Prefrontal Cortex

Prefrontal Cortex

The prefrontal cortex is the most anterior portion of the

frontal lobe. It responds mostly to stimuli signaling the need

for movement, however it is also responsible for many other

specialized functions. It receives information from all sensory

systems and can integrate a large amount of information (Kalat

2004).

Studies have shown that the prefrontal cortex is

responsible for working memory. Working memory is defined as

"the information that is currently available in memory for

working on a problem" (Anderson 2005). The prefrontal cortex

(PFC) also controls behaviors that depend on context (Kalat

2004). For example, if my cell phone rings when I am at the

mall or grocery store I would answer it. If it rings while I am

at the movies or in class I wouldn't answer it. People with

frontal lobe damage often exhibit inappropriate behaviors due to

the inability to recognize context.

Other studies indicate that the PFC is also responsible for

regulating emotions and decision-making. A study was conducted

in which participants were presented with three dilemmas. One

dilemma was called the Trolley Dilemma: a trolley is headed

toward five people standing on the track. You can switch the

trolley to another track killing only one person instead of

five. Subjects were asked to decide between right and wrong.

Brain scans of the participants show that contemplating the

dilemmas activates the prefrontal cortex and other areas that

respond to emotion (Kalat 2004).

Sustaining a lesion to the prefrontal cortex produces a

wide variety of side effects. The effects range from minor to

severe. You can get a lesion by head trauma or stroke (CJ Long

2005).

Possible deficits associated with minor lesions of the

prefrontal cortex:

- Inability to respond quickly to verbal instructions

- Speech dysfluency

- Disturbances in understanding complex pictures or words

- Difficulties with problem-solving

- Deficits in complex tasks requiring inhibition of habitual

behavior patterns

With more extensive lesions the person experiences greater

behavior deficits. These deficits include: perseveration, which

is the inability to make behavioral shifts in attention,

movement and attitude, decreased creativity, poor recall of

verbal and nonverbal material, difficulty writing, and deficits

in comprehension of logical-grammatical constructions (CJ Long

2005).

Other effects of extensive lesions:

- easily distracted

- disturbances in memory

- defects in time sense

- decreased anxiety

- less critical of oneself

- difficulty with unfamiliar analogies

- impulsivity