Frontal Lobe Function Flashcards
What are two results of lesions to the primary motor cortex which we have previously covered?
- Hemiplegia
- Re-emergence of Babinski’s sign
What are two results of lesions to the pre- and supplementary motor cortex which we have previously covered?
- Frontal Eye Field damage impairs inhibitory control over the visual grasp reflex
- Alien Hand Syndrome
What two degenerative diseases are linked to degeneration of the frontal lobes?
- Alzheimer’s Disease
- Pick’s Disease
In terms of the motor homunculus, how would damage to the ACA or MCA play put differently?
ACA is lower limb territory, the hips, knees, ankles and toes.
MCA territory covers the rest.
What happens when a patient has unilateral frontal eye field damage?
They make abnormally frequent reflexive eye movements toward contralesional targets.
Taking together fMRI data and patient data relating to the N-back Task - what does this suggest?
fMRI data: Prefrontal brain regions showed increased activation with increasing working memory load during letter N-back tasks. These data indicate prefrontal involvement in working memory.
Patient data: Patients with dorsal and ventral prefrontal cortex damage exhibited impaired n-back performance, particularly 2-back. These data indicate that working memory performance depends on prefrontal cortex.
Why is it important to compare fMRI and Lesion data?
When looking at fMRI data, activation of a region of cortex during a specific task does not indicate whether the region of cortex activated by the task makes an indispensable contribution to performing that task.
By combining it with lesion data we can determine whether a specific brain region makes a critical contribution to a specific task.
What happened to Patient Michael?
He had frontal lobe damage due to shrapnel penetration.
After this he had difficulty keeping a job and behaving appropriately in social situations. He has poor judgement during a gambling task and has limited insight into his condition. He has difficulty working toward long-term goals and considering consequences, as well as increased distractibility and social problems.
What does Patient Michael inform us about the frontal lobes.
Supports the idea that the frontal lobes play a critical role in allowing us to develop effective plans and execute them.
Are anterior frontal lobe lesions easy to detect?
Patients with these lesions have no deficits that can be detected by routine neurological testing, even though they may be completely unable to function normally in their lives.
What is Aphemia?
Effortful, poorly articulated speech sometimes referred to as foreign accent syndrome.
It involves severe apraxia of the speech articulatory apparatus, without language disturbance.
In contrast to Broca’s patients these patients have normal written language.
They have trouble in coordinating the movements to speak normally.
What is Aphemia caused by?
A small left frontal lesion restricted to Broca’s area.
What is apraxia?
Loss or impairment of the ability to execute complex coordinated movements that is not due to
- muscular impairment
- a primary motor deficit
- language impairment
Apraxia reflects impaired higher-order motor planning, which can affect complex movements of the limbs or the speech apparatus.
