Researchers chemically lesion a portion of a macaque monkey brain. As a result, the monkey's circadian rhythms appear disrupted. The lesion probably destroyed the nucleus in the monkey's .es

Researchers chemically lesion a portion of a macaque monkey brain. As a result, the monkey's circadian rhythms appear disrupted. The lesion probably destroyed the _superchiamatic_ nucleus in the monkey's _hypothalamus_.

Explanation:

Suprachiasmatic nucleus is mainly responsible for producing the circadian clocks in mammals. Circadian clock is the like internal clock of the body and produces circadian rhythms. circadian rhythms help to maintain the physiology and behaviour of mammals and help them to adapt to environmental changes. Like a person awake at the same time after sleep is because of this biological clock.

The suprachiasmatic nucleus as the name indicates is located in hypothalamus just above the optic chiasm. It control the 24 hours activities of mammals through hormonal and neuronal activities. The nucleus is composed of core which receive inputs mainly from retina and shell which receive inputs majorly from hypothalamus and thalamus.

As monkey is also a mammal so any damage to suprachiasmatic nucleus in brain must affect his circadian rhythms.