This lobe is involved in perceptual and socialization processes.
However, there is a lobe that, because it is deep in the brain, its observation is more difficult. Specifically, this structure is the insula, a region that is highly involved in the processing of emotional information.
Let’s see in more detail this part of our brain, so hidden but, at the same time, so important in the experience of sentimental experiences.
- Recommended article: “The 6 lobes of the human brain (anatomy, functions and images)”
What is the insula?
The insula, also called the insular cortex or insular lobe , is a structure of the mammalian brain that lies deep in the lateral sulcus or Sylvian fissure, which separates the temporal lobe from the parietal and frontal lobes.
This lobe is a hub between the limbic system and the neocortex. That is why it has been associated with many functions, especially linked to emotions, consciousness and regulation of the body’s homeostasis. Among these functions are empathy, motor control, perception and cognitive aspects.
Components of this lobe
The insula is divided into two main parts , which are separated by the central insular sulcus: the anterior insula and the posterior insula.
The anterior insula, which is subdivided by three to four small gyri, receives direct projections from the basal part of the medial ventral nucleus of the thalamus and also from the central nucleus of the amygdala . Also, the anterior insula projects to the amygdala. A population of von Economo neurons is found in this part of the insula.
The posterior insula is formed by a single large gyrus. This structure connects with the secondary somatosensory cortex and receives projections from the ventral posterior inferior thalamic nuclei. It also receives projections from the ventromedial nuclei of the thalamus, part of which is highly specialized in analyzing homeostatic information, such as signals of pain, temperature, local oxygenation and touch in parts considered sensually stimulating.
Insular functions
Next we are going to know the functions of the insula .
1. Perception of taste and smell
The primary sensory area for the sense of taste and smell is located in the lower part of the insula and parietal cortex.
At this point, taste information becomes conscious, being perceived as an experience marked by subjectivity and emotionality. It is for this reason that some flavors and smells bring us back to our childhood or remind us of specific experiences.
It should be said that with respect to the sense of smell, although the insula plays an important role, as we have seen, this sense has a neural network dispersed throughout the entire brain.
2. Vestibular function
The balance and control of the body are directly related to the insula, since it is this structure that plays a very important role in your conscious perception.
This means that, if an insula is in good condition, the person will be able to know what position their extremities are occupying in physical space and, if they change their position, they will quickly update the new information.
3. Visceral control and somatoperception
The insula regulates the functioning of the organs and viscera. It is also involved in swallowing and gastric movements.
It has been described as the control center, in charge of heart rate and blood pressure during physical activity. Manages the respiratory and digestive systems.
4. Integration of emotional and perceptual information
The insular cortex functions as a structure in which the association between emotion and perception is made.
This function is very important, since thanks to it it is possible to learn from experiences by relating them to subjective sensations, which may be pleasant or unpleasant, and linking them to consequences that may be more or less desirable.
5. Empathy and emotional recognition
Several investigations indicate that the insular cortex, specifically the anterior part of this structure, has a very important role in the recognition of emotions and, consequently, in the manifestation of empathy.
It has been seen that people who lack the insula have a reduced capacity for emotional recognition. In these cases, the emotional deficits may be comparable to those manifested by people with autism, personality disorders, and behavioral problems.
It has been associated with the conscious experience of feelings. Research has pointed out that this structure is of great importance in the perception of basic emotions such as anger, fear, disgust, sadness and happiness.
It has also been suggested that it could be involved in volitional acts related to basic needs, such as being hungry or the need to use drugs.
6. Control motor
The insula contributes to movement control, especially hand-eye coordination and articulation while speaking.
It has also been linked to motor learning and appears to play an important role in motor recovery after a stroke.
Associated medical problems
What medical and neurological problems can affect the insula? We will meet them below.
1. Progressive expressive aphasia
Expressive aphasia, also known as Broca’s aphasia or motor aphasia, is the impairment of normal language function. This type of aphasia is associated with hypometabolism and atrophy of the left anterior insula.
This problem implies that the person loses the ability to communicate fluently, however, they still have the ability to understand what is said or, at least, small groups of words.
This type of aphasia can be found in multiple pathologies, such as Pick’s disease, Alzheimer’s, corticobasal degeneration, motor neuron disease and frontotemporal dementia.
2. Addictions
Due to its relationship with the limbic system, research has tried to see how the insula is involved in reward at the brain level.
Several investigations have seen that this structure is involved in the development and maintenance of addictions to some drugs, such as alcohol, nicotine, opiates and cocaine, contributing to the continuation of the behavior.
The insular region is involved in the integration of emotional and cognitive information, being behind the craving, that is, the intense desire to consume the substance.
Bibliographic references
- Allen, G.V.; Saper, C.B.; Hurley, K.M. & Cechetto, D.F. (1991). Localization of visceral and limbic connections in the insular cortex of the rat. J Comp Neurol; 311: 1-16
- Duke, J.E.; Hernán, O. and Devia, A. (2004). The insular lobe. A lobe of visceral cortical processing. Acta Neurol. Colom. Vol 20, 2.
- Guenot, M.; Isnard, J. & Sindou, M. (2004) Surgical anatomy of the insula. Adv Tech Stand Neurosurg; 29:265-288
- Ostrowsky, K.; Isnard, J.; Ryvlin, P.; Guénot, M.; Fischer, C. & Mauguière, F. (2000). Functional Mapping of the insular cortex: clinical implication in temporal lobe epilepsy. Epilepsia; 41: 681-6
- Türe, U.; Yasargil, D.C.H.; Al-Mefty, O. & Yasargil, M.G. (1999). Topographic anatomy of the insular region. J Neurosurg; 90: 720-33.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.