Reticular Activating System and Limbic System

Reticular Activating System and Limbic System
 Reticular activating system runs from the medulla through the midbrain into the hypothalamus.
 Responsibility for activation of all areas of the brain and if damaged – coma ensues
 Limbic system controls emotion and it has three sub-circuits

Limbic System - emotions
 Amygdala and hippocampus – essential for self-preservation, includes aggression.
 Cingulate gyrus, the septum, and areas of the hypothalamus – pleasure and sexual excitement.
 Areas of the thalamus and hypothalamus – important to socially relevant behaviour

Diencephalon
Thalamus
Chief relay centre for directing sensory messages and helps regulate awareness.
Relays commands going to the skeletal muscles from the motor cortex.
Hypothalamus
Command for the control of autonomic functions such as heart rate, blood pressure, hunger, thirst.
Role in emotions and motivation (e.g., thoughts about fear get translated into arousal through hypothalamus.)

Cerebellum
 Maintains body balance and coordination of movement
 Damage to the cerebellum results motor disorders such as ataxia.
 Ataxia is a condition where our movements become jerky and uncoordinated.
Hindbrain
 Consists of:
 Pons – involved in eye movement, facial expressions and eye movement
 Medulla – controls breathing, heart rate, blood pressure
Midbrain
 Midbrain – top of brain stem, receives visual and auditory information, also important in muscle movement.
 Reticular formation – controls states of sleep, arousal, and attention.
Spinal cord
 Transmits messages from the brain to the other areas of the body.
 Efferent – away from the brain out to the body (Produces muscle action)
 Afferent – from the periphery to the brain (Relays information from the sensory organs)