Frontal lobes Flashcards
According to Luria, why due frontal lobe patients have difficulty with problem solving?
The can access fragmentary operations but cannot combine them into an overall schema
How do lesions to the prefrontal areas affect attention?
Tilt emphasis away from internal mental processes toward stimulus-bound behavior
Orbitofrontal circuit
Mediation of emotional & social responses
Lesions to the frontal eye fields result in
Impaired exploratory eye movements even when spot eye movements are intact
Witzelsucht
Tendency to joke inappropriately
Lesions to the motor association areas anterior to M1 lead to
Complex deficits of mvmt in absence of weakness, dystonia, dysmetria, or hyperreflexia; reflect a disconnection between cognition & action
Stuss & Benson divided the functions of the frontal lobes into what 2 groups?
1st concerned with sequencing behaviors, forming mental sets, & integrating various behaviors 2nd concerned with more primitive processes such as drive, motivation, will
The frontal eye fields project to
Superior colliculus, caudate nucleus, PPRF
Mesulam describes 2 general types of frontal lobe syndromes. What are they?
Frontal abulia (lesions to heteromodal cortex) Frontal disinhibition (lesions to paralimbic cortex)
Manifestations of frontal lobe syndromes can result from
Lesions in the head of the caudate or MD of thalamus, multifocal WM disease, metabolic encephalopathy, multifocal parietal lesions
Personality changes is the hallmark of dysfunction in what frontal lobe circuit?
Orbitofrontal
Role of Broca’s speech area
Translating neural word forms into articulatory sequence, sequencing words/endings into utterances that have meaning (appropriate syntactic structure)
Dorsolateral prefrontal syndrome
Poor problem solving, poor organizational strategies, impaired set-shifting, perseveration, impersistence, memory may be disrupted, apathy & psychomotor slowing, poor motivation/abulia, decreased emotional range
Frontal release signs
Reflexes (e.g., grasp, snout, glabellar) that are usually inhibited by the frontal lobes
Fuster’s temporal processing model
Prefrontal cortex is principally involved with representing the ‘temporal structure of behavior’; to encode temporal aspects of behaviors, the prefrontal cortex must be involved in the formation of ‘cross-temporal contingencies’
Anterior cingulate circuit
Response monitoring, error detection, conflict resolution, inhibition, selective & divided attention, motivation
What are the two groups of processes in working memory, according to Mesulam?
1) Volitional manipulation (prefrontal dorsolateral) 2) On-line maintenance (both prefrontal & post parietal)
According to Norman & Shallice’s framework, what are the 2 basic control mechanisms that determine how we monitor our activities?
Automatic contention scheduler (ACS) - automatic & direct priming of stored knowledge by stimuli in the environment or conceptual thought Supervisory attention system (SAS) - conscious awareness of what we know that set the priorities for action (SAS can override ACS); this system is damaged in frontal lobe dysfunction
Orbitofrontal syndrome
Disinhibited, poor impulse control, distractible, emotional lability/emotional dysregulation
Bilateral lesions to which frontal-subcortical circuit can lead to akinetic mutism?
Anterior cingulate
Medial frontal syndrome
Akinetic & apathetic, little initiation of mvmt or speech, lack of interest & indifference, emotional blunting, memory can be impaired, incontinence
Utilization behavior
Patient uses objects without a specific goal or need (e.g., sipping from an empty cup when satisfied)
Dorsolateral circuit
Attentional control, working memory, preparatory motor set, response monitoring
