Figure showing the insular cortex (circled) in a coronal section indicated by the blue line in the inset, Modified from Original Image by John Beal PhD, Dep’t. of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center Shreveport, CC-BY
In this series of posts I am describing the process of building a model of the Insular Cortex. I thought the most straightforward way to develop such a model is to begin with a narrative. This informs a top-down approach where an overview is gained before the details are filled out. Although this model is specific to the Insular Cortex, the approach can be applied to other brain regions. I have described this as an open model – one which uses the principles of the web which is collaboration. There have been numerous contributions which I can delineate more clearly once the basic structure starts to take shape.
In the series so far there have been four parts each focusing on a different narrative.
Part 1 – The intensity of emotional experience is dependent on two factors
1. The GABA receptor density in the Anterior Insular Cortex
2. The sensory input to the Anterior Insular Cortex
Furthermore a reduction in emotional experience can lead to difficulties in relationships with others.
Part 2 – Looking at Craig’s work there is a brief look at Craig’s idea that the Von Economo Neurons which are highly interconnected to other widely dispersed neurons, form the basis for conscious experience.
Part 3 – Looking again at Craig’s model of the Insular Cortex he proposes that
1. The Anterior Cingulate Cortex and the Anterior Insular Cortex are tightly linked
2. The Anterior Insular Cortex acts as the Limbic Sensory Cortex
3. The Anterior Cingulate Cortex acts as the Limbic Motor Cortex
4. That emotions are associated with actions
5. The Anterior Cingulate Cortex is the locus for our sense of agency associated with an emotion
6. The Anterior Insular Cortex is the locus for our experience of an emotion
Part 4 – Looking again at Craig’s model, he argues that the Anterior Insular Cortex is the locus for human awareness or consciousness as it is activated in numerous functional Magnetic Resonance Imaging studies.
I argue that this narrative is countered by critiques of functional Magnetic Resonance Imaging methodology where there are alternative explanations for apparent Anterior Insular Cortex activity. Instead consciousness exists as a modular phenomenon which is mapped onto distributed brain regions.
Part 5 – Looking again at Craig’s model, he looks at an evolutionary explanation of the Insular Cortex in which
1. The Hippocampus and Amgygdala received olfactory inputs in early mammals
2. The Anterior Cingulate Cortex initiated actions in response to the processing of these stimuli
3. Mammals organised group behaviours in response to olfactory stimuli
4. They started to respond to autonomic activity which was processed by the Insular Cortex
5. The Insular Cortex expanded and utilised the Anterior Cingulate Cortex to effect motor responses to the autonomic input
There are many other aspects of Craig’s model to examine and a wider body of research literature and comments to incorporate into the model.
Insular Cortex Resources on this Site
Developing a Model of the Insular Cortex and Emotional Regulation: Part 1
Building a Model of the Insular Cortex – Part 2
Building a Model of the Insular Cortex – Part 3
Building a Model of the Insular Cortex – Part 4
What does the Insular Cortex Do Again?
Insular Cortex Infarction in Acute Middle Cerebral Artery Territory Stroke
The Insular Cortex and Neuropsychiatric Disorders
The Relationship of Blood Pressure to Subcortical Lesions
Pathobiology of Visceral Pain
Interoception and the Insular Cortex
A Case of Neurogenic T-Wave Inversion
Video Presentations on a Model of the Insular Cortex
MR Visualisations of the Insula
The Subjective Experience of Pain
How Do You Feel? Interoception: The Sense of the Physiological Condition of the Body
How Do You Feel – Now? The Anterior Insula and Human Awareness
Role of the Insular Cortex in the Modulation of Pain
The Insular Cortex and Frontotemporal Dementia
A Case of Infarct Connecting the Insular Cortex and the Heart
The Insular Cortex: Part of the Brain that Connects Smell and Taste?
Stuttered Swallowing and the Insular Cortex
YouTubing the Insular Cortex (Brodmann Areas 13, 14 and 52)
New Version of Video on Insular Cortex Uploaded
Index: There are indices for the TAWOP site here and here Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link. Podcast: You can listen to this post on Odiogo by clicking on this link (there may be a small delay between publishing of the blog article and the availability of the podcast). It is available for a limited period. TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link. Responses: If you have any comments, you can leave them below or alternatively e-mail email@example.com. Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.