Psyc201 Test 1, Week 4 Flashcards
Behavioural Methods (Cognitive Neuroscience Techniques)
Use patterns of performance (RT, accuracy) to infer cognitive processes.
Lesion Methods (Cognitive Neuroscience Techniques)
Examine the effect of brain damage or disruption on cognitive function.
Recording Methods (Cognitive Neuroscience Techniques)
Use measures of brain activity (EEG, fMRI, PET) to identify cognitive processes.
Donders’ Method of Subtraction
Isolates cognitive processes by comparing reaction times in different tasks.
Simple Reaction Time (RT)
Measures time to respond to a single stimulus. (Press a button when you see a light.)
Choice Reaction Time (RT)
Measures time to respond to one stimuli and make a decision. (Press one key if the light is on the left, and another key if the light is on the right.)
Dissociation
Damage affects some cognitive functions, but not others.
Double Dissociation
Two patients with opposite patterns of deficits and preserved abilities.
Anterograde Amnesia
Inability to form new memories after brain damage.
Retrograde Amnesia
Inability to remember events before brain damage.
What does this tell us about the function of the hippocampus (H.M.)?
Hippocampus is important for creation of memories but does not store memories. Different memory systems are distinct.
What do double dissociations tell us?
Double dissociations tell us that two systems are independent. You can damage one, without affecting the other.
Concerns about patient studies?
- Small samples (sometimes unique)
- Atypical brains to begin with
- Rarely have pre-injury data (do not know how they were before accident)
- Identifies only areas that are essential for a task- does not always take wider system into account
- Brain reorganization during recovery- in response to environment, lose plasticity as we get older
- Lesions are not clean (tend to be quite big/messy and have different boundaries)
Single Cell Recordings
Measure the activity of individual neurons.
Temporal Resolution
Precision of measurement with respect to time (e.g., EEG/ERPs have high temporal resolution).
Spatial Resolution
Precision of measurement with respect to location (e.g., fMRI has high spatial resolution).
ERPs = Event Related Potentials
To find specific event-related activity (brain response):
* Measure activity when the event occurs
* Compare to a control condition that is identical in all respects – except the event doesn’t occur (subtraction method!)
- A double dissociation in ERPs – semantic (meaning) vs. syntactic (grammar) processing- latter occurs a few milliseconds later
- The dissociation is temporal (i.e., in time)
- ERPs are good for inferring WHEN a process occurs, but not WHERE it occurs
DTI (Diffusion Tensor Imaging)
Visualizes white matter tracts (myelinated axons) in the brain.
Subtraction Method (fMRI)
Subtracts brain activation patterns from two tasks to isolate the neural activity related to a specific cognitive process.
Fusiform Face Area (FFA)
Brain region in the temporal lobe specialized for face recognition.
Converging Operations
Using multiple research methods with different limitations to strengthen conclusions.
Transduction
The process of converting physical stimuli into neural signals.
Psychophysics
The study of the relationship between physical stimuli and psychological perception.
Reification
The brain’s interpretation of sensory input to create a coherent representation of the external world.
Bottom-Up Processing (Data-Driven)
Perception driven by sensory input, e.g. cow picture: first time trying to piece together the information in the picture to see the image
Top-Down Processing (Conceptually-Driven)
Perception influenced by prior knowledge, expectations, and context, e.g. cow picture: The second time it was conceptually-driven → because you know the image is there it pops out at you
Nasal Receptors
Receptors, neurons in nasal cavity respond to chemicals floating around us, carbon based chemicals make up most chemicals humans can smell, molecules have particular shapes, banana doesn’t smell like anything just dumping chemical out into the world, it’s odourless because we don’t have the right receptors, some shapes can fit into receptors, about 50,000 different types of receptors, anything that we don’t have receptors to doesn’t smell, smell happens in your head, created by chemicals, 6 million receptors in humans, 100 millions in dogs
A Sound Wave
air pressure wave, air molecules (oxygen/nitrogen etc..) disturbed by waves, vibrating back and forth, eardrum vibrate and create waves in fluid and wave makes cells in cochlea shake, creates action potentials, gets sent to auditory cortex
Synesthesia
A perceptual phenomenon where stimulation of one sensory modality triggers experiences in another.
Wavelength
spectrum, colors of the rainbow, visible light is a form electromagnetic radiation, different frequencies, very short wavelengths pass through objects (gamma/x-ray/ultra violet), very big waves roll over/go around things (radar/fm/tv/am/ac circuit), we have photoreceptors that respond to light in this range (the rainbow in middle), sweet spot is too big to go through/too small to go over so it bounces off objects, good signal that there is something there, different chemicals/pigments reflect different wavelengths, brain uses information to create color, no color in light, it’s just electromagnetic radiation
Retina
The light-sensitive layer at the back of the eye containing photoreceptors (rods and cones)
Rods
Photoreceptors sensitive to low light levels, abundant in peripheral vision.
Cones
Photoreceptors sensitive to color and high light levels, concentrated in the fovea.
Fovea
The central region of the retina with the highest concentration of cones, responsible for sharp vision.
Color Vision
Based on the activity of three types of cones: short (blue), medium (green), and long (red) wavelengths.
Rods and Cones extra info
Rods and cones, different wiring, each cone attaches to one or two bipolar cells, for rods sometimes dozens are all feeding into one bipolar cell, each cone will depolarise bipolar cell a little bit
Cones are less sensitive than rods
Cones must be activated by intense light to pass on an action potential.
Weak signals from many rods can sum together to pass on an action potential.
Cones have better acuity than rods
