The Limbic Lobes
Limbic lobes are located deep within the brain. They differ in function from the four lobes visible on the exterior of the brain: the frontal, parietal, occipital and temporal lobes.
The limbic lobes form a ring of interconnected structures around the brain stem that connects the cerebral hemispheres to the top of the brain stem. The limbic lobes are visible only from a sagittal or midsagittal view of the brain. A sagittal view divides the brain into multiple parts, and a midsagittal view divides it into two equal parts. These views can be obtained either surgically or by magnetic resonance imaging (MRI).
In the event of a traumatic brain injury (TBI) the limbic lobes can be impacted and affect the individual’s ability to differentiate between odors, decrease his or her ability to sense danger and make it nearly impossible to develop new memories. Proper and timely post-acute rehabilitation and care may determine the difference between disability and independence.
A more precise way to describe the limbic lobes is as a “system.” In fact, they are often referred to as such because both anatomically and functionally, three main, separate and important structures are grouped together and essentially function together. All of them are necessary for normal human function, and together, they form the limbic system. They are the olfactory cortex, the amygdala and the hippocampus.
1. The olfactory system begins in the roof of the nasal cavity and consists of receptors that are capable of detecting many different odors. The receptors transmit the stimuli to the mitral cells of the olfactory bulbs. The olfactory bulbs constitute an important connection to the brain and permit the differentiation of odors. An injury to this area can result in the loss of smell.
2. The amygdala is often referred to as the “fear center” of the brain and is located deep within the temporal lobe. In a “fight or flight” situation, the amygdala is the “flight” pilot. It receives and processes sensory data, including, visual and auditory, to recognize and remember signs of danger. It must be capable of remembering the importance of that data in order to allow for an instant response.
While it is hard to study the amygdala in humans because damage to it alone is rare, it affects the ability to recognize the expression of fear on human faces. It also seems to be involved with positive or negative emotional responses to an event. Damage to this part of the brain in monkeys appears to make them social outcasts.
3. The hippocampus is located deep within the temporal lobe. While all of its functions are not known, it is generally agreed that it does play a major role in forming new memories about past experiences. It may also be involved in “declarative memory,” that refers to memories that can be expressly verbalized. Damage to this part of the brain usually results in the inability to form new memories and in the inability to access memories formed prior to the injury.
The limbic system is primarily involved in these functions, in addition to those explained above, it:
· Sets the emotional tone of the mind and mood by filtering external events through one’s internal state of mind and helps to control that state of mind.
· Identifies events in order of importance.
· Stores memories that were highly emotionally charged.
· Modulates motivation.
· Controls sexual desire.
· Promotes bonding in relationships.
Other structures in the brain that are part of the limbic system are:
1. The thalamus, meaning “inner room” in Greek. The thalamus is located deep within the brain on top of the brain stem. The thalamus is referred to as the “gateway to the cortex” because virtually all sensory inputs pass through it in order to enter the higher levels of the brain.
2. The hypothalamus is located under the thalamus at the top of the brain stem. It controls functions including, emotional response and behavior, temperature regulation, hunger, thirst, sleep-wake cycles and the endocrine system.
3. The cingulate gyrus is an area surrounding and partly connected to portions of the limbic system. It operates as a conduit for messages to and from the limbic system.
4. The basal ganglia are involved in planning and coordinating motor movements and posture. Disorders of the basal ganglia can result in exaggerated or uncontrolled physical movements.
Limbic system disorders can be managed in many ways, depending in part, upon the location of the disorder. Treatment can range from nutritional and behavioral intervention, sleep aids, relaxation techniques and smoking cessation.
NeuLife clients undergo a comprehensive physical and psychological evaluation as the first step in tailoring the most appropriate plan of care. Our team of multidisciplinary professionals is guided by expertise and experience and by client and family concerns and desires to chart the best course of care. Optimum function consistent with the client’s physical and psychological abilities is our goal.
NeuLife, in Mount Dora, Florida, is a fully accessible specialized residential post-acute program providing specialized rehabilitation to individuals diagnosed with traumatic brain injury (TBI), spinal cord injury (SCI), traumatic amputations and other catastrophic injuries.
2725 Robie Avenue
Mount Dora, Florida 32757
Call: 800.626.3836
Email: [email protected]
Visit: NeuLifeRehab.com
