Frontal Lobes !

One of four main regions of the cerebral cortex is the frontal lobes. They are at the front most region of the cerebral cortex. The frontal lobes are involved in problem solving, decision making, movement and planning. The frontal lobe has 3 main division consisting of the prefrontal cortex and the pre-motor area and the motor area. The pre-motor and motor areas of the frontal lobes contain nerves that control execution of voluntary muscle movement and the prefrontal cortex is responsible for personality and expression and the planning of complex cognitive behaviour..

Although the frontal lobe is the largest lobe in the brain however in routine neurologic examinations it is not usually specifically evaluated as cognitive tasks usually require multiple brain regions both within and outside the frontal lobes and so therefore it can be difficult during examinations. Dysfunctions or damage to the frontal lobes can cause relatively specific clinical syndromes. In most cases when a patients history suggests that they have a dysfunction of the frontal loves neurobehavioral evaluation is necessary.
Lesions of the frontal lobes and deeper brain structures generate relatively distinctive clinical behaviors such as these:

• The dorsolateral frontal cortex is concerned with planning, strategy formation, and executive function. Patients with dorsolateral frontal lesions tend to have apathy, personality changes, abulia, and lack of ability to plan or to sequence actions or tasks. These patients have poor working memory for verbal information (if the left hemisphere is predominantly affected) or spatial information (if the right hemisphere bears the lesion brunt).
• The frontal operculum contains the center for expression of language. Patients with left frontal operculum lesions may demonstrate Broca aphasia and defective verb retrieval, whereas patients with exclusively right opercular lesions tend to develop expressive aprosodia.
• The orbitofrontal cortex is concerned with response inhibition. Patients with orbitofrontal lesions tend to have difficulty with disinhibition, emotional lability, and memory disorders. Patients with such acquired sociopathy, or pseudopsychopathic disorder, are said to have an orbital personality. Personality changes from orbital damage include impulsiveness, puerility, a jocular attitude, sexual disinhibition, and complete lack of concern for others.
• Patients with superior mesial lesions affecting the cingulate cortex typically develop akinetic mutism.
• Patients with inferior mesial (basal forebrain) lesions tend to manifest anterograde and retrograde amnesia and confabulation.

The image below shows an MRI that is suggestive of frontotemporal dementia: