Neurological DisordersLesson 4.5How do circuits regulate their output?

Do Now:

• Review last night’s homework with a partner.

• Be sure you can:

– Describe the how the SCN connects to the flip-flop switch (sleep-wake circuit).

– Describe how the activity of the SCN is regulated.

VLPO Arousalneurons

How does the SCN connect?

Orexin neurons

Arousalneurons

VLPO

Orexin neuronsSCN

Pineal Gland

Light

How does the SCN connect when there is light?

VLPO

Arousalneurons

Orexin neurons

Melatonin

How does the SCN connect in darkness?

Dark

SCN

Pineal Gland

Clock Genes

How is the activity of the SCN controlled?

Clock Proteins

Behaviors & Activity

Feedback InhibitionWhat is this type of control called?

Why do traffic lights have both green and red lights?

Student Model of Neuronal Control

Excitatory neuron (1)

Inhibitory neuron (1)

Primary Neural Cell Body

Output (ON/OFF)

Input

What is this type of inhibition called?

Student Model 1

Feedback inhibition

Excitatory neuron (1)

Inhibitory neuron (1)

Primary Neural Cell Body

Output (ON/OFF)

Inhibitory neuron (2)

Input

Excitatory neuron (2)

What is this type of inhibition called?

Student Model 2Input

Feed-forward inhibition

Excitatory neuron

Inhibitory neuron

Primary Neural Cell Body

Output (ON/OFF)

Inhibitory neuron

Input

Excitatory neuron

Neuronal ControlInput

Feed-forward inhibition

Feedback inhibition

Neurons in which feedback and feed-forward control is important

Why do we need feedback and feed-forward control?

Jet Lag Seasonal Affective Disorder

Monday Morning Blues