Consciousness and the Brain Flashcards
preconscious
accessible but not accessed, it lay dormant amid the vast repository of unconscious states
attention James (1890)
‘the taking possession of the mind, in clear or vivid form, of one out of what seem severalal simultaneously possible objects or trains of thought
conscious access
‘taking possession by the mind’ it is the bringing of info to the forefront of our thinkings such that it becomes a conscious mental objects that we ‘keep in mind’
metacognition
the capacity to think about one’s own mind
binocular rivalry
two incompatible images like a face and a house fight for conscious perception
subliminal
below threshold
supraliminal
above threshold
subcortical circuits
groups of neurons that lie beneath the cortex like amygdala or colliculus that are there to perform dedicated functions such as detection of fearful stimuli enz
blindsight
patients with lesions of the primary visual cortex, main source of visual inputs into the cortex. they can locate where objects are but can not consciously see them
visual form agnosia
for shape recognition
spatial neglect
a lesion to the right hemisphere, (typically in inferior parietal lobe) prevents a patient from attending to the left side of space, as a result he or she often misses the entire left half of a scene or object
subliminal priming
briefly flashing a subliminal word or picture (prime) and immediately followed it with another visible item (the target)
fusiform gyrus
houses advanced mechanisms of shape recognition and implements the early stages of reading // area associated with high level processing of visual objects and visual ares V1 V2 V3 and V4
mcgurk effect
illusion : when seeing a visual person saying “ga” but auditory says “ba” your brain mashes it up to da because it is in conflict
routine bindings
those that are coded by dedicated neurons committed to specific combinations of sensory input
non routine bindings
are those that require the de novo creation of unforeseen combinations, and they may be mediated by a more conscious state of brain synchrony
attentional blink
when two targets T1 and T2 embedded in a rapid stream of events are presented in close temporal proximity the second target is often not seen
refractory period
before a second target enters consciousness, it must wait until the conscious mind is done with the first one
global ignition
whenever we become aware of an unexpected piece of info, the brain suddenly seems to burst into a large scale activity pattern
phase tranistion
a sudden nearly discontinuous change in the state of a physical system// like freezing, consciousness exhibits a threshold, you have to get over this threshold to be consciously seen
recurrent processing theory
the reinfection of information into the same circuit that originated it ‘we could even define consciousness as recurrent processing/// consists both excitatory long-range feedback connections as well as lateral inhibitory connections to integrate and select information// a conscious process corresponds to any neural code that is shaped by recurrent loops from higher order to lower order areas and back
global workspace
an internal system, detached from the outside world, that allows us to freely entertain our private mental images and to spread them across the mind’s vast array of specialised processors
thalamus
involved in attention, vigilance, and synchronization
role : awakening of the entire network, relates to changes in state (with from unconscious to conscious brain)
basal ganglia
crucial for decision making and action (can also be unconsciously activated)
hippocampus
essential for memorising the episodes of our lives and for recalling then
disconnected patterns
encapsulated in our brain stem, the firing patterns that control your breathing are disconnected from the global workspace system in prefrontal and parietal cortex
coma
typically occurs within minutes to hours following damage to the brain, defined clinically as a prolonged loss of the capacity to be roused. no amount of stimulation can awaken him and he shows no signs of awareness of himself or his environment.
many types of problems can cause coma (damage to reticular activating system in the brainstem, damage to cortex)
brain death
distinct state, characterised by a total absence o brain stem reflexes, together with a flat EEG and an inability to initiate breathing. in brain dead patients PET and other measures show that cortical metabolism and the perfusion fo blood to the brain are annihilated. brain death state is irreversible. Cortical and thalamic neurons quickly degenerate
vegetative state
a preserved sleep-wake cycle with no signs of consciousness, a condition that may persist for many years.
locked in syndrome
damage to the brain stem (the pons). condition In which the patient is fully conscious and awake but unable to move or communicate verbally due to complete paralysis of almost all muscles in the body except the eyes. /////
a lesion disconnects the cortex from its output pathways in the spinal cord. it leaves consciousness entirely intact, they cannot be considered as suffering from a disorder of consciousness
mismatch response MMN(mismatch negativity)
as early as 100 milliseconds after the onset of the sound, the auditory cortex is generating a large response to the deviant (it shows as a negative voltage on top of the head). it is an automatic response to the auditory novelty the occurs whether a person is attending, mind-wandering, reading a book watching a movie or even falling asleep or lying in a coma
// the detection of novel auditory stimulus includes 2 distinct neural events : MMN, and later neural response (P300/P3a and P3b)
weighted symbolic mutual information
a program to compute this mathematical quantity, designed to evaluate how much information was being shared between two brain sites
brains conversation was bidirectional
specialised areas of the back of the brain were talking to the generalist areas of the parietal and prefrontal lobes, which returned backward signals
easy problem
re about abilities and functions: we need only nechanisms to explain those. These are problems that we have not solved (perception, memory etc) but in principle we know how to solve even if we have not done yet)
hard problem
why and how do subjective experiences arise from objective brains (neural processes)? “explaining the function doesn’t explain the experience”
dualistic ideas about consciousness
the mind and body are not identical and consciousness cannot be reduced to pure brain activity (video David Chalmers)
materialism
all emergent phenomena, including consciousness, are the result of material properties and interactions in the brain
hemispatial neglect
while drawing neglecting the left side of the drawing
visual form agnosia
unable to identify the shape of objects
dorsal stream
where, acting (unconscious)
ventral stream
what, perceiving (conscious)
color agnosia
usually caused by damage to visual area V4, see the world in black and white
prosopagnosia
face blindness, damage to fusiform area
motion blindness
MT/V5, people cannot perceive smooth motion
neural correlates of consciousness NCC
the minimal set of neuronal events necessary and sufficient for conscious experience
set
lesast number of regions
a necessary condition
for consciousness is a condition that must be satisfied in order for consciousness to arise, for example properly working eyes
sufficient condition
condition that, if satisfied, guarantees consciousness to arise
vigilance
the state of wakefulness, which varies when we fall asleep, wake up, faint, enter a coma or anesthesia
attention
the focus on our mental resources onto a specific piece of information
conscious access
the fact that some of the attended information eventually enters our awareness and becomes reportable to others (in any way)
access of content
‘i was not conscious of the red traffic light’ subliminal, rreconscious, phenomenal, access etc
level of consciousness
(wakefulness or vigilance) the patient was still conscious (coma, vegetative state, sleep, wakefulness, etc)
binocular rivalry
when two distinct images are presented to your two eyes, the brain will spontaneously oscillate and let you see one picture, then the other but never both at the same time
breakthrough time (binocular rivalry )
an image can come up into consciousness suddenly, good for studying sponanteous switches of perception, not optimal for isolating the NCC, because there is no ‘unconscious condition’ to contrast it with
masking (or subliminal representation)
we can flash a word so briefly that study participants will fail to notice it
crowding
creating a carefully cluttered visual scene, wholly invisible to a participant because the other items always win out of the inner competition for conscious perception