Lecture11 Flashcards
What functions are the frontal lobes responsible for?
Supervisory/executive functions (working memory, inhibition, control, decision making, interacting with social & physical environment); personality & behaviour
What were some of the behavioural/personality changes expressed by Phineas Gage after a steel rod penetrated the front of his skull?;
What began occurring a few months before his death?
Fitful, irreverent & grossly profane; impatient & obstinate, yet capricious & vacillating, unable to settle on any future plans; irritable, often confused & unable to perform foreman duties;
Epileptic seizures
What symptoms were present in Arnold Pick’s life?;
What was found in his brain after he died?;
How is this feature different to Alzheimer’s disease?
Progressive loss of speech & dementia;
A shrinkage caused by brain cells dying in localised areas;
The atrophy is more generalised in AD
Describe the neuropathology associated with Pick’s disorder
Frontotemporal atrophy with “knife-like” thinning of the gyri in frontal lobes & temporal lobes; marked atrophy with ventricular dilation; swollen brain cells with abnormal tau protein inclusions
Describe the abnormal spontaneous behaviours associated with Frontotemporal dementia (FTD/Pick’s) during examination;
What other behavioural symptoms are present?
Inappropriate jocularity; echolalia (repeating examiner’s words); echopraxia (repeating examiner’s gestures); disinhibited approach or utilisation behaviours;
Unkempt; depressed in early stages; primitive reflexes such as grasp, suck, snout & toes
Clinically, during the first 2 years of Pick’s disease, psychiatric abnormalities related to the classic frontal lobe syndromes occur. What do these include?
Orbitofrontal dysfunction: aggressive & social inappropriateness (may steal or demonstrate obsessive or repetitive stereotyped behaviours) apathy & disinhibition; dorsomedial or dorsolateral frontal dysfunction: lack of concern, apathy, or decreased spontaneity
What speech & language abnormalities can occur with Pick’s disorder?;
Memory impairment is relatively…;
What kind of movement disorders can occur?
Verbal output is often non-fluent, with poor naming of objects (abnormalities often appear early & progress fast);
Less severe than speech/language & behavioural changes;
Akinesia, plastic rigidity, or paratonia on motor examination (involuntary resistance to movement) & perseveration (repetitive responses)
How was a frontal lobotomy performed?
Leucotome inserted 6 times into the patient’s brain with the cutting wire retracted; after each insertion the cutting wire was extruded & the leucotome rotated to cut out a core of tissue
What was reported in patients after receiving a frontal lobotomy?
Patients were “stimulus-bound”; they reacted to whatever was in front of them & didn’t respond to imaginary situations, rules or plans for the future; some gained significant weight &/or became sexually promiscuous; could not form/sustain goals; distracted by circumstances
Patient W.R (the man who lost his ego) suffered a seizure in his last year of college. Although PET & CT scans found no identifiable cause at the time, what did they find when a CT was re-done?;
What was the prognosis?;
What was W.R’s response?
An extremely large Astrocytoma transversing along the callosal fibres, invading extensively the lateral prefrontal cortex in the left hemisphere, & considerably in the right;
Death within a year;
Passive, detached, no rage, minimal anguish, general absence of concern; dissociation of what he could describe & feel emotionally
What are the most common types of brain tumours?;
What do they arise from?
Gliomas (40-50% of all brain tumours);
Any type of glial cells, hence gliomas, astrocytomas & oligodendrogliomas (they’re relatively fast growing)
What range of behaviours can occur from frontal lobe damage?
Apathy, irritability, aggression, poor social control, inappropriateness, poor planning & self-direction, distractibility, stimulus-bound (hyper-sensitive to stimuli in the environment)
On the face of it, unilateral damage to the lateral prefrontal cortex presents what kind of deficits?;
But behaviour is…
Mild, with intact intelligence & language;
Reflexive, elicited by environmental circumstances & purposeless: stimulus-driven; & cannot keep interpreting the environment based on previous knowledge; struggles with on-line manipulations
What does the lateral prefrontal cortex focus on?
Working memory; stimulus-driven behaviour (utilisation); concept formation; shifting concepts; temporal organisation; goal-oriented behaviour
How did Baddeley & Hitch come up with the Working Memory model?
Unitary STM concept was not enough to explain how information is maintained & worked on over short periods; limited capacity over the short term; performing mental operations (more than just rehearsal) on contents of store; contents may be new sensory info &/or retrieved info (can manipulate past experiences & reorganise)
