The best insular cortex presentation the world has ever seen.

1. Insula
The Hidden Cortex
Rebecca E. Martin
January, 2009

2. Insula
The Hidden Cortex
The insula is the cortical part of the brain
that is not visible when looking at the
surface of the brain.
Rebecca E. Martin
January, 2009

3. A?
UL
INS
the

4. A?
UL
INS
the
Anatomy

5. Insula is Latin for

6. Insula is Latin for
ISLAND

7. The Insula Looks Like a
Seashell FIG 2. The transverse gyrus and the orbitofrontal insula rela-
tionship. Base view of the orbital surface of the left frontal lobe
after resection of part of the gyrus rectus (GR) and the anterior
portion of the temporal lobe (T). Medial is to the reader’s left. I
indicates olfactory bulb; II, optic chiasm and tract. The H-shaped
orbital sulcus (arrowheads) defines the MOG, POG, anterior
orbital gyrus (AOG), and lateral orbital gyrus (LOG). At the pos-
teromedial aspect of the orbitofrontal surface, the posterior por-
tion of the MOG merges with the medial portion of the POG to
form the prominent PMOL. PMOL gives rise to the transverse
insular gyrus (t) that extends laterally to form the pole (po) of the
insula just anteroinferomedial to the apex (asterisk) of the insula.
The CS (dashed line) curves inferiorly immediately behind and
below the apex and the pole en route to join the stem of the
sylvian fissure. The ASG (a) and the PSG (p) converge to form the
apex of the insula anterior to the CS. In this image, the deliberate
slight rotation used to illustrate the course of the transverse
gyrus from the PMOL to the pole also rotates the apex medially,
so the apex does not appear to lie as far lateral in position as it
would in a true base view.
cases, including two in which the MSG was equal to
the ASG in size).
FIG 1. A–C, Anatomy of the convexity surface of the left insular
The PSG formed the precentral gyrus of the insula
lobe after resection of the overlying opercula, vessels, and pia-
immediately anterior to the CS in all cases. Typically,
arachnoid. Gross anatomic specimens from a 50-year-old woman
(A), a 63-year-old man (B), and a 71-year-old man (C). The anterior the short insular sulcus separated the ASG from the
PS (APS), superior PS (SPS), and inferior PS (IPS) define the base
MSG, whereas the precentral sulcus of the insula
of the insular lobe. The oblique CS of the insula subdivides the
separated the MSG from the PSG (Table 2). In one
insula into larger anterior and smaller posterior lobules.
case with absent MSG, the short insular sulcus and
Anterior lobule: The ASG (a), MSG (m), and PSG (p) form most
of the convexity surface of the anterior lobule. The short insular the precentral sulcus merged completely, so they
sulcus (SIS) separates ASG from MSG. The precentral sulcus
could not be identified as separate structures.
(preCS) separates MSG from PSG. MSG shows variable size and
The apex of the insula was formed by the short gyri
depression below the surface of the insula. The number of gyri
Naidich et al., 2004
in all cases, but the specific pattern of the short gyri
on the convexity surface of the anterior lobule varies substan-
tially: two in A, three in B, and four in C. The apex (asterisk) of the and the contribution of each short gyrus to the apex
insula forms by the convergence of the inferior ends of some or
were variable (Fig 1). The ASG contributed to the

8. Central Limen
Insular
Sulcus
Gray’s Anatomy

9. Anterior
connects to
limbic
structures
i.e.
amyg
thalamus
hippocamp
Central Limen
Insular
Sulcus
Gray’s Anatomy

10. Anterior
connects to
limbic
structures
i.e.
amyg
thalamus
hippocamp
Posterior
associated with
Central Limen somatosensory areas,
Insular pain pathways
Sulcus
Gray’s Anatomy

11. The Insula’s
Neighborhood

12. It is covered by the operculum

13. It is covered by the operculum

14. It is covered by the operculum

15. It is covered by the operculum

16. It is covered by the operculum
Thanks for the pics, Dianne and Hendrik!

17. Adjacent to the lateral ventricle

18. Insula
REVIEW! TÜRE et al., 1999

19. Insula
REVIEW! TÜRE et al., 1999

20. Insula
REVIEW! TÜRE et al., 1999

21. Insula
REVIEW! TÜRE et al., 1999

22. Insula
REVIEW! TÜRE et al., 1999

23. Insula
REVIEW! TÜRE et al., 1999

24. Insula
REVIEW! TÜRE et al., 1999

25. Medial to the Insula TÜRE et al., 2000

26. Vascularization
TÜRE et al., 2000

27. Vascularization
TÜRE et al., 2000

28. Vascularization
TÜRE et al., 2000

29. Vascularization
The Insula is fed entirely by the middle cerebral artery TÜRE et al., 2000

30. More Arteries

31. Embryology Afif et al., 2007

32. Embryology Afif et al., 2007

33. Embryology Afif et al., 2007

34. Embryology Afif et al., 2007

35. Embryology Afif et al., 2007

36. Embryology Afif et al., 2007

37. Embryology Afif et al., 2007

38. Embryology Afif et al., 2007

39. Embryology Afif et al., 2007

40. Embryology Afif et al., 2007

41. Architecture and Histology
Chikama, et al., 19970

42. Anterior
agranular
Posterior
granular
Central Limen
Insular
dysgranular
Sulcus
Gray’s Anatomy

43. granular
dysgranular
agranular
granular - 6 layers
dysgranular - 5-ish layers
agranular - 5 or less layers
Augustine, 1996

44. granular
dysgranular
agranular
Wow, that’s similar
to the OFC and the
granular - 6 layers Cingulate!
dysgranular - 5-ish layers
agranular - 5 or less layers
Augustine, 1996

45. Spindle Cells
Phylogeny Manger, et al., 1998

46. Spindle Cells
are only found in
cingulate and insular
regions
Phylogeny Manger, et al., 1998

47. Connectivity

48. Major Fiber Tracts Surrounding Insula
TÜRE et al., 1999

49. Major Fiber Tracts Surrounding Insula
TÜRE et al., 1999

50. Major Fiber Tracts Surrounding Insula
TÜRE et al., 1999

51. EFFERENT CONNECTIONS
Augustine, 1996

52. AFFERENT CONNECTIONS
Augustine, 1996

53. Augustine, 1996

54. Augustine, 1996

55. Function
gustatory
vomiting!
cravings
singing!
auditory
visual - awareness,
monitoring
subjective feeling
autonomic (e.g.
cardiac rhythm)
NYTimes, 2007

56. But Also...
Olfactory (close to
olfactory bulbs!)
Post-stroke recovery of
motor function
Associated with neglect
Thermal heat pain

57. Connectivity Between the Amygdala and Insula
Morris, 2002

58. A Primary Gustatory Area
Taste (lesion studies
indicate taste intensity
and recognition problems)

59. A Primary Gustatory Area
Taste (lesion studies
indicate taste intensity
and recognition problems)
Fun fact: Taste info from
both sides of mouth
passes though left insula

60. Activation Studies
The Insula is:
A Visceral Sensory Area
Role in integration of
multimodal sensory
information, gut feelings,
disgust, temperature
perception, pain recognition
Interoception i.e. “How We
Feel”

61. Interoception
◦ subjective feelings, emotion, self-awareness (Craig, 2009, 2002;
Critchley, 2004)

62. View of Insula and Uncus
TÜRE et al., 1999

63. The (left) Insula is also:
Involved in Language and Memory
Part of an “articulatory loop”
Coordinates speech articulation
Singing!
(Right insula may mediate control of vocal tract)
Insula lesions have been noted to cause aphasia
Part of network involved in verbal memory - mental navigation
along memorized routes (hippocampus -> precuneus -> insula)
Humor (particularly gag and language humor, Watson et al., 2006)

64. Lesion Studies
The Insula:
Is associated with certain types of
mental illness
Early Alzheimers (atrophy)
Schizophrenia (abnormalities, e.g. decreased
grey matter)
OCD, PTSD, Anxiety, Depression
May Play a Role in Addiction
Conscious urges to take drugs (Naqvi,
Bechara, Damasio, 2008)

65. Proposed Drug Craving Pathways

66. References
Afif, A., Bouvier, R., Buenerd, A., Trouillas, J., & Mertens, P. (2007). Development of the human fetal insular cortex:
study of the gyration from 13 to 28 gestational weeks. Brain Structure and Function, 212(3), 335-346.
Augustine, J. R. (1996). Circuitry and functional aspects of the insular lobe in primates
including humans. Brain Research Reviews, 22(3), 229-244.
Augustine, J. R. (1985). The insular lobe in primates including humans. Neurological Research, 7(1), 2-10.
Balleine, B. W., & Dickinson, A. (2000). The Effect of Lesions of the Insular Cortex on Instrumental Conditioning:
Evidence for a Role in Incentive Memory. J. Neurosci., 20(23).
Cereda, C., Ghika, J., Maeder, P., & Bogousslavsky, J. (2002). Strokes restricted to the insular cortex. Neurology,
59(12), 1950-1955.
Craig, A. (. (2003). Interoception: the sense of the physiological condition of the body. Current Opinion in
Neurobiology, 13(4), 500-505.
Critchley, H. D., Wiens, S., Rotshtein, P., Ohman, A., & Dolan, R. J. (2004). Neural systems supporting interoceptive
awareness. Nat Neurosci, 7(2), 189-195.
Manger, P., Sum, M., Szymanski, M., Ridgway, S., & Krubitzer, L. (1998). Modular Subdivisions of Dolphin Insular
Cortex: Does Evolutionary History Repeat Itself? Journal of Cognitive Neuroscience, 10(2), 153-166.
Morris, J. (2002). How do you feel? Trends in Cognitive Sciences, 6(8), 317-319.
Nagai, M., Kishi, K., & Kato, S. (2007). Insular cortex and neuropsychiatric disorders: A review of recent literature.
European Psychiatry, 22(6), 387-394.
Naidich, T. P., Kang, E., Fatterpekar, G. M., Delman, B. N., Gultekin, S. H., Wolfe, D., et al. (2004). The Insula:
Anatomic Study and MR Imaging Display at 1.5 T. AJNR Am J Neuroradiol, 25(2), 222-232.
Naqvi, N. H., Rudrauf, D., Damasio, H., & Bechara, A. (2007). Damage to the Insula Disrupts Addiction to Cigarette
Smoking. Science, 315(5811), 531-534.
Oppenheimer, S. (2006). Cerebrogenic cardiac arrhythmias: Clinical Autonomic Research. Clin Auton Res, 16(1),
6-11.
Türe U, Yasargil DCH, Al-Mefty O, Yasargil MG. (1999). Topographic anatomy of the insular region. J Neurosurg,
90, 720 –733
Türe U, Yasargil MG, Al-Mefty O, Yasargil DCH. (2000). Arteries of the insula. J Neurosurg, 92:676 – 687

67. Thanks!
NYTimes, 2007