Attention and Consciousness II Flashcards
What types of attentional networks exist?
Top-Down (Control Network)
- Engages a more dorsal in the brain (at the top of brain); Fronto-parietal network
- More medial parts of the parietal and frontal cortex are active to direct attention
Bottom-Up (Transfer Processing)
- Engages a more ventral meaning further down the network
- More lateral parts of the parietal and frontal cortex are active to direct attention
What are the functions of the attentional networks?
Top-Down (Control Network)
- Voluntary attentional network
- Control Network (DLF, IPL, STS, PC, MF) are activated during cue presentation and involved in attentional control
Bottom-Up (Transfer Processing)
- Automatic capture of attention
- Network for novelty and attentional regarding
- Target Processing areas are activated in stimulus presentation and involved in stimulus processing (but not in direct attention)
Name the areas involved in the different networks
Top-Down (Control Network)
Cortical:
- DLF: Dorso Lateral Frontal Cortex
- IPL: Infra Parietal Lobule
- PC: Posterior Cingulate Cortex
- STS: Superior Temporal Cortex
- MF: Medial Frontal Cortex
Bottom-Up (Transfer Processing)
Cortical:
- TPJ: Temporal Parietal Junction
- VFC: Ventral Frontal Cortex
What is the difference between spatial and object-centred neglect?
- For spatial neglect, you would only be able to perceive one side of your visual world (divide the whole view in half and only take the side opposite to brain lesion’s side)
- For object-centred neglect, you would be able to perceive one side of each object in your visual world (take each element in your view and divide it in half)
Which are the brain areas most often affected by spatial and object-centred neglect?
- Spatial neglect: IPL/TPJ (Intra Parietal Lobule/ Temporal Parietal Junction
- Object-centred neglect: STG (Superior Temporal Gyrus)
Are there attentional memory deficits?
- Yes, neglect also occurs in the domain of memory
- In this study, the memory was tested for known spaces
- The patient had a neglected side in visual memory (shaded gray), which was contralateral to the side with cortical damage
- If the patient was asked to turn around, the neglected memory side turned as well
What are the features of attentional memory deficits?
What is the attentional network?
- Model of the executive control systems and the way in which visual cortex processing is affected by the top-down control of a network of brain areas
How does the attentional network influence sensory processing?
Do different forms of attention engage different networks?
Midbrain attentional networks and cortical attentional networks
Midbrain Attentional Networks
- Brain regions involved in early visual processing (introducing the superior colliculus)
- Superior Colliculus receives visual information, auditory information and some sensory information
- Superior Colliculus is critical in visual attention and in orienting to the external world
Premotor Theory of Attention
- Attention is like a motor plan -> We plan to focus on this part of the world before we execute it
Neurology - How attention can be affected by many types of brain lesions
- Neglect and Extinction
Lesions and Different Control Networks:
- Superior Temporal Gyrus
- Supramarginal Gyrus
- Angular Gyrus
- TPJ
- Inferior Parietal Lobule
- Intraparietal Sulcus
- Superior Parietal Lobule
- Central Sulcus
- Frontal Lobe
How can we identify the attention network in humans?
- Spatial Cuing Paradigm: Fixation -> Cue -> Delay -> Stimulus
- Measured by event-related fMRI
- Long delay btwn cue and stimulus allows us to identify which areas are part of the attentional control network
What does it mean when a person suffers from extinction?
- If two things happen simultaneously in the external world, they can only respond to the one where the hemisphere is not damaged BUT if only one thing happens, they still perceive it
- A milder form of neglect
Example: Lesion in the right side of visual cortex
- Can see two fingers wiggled on right hand
- Can see two fingers wiggled on left hand
- If wiggled on both sides, person will only point to the right hand (right side VC impacts left side visual perception)
