LECTURE 3 Flashcards
What does AFFERENT vs. EFFERENT mean? [hint: think E as in exit]
afferent receptor neurons send impulses TOWARD CNS, efferent AWAY from CNS
What are the five sensory systems?
visual, auditory, somatosensory, olfactory, gustatory
What is early processing?
responses to BASIC sensory stimuli
What is late processing?
more COMPLEX perceptual or cognitive processes (e.g., illusions or mis-match negativity)
Multisensory info is processed in a PARALLEL manner. What is SERIAL vs. PARALLEL processing?
when info is processed one after another vs. simultaneously gathered in the brain in parallel manner then integrated
What is the basic argument from multisensory researchers?
our senses efficiently process info from various sensory channels in a concerted manner
early MSI researchers (Stein & Meredith) used ___ to study the integration of auditory, visual and somatosensory evoked responses in the ___ of anesthetized cats.
depth electrodes, superior colliculus
What are depth electrodes used for?
to attain-cell recordings
The superior colliculus is a midbrain structure, located superior to the ___ and inferior to the ___. .
brainstem, thalamus
The superior colliculus contains ___ layers of alternating gray and white matter.
7
Inputs from the sensory systems terminate in the deeper layers of the ___ where unisensory info ___.
superior colliculus, converges
SC receives ___ and ___ inputs in its superficial layers (I-III).
visual, auditory
The deeper layers (IV-VII) of the SC are involved in ___ and ___ to various stimuli (e.g., head gaze).
attending, orienting
SC contains a high proportion of ___ neurons which are responsible for ___.
multisensory, a 2-D mapping of the world
Multisensory neurons in the SC play a direct role in the ___ control of ___ behaviors of the eyes, ears, and head towards various stimuli.
motor, orientation
The SC is specialized for ___ and subsequent ___.
stimulus detection, gaze-orienting
Neural responses elicited from two or more concurrent sensory inputs causes a change in a cell’s responsiveness (i.e., excitation) that is either ___ or ___ than the ___ of responses to the unisensory inputs.
less, greater, sum
Certain stimulus properties highly affect ___ of multisensory inputs.
integration
What are the three basic “rules” that govern MSI?
temporal, inverse-effectiveness, spatial
Which rule states that integration of multisensory inputs in SC is greatest for inputs presented simultaneously?
temporal rule
Which rule states that the strength of the multisensory responses is inversely related to the magnitude of the unisensory inputs?
inverse-effectiveness rule
Which rule states that multisensory effects become greater as the detectability of the unisensory inputs decrease?
inverse-effectiveness rule
Which rule states that MSI is greatest when stimuli are presented to the same spatial location?
spatial rule
What are commonly studied multisensory areas?
STS, temporoparietal cortex, intraparietal areas, premotor cortex, prefrontal cortex
What are various methods for the study of MSI?
PET, MRI & fMRI, MEG, EEG, psychophysics
Which imaging methods have better spatial resolution?
MRI & fMRI, PET?
Which imaging methods have better temporal resolution?
EEG, MEG?
What are the three different neural projection circuit models?
feed-forward (IV to others), feedback (others to IV), lateral (all layers at same time)
Initial cortical responses occur predominantly in lamina __.
4
What is a redundant signals effect (RSE)?
when 2 sources of info are presented at same time they offer redundant signals; this redundancy gives rise to faster detection responses
This kind of RSE model assumes that the signal that is processed the fastest is the signal that produces the response (i.e., “wins”).
race models
This kind of RSE model assumes that the faster RT is due to interactions that allow signals from redundant sources to combine.
coactivation models
___ models are supported when RTs to multisensory stimuli are faster than predicted by ___ models.
coactivation, race
What effect will averaging event-locked segments have?
Anything (e.g., noise, jittered ERPs) not precisely time-locked to the event will be flattened out, and precisely event-locked ERPs will be preserved
What are some VEP components used as dependent measures to characterize MSI effects?
P1, N1, P2, N2, P300
Human ___ studies show that multisensory interactions are often found within the first ___ ms post-stimulation.
ERP, 100
The objective of Jeanette’s doctoral research was to determine the impact of ___ of different sensory inputs on ___ in the brain, to test the so-called ___ rule set forth by Stein & Meredith.
spatial alignment, MSI, spatial rule
What was the design of Jeanette’s doctoral experiment?
visual alone, somatosensory alone, simultaneous visual and somatosensory (spatially congruent and incongruent)
What apparatuses were used in Jeanette’s doctoral experiment?
LED (on index finger), tactile stimulator (on thumb)
What was the analytic strategy Jeanette used in her doctoral experiment?
compare sum of ERPs to V and S with ERPs to paired VS [(V+S)-VS]; any difference implies MSI.
In Jeanette’s experiment, how many stimulus conditions? How many trials per condition?
8, 600
What was the ISI in Jeanette’s experiment?
inter-stimulus interval was 1 to 3 seconds
In Jeanette’s experiment, ___-density ___ recordings were collected from ___ channels to obtain ___.
high, EEG, 168, ERPs
What were the behavioral results of Jeanette’s experiment?
RTs to all MS events were faster than predicted by race model, and faster than any unisensory condition, regardless of spatial alignment.
What were the Regions of Interest in Jeanette’s experiment?
left and right central, left and right occipital
In Jeanette’s experiment, there was a main effect for ___ for Soma P1 50-70 ms, demonstrating clear effects of ___.
VS integration (post-hoc) 90-110 ms, alignment
A conclusion from Jeanette’s experiment is that the first stage of multisensory __ integration occurs regardless of __, whereas __ affects the second stage.
VS, spatial alignment, spatial alignment
The results of Jeanette’s experiment are consistent with what model?
a two-stage Time-Window-of-Integration (TWIN) model
What is the McGurk Effect?
a higher-order MS illusion showing that visual overrides auditory info
There are a limited number of studies conducted on MSI in ___, most of which examine ___ interactions.
aging, AV
It is important to study somatosensory info in aging because __ may be related to __, __, and __.
VSI, loss of mobility, disability, falls
Results from aging study:
- all Ps had faster RTs to all __ stimuli compared to __
- RT facilitation was greater in MS conditions containing ___ stimulation
- older adults had had greater RT facilitation than younger adults in the multisensory ___ condition
- MS, unisensory
- somatosensory (AS and VS)
- VS
MSI research investigates the complexities of processing ___ sensory info.
simultaneously presented
MS researchers argue that our senses are ___ to efficiently process info from various sensory channels in a ___ manner.
designed, concerted
Efficient MS processing enhances the probability that objects and events will be __ rapidly, __ correctly, and __ appropriately.
detected, identified, responded to
V and S impairments have separately been linked to __, __, __, and __.
slower gait, functional decline, increased risks of falls, and worse QoL
MSI aging researchers speculate that increased MSI effects are due to __ in __ during the aging process.
basic degenerative changes, neuronal architecture
MSI in older adults might be a __ process used to overcome age-related declines in __ processing.
compensatory, unisensory
