Nervous Systems

Page
6

Slide 42

Diencephalon

Slide 43

Biological Clock Regulation by the Hypothalamus

The hypothalamus also regulates circadian rhyths such as the sleep/wake cycle.

Mammals usually have a pair of suprachiasmatic nuclei (SCN) in the hypothalamus that function as a biological clock.

Biological clocks usually require external cues to remain synchronized with environmental cycles.

Slide 44

Cerebrum

Slide 45

Cerebrum

The cerebrum has right and left cerebral hemispheres.

Each cerebral hemisphere consists of a cerebral cortex (gray matter) overlying white matter and basal nuclei.

In humans, the cerebral cortex is the largest and most complex part of the brain.

The basal nuclei are important centers for planning and learning movement sequences.

Slide 46

A thick band of axons called the corpus callosum provides communication between the right and left cerebral cortices.

The right half of the cerebral cortex controls the left side of the body, and vice versa.

Slide 47

Human Brain viewed from the rear

Corpus

callosum

Thalamus

Left cerebral

hemisphere

Right cerebral

hemisphere

Cerebral

cortex

Basal

nuclei

Slide 48

Evolution of Cognition in Vertebrates

The outermost layer of the cerebral cortex has a different arrangement in birds and mammals.

In mammals, the cerebral cortex has a convoluted surface called the neocortex, which was previously thought to be required for cognition.

Cognition is the perception and reasoning that form knowledge.

However, it has recently been shown that birds also demonstrate cognition even though they lack a neocortex.

Slide 49

The cerebral cortex controls voluntary movement and cognitive functions

Each side of the cerebral cortex has four lobes: frontal, temporal, occipital, and parietal.

Each lobe contains primary sensory areas and association areas where information is integrated.

Slide 50

human cerebral cortex

Speech

Occipital lobe

Vision

Temporal lobe

Frontal lobe

Parietal lobe

Somatosensory

association

area

Frontal