Basal Nuclei

The nuclei are involved in monitoring muscle movements that are relatively slow and sustained or patterned

The nuclei also regulated the intensity of these movements

Additionally, they inhibit antagonistic or unnecessary movements

When the basal nuclei are impaired, the result is disturbances in posture and muscle tone, involuntary movements including tremors, and abnormal slowness

The Diencephanlon

Forms the central core of the forebrain and is surrounded by the cerebral hemispheres

The Diencephalon

–Thalamus

–Hypothalamus

– Epithalamus

These structures

effectively enclose the Hypothalamus third ventricle

Epithalamus

The Diencephalon

The three structures of the diencephalon

–Thalamus

–Hypothalamus

–Epithalamus

These structures are shown with the hemispheres removed

Thalamus

The egg shaped thalamus makes up 80% of the diencephalon and forms the superolateral walls of the third ventricle

composed of bilateral masses of gray matter held together by a mid­ line commissure called the intermediate mass

Intermediate Third

mass Ventricle

Thalamus

The thalamus has many different nuclei, most named for their location

Each of these nuclei has a functional specialization

Each projects fibers to and receives fibers from a specific region of the cerebral cortex

The Thalamus

Sensory inputs are not the only type of information relayed through the thalamus

Every part of the brain that communicates with the cerebral cortex must relay signals through the nucleus of the thalamus

The thalamus can therefore be thought of as the gateway to the cerebral cortex

Thalamus

Afferent impulses from all senses and all parts of the body converge on the thalamus and synapse with at least one of its nuclei

Within the thalamus, a sorting­out and information “editing” process occurs

Thalamus

Impulses having to do with similar functions are grouped together and relayed via the internal capsule to the appropriate area of the sensory cortex as well as specific cortical association areas