[W2] - CH13 Flashcards
Executive Functions as a Unitary Construct
Views executive functioning as a singular dynamic construct (a.k.a the central executive); similar to intelligence. Considers executive functioning a “supervisor” of other subordinate or lower-level cognitive processes
[Example: McCloskey’s Holarchical Model of Executive Functions (HMEF)]
Executive Functions as an Associated Conglomeration of Multifaceted Components
Considers executive functions to be distinct, but related, complex higher order abilities or skills. However, the exact components that could be classified as executive functions under this definition are still hotly debated.
Three main constructs that have been consistently accepted by the majority as components of executive functions are: working memory, inhibition, and cognitive switching.
A conceptualization of EF as a constellation of higher order cognitive processes that enable reasoning, problem solving, planning and cognitive organization (e.g., can serve as facilitators/inhibitors for other functions).
How does the Integrated SNP/CHC Model conceptualize executive functions?
Integrated SNP/CHC Model conceptualizes executive functions as independent but moderately correlated constructs and categorizes cognitive flexibility, concept recognition and generation, inhibition, planning, reasoning, and problem solving as executive functions.
Miller views other common elements of executive functions such as attention, working memory, and processing speed as separate neurocognitive constructs that serve as facilitators/inhibitors of higher order complex processes.
The neuroanatomy of executive functions
Historically, executive functions have been linked with the frontal lobe. While the frontal and prefrontal lobes do play major roles in executive functioning, there are also excitatory and inhibitory pathways that start in subcortical regions of the brain and project to the frontal cortex (and vice versa).
Alexander and colleagues (1986) introduced the idea that there is a parallel, but segregated, set of frontal-subcortical (FSC) circuits that influence both movement and behaviour.
The Major Functions of the Skelemotor (FSC)
Regulates large and fine muscle movements.
The Major Function of the Oculomotor (FSC)
Regulates eye movements.
The Major Functions of the Dorsolateral Prefrontal (FSC)
The Executor of the Brain. The majority of neuropsychological and cognitive tests activate this circuit. It primarily regulates most cognitive executive functioning skills, which are critical to the execution of a goal directed academic task in school.
Neurocognitive deficits associated with damage to this region include:
- Decreased verbal and nonverbal retrieval
- Abnormal motor programming
- Impaired set shifting
- Reduced learning and memory retrieval
- Disruptions in working memory.
- Poor organizational skills
- Poor constructional strategies in copying
- Poor problem solving, goal selection, planning, monitoring, and use of feedback in task performance.
- Difficulty focusing attention and sustaining attention.
- Difficulty generating hypotheses.
The Major Functions of the Orbitofrontal [lateral, ventromedial] (FSC)
The orbitofrontal circuit mediates empathic, civil, and socially appropriate behaviors; personality change is the hallmark of orbitofrontal dysfunction (think Phineas Gage and the iron rod).
It regulates our abilities to inhibit [behavior], evaluate, and act on social and emotional decision-making. Damage to it seems to disconnect the frontal monitoring systems from the emotional responses of the limbic system. Right orbitofrontal damage tends to produce greater disinhibition and loss of socially appropriate behaviors than damage to the left.
It integrates emotional information into contextually appropriate behavioral responses, and emotional functions with internal states.
Neurocognitive deficits associated with damage to this region include:
- Impulsivity
- Antisocial behaviour
- Inappropriate feelings under normal circumstances (e.g., laughing/crying)
- Irritability
- Tactlessness
- Undue familiarity
- Reduced empathy
- Obsessive-compulsive symptoms
The Major Functions of the Anterior Cingulate (FSC)
Responsible for:
- Motivational mechanisms (e.g., apathy)
- Allocation of attentional resources
- Behavioral Initiation responses
- Creativity and concept formation
The anterior cingulate circuit regulates motivational mechanisms. On neuropsychological measures, the most prevalent deficit is the failure of response inhibition (i.e., responding square to a picture of a circle). The anterior cingulate has been hypothesized to operate as an Executive Attention System; allocating attentional resources to other parts of the brain to ensure that a task is handled efficiently (akinetic mutism is present when there is bilateral damage to the anterior cingulate)
Neurocognitive deficits associated with damage to this region include:
- Apathy
- Limited spontaneous speech
- Indifference to pain, thirst, or hunger (in severe cases)
- Obsessive-compulsive characteristics
- Poor response inhibition (impulsive)
- Poor creativity or generation of new concepts
- Poor allocation of attentional resources
Define Abulia; Echopraxia; Emotional Lability; and Perseveration
- Abulia: Lack of initiation or drive.
- Echopraxia: Pathological copying of another person’s speech. Associated with
frontal lobe disorders. - Emotional lability: Abnormal variability in emotional expression characterized
by repetitive and abrupt shifts in affect. Often seen after damage to the
orbitofrontal regions of the frontal lobes. - Perseveration: A tendency to repeat the same response over and over, even
when it is shown to be inappropriate. Perseveration may involve motor acts,
speech, or ideas.
Define Anterior Cingulate Syndrome; Dorsolateral Frontal Syndrome; Orbitofrontal Syndrome
Anterior cingulate syndrome: Symptoms consist of reduced spontaneous activity
(increased apathy, do not speak spontaneously, eat and drink only if fed, show
little to no emotion, and may be incontinent)
Dorsolateral frontal syndrome: Symptoms consist of difficulty with generating
hypotheses, cognitive flexibility, shifting of cognitive sets, reduced verbal or
design fluency, poor organizational strategies for learning, constructional
strategies for copying complex designs, and motor programming deficits.
Orbitofrontal syndrome: Characterized by prominent personality changes
including: emotional lability, impulsivity, irritability, becoming more outspoken
and less worried, and occasionally showing imitation and utilization
behaviors.
Define Initiation Deficit; and Utilization Behavior
Initiation deficit: The failure to act, or behavior requiring extensive cueing,
despite a demonstrated ability to perform the desired behavior. Child may
be able to describe the intended action but not be able to initiate the
action. Characteristic of damage to the anterior cingulate region of the
frontal lobes.
Utilization behavior: The tendency to grasp and use objects within reach
regardless of whether they are related to the current task. An example would
be a child feeling compelled to start hammering when handed a hammer. This
behavior is thought to arise from an enslavement to the environment and is
associated with bilateral frontal lobe damage.
What is cognitive flexibility/shifting attention?
The ability to consciously reallocate attentional resources from one activity to another is referred to as shifting attention.
A task that measures this capacity is the Wisconsin Card Sorting Test: where sorting rules change mid-task from sorting by colour to sorting by number of objects on the card.
When a student cannot complete this shift of attention from one activity/method of sorting to the next, this is called a preservation error.
Behavioral vs. Cognitive Response Inhibition
Behavioral response inhibition difficulties might manifest themselves as an inability to not lash out at another child nearby.
Cognitive response inhibition difficulties might manifest as an inability to complete the Stroop task (i.e., cannot inhibit the tendency to read the word to name the colour).
The items on The Neuropsychological Processing Concerns Checklist for Children and Youth (NPCC-3) pertaining to executive function difficulties.
[Behavioral/Emotional Regulation Difficulties; Planning Difficulties; Problem Solving and Organizing Difficulties]
Behavioural/Emotional Regulation Difficulties:
- Demonstrates signs of over activity (hyperactivity).
- Does not seem to think before acting.
- Difficulty following rules.
- Demonstrates signs of irritability.
- Lacks common sense or judgment.
- Cannot empathize with the feelings of others.
Planning Difficulties:
- Difficulty with making plans.
- Quickly becomes frustrated and gives up easily.
- Difficulty figuring out how to start a complex task.
- Difficulty sticking to a plan of action.
Problem Solving and Organizing Difficulties:
- Difficulty solving problems that a younger child can do.
- Difficulty learning new concepts or activities.
- Makes the same kinds of errors over and over, even after corrections.
- Frequently loses track of possessions.
