Ch 7 Flashcards
how to study the control of attention
monitoring brain activity and behaviour of subjects with and without brain damage has lead to the understand of which brain regions are important for the control of attention
Which brain regions control attention?
Vonluntary (top-down, endogenous) attention
Involuntary (bottom-up, exogenous) attention
Default-mode network (internal attention, resting state)
Vonluntary (top-down, endogenous) attention
Dorsal frontoparietal network
- SPL (superior parietal lobe)
- FEFs (frontal eye fields)
- MFG (middle frontal gyrus)
Frontal first, then parietal, then sensory
Involuntary (bottom-up, exogenous) attention
Right-lateralized ventral frontoparietal network
- TPJ (temporoparietal junction)
- IFG (Inferior frontal gyrus)
- MFG (middle frontal gyrus)
Sensory first, then parietal (right TPJ), then frontal. This system can shut down the voluntary attention system
Default-mode network (internal attention, resting state)
Medial frontoparietal network
- PCC
- MPC
- AG
subcortical structures crucial for different aspects of attention
TPJ: disengaging attention
Superior colliculi: moving attention
pulvinar: engaging attention
Contralateral Neglect
bottom-up problem:
results from damage (most often) to the right inferior parietal cortex, leading to the neglect of stimuli in the left visual field
an attentional deficit, not sensory (visual) deficit
can basically still SEE the left visual field, just can’t attend to it on their own
Extinction
stimuli in both visual fields compete for attention
—> the right visual field dominates and extinguishes stimuli in the left visual field
—> ignoring the left object (in case of two stimuli) when a similarly object is shown in the right visual field at the same time
ex: spoon (left) and fork (right) are both seen
left and right: spoon the left is ignored
Balint’ syndrome
top-down network in the parietal lobe is damaged:
- simultanagnosia
- optic ataxia
- oculomotor apraxia
simultanagnosia
Inability to attend to more than one visual stimulus at a time
Optic ataxia
Difficulty with reaching and grasping (no visual guidance of movement)
Oculomotor apraxia
Difficulty making voluntary eye movements to objects
fMRI and Event-related potentials
Since fMRI signals are slow and provide low temporal resolution, combining data of identical attentional cuing paradigms of fMRI studies and ERPs can tackle this problem
fMRI and Event-related potentials
Since fMRI signals are slow and provide low temporal resolution, combining data of identical attentional cuing paradigms of fMRI studies and ERPs can tackle this problem
Lateral intraparietal (LIP) area
Involved with planning eye movements. The amount of activity in these neurons has been suggested to depend on stimulus salience (how noticeable a stimulus is
Frontal eye fields (FEF)
Part of the dorsal frontal cortex. Involved with controlling eye movements. Activity is seen in FEF when monkeys are about to make an eye movement and when a stimulus appears in an area that the monkey is attending to. Activity in FEF has led to the premotor theory of attention.
Premotor theory of attention
shifting attention is closely related to planning action to achieve a goal because they are controlled by the same sensory-motor mechanism. Eye movements assist the control of visuospatial attention
Endogenous
FEF neurons, then LIP neurons.
Frontal, then parietal.
Accurately cued targets are identified more quickly, more accurately and elicit a larger response from the visual cortex
Exogenous
LIP neurons, then FEF neurons.
Parietal, then frontal.
Invalidly cued targets activate the right temporoparietal junction (TPJ) more strongly than accurately cued targets
Visual search
The process of looking for a target stimulus in an array of distracters
Pop-out stimuli
Targets that are detected quickly because they differ in a single feature from distracters. The time it takes to locate a pop-out stimulus is independent from the number of distracters present.
(Bottom-up, stimulus driven, exogenous)
Conjunction target
A stimulus defined by a conjunction of features that are present in the array. This stimulus does not pop out and the time it takes to find it increases with the number of distracters present.
Requires focused attention to various items to see which has a
combination of features. Takes longer with more distracters
because the process must be repeated until the target is found. (Top-down, voluntary, endogenous)
