Orbitofrontal Cortex

Anatomy

• Ventral surface of the frontal lobe above the orbit: gyrus rectus (medial), orbital gyri, olfactory sulcus.
• BA 11, 12/47 (lateral orbital), 13 and 14; the lateral part extends into the pars orbitalis of the inferior frontal gyrus.
• Secondary olfactory and gustatory cortex; where taste, smell, visual and interoceptive information converge.
• Blood supply: ACA (medial orbitofrontal branch) and MCA (lateral orbitofrontal artery).

Functions

• Coding the reward/punishment value of stimuli and comparing expected with actual outcomes.
• Reversal learning: updating behavior when the stimulus–reinforcer relationship changes.
• Emotional decision-making (somatic marker hypothesis, together with the vmPFC).
• Context-appropriate social behavior and inhibition of impulsive responses.
• Combining smell and taste information with hedonic value.

Connections and chemistry

• Amygdala (emotional value)
• Nucleus accumbens / ventral striatum (limbic loop)
• Head of the caudate (OFC–striatal loop, OCD)
• Thalamus — mediodorsal nucleus
• Insula and hypothalamus
• Dopamine (VTA), serotonin (raphe)

Development

Developmental course through childhood and adolescence.

• Matures slowly; in adolescence reward sensitivity is high while the OFC’s regulatory contribution is not yet complete.
• Early-life adversity (neglect, abuse) has been linked to OFC volume and function.
• Self-control and the ability to delay reward develop markedly through the school years.

Clinical

• OCD: OFC hyperactivity in the cortico-striato-thalamo-cortical (CSTC) circuit; it decreases with treatment response.
• Conduct disorder and callous-unemotional (CU) traits: OFC/vmPFC dysfunction in reward/punishment learning.
• Substance use: distorted reward value, compulsive use.
• ADHD: delay aversion, choosing a small immediate reward over a large delayed one.
• Eating disorders: differences in reward and taste processing.
• Large structural sample in OCD (ENIGMA-OCD; 1,905 patients, 1,760 controls): thinner inferior and superior parietal cortex in children; parietal thinning and reduced temporal surface area in adults; small effects (d −0.10 to −0.33). Frontal differences were more widespread in medicated patients. OFC hyperactivity is a functional finding; structurally, the most consistent difference is parietal (ENIGMA-OCD, 2018). A

Treatment

This region from the perspective of medication, psychotherapy and neuromodulation. Letter badges are evidence levels.

• First line in OCD: CBT with exposure and response prevention (ERP) and SSRIs; the two are often combined in moderate to severe childhood OCD. Effective treatment reduces OFC–caudate hyperactivity. A
• Deep TMS (H7 coil, mPFC and ACC): FDA-cleared for adult treatment-resistant OCD (2018); details on the mPFC card. A
• Interventions targeting delay discounting and impulsivity (contingency management, reward-delay training) draw on the OFC’s value computation in ADHD and substance use.

Assessment

Neuropsychological tasks and measures that probe this region's function.

• Iowa Gambling Task (IGT) — child versions available
• Probabilistic reversal learning
• Delay discounting
• Go/No-Go and social decision games (Ultimatum game)

Lesions and damage

Clinical findings expected with damage or dysfunction.

• “Pseudopsychopathic” picture: disinhibition, social inappropriateness, impulsivity; classic example: Phineas Gage.
• Moria / Witzelsucht (inappropriate joking), increased argumentativeness.
• Anosmia (proximity to the olfactory tracts).

In the model

How this structure is defined in the 3D model, and the data source.

HCP-MMP1.0 areas (Glasser et al., 2016; MNI volumetric version: Horn, 2016): 11l, 13l, OFC, pOFC, 47m, 47s, 47l, a47r, p47r. CerebrA lateral orbitofrontal and pars orbitalis where there is no HCP match.

References

Full citations for the card; links go to the paper (DOI) or a PubMed search.

1. ENIGMA-OCD Working Group. Cortical abnormalities associated with pediatric and adult obsessive-compulsive disorder. Am J Psychiatry 2018;175(5):453–462. Search PubMed