle away from the center of your view

How does a photoreceptor detect light?

Rhodopsin molecules in outer segment of a photoreceptor under goes conformational change when struck by a photon.

What is a characteristic of the g-protein cascade?
How does this property aid the function of the visual
system?

Amplification. Allows sensitivity to a single
photon

What brain region was likely affected in this
disorder (called akinetopsia)?

Dorsal Steam

What brain region is likely affected in
prosopagnosia?

Ventral Stream

What is akinetopsia?

A rare neurological disorder that makes it difficult to perceive movement. People with akinetopsia may have difficulty perceiving motion in depth or rapid motion, and may see fast targets appear to jump. They may also have trouble perceiving differences in speed or direction.

What is prosopagnosia?

Face blindness. People see faces normally, but they can't recognize them

What kind of stimulus is a sound wave? What kind of sensor is needed to detect a sound wave?

Mechanical stimulus needs a mechanoreceptor
to detect movement

High sound frequencies cause maximal
vibrations near the cochlea’s base. What
sounds cause max vibrations in the apex?

Low pitch sounds

What kind of sensor is needed to provide information about equilibrium spatial orientation and motion?

Mechanoreceptor to detect movement and tilt

How many different tastes do we have?

Five

Where in the tongue are
these taste buds located?

Intermixed throughout the
tongue.

Where are taste buds located?

Stomach, intestines, deep groves at the back and sides of the tongue, tips to tiny mounds on the tongue

What would happen to your sense of taste if you
did not have T1R2?

No attraction to sweet

What is cribriform plate?

The part of the ethmoid bone that forms the roof of the nasal cavity and is the thinnest portion of the base of the skull. A horizontal bone plate that forms the roof of the nasal cavity and separates it from the brain

What is the relationship between odorants
and receptors?

A particular odorant activates a specific combination
of receptors.

Which container holds a spicier liquid?

A) Oil infused with chili peppers

B) Water infused with chili peppers

Oil infused with chili peppers

Help! I just spent an hour cutting
jalapeño peppers. Now my hand is
burning. What can I use to stop the
pain?

TRPV1 antagonist

Which of the spinal cord tracts below is likely to transmit sensory information?

Spinothalamic

What do you notice about the representation of the homunculus in the somatosensory cortex?

Larger representation for skin with smaller receptive fields

What is retinotopy and tonotopy?

1) Retinotopy is the process of mapping visual input from the retina to neurons in the brain, particularly in the visual stream. It's also known as retinal mapping.

2) The organization of neurons in the auditory system based on their response to different sound frequencies

Retinotopy refers to the spatial organization of visual information in the brain, where neighboring points on the retina are represented by neighboring areas in the visual cortex, essentially creating a "map" of the visual field on the brain, while tonotopy is the spatial arrangement of neurons in the auditory system based on their sensitivity to different sound frequencies, meaning that neurons responding to similar pitches are located close together in the brain; both are examples of topographic maps where sensory information is organized in a spatially consistent manner based on the physical layout of the sensory organ

What is chemotopy? How does retinotopy and tonotopy contrast with chemotopy?

Chemotopy is the hypothesis that the olfactory bulb's glomeruli are grouped into regions based on the chemical features of the odorants that activate them. The idea is that nearby glomeruli are tuned to odors that share similar molecular features.