Key Concepts in Neurobiology: Eating, Thirst, and Sleep Regulation

These flashcards cover key concepts related to neurobiology, focusing on the regulation of eating, drinking, and sleep.

What happens when AgRP neurons are ablated with diptheria toxin?

It results in starvation.

How does activating AgRP neurons affect feeding?

It increases feeding.

How does leptin affect AgRP and POMC neurons?

Leptin oppositely affects AgRP neurons and POMC neurons, which then oppositely control downstream neurons.

What do AgRP neurons and POMC neurons integrate to regulate eating?

They integrate hormonal and viscerosensory cues.

What is the function of SFO neurons in hydration?

Optogenetically activating excitatory SFO neurons increases drinking behavior.

What is necessary for water drinking behavior according to the lecture?

The MnPO brain region is necessary.

What are the two theories of motivation driving hunger and thirst behavior?

Drive reduction theory and incentive salience theory.

What happens when MnPO neurons are stimulated during dehydration?

They trigger water dispense or pause stimulation.

What role do circadian rhythms play in sleep?

They are driven by auto-inhibitory transcriptional feedback loops.

What is the significance of the SCN (suprachiasmatic nucleus) in circadian rhythms?

It is essential to circadian rhythms; lesioning it causes arrhythmicity.

How do hypocretin-expressing neurons affect wakefulness?

Activating these neurons in the lateral hypothalamus increases the likelihood of awakening.

What does the glymphatic system do during sleep?

It clears metabolic waste, including beta-amyloid peptides.

What is the main function of POMC neurons in relation to feeding?

They suppress feeding.

How does ghrelin, often called the 'hunger hormone', stimulate feeding?

It activates AgRP neurons, promoting appetite.

What effect does insulin have on AgRP and POMC neurons?

Insulin, similar to leptin, inhibits AgRP neurons and stimulates POMC neurons to reduce food intake.

What type of cells in the SFO detect changes in blood osmolarity?

Osmoreceptors.

What hormone primarily mediates thirst in response to decreases in blood volume or pressure?

Angiotensin II.

What is the primary role of vasopressin (ADH) in hydration?

It promotes water reabsorption by the kidneys to conserve body fluid, also called antidiuretic hormone.

According to Drive Reduction Theory, what is the primary goal of motivated behavior?

To reduce an unpleasant internal state or 'drive', returning the body to homeostasis.

How does Incentive Salience Theory differ from Drive Reduction Theory?

It emphasizes the 'wanting' or 'craving' for a reward, separate from its 'liking' or hedonic impact, suggesting motivation can be independent of drive reduction.

What are the two main phases of sleep?

REM (Rapid Eye Movement) sleep and Non-REM (NREM) sleep.

What are the primary functions of NREM sleep?

It is crucial for physical restoration, growth, and consolidation of declarative memories.

What is the primary function of REM sleep?

It is important for emotional regulation, procedural memory consolidation, and brain development.

What key brain region regulates the sleep-wake cycle beyond the SCN?

The ventrolateral preoptic nucleus (VLPO) promotes sleep by inhibiting wake-promoting regions.

What is narcolepsy characterized by, and what is its link to hypocretin?

Excessive daytime sleepiness and sudden sleep attacks, often associated with a loss of hypocretin-producing neurons.