Reference no: EM132520889

Muscles are controlled by the nervous system. Muscles also send information back to the nervous system.

i. Describe one piece of information that muscles send back to the nervous system and a specialized receptor cell that detects and conveys that information.

Many songbirds are sexually dimorphic: only male songbirds sing. The brains of male and female songbirds are different, too: the motor cortex of males is twice as big as the motor cortex in females. However, if you inject a female songbird with testosterone when she is young she will learn to sing and her motor cortex will be bigger, but not if you wait to inject her with testosterone until she is an adult. This process is called masculinization.

ii. What stage of development do you think is particularly important for the masculinization of the female songbird's motor cortex and why?

Each songbird can produce 100 unique notes, which are simple movements akin to a monkey pointing its finger to a point in space. A bird creates a song by picking 5 of these 100 notes and singing them one after the other. Imagine that you're a scientist recording from all 1000 neurons in a songbird's motor cortex.

iii. How many unique notes do you think a single neuron in the motor cortex would typically be active during?

You want to decode what note a bird is singing by observing the activity of 1000 motor cortex neurons. During the first phase, you are allowed to observe the activity of all 1000 neurons as the bird sings each of its 100 notes a few times. In the second phase, the bird is placed in a sound proof room and he will sing 1 note.

iv. Why is the first phase important?

v. How will you use what you learned during the first phase to know what note the bird is singing in the second phase?