PSYC 213
Cognition
Jan 18 - Visual perception: Physiology and Awareness
Last class:
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Functional specialization: Different areas of the brain support different functions, The
idea of localization / Modularity and phrenology
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Opposition to functional specialization: Franz and Lashley / Mental processes relate
to activity of the brain as a whole, and not individual parts.
The mind-brain link
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Interactionism: The mind and brain are separate entities that interact and influence
each other.
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Epiphenomenalism: Mental events are caused by physical events.
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Parallelism: The mind and brain are two aspects of the same reality.
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Isomorphism: The correspondence between mind (consciousness) and the brain is
Structural.
Cognitive neuroscience methods
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Animal Models
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Human Psychophysiological Experiments
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Neuropsychology Cases: Split brain patients.
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Neuroimaging Techniques: EEG methods: Good temporal resolution / PET: Use of
radioactive tracers to measure brain metabolism / fMRI: Good spatial resolution to
measure brain activity / MEG: Temporal and spatial resolution, but the signal decay /
Brain stimulation techniques: Temporarily impair/enhance brain function.
Timing versus Location
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MEG/EEG – brain activity at the level of the millisecond
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PET/fMRI – brain activity at the level of the millimeter
Brain stimulation
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Review: TMS is a procedure in which brain activity is influenced by a magnetic field,
either increasing or decreasing the brain’s electrical signals. This results in
behavioral changes.
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Related: Deep brain stimulation (DBS). Implant tiny electrodes in the brain
to send an weak and constant electrical current to targeted regions of the brain /
Reduces symptoms in cases like depression, Parkinson's / Mechanisms not known.
This class: Perception
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Sensations and Perceptions.
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Physiology of Visual Perception: How information travels from the eyes to the brain.
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Perception with and without awareness: Conscious and unconscious processes.
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Visual Illusions: Visual perception is constructive and relies on assumptions.
Sensation to perception
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Stimulus energy → Sensory receptors → Neural impulses --------------→ Brain
→ Sensations -------------------------------------------------------→ Perception ------→
Confusing the senses: Synaesthesia
1
PSYC 213
Cognition
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Stimulation of one sense simultaneously produces another sensation in a different
modality.
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For example: Grapheme-color synesthesia. Seeing certain numbers or letters as
certain colors.
McGurk Effect: Hearing Lips
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Speech sound /ba/ simultaneously presented with visual speech sound /fa/ heard
as /fa/.
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A multisensory illusion: a change in auditory perception from visual input.
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Demonstrates two concepts: The integration of sensory information. *The power of
visual input*: It overrides audio input!
