Week 4: Chapter 16 - The Frontal Lobe Flashcards
What role do the frontal lobes play in behaviour regulation?
They regulate behaviour according to time and place, relying on sensory input and memory-related information.
What percentage of the neocortex is occupied by the frontal lobes?
Approximately 30–35% of the neocortex.
What are the four primary regions of the frontal cortex?
Primary motor cortex, premotor cortex, prefrontal cortex, and anterior cingulate cortex.
What is the function of the primary motor cortex?
It produces basic voluntary movements and sends descending projections to motor centres.
Where is the premotor cortex located and what is its function?
Just anterior to the primary motor cortex; it supports movement planning, selection, and preparation.
What are mirror neurons and where are they found?
Specialized cells in the ventral premotor cortex that enable understanding and imitation of actions.
How do premotor areas influence movement?
Directly via spinal projections and indirectly by modulating the primary motor cortex.
What functions are associated with the prefrontal cortex (PFC)?
Executive functions including planning, decision-making, attention, inhibition, and emotional regulation.
What distinguishes the PFC in terms of connectivity?
It connects with the thalamus, limbic system, and dopaminergic systems.
What are the functional subdivisions of the PFC?
Dorsolateral, orbitofrontal, and ventromedial regions.
What is the role of the dorsolateral PFC?
Supports working memory, reasoning, and goal-directed behaviour.
What inputs does the orbitofrontal PFC receive and what is its role?
Receives multisensory inputs and is involved in emotion processing and autonomic regulation.
What is the ventromedial PFC involved in?
Emotion-driven decision-making and internal state monitoring.
What functions does the anterior cingulate cortex (ACC) support?
Conflict monitoring, error detection, action motivation, and affect regulation.
Which networks are the frontal lobes central to, according to connectome research?
Default network and salience network.
What is the default network associated with?
Autobiographical memory, future planning, and mind-wandering.
What is the salience network responsible for?
Activating behavioural shifts and modulating other networks.
What happens if the salience network is disrupted?
It can lead to excessive default network activity, attentional lapses, and cognitive instability.
Which area is implicated in mood-related circuits?
The ventromedial prefrontal cortex.
What is linked to abnormal activity in the ventromedial prefrontal cortex?
Mood disorders such as depression.
What cognitive ability is central to frontal-lobe function?
Temporal organization of behaviour in response to internal goals and external demands.
What difficulties do people with frontal-lobe damage experience?
Struggle with action selection, ignoring distractions, and tracking sequences—indicating impaired goal-directed control.
What role does the premotor cortex play?
Bridges perception and action, selecting movements based on environmental cues.
How is the supplementary motor area (SMA) functionally distinct?
Contributes to internally generated movements like spontaneous exploration.
What is the role of frontal eye fields?
Support gaze shifts, with distinct regions for stimulus-driven and internally guided eye movements.
What did Per Roland’s research reveal about motor sequence control?
Internally paced sequences activate the SMA; externally cued movements engage the premotor cortex.
How does the prefrontal cortex regulate behaviour?
Selects actions based on internal and external cues, ensuring contextually appropriate responses.
What is temporal memory and which prefrontal region is involved?
A working memory form tracking event order; dorsolateral prefrontal cortex is involved.
What happens when temporal memory is impaired?
Behaviour becomes stimulus-bound and goal tracking suffers.
What role does the orbitofrontal cortex play in behaviour?
Supports associative learning and using reinforcement history to guide decisions.
What is the effect of orbitofrontal cortex damage?
Disorganized decision-making and inability to use rewards for behavioural guidance.
Why is context important in behaviour regulation?
Behaviour must adapt to social norms and environmental conditions, processed via prefrontal input from the temporal lobe and amygdala.
What deficits can result from damage to context-processing areas?
Inappropriate social behaviour, poor judgment, and reduced self-insight.
What is autonoetic awareness?
A self-reflective awareness integrating past, present, and future for meaningful behaviour.
Which areas support autonoetic awareness and what happens if damaged?
Medial and ventral prefrontal regions; damage disrupts self-identity and social function.
How does frontal-lobe function exhibit hemispheric asymmetry?
Left frontal lobe is more involved in language, right in nonverbal actions.
What evidence supports bilateral integration in frontal-lobe function?
Bifrontal lesions impair complex tasks more than unilateral lesions.
What memory roles are associated with left and right prefrontal cortices?
Left is involved in encoding new info; right in memory retrieval.
What hypothesis explains frontal-lobe specialization?
Cognitive demands increased specialization due to limited cortical space.
What does research by Shallice and Burgess suggest about frontal-lobe organization?
There is substantial heterogeneity—different regions support distinct cognitive tasks.
What conclusions follow from frontal-lobe heterogeneity?
Symptoms vary by lesion location, and different networks underlie specific behaviours.
What are the five principal symptom categories of frontal-lobe lesions?
Motor function, divergent thinking, environmental control of behaviour, temporal memory, and social/sexual behaviour.
What motor impairments result from frontal-lobe damage?
Loss of fine movements, reduced speed/strength, movement sequencing errors, and disrupted eye movements.
How does frontal damage affect voluntary gaze?
Disrupts visual scanning and fixations due to frontal eye field damage.
What is corollary discharge and how is it affected by frontal-lobe lesions?
It’s the prediction of movement’s sensory effects; damage disrupts sensory stability during motion.
What speech deficits are linked to frontal-lobe damage?
Agrammatism and mutism from damage to Broca’s area and supplementary speech area.
How is divergent thinking affected by frontal-lobe lesions?
Impaired ability to generate novel ideas and flexible problem-solving.
What is behavioural spontaneity and how is it impaired?
Spontaneous action/speech generation is reduced; patients show low output and perseveration.
What role does the frontal lobe play in strategy formation?
Essential for formulating strategies in novel situations and integrating variables on the fly.
What is response inhibition and how is it tested?
Inhibiting prepotent responses, tested with the Wisconsin Card Sorting and Stroop Tests.
What behavioural tendencies are seen in risk-taking tasks with frontal damage?
Rule-breaking, impulsivity, and failure to avoid risky options.
How does frontal-lobe damage affect self-regulation?
Disrupts autonoetic awareness, impairing autobiographical memory and social function.
What kind of associative learning is impaired by frontal damage?
Stimulus-response learning, especially when competing responses must be filtered.
What is the nature of temporal memory deficits in frontal-lobe patients?
Difficulty remembering the order/timing of events, not general memory loss.
Which frontal region supports spatial working memory?
The dorsolateral prefrontal cortex (DLPFC).
What findings did Jacobsen (1936) report in monkeys with frontal lesions?
Failed delayed-response test due to impaired working memory for spatial info.
How do Milner et al. (1991) distinguish frontal vs temporal memory deficits?
Frontal patients fail recency judgment; temporal patients fail recognition.
What changes occur in social and sexual behaviour after frontal damage?
Disinhibition, inappropriate social/sexual actions, and impaired emotional understanding.
What are pseudodepression and pseudopsychopathy?
Syndromes of apathy or disinhibition associated with left or right frontal damage.
What role does the orbitofrontal cortex play in social behaviour?
Supports social inhibition and interpretation of facial expressions.
Does the frontal lobe support spatial cognition?
It supports short-term spatial memory and spatially guided behaviour selection.
Which clinical tests detect frontal-lobe damage?
Wisconsin Card Sorting, Thurstone Word Fluency, Design Fluency, Tower of Hanoi/London.
How are language deficits assessed in frontal damage?
Token Test, spelling and phonetic tasks for Broca’s and surrounding areas.
What disorders show frontal-like symptoms?
Schizophrenia, Parkinson’s, Korsakoff’s, addiction, and chronic stress.
What frontal-related dysfunctions occur in schizophrenia?
Reduced frontal blood flow, atrophy, and impaired eye movement control.
How does Parkinson’s disease affect the frontal lobe?
Through dopaminergic disruption affecting planning and flexibility.
What frontal deficits are seen in Korsakoff’s syndrome?
Impairments in spatial memory and sequencing, similar to DLPFC damage.
How does drug addiction relate to frontal dysfunction?
Orbitofrontal damage leads to impulsivity and poor decision-making.
What are the effects of chronic stress on the frontal lobe?
Alters neuronal architecture, impairs memory and goal-directed action.
