1. RETICULAR
FORMATION IN
CONTROL OF MOTOR
FUNCTIONS

2. RETICULAR FORMATION IS THE
CENTRAL CORE OF THE BRAINSTEM
Extends from the rostral midbrain to the caudal medulla.
Reticular formation is concerned with the locomotor control not
only through its direct reticulospinal projections to lower motor
centers, but indirectly, by influencing the activities of the
cerebellum, red nucleus, substantia nigra, subthalamic
centers, the corpus striatum and the cerebral cortex

3. MOTOR CONTROL.
RETICULOSPINAL TRACT
Reticulospinal tract extends from reticular formation to the spinal
cord.
It has two parts:
 Medial (pontine) - MRST;
 Lateral (medullary)- LRST

4. MOTOR CONTROL.
RETICULOSPINAL TRACT
Medial (pontine)- MRST;
The fibers of this tract arise from the caudal
pontine reticular nucleus and the oral pontine
reticular nucleus and project to the lamina VII
and lamina VIII of the spinal cord

5. MOTOR CONTROL.
RETICULOSPINAL TRACT
Lateral (medullary)- LRST
The fibers of this tract arise from the medullary
reticular formation, mostly from the
gigantocellular nucleus, and descend the length
of the spinal cord in the anterior part of the
lateral column. The tract terminates in lamina VII
mostly with some fibers terminating in lamina IX
of the spinal cord.

6. CONTROL OF SKELETAL MUSCLE
 Modulate muscle tone and reflex activity: Through the reticulospinal and
reticulobulbar tracts, the reticular formation can the activity of the alpha
and gamma motor neurons.
 Reciprocal inhibition
 Maintaining the tone of the antigravity muscles when standing: assisted by
the vestibular apparatus of the inner ear and the vestibular spinal tract.
 Control of the respiratory muscle

7. CONTROL OF SKELETAL MUSCLE

Controlling the muscles of facial expression when associated with
emotion: For example, when a person smiles or laughs in response to a
joke, the motor control is provided by the reticular formation on both sides
of the brain. The descending tracts are separate from the corticobulbar
fibers.
 During movement, signals pass from the brain's cortex, via reticular
formation and spinal cord (pathway A), to muscles, which contract. Other
signals pass, by pathway B, to the basal ganglia; these damp the signals in
pathway A, reducing muscle tone so that movement is not jerky.
Dopamine, a nerve transmitter made in the basal ganglia, is needed for this
damping effect. Another transmitter, acetylcholine, inhibits the damping
effect

8. EFFECTS
It is responsible for:
 tone,
 balance,
 posture, especially during movement.

9. THE EFFERENT CONEXIONS OF
THE RETICULAR FORMATION
The efferent conexions of the reticular formation are:
 Autonomic and locomotor control centers and interneuronals points of
spinal cord via the reticular spinal tracts
 By short desdcending pathways to similar centers in the brain stem
 To the cerebellum
 To the red nucleus, substantia nigra and tectum of the midbrain
 To numerous nuclei in the subthalamus, thalamus and hypothalamus
 Indirectly through radiations of the later diencephalic nuclei to the corpus
striatum and to the cerebral cortex, including most regions of the
neocortex and many areas of the limbic system

10. RETICULAR FORMATION
Reticular formation convergent information channels
from all the principal parts of the nervous system, in
turn it projects directly or indirectly back on these
regions.
It is essentially involved in all the major functional
activities of the nervous system.