RETICULAR FORMATION Flashcards
Mass of neurons and nerve fibers extending from caudal medulla to rostral midbrain and continuous with subthalamus and midline,
intralaminar and reticular nuclei of the thalamus
RETICULAR FORMATION
‘reticular’ = ‘net’ of neurons
Located in brainstem tegmentum and comprises a neural system with multiple inputs and multiple synaptic system of impulse conduction
RETICULAR FORMATION
Strategically placed among important nerve
tracts and nuclei
Receives input from most sensory systems and
sends efferent fibers to all parts of CNS levels
Influence skeletal muscle activity, somatic and
visceral sensation, ANS and endocrine systems
as well as level of consciousness
RETICULAR FORMATION
Recite THE GENERAL ARRANGEMENT of reticular formation
● Deeply placed continuous network of nerve cells
and fibers extending from brainstem, towards
subthalamus, hypothalamus and thalamus
● Contains highly organized groups of
transmitter-specific cells that influence specific
CNS areas
● Polysynaptic
● 3 longitudinal columns:
1.Median column - at median plane;
intermediate-sized neurons; at center
2. Medial column - contains large neurons
3. Lateral column - small neurons
● Inferiorly, continuous with interneurons of gray
matter of spinal cord
● Superiorly, impulses are relayed to cerebral
cortex and cerebellum
● Continues into the diencephalon
TRUE or FALSEMedian group & paramedian are a separate entity
FALSE, are deemed as one
Name the 5 structures of the median groups (RETICULAR COLUMNS)
Superior Central, Raphe Pontis,Raphe Magnus, Raphe Pallidus, Raphe Obscurus
Name the 5 structures of the medial groups
RAPHE NUCLEI, reticularis pontis oralis, reticularis
pontis candalis, reticularis gigantocellularis
Name the 5 structures of the lateral groups
cuneiform and subcuneiform
nuclei, pedunculopontine, parabrachial,
reticularis pervocellularis, reticularis lateralis
________ of medulla receive inputs from
spinal cord, trigeminal sensory nuclei and
periaqueductal gray matter of the midbrain;
project to cerebellum, dorsal horn of spinal cord
and trigeminal nuclei
Raphe Nuclei
Facilitatory input from the periaqueductal gray
matter to medullary raphe nuclei and its
inhibitory projections on spinothalamic neurons
in dorsal horn of spinal cord. What will be produced?
ANALGESIC EFFECT. Thus, inhibiting raphe nuclei and will produce less pain
receive inputs from prefrontal cortex, limbic
system and hypothalamus and project widely to
forebrain, cerebellum and brainstem
Raphe nuclei of rostral pons and midbrain
involved in pain
mechanisms
Caudal raphe nuclei
involved with
wakefulness, alertness and sleep
Rostral raphe nuclei
● Receives inputs from spinal cord, cerebral
cortex, vestibular nuclei
● Project to cerebellum
CONNECTIONS OF PARAMEDIAN GROUP
● Input from spinal cord, ascending sensory
systems, superior colliculus,
vestibulocerebellum, hypothalamus, and
cerebral cortex
● Descending projections project to spinal cord -
motor control
● Ascending projections to intralaminar nuclei of
the thalamus and basal cholinergic nuclei (aka
nucleus basalis of Meynert) - consciousness and
alertness is located in medial column
● Nucleus reticularis pontis caudalis - paradoxical
(REM, rapid eye movement) sleep; time when
deep sleep of a person happened, when we
dream
CONNECTIONS OF MEDIAL GROUP
● Lateral nuclei in medulla and pons
(parvocellularis and lateralis) constitute the
receptive components of reticular nuclei
● Pedunculopontine nucleus on rostral pons to
caudal midbrain
● Parabrachial nucleus on rostral pons to caudal
midbrain
CONNECTIONS OF LATERAL GROUPS
Continuation of reticular formation from
brainstem
Receives input from cerebral cortex and other
thalamic nuclei
RETICULAR NUCLEUS OF THALAMUS
Project it further to other thalamic nuclei; Integrating and gating thalamic nuclei activities
RETICULAR NUCLEUS OF THALAMUS
Neurotransmitter of RETICULAR NUCLEUS OF THALAMUS
GABA
○ Function with diencephalic nuclei to maintain
alert conscious state
○ Mainly for consciousness
Rostral reticular formation of the mesencephalon
and upper pons
Work with CN nuclei and spinal cord to carry
out motor, reflex and autonomic functions
Caudal reticular formation of pons and medulla
Neuromodulatory cholinergic neurons
with widespread projections at: Pontomesencephalic region of brainstem and Basal Forebrain
Acetylcholine
It is the pedunculopontine tegmental nuclei and
laterodorsal tegmental nuclei
○ Travel to thalamus, including intralaminar
nuclei, which project to cerebral cortex
○ These nuclei have extensive connections
with basal ganglia, tectum, cerebellar nuclei
Pontomesencephalic region of brainstem
aka Nucleus basalis of Meynert
■ Project to almost entire cerebral cortex
○ Medial septal nuclei and nucleus of the
diagonal band of Broca to hippocampal
formations
■ Memory
Basal Forebrain
