Reticular Formation and monoamines Flashcards
Understand the Reticular Formation Definition and diffuse Zones Descending reticulospinal pathways overview of reticular formation functions reticular nuclei and there neurotransmitters ++monoaminergic pathways affecting consciousness and attention (77 cards)
What is a diffusely organized area forming the central core of the brainstem
The Reticular Formation
What is a diffusely organized area forming the central core of the brainstem
The Reticular Formation
1 Reticular Formation Neuron may synapse with
25000 other neurons
The reticular formation connects to a different areas by a great deal of convergence and divergence
in the Brainstem, Cerebellum, Cerebrum, and Spinal Cord
The reticular formation areas overlap considerable in Function
True
The Reticular Formation consist of which zone
Medial and Lateral
and midline zone
The lateral zone receives most
afferent input and projects to the medial –the output (efferent) area.
Which two descending pathways send major projections into the spinal cord
Medial (pontine) reticulospinal tract
Lateral (medullary) reticulospinal tract
What is the function of the lateral zone
integrates sensory and cortical input for generalized arousal
What is the function of the medial zone
regulates vital functions somatic motor activity and attention
What is the function of the midline zone
adjust transmission of pain information, somatic motor activity and conscious levels
Pontine (Medial) Reticular formation
Uncrossed medial reticulospinal tract
+In brainstem this tract travels just ventral to the MLF
+Descends all SC levels
Mainly an excitatory + function on extensor alpha motorneurons
+Especially to trunk and proximal extremity muscles
Brainstem UMN overreactivity leads to spasticity and hyperreflexia
+indicates excessive reticulospinal or vestibulospinal trace signals to LMN’s
Medullary (Lateral Reticular Formation)
Primary uncrossed lateral reticulospinal tract
Descends to all SC levels
++Tract conveys autonomic+ information from higher levels to preganglionic ANS neurons++
++Influencing respiration, circulation, sweating/shivering, pupil dilation, visceral wall smooth muscle++
Role(?) with alpha/beta/gamma neurons
What is the reticular connection to sensory control?
Integrates cerebral cortex and sensory
+motivation, decision-making, moods
What is the reticular formation function in motor control
Regulates somatic motor activity
what is the reticular connection to visceral control
regulates ANS function
Reticular Formation connection with Control of Conscious
regulates levels of consciousness
+sleeping-waking cycles
What is the reticular connection for Pain Control
Modulates nocioceptive information
RF Sensory Control:
Reticular neurons exert control over activity in the
**Spinal polysynaptic reflex arcs (supraspinal control)
RF Sensory Control:
**Tonic inhibition (-) of flexor reflexes originates in the Reticular formation
RF Sensory Control
**Important in the regulation of pain perception by
inhibiting some sensory interneurons and tracts in the spinal cord
RF: Motor Control
Some regions closely associated with the cerebellum and its motor functions
It receives input from the red nucleus** in the midbrain
RF: Motor control
2 descending reticulospinal tracts in near the MLF**
A major alternate route to the pyramidal tract by which spinal motor neurons are controlled
–Also carry descending motor commands generated in the RF itself
RF: Visceral Control • Visceral information reaches the RF • programs appropriate responses to environmental changes • projects to the autonomic nuclei of the brainstem and spinal cord • **Control centers for inspiration, expiration, and normal breathing rhythm • ** Control centers controlling heart rate and blood pressure
Control of Consciousness (ARAS)
• **Ascending Reticular Activating System
• Ascending projections from RF
terminate in the thalamus, subthalamus,
hypothalamus, and cerebral basal nuclei
(caudate, putamen, globus pallidus)
• Activity in the pathway to the thalamus
is essential in maintenance of a normal
state of consciousness
• RF input to the normal cerebrum is needed
for conscious functioning