Task 1 Flashcards
(43 cards)
1.1.: What brain structures/systems are involved in planning an action in response to visually
presented object?
Intraparietal cortex (IPC), PFC, FEF, (pre)SMA & PMd+M1
Function of Intraparietal cortex (IPC)?
‘What?’
- Representing relevant stimuli
- Helps selecting motor goals
- Salience map for spatial attention
- Guides visual attention
Function of (lateral) PFC?
‘What?’
- Translates visual targets into motor goals
- Encodes relationship between object & goals –> according to rules
- Determines whether to proceed motor action or to inhibit –> influenced by priming & difficulty
Function of frontal eye filed (FEF)?
‘What?’
- Represents motor goals selected on behalf of stimuli
- Initially several target choices but evolves to only one goal –> Drift diffusion model
Function of (pre)-SMA?
‘How?’
- Action selection
- Control over voluntary actions in situations of response conflict
- PRE-SMA: Monitoring of outcomes
- SMA: Inhibition of primed actions
Function of PMd + M1?
‘How?’
- Movement specification
- Determine motor command of limb & postural adjustment
- Activity before movement –> define how it is executed
1.2.: Explain Wong’s scheme –> WHAT pathway (selection of motor goals)
Observation of environment (LIP) –> Attention –> Object selection (LIP) –> Application of task rules to select object (PFC) –> Motor goals (FEF)
Explain Wong’s scheme –> HOW pathway (motor planning)
Action selection (pre-SMA, PMv) --> Movement specification (PMd & M1) => complex tasks: abstract cinematics
What’s the role of feedback control policies?
o We flexibly change plans
o Allows us to be more flexible, it’s less effortful
o Corrections to initial movement plan
o Flexibly reapplies + changes old plan rather than making a new plan
==> Inverse model: comparison between predicted vs actual sensory feedback
1.3.: What is the HOW-pathway? Its function? (EXOGENOUS pathway)
- dorsal pathway
- -> visuomotor integration
- -> how to direct action with regards to stimulus
- -> motor planning
Where is the HOW (dorsal) pathway in the brain?
visual cortex –> parietal cortex –> premotor cortex
Where is the dorso-dorsal stream in the brain?
V3a –>V6 –> V6a –> dorsal PMA
Function of dorso-dorsal stream? Important for what- grasp or use?
-Online visually guided motor control
-Processes structural characteristics (size, shape, orientation) to guide online action toward a currently visible stimulus
-Structure-based action
==> GRASP system
Which disorder does a lesion in dorso-dorsal stream lead to?
optic ataxia –> misreaching visual targets
Where is the ventro-dorsal stream in the brain?
Medial superior temporal area –> inferior parietal lobe –> ventral PMA
Function of ventro-dorsal stream? Important for what- grasp or use?
-More cognitive, based on long-term experiences with objects
-Important for ‘praxis’ + tool use
-Transforms visual inputs into representations
-Function-based actions
==> USE system
Which disorder does a lesion in ventro-dorsal stream lead to?
ideomotor/limb apraxia ==> impaired performance of skilled motor acts (without direct visual control)
(but intact sensory, motor + language function)
Visual pathway: Ventral ‘what’ pathway
- Recognition of objects
- ‘what am I seeing?’
- From V1-V4 to inferior temporal cortex
Visual pathway: Dorsal ‘how’ pathway
- Involved in visually guided behaviour
- ‘How to adjust my behaviour based on visual perception?’
- V1-V4 to parietal cortex
- Subdivison into 2 pathways
1. dorso-dorsal pathway - -> online visually guidance of actions
2. ventro-dorsal pathway - -> skill-based/tool-based action
1.4: Endogenous action- which areas are involved in self-generated movement?
Medial frontal lobe: Pre-SMA, SMA, ACC + SEF (=supplementary eye field)
Evidence from monkey studies- what happenes when you remove (pre)-SMA or cingulate motor areas?
Reduction in self-initiated movements + inability to learn new movements
Evidence from Sumner study (lesioned patients)
one of the roles of the SMA + SEF is to contribute automatic inhibition of primed actions
Role of SMA & SEF in voluntary behaviour
-involved in unconscious + involuntary motor control
-mediate automatic effector-specific suppression of motor plans
==> Automatic inhibition is an important part of flexible, volitional behaviour
Role of pre-SMA in voluntary behaviour
- parietal external + medial-prefrontal internal source of action control
- > kept in balance from the pre-SMA
- Activity starts earlier when self-initiated than externally motivated actions
