Selective attention and anatomy of attention

taxonomy of attention can be separated into…

three different components; alerting role of thalamus; conflict monitoring orienting(selective attention)

alerting role of thalamus

maintenance of an aroused state

what are the two different states of the thalamus?

bust mode and tonic mode

burst mode

captures moment-to-moment fluctuations in this state of internal readiness

tonic alertness (tonic mode)

captures the sustained vigilance of an aroused state

neural activity seen in tonic mode

regular firing

neural activity seen in burst mode

sharp bursts in activity → brings an organism to a more aroused state and drives the sensory system to detect the stimulus

conflict monitoring

• reliant on the frontoparietal and cingulo-opercular networks

• involves detecting and resolving competition between dominant and non dominant responses

classic example of conflict monitoring and what it is

stroop task → color does not match the word it takes longer to inhibit the dominant response?; need to say the color not the word

orienting is also known as

selective attention

orienting (aka. selective attention)

concerned with prioritizing the sensory representations that capture our attention

• can be top-down, goal driven, OR through bottom-up, salient stimuli

• usually measured with spatial attention tasks

what we are focusing on

Anatomy of Attention: Orienting network

widespread, but highly specific cortical and subcortical areas

selective attention vs. arousal

• NOT THE SAME

  Arousal(modulated by thalamus in part) - global physiological and psychological state of organism

• Selective attention - ability to prioritize some things and not others (at any level of arousal)

is multitasking possible?

no. we don’t actually multi-task, we just rapidly switch our attention between tasks

william james on attention (selectove attention)

we have to withdraw some things in order to deal with others; never detecting everything

is attention limited

yes; you can’t simultaneously attend to two things at once.

• ex. texting while driving → you are not fully paying attention to the changing conditions of the road

selective attention involves

a. focusing on certain things while ignoring others

b. focusing sequentially on the items around you

c. remembering things using small details

d. multitasking while learning

a.

top down processing is also known as

goal-driven control

top down processing

a form of information processing in which an overall hypothesis about or general conceptualization of a stimulus is applied to and influences the analysis of incoming stimulus data

• in part based of our expectations of what we know already

• from the higher orders of the brain and how that’s influencing how we perceive stimuli that are incoming

bottom-up processing is also known as

stimulus-driven control

bottom-up processing

A form of information processing in which incoming stimulus data initiate and determine the “higher-level” processes involved in their recognition, interpretation, and categorization

• we are just taking the stimulus as is; driven by the stimulus itself

• raw sensory information from the envirionemnt and processing it without relying on prior knowledge or expectations

how would we use top-down processing for this?

• see B and 13

  • we have seen B’s and 13’s before

  • are able to switch btwn those two based on our expectations, prior knowledge, and symbols we have seen before

how would we use bottom-up processing for this?

• two thick verticles lines and three little horizontal lines in blueencodi

encoding

how we go from stimulus to neural code

inference

use expectations and/or thoughts in order to come to a rule/conclusion based on evidence (inferring something)

what is the most important difference between top-down and bottom-up processing of stimuli? and explain why each answer choice is wrong

a. automaticity

b. inference

c. encoding

d. sensitivity

ANSWER: B (Inference) → best answer bc we are making an inference when we have top-down processing; we are inferring something about the stimulus

• A. automaticity → depends on context and the stimulus which process you will depend on more

• C. encoding → both process end with some type of neural code

The first time Joe had to put together a bicycle, it took a long time. Now that he has built several bicycles, he can put together a bicycle quickly and easily because he knows what the final product should look like. Joe’s improved speed and skill can be attributed to

a. bottom up processing

b. top down processing

c. perceptual expectancy

d. object constancy

b

how do we begin to understand the neural systems of attention?

brain damage, imaging studies, electrophysiology

ADHD and why not study ADHD to learn about attentional networks?

• Attention Deficit Hyperactivity Disorder (ADHD)

• Heterogeneous genetic and environmental factors

• May result from reduced white matter throughout the brain, especially prefrontal cortex

• but we still don’t know which networks affected by the disorder

symptoms of Bálint’s syndrome

attentional disorder

• difficulty perceiving visual field as a whole scene

• inability to guide eye movements voluntarily

• difficulty reaching to grab an object

example of Bálint’s syndrome

showed a patient a comb only and patient saw it; showed patient a spoon only and patient saw it; showed a patient a comb and a spoon and patient couldn’t see both (meaning couldn’t attend to and report on) [can switch btwn seeing comb or spoon, but will not see both]; sometimes shaking object helps

causes of Bálint’s syndrome

caused by bilateral damage to regions of posterior parietal(sensory association areas taht allow us to detect where things are in space) and occipital cortex; could be caused by stroke, dementia

Visuospatial Neglect

• attentional disorder

• occurs from brain damage to the posterior parietal areas but its localized to one hemisphere

• right hemisphere has damage, which affects the attention to the left visual field (left-sided neglect)

• patients have normal vision, patients exhibit deficits in attending to and acting in the direction opposite to the side of unilateral brain damage

Visuospatial neglect example

Self-portraits by Anton Räderscheidt as he recovered from a stroke; in first picture can see that ignored left side completely; as time goes on move on to the right can see improvements

patients with left side neglect have damage to the

a. left side of the brain

b. right side of the brain

c. both hemispheres

b

how do you test visuospatial neglect?

neuropsychological tests of neglect

neuropsychological tests

• test paper (with horizontal lines on it)

• test this by having patients intersect the lines

• can see in this image the patient left some of the lines on the left completely empty and even within the line it is not on the center it is more towards the right

Visuospatial neglect also affects…

imagination

Visuospatial neglect extra

• only attentional issue not a visual issue

• don’t realize something is wrong

Visuospatial neglect example with famous building

patients asked to recall famous building; always ignored left when asked to recall (no matter from what angle)

• not a problem with memory or recall itself; but that attention to parts of recalled images was biased

extinction

• visuiospatial neglect

occurs when the patient is presented with two stimuli simultaneously - the presence of the competing stimulus in the ipsilateral hemifield prevents patients from detecting contra-lesional stimulus

• neglect patients can detect items in their neglected field when presented in isolation

extinction example

when 2 fingers moved patients identified the right side (attention drawn to right side); when moved fingers individually could identify both