Animal Behavior/Neuroanatomy

Organization of the Mammalian Nervous System

The neurons can all be placed in one of two systems, the central nervous system or the peripheral nervous system.

Central Nervous System

The central nervous system has a fundamental role in the control of behavior. It contains the brain and the spinal cord which are both encased in bone which shows their importance. Both the brain and spinal cord receive signals from the afferent neurons and send signals to muscles and glands through efferent neurons.

Structure and Function

The brain is split up into three major layers, the hindbrain is the first, the second is the midbrain, and the forebrain is last.

Hindbrain

The hindbrain is a well protected central core of the brain and includes the cerebellum, reticular formation, and the brain stem. The cerebellum plays an important role in the integration of sensory perception and motor output. It utilizes constant feedback on body position to fine-tune motor movements. The brain stem contains the pons, and the medulla oblongata. The pons relays sensory information between the cerebellum and cerebrum. The medulla oblongata is the lower portion of the brainstem. It controls autonomic functions such as breathing and vomiting, and relays nerve signals between the brain and spinal cord. The reticular formation is a part of the brain which is involved in stereotypical actions, such as walking, sleeping, and lying down.

Midbrain

This part of the brain is located between the forebrain and the hindbrain making up part of the brain stem. All sensory and motor information going to and from the fore brain and the spinal cord must pass through the midbrain.

Forebrain

The anteriormost division of the developing vertebrate brain that contains the most complex neural network in the CNS. The forebrain has two major divisions, the lower diencephalon, which contains the thalamus and the hypothalamus, and the upper telencephalon, which contains the cerebrum.

Methods for observing or evaluating brain activity

In the past only two methods of observation were available. The first was observing individuals who have received brain damage and assume that the part of the brain that was damaged controlled the behavior or sense that had changed. The second was connecting electrodes to the outside of someones head and recording the readings.

Newer methods include computed tomography (CT scan), positron emission tomography (PET scan), magnetic resonance imaging (MRI), and superconduction quantum interference devices (SQUID).

Peripheral Nervous System

Any part of the nervous system that is not part of the central nervous system is part of the peripheral nervous system. The nerves in the peripheral nervous system is split up into the autonomic and somatic. The somatic connect the central nervous system to sensory organs (such as the eye and ear) and muscles, while the autonomic connect other organs of the body, blood vessels and glands.