Question

A monkey with an intact MT cortex can detect the direction of moving dots when coherence is 1-2%, while a monkey with a lesioned MT cortex detects the direction when coherence is:

a) 0-1%
b) 2-3%
c) 4-5%
d) 6-7%

Answer 1

A monkey with a lesioned MT cortex generally requires motion coherence of 4-5% to detect the direction of moving dots, indicating a reduced sensitivity to motion compared to a monkey with an intact MT cortex.

Step-by-step explanation:

The question you're asking relates to the ability of monkeys to detect the direction of moving dots with varying levels of coherence and how this ability is affected by lesions in the MT (middle temporal) visual cortex.

Monkeys with an intact MT cortex can detect the direction of motion at very low coherence levels (1-2%). After MT cortex lesions, their ability to detect direction typically requires higher coherence levels. The correct answer would be c) 4-5%, indicating that a monkey with a lesioned MT cortex generally needs higher motion coherence to determine directionality of moving dots.

The MT cortex, also known as V5, is a region of the brain particularly involved in the processing of motion. When this area is damaged, monkeys, and by extension humans, have greater difficulty in detecting motion, which is evidenced by needing a higher percentage of coherence in the moving dots to discern the direction of movement.