Cerebellum & EF Flashcards
The purpose of our brain
Control over movement
How does the brain engage with our environment?
Object recognition
Spatial recognition – object location
Detect movement & engage in voluntary action
- We are either thinking about doing OR doing
Types of movement we need to learn to manage our environment:
Predictable and unpredictable:
Predictable:
Fixed, routine automatic responses
Unpredictable
Novel and require flexible responses
SO we need both habit and thinking systems that interact
What are the 2 re-entrant systems
Cortico-striatal system - reward & Categorisation
Cerebro-cerebellar system
What are the characteristics of re-entrant systems?
- Closed systems that connect 2 or more brain regions together
- couple the function of multiple brain area
- Non-direct
- Via thalamus or 1/2 afferents/efferents that cross deep cerebellar nuclei
- Closed loop
- they allow the cerebellum to generate models of the brain
Connections between cerebellum & Cortex
Anterior cerebellum ==> Sensorimotor
Posterior cerebellum ==> ‘cognitive region’
PFC + Parietal Association area
Vermal Region
Damage = affective/behavioural malformations
Which 2 brain areas have grown in sync?
PFC + Cerebellum have grown in sync
Balsters, Joshua et al (2014)
Functions of the cerebellum:
movement, Cognition & Affect
LOTS of overlap between large regions of cortex + subcortical regions in tandem
- Serves consciously controlled + automatic adaptive behaviour
Assigned pathway to brain function
We can’t distinguish Perception + Cognition + Action; overlap makes it difficult to distinguish perception, cogntiion and action
What does the Ecological Perspective to Brain Organisation postulate?
- The control of interactive behavior involves competition between parallel sensorimotor control loops
- Neural representations involved in this control are pragmatic and dependent upon the environment
‘Cool’ Executive functioning is:
Meta-cognitive Top down Under deliberate conscious control - Problem solving - Planning/goal setting - Fluency - Concept formation - Self-directed attention/shifting
‘Hot’ EF is:
Emotional
Bottom up
- Affected by dysregulation and arousal problems
- Coordinating cognitive with motivation
Brain areas involved in EF
Cerebellum + Cortex + BG
Role of BG & Cerebellum in EF
Do not not have the capacities for sensory processing and motor programming
BUT
Play central role in deciding what information is or is not used by the cortex
Role of the cortex in EF
has sensory capacities + motor programming that they use for calculation
Is EF unique to humans?
No - all animals have the capacity to problem solve and engage in goal directed behaviour
What % of brain volume does the cerebellum encompass?
10%
What % of neurons does the cerebellum hold?
80%
When does the cerebellum develop?
3rd trimester - therefore susceptible to premature injury
19% of prems have cerebellar injury
How is the CB involved in action?
Through interactions between the thalamus, neocortex and CB - cerebro-cerebellar circuit:
->the CB helps the brain decided WHEN to act
- > how to act
- refined rhythm, rate and force
-> shift responses according to a situation
Feed-forward model: Cerebro-cellerbellar circuit & Movement
- Sensory information and feedback is fed from the cortex
this allows the CB to refine movement accordingly
& refine movement over time and practice
Cerebellum & social cognition
Social cognition requires you to be constantly online - therefore it needs the cerebro-cerebellar system to be intact
How does the CB develop automaticity
Creates automaticity: through the repetition of movement & integration of feedback the CB obtains more information & become more accurate
It creates inverse models
What is a cerebellar inverse model?
It is a model that facilitates automaticity to develop
They are: rapid, coordinated, highly skilled movement (and thought) that occur at an unconscious level, outside the awareness of cortically based working memory
How they are carried out:
inverts the information flow of the forward model by inputting the desired goal of the movement, i.e. its desired sensory consequences, and back calculating the motor commands that would be required to achieve this. In other words it is the inverse model that actually generates the programme of motor commands to make the movement
Disordered rate, rhythm or force of the behaviour
Dysmetria
Over or under-shooting in an attempt to match movement to environment
Symptoms of CAS
Cerebellar Cognitive Affective Syndrome a.k.a Schmahmann’s syndrome
Attentional Control Emotional Control Autism Spectrum Psychosis Spectrum Social skill set
Behaviour clusters of CAS
Behaviours are clustered into positive (overshooting/exageratted) or negative (undershoot/underrepresented)
e.g.
Inattentiveness vs. Obsessional thought
Cerebro- cellebellar circuit & ASD
Posterior vermis Limbic area
Posterior vermis Limbic area
Affective dysregulation
Social processing deficits
Irritability
Cerebro- cellebellar circuit & ASD:
Anterior Lobe somatosensory
Stereotyped & repetitive behaviour
Motor impairment
Cerebro- cellebellar circuit & ASD: Anterior Vermis (VIIIA & VIIIB) somatosensory
Stereotyped & repetitive behaviour
Cerebro- cellebellar circuit & ASD:
Right Crus 1 & II (Posterior Lobe) fronto-language areas
CB (Posterior Lobe) fronto-language areas:
Language Deficits Social Cognition Deficits Theory of mind deficits Imitation impairment Stereotyped and Repetitive behaviours
Cerebrocellebellar circuit & ASD
Disruptions to the cerebro-cerebellar circuit has been implicated in ASD
What to consider when thinking about EF in clinical practice:
- consider problems navigating rate, rhythm and force of emotions and behaviour
- our ability to automatise and anticipate is key for adaptive functioning
Neurodevelopmental Disorders & EF
- > Ability to make and implement effective, adaptive decisions about what to do, when to do it and how to do it
- > difficulty with Bringing intentions to constructive execution
- > Sensorimotor difficulties – sensory meltdown
- > Poor automaticity burden higher order control
- ->Too much of your brain is used & slows down performance
->Trouble developing internal models makes it hard to generalise effectively
