Chapter 21: The Resting Brain, Attention, and Consciousness Flashcards
: instead of being idle, a network of brain areas is more active during resting than active states
Resting state
(): the brain must deal with the enormous volume of sensory information. Rather than trying to process all of these signals simultaneously, we selectively focus on things that catch our attention
Attentive state
(): ability to focus on one aspect of sensory input; preferentially process some information and ignore the
rest
Attention
attention involves corresponding changes in the () of neurons at many locations in the brain
sensitivity
(): awareness of something
Consciousness
Generally, neurons become more active in () processing ongoing perceptual or motor information.
cortical areas
quiet and active regions of the brain in the absence of active processing were revealed by ()
PET and fMRI imaging of whole brain
Resting State Brain Activity
- Hans Berger (1929): () activity does not cease even during a rest.
- Ingvar: () activity reached high levels during rest states (regional cerebral blood flow was measured using xenon 133 inhalation technique.)
- Increased activity during rest is localized to specific brain regions that prominently include ().
- EEG
- Frontal
- prefrontal cortex
Some brain regions are always active at rest and less active during any task
default mode network
anticorrelation -> negative correlation
2 hypotheses for the function of the default mode network
- sentinel hypothesis
- internal mentation hypothesis
functions of the default brain network
even at rest, we must broadly monitor the environment
sentinel hypothesis
normal visual field but unable to integrate simultaneous info to understant a complex scene
simultagnosia
component of Balínt syndrome
functions of the default brain network
suggests that the default mode network supports thinking and remembering (i.e. the sort of daydreaming we do while sitting quietly)
internal mentation hypothesis
the internal mentation hypothesis suggests that memory tasks activate the brain in a similar manner to ()
daydreaming about one’s life
when we relax, it is common to daydream, remember, and imagine
spontaneous cognition
limited resource or bottleneck in brain processing
(selective) attention
(): takes place when we block out certain features of our environment and focus on one particular feature.
Selective attention
(): is used when we are paying attention to two things at once
Divided attention
(): happens when we can concentrate on a task, event, or feature in our environment for a prolonged period of time
Sustained attention
(): is the attention we use when we are making steps toward a particular end
Executive attention
directing attention (2 ways)
– A stimulus attracts attention without cognitive input
– Like animal detecting predator
Exogenous attention—bottom–up attention
directing attention (2 ways)
– Deliberately directed by the brain
– To serve a behavioral goal
Endogenous attention—top–down attention
examples of the behavioral consequences of attention
enhanced visual sensitivity and reaction time
While attention may be a high-level cognitive process, effects of attention can be observed in numerous ()
sensory areas
a common analogy for the behavioral consequences of attention is that there is a () that moves to illuminate objects of particular interest or significance
spotlight of attention
PET imaging of attention to visual features
V4, IT, and other visual areas in temporal lobe -> activated when attending to changes in ()
color and shape
PET imaging of attention to visual features
Area MT -> activated when attending to changes in ()
speed of motion
assumption as to what happens when you’re paying attention to one thing but suddenly notice something else in your peripheral vision
you shift your attention to the new thing before you move your eyes to focus on it
enhanced neuronal responses in the parietal cortex is a result of an () needed to accurately perform the task
attention shift
Brain Circuits for the Control of Attention
Studies suggest that the circuitry responsible for () plays a key role in guiding attention
saccadic eye movements
– Reciprocal connections with most visual areas
– Increased neuronal activity with attention to the neuron’s receptive field
– Regulates visual information flow
pulvinar nucleus (subcortical component)
humans with lesions in the pulvinar nucleus respond abnormally slowly to stimuli on ()
contralateral side
- cortical area in the frontal lobe; connected to areas influenced by attention
- sufficent electrical stim causes saccade to certain place
frontal eye fields (FEF)
saccades to motor field
small areas in the visual field of neurons in the FEF
motor field
hypothesis of how certain visual features grab attention
in bottom-up attention, a () shows locataions of conspicuous features
salience map
hypothesis of how certain visual features grab attention
in top-down attention, a () shows locations where attention should
be directed based on cognitive input
Priority map
priority map = salience map + top-down modulation
()—creates priority map based on bottom–up and top–down inputs; guides eye movements and attention
Lateral intraparietal cortex (area LIP)
Lesions in () associated with neglect syndrome
parietal cortex
The posterior parietal cortex is implicated in attending to objects at () in extrapersonal space
different positions
Pespective on Consciousness
– Consciousness arises from physical processes
– Based on structure and function of nervous system
materialism
Perspectives on Consciousness
– Mind and body are different things.
– One cannot be fully explained by the other.
Dualism
easy problems of consciousness
Phenomena answerable by scientific methodology
hard problem of consciousness: experience of consciousness itself
how subjective experiences arise from physical (objective) processes
‘()’: introspectively accessible, phenomenal aspects of our mental lives.
Qualia
minimal neuronal events sufficient for a specific conscious percept
neural correlates of consciousness
changes in () that correlate with changes in perception may be related to our conscious awareness of one object or another
neural activity
different images are seen by the two eyes, and perceptual awareness alternates between the 2 images
binocular rivalry
Human neural activity during visual imagery
there is evidence suggesting that () activates some of the same vsual processes drives by external visual stimuli
imagery
goal in the search for neural correlates of consciousness
find the minimal brain activiy sufficient for some conscious experience
it is possible to have your attention be drawn but still not perceive it; implies ()
attention is or can be independent of awareness
examples of conscious awareness without attention
- Artificial sensory experiences by brain stimulation
- Involuntary hallucinations and pathological sensations
(e.g., tinnitus or auditory verbal hallucinations) - Dream episodes
- Spontaneous awareness of an unattended image in binocular rivalry
