Unit 8 - The Attending Brain Flashcards
What is attention?
The process by which certain information is selected for further processing while other is discarded
Can be described as a filter or bottleneck in processing
How is attention linked to sensory overload?
Attention is needed to avoid sensory overload by ensuring that importance is only given to the most important aspects.
What are bottom-up and top-down in relation to attention?
Bottom-up influences are created by our environment, while top-down are created by our goals and inner motivations.
What is inattentional blindness?
A failure to notice the (dis)appearance of a visual stimulus because attention is directed away from it
If attention is split between two nonadjacent locations, does the location in the middle of the two have to be included?
No.
What is change blindness?
A failure to notice the (dis)appearance of objects between two alternating images
What is the connection between attention and eye fixation?
They usually go together since visual acuity (the discrimination of fine details) is greatest at the point of eye fixation.
What is a salient?
Any aspect of a stimulus that stands out from the rest
What is orienting?
The moving of the focus of attention
What is the spotlight metaphor? What are some of its advantages?
Attention is like a spotlight beam:
-Focuses on one location, processing
everything within the beam.
-Ignores information outside the
beam.
Highlights limited capacity and spatial aspects of attention but oversimplifies its complexity.
What is overt orienting?
The moving of the eyes or head along with the focus of attention
What is covert orienting?
The moving of the focus of attention without moving the eyes or head
What does inhibition of return refer to?
The processing cost in terms of reaction time associated with going back to the previously attended location.
What is visual search? How does it relate to endogenous and exogenous orienting?
A task of detecting the presence or absence of a specified target object in an array of other distracting object
Is a mix of both since it involves the perceptual identification of objects and features (bottom-up) as well as holding in mind the target and endogenously driving orienting of attention (top-down)
What is exogenous orienting? How about endogenous orienting?
Attention that is externally guided by a stimulus (bottom-up)
Attention that is guided by the goals of the perceiver (top-down)
What are two types of non-spatial attention mechanisms?
Object-based attention processes
Time-based/temporal attentional processes
What is attentional blink?
An inability to report a target stimulus if it appears soon after another target stimulus
What is the “what” pathway?
The ventral stream leading to the temporal lobes involved in object perception, memory and semantics.
What is the specialisation of frontal regions vs parietal regions?
Frontal regions are more implicated in task and motor selection, while parietal regions act as a hub for pulling together bottom-up and top-down signals.
What is the lateral intraparietal area (LIP)?
Contains neurons that respond to salient stimuli in the environment and are used to plan saccades
What is the “where” pathway?
The dorsal stream leading to the parietal lobes involved in attending to and acting upon objects (locating objects in space)
What is a salience map and which area contains it?
A spatial layout that emphasises the most behaviourally relevant stimuli in the environment
the LIP
What is the Frontal Eye Field (FEF)?
The part of the frontal lobes responsible for voluntary movement of the eyes
To which types of stimuli does the LIP react to specifically?
Unexpected stimuli or those relevant to a given task
When the target is linked to a strong reward or punishment
What are saccades?
Fast, ballistic movements of the eyes
What are the two possible splits of the dorsal stream?
The dorso-dorsal branch and ventro-dorsal branch.
What is remapping and how is it linked to salience maps?
Adjusting one set of spatial coordinates to be aligned with a different coordinate system, e.g., to combine input from the ears and eyes which are located in different places
Used by salience maps to make inputs from different senses spatially aligned
What does the ventro-dorsal branch specialise in?
Circuit breaking, or interrupting ongoing cognitive activity to direct attention outside of the current focus of processing (involves TPJ)
What does the dorso-dorsal branch specialise in?
Orienting within a salience map (involves LIP and FEF)
What is hemispatial neglect?
A failure to attend to stimuli on the opposite side of space to a brain lesion
Where does the right parietal lobe show maximal responsiveness to stimuli? How about the left?
On the left
On the right
What is pseudo-neglect?
When in a non-lesioned brain there is over-attention to the left side of space
Function of right hemisphere vs left hemisphere:
Right important for attending to a salient stimulus
Left important for suppressing a non-salient stimulus
Difference in between Attention, Awareness, and Perception:
Attention is a mechanism for the selection of information
Awareness is an outcome, or conscious state
Perception is the information that is selected from and ultimately forms the content of awareness
What is the connection between perception and attention?
When an object or a perceptual feature is attended there is an increased activity in the brain regions involved in perceiving those stimuli.
What is the relation between attention and awareness?
There is greater activity in the regions involved in perception when participants are aware of a stimulus vs unaware.
There is a spread of activity to distant brain regions in the aware state.
What is phenomenal consciousness? What is access consciousness?
Phenomenal consciousness is the experience of perceiving itself, i.e., the raw feeling of a sensation, the content of awareness.
Access consciousness is the reportability of that experience, i.e., the ability to report on the content of awareness.
What are the three theories of attention? What is each of them a theory of?
The feature integration theory - spatial attention
The biased competition theory - more general account on attention
The premotor theory - spatial attention
What are tests of line bisection and how are they related to neglect?
Tasks involving judging the central point of a line
Can show whether patients see the entire visual field
What is late selection?
A theory of attention in which all incoming information is processed up to the level of meaning before being selected for further processing.
What is the Feature Integration Theory?
Feature Integration Theory (FIT):
- Attention binds features (color,
shape) into a cohesive experience.
- Features are coded in parallel before attention.
- Distinct features make objects “pop
out.” - Multiple features are combined for
detection. - Spatial attention targets candidate
objects. - Search time increases linearly with
more distractors. - Indicates serial inspection of each
candidate object.
What is meant by illusory conjunctions?
A situation in which the visual features of two different objects are incorrectly perceived as being associated with a single object.
That is, individual features incorrectly combine if attention is not properly deployed.
What is meant by pop-out?
When the target object does not share features with other objects (distractors), it “pops out.”
What is early selection?
A theory of attention in which all incoming information is selected solely according to perceptual attributes
What is negative priming? To which theory of attention is it most linked?
If a previously ignored object suddenly becomes the attended object, participants are slower at processing
Late selection
What is biased competition theory?
- Rejects the spotlight metaphor of attention.
- Attention is a broad set of mechanisms
for reducing many inputs to limited
outcomes. - No distinction between pre-attentive
and attentive stages. - Competition occurs at multiple,
dynamic stages, not at a fixed
bottleneck. - Degree of competition depends on
perceptual similarity. - When two stimuli share a receptive
field, neuron responsiveness is
reduced. - Attention is not deployed serially but
through parallel perceptual
competition.
What is extinction in the context of attention? Damage to which area causes it?
Unawareness of a stimulus in the presence of a competing stimulus
Caused by damage to the parietal lobe.
What is the premotor theory?
- Orienting attention is preparation for
motor actions.
Minimal effort extends leftward eye movement further left.
Switching from leftward to rightward movement requires a new motor program.
Attention is a preparatory motor act.
Neural substrates of attention are the same as for motor preparation.
Theory may only be valid for certain situations and can fail in others.
What is Balint’s syndrome?
Severe spatial disturbances due to damage to both the left and right parietal lobes
What other tests exist for neglect besides line bisection and cancellation tasks?
Drawing from memory and copying drawings
What is simultagnosia?
A condition where patients are only able to perceive one object at a time and not more
What are cancellation tasks and how are they related to neglect?
A variant of the visual search paradigm in which the patient must search for targets in an array, normally striking them through as they are found.
What does neglect represent?
A failure to attend to stimuli on the opposite side of space to their lesion
Is neglect considered more linked to awareness or attention?
Attention, since it tends to be multisensory in nature, meaning that the deficit is more pronounced when demands on attention are high.
What is allocentric space?
A map of space coding the locations of objects and places relative to each other.
What is egocentric space?
A map of space coded relative the position of the body
What does representational neglect refer to?
Neglect in mental representations of patients
Double dissociations existing between types of neglect:
Near versus far space
Personal (body) and peripersonal space (space outside their body)
Within object versus between objects
