Damage Destruction of the OFC through
acquired brain injury typically leads to a pattern of
disinhibited behaviour. Examples include swearing excessively, hypersexuality, poor social interaction, compulsive gambling, drug use (including alcohol and tobacco), and poor empathising ability. Disinhibited behaviour by patients with some forms of
frontotemporal dementia is thought to be caused by degeneration of the OFC.
Disruption When OFC connections are disrupted, a number of cognitive, behavioral, and emotional consequences may arise. Research supports that the main disorders associated with dysregulated OFC connectivity/circuitry center around decision-making, emotion regulation, impulsive control, and reward expectation. A recent multi-modal human neuroimaging study shows disrupted structural and functional connectivity of the OFC with the subcortical limbic structures (e.g., amygdala or hippocampus) and other frontal regions (e.g., dorsal prefrontal cortex or anterior cingulate cortex) correlates with abnormal OFC affect (e.g., fear) processing in clinically anxious adults. One clear extension of problems with decision-making is drug addiction/
substance dependence, which can result from disruption of the striato-thalamo-orbitofrontal circuit.
Attention deficit hyperactivity disorder (ADHD) have also been implicated in dysfunction of neural reward circuitry controlling motivation, reward, and impulsivity, including OFC systems. Some dementias are also associated with OFC connectivity disruptions. The behavioral variant of
frontotemporal dementia is associated with neural atrophy patterns of white and gray matter projection fibers involved with OFC connectivity. Finally, some research suggests that later stages of
Alzheimer's disease can be impacted by altered connectivity of OFC systems.
Assessment Visual discrimination test The visual discrimination test has two components. In the first component, "reversal learning", participants are presented with one of two pictures, A and B. They learn that they will be rewarded if they press a button when picture A is displayed, but punished if they press the button when picture B is displayed. Once this rule has been established, the rule swaps. In other words, it is now correct to press the button for picture B, not picture A. Most healthy participants pick up on this rule reversal almost immediately, but patients with OFC damage continue to respond to the original pattern of reinforcement, although they are now being punished for persevering with it. Rolls et al. noted that this pattern of behaviour is particularly unusual given that the patients reported that they understood the rule. The second component of the test is "extinction". Again, participants learn to press the button for picture A, but not for picture B. However, this time, instead of the rules reversing, the rule changes altogether. Now the participant will be punished for pressing the button in response to
either picture. The correct response is not to press the button at all, but people with OFC dysfunction find it difficult to resist the temptation to press the button despite being punished for it.
Iowa gambling task A simulation of real-life
decision-making, the
Iowa gambling task is widely used in cognition and emotion research. Participants are presented with four virtual decks of cards on a computer screen. They are told that each time they choose a card they stand to win some game money. They are told that the aim of the game is to win as much money as possible. Every so often, however, when they choose a card they will lose some money. The task is meant to be opaque. That is, participants are not meant to consciously work out the rule, and they are supposed to choose cards based on their "
gut reaction." Two of the decks are "bad decks", which means that, over a long enough time, they will make a net loss; the other two decks are "good decks" and will make a net gain over time. Most healthy participants sample cards from each deck, and after about 40 or 50 selections are fairly good at sticking to the good decks. Patients with OFC dysfunction, however, continue to
perseverate with the bad decks, sometimes even though they know that they are losing money overall. Concurrent measurement of
galvanic skin response shows that healthy participants show a "stress" reaction to hovering over the bad decks after only 10 trials, long before the conscious sensation that the decks are bad. By contrast, patients with OFC dysfunction never develop this physiological reaction to impending punishment. Bechara and his colleagues explain this in terms of the
somatic marker hypothesis. The Iowa gambling task is currently being used by a number of research groups using
fMRI to investigate which brain regions are activated by the task in healthy volunteers as well as clinical groups with conditions such as
schizophrenia and
obsessive compulsive disorder. The faux pas test is a series of vignettes recounting a social occasion during which someone said something that should not have been said, or an awkward occurrence. The participant's task is to identify what was said that was awkward, why it was awkward, how people would have felt in reaction to the faux pas and to a factual control question. Although first designed for use in people on the
autism spectrum, the test is also sensitive to patients with OFC dysfunction, who cannot judge when something socially awkward has happened despite appearing to understand the story perfectly well. ==Additional images==