Intro to consciousness Flashcards
Where has research on consciousess focused in the past decades and what problem is associated with this?
There has been much progress on “easy” problems of consciousness – memory, attention, decision-making, sensory discrimination (etc.) But: we refrain from asking deeper questions, e.g. how is phenomenal content associated with neural activity (”hard” problem; Chalmers)
What is meant by phenomenal content?
Having qualitatively rich experiences (What is it like to be a bat? An orca? Octopus?)
Exemplify the hard problem in regards to a painting
correlate pictorial elements (shape, color, etc.) with neural activity in different brain areas; but what is their exact relationship? “Neural correlate of consciousness” (How is our appreciation of its rich qualities associated with simple neural correlates in the brain.) There is also differences in the physical description of light in terms of its waves and how we actually experience colour.
What are some things consciousness is often conflated with but is distinct from?
Consciousness vs. Self-consciousness (consciousness ~ awareness). Consciousness is different from responsibility, volition, deliberation
Evaluate the stance of eliminative materialism in terms of consciousness
Can everything about the “mind” be phrased/ explained in terms of neurons? If so, we can abolish “folk psychology”: set of assumptions and ‘mental’ concepts we use in daily life to describe behaviour and experiences of ourselves and others. Eliminative materialism tries to get rid of all these ‘mental’ terms. Through this, however you may get rid of some important aspects such as the perception of colour. However can we say that a colour experience is an experience of a particular electromagnetic wavelength?
Do the following terms refer to consciousness?
Perception
Sensing
Sensation
Detecting
*“Sensing”: ambiguous term (e.g. “smoke sensor”) in terms of (non-) consciousness
*“Detecting”: mere signalling of a specific event (can be conscious or non-conscious)
*Perception/sensation: refers to conscious experience (or just: “experience”)
What is self consciousness and how is it not the same as consciousness?
It is the concept of I, however consciousness can happen independent of this.
What is meant by intentionality in the brain?
Neurons somehow represent things that have meaning; they represent things that are not themselves. e.g. imagine fireworks – somehow neurons are able to
represent exploding colorful sparks without exploding themselves! (lesion neurons => lose experience)
Brain generates something having intentionality – “aboutness”, e.g. we think about vegetables without having them in our brains
How is there dual use of the term meaning in
Associative meaning: set of learned connotations associated with a percept
Phenomenal meaning: percept stripped of those associations (“memoryless”)
What does the term phenomena mean?
Subjectively experienced
Give two ‘ideas’ of what representations are
*Idea #1 (broad): any sort of depiction / rendition / model
*Passive carrier: has no idea what the depiction means (e.g. flatscreen)
*Idea #2 (narrow): information package conveyed by brain activity (active in the sense: it has meaning to the carrier)
We are more concerned with 2 obviously
Give three examples of maps as brain representations
*Example: retinotopic map in visual cortex (e.g. V1)
*Tonotopic map in auditory cortex (A1; frequencies)
*Somatotopic map in somatosensory cortex (e.g. S1)
How well are maps associated with consciousness?
Maps also widely found in subcortical regions,
not particularly associated with consciousness
How is there a disparity between the types of maps and our perception?
Diversity of maps: e.g. retinotopic, craniotopic, allocentric: but we seem to have one common viewpoint (=visual perspective)
What problem arises with this disparity of brain maps and perception?
Notion of brain map: unclear how meaning arises
Who or what reads our brain maps?; Is there a homunculus reading our brain maps?
What makes the visual cortex “visual”?
Classically: the fact that it receives inputs (electrical impulses) indirectly from the eyes
What is an alternative hypothesis to this classic interpretation of the visual cortex?
Labelled lines hypothesis: sensory modality is determined by peripheral receptor and afferent nerve (e.g. retina & optic nerve)
What are two problems with this labelled lines hypothesis?
Problem 1: a cortical neuron has no knowledge
where its inputs are coming from
(action potentials arriving are not “labelled”)
Problem 2: just having sensory or feature detectors is not enough for perception (a smoke detector is also not considered to “smell” the smoke; it just transmits numbers)
How does the rest of the brain “know” what it means if a feature detecting neuron is firing
What does it mean to say that cortical areas are not intrinsically “visual” or “auditory” ?
Neocortex is ~‘equipotential’: if retinal input is rerouted to the auditory cortex, then ‘auditory’ cortex develops a map of visual space (retinal), not a tonotopic (cochlear) map.
Describe a study that demonstrates how the neocortex is equipotential
- Ablation (burning/ freezing to cause scarring )of the superior colliculus carried out
- Removal of inferior colliculus fibers innervating the MGN is also carried out
This resulted in the optic fibers connecting to MGN (medial geniculate nucleus; auditory thalamus) and hence photic inputs reach ‘auditory’ cortex.
Result: The ‘auditory’ cortex develops a visual map, not a tonotopic (cochlear) map
What conclusion can we draw about the auditory cortex from this study on the retinotonic map in the MGN?
Formation of a tonotopic map (for sound) is not an intrinsic property of the (auditory) cortex, but is imposed on it during development
How was this research on rewiring in AC further developped in a future study?
Visual orientation tuning was achieved in the ferret AC through similar rewiring measures; rewired auditory cortex behaves much like a normal primary visual cortex
Concl: cortical areas are not “predestined” to process a modality
What can we concluse about encoding as a whole from this work?
*Auditory cortex is not intrinsically “auditory”
*Peripheral input is important for how a cortical area processes inputs (cortex has
developmental equipotentiality)
*This likely relates to the input statistics, needed to generate specific feature detectors
Therefore, are feature detectors enough? Give an example
No: Example: map of simple luminance-sensitive neurons depicting a face in pixels (see docs). How does a neutral observer (unaware of retinal origin) figure out that this represents the visual image of a face?
=> Activated neurons may as well be part of a tonotopic or somatosensory map
N.b., an external observer knows about positioning of neurons relative to each other – unlike a brain system processing the maps ́s output
=>A priori: input statistics could apply to any modality
=>Just having these statistics is not enough to infer the modality