Neurobiology of Attention Flashcards
Attention
Taking possession of the mind, in clear and vivid form, of one out of several simultaneously possible objects or trains of thought.
Endogenous attention
Internal shift in attention
driven by intention
top-down
voluntary control
Covert attention
An internal shift of attention without moving the eyes.
Important in social interaction, sports, combat
laboratory setting - same photoreceptors activated on retina
Spatial attention
Attending to a specific location in space.
Object-based attention
Attending to multiple features of an object as a whole.
Receptive fields RF
Part of sensory space that elicits a response
Prefrontal cortex (PFC)
The region of the brain that represents abstract concepts and goals and sends feedback to visual cortices (top-down projections)
modifies incoming sensory information with a delay
Frontal Eye Field (FEF)
A region in the prefrontal cortex that elicits saccades to specific location
insert electrode in FEF - finds region the eyes are driven to
statistics
5 million cone cells in the retina
200,000 RGCs in the fovea (no. of information channels)
info entering the brain per second = 7 million bits per second
role of attention
prevents an overload of information
attention is a limited resource
overt attention
orientating by moving our eyes
filters out by looking away
shift in attention + gaze shifting
exogenous attention
something salient appears e.g. sound
bottom up
reflexive (involuntary)
feature-based attention
attend to a specific feature such as colour, orientation, direction of motion
location-independent
how to record attention
MRI scanner
electrodes (monkeys)
lick port in response to stimulus (mice)
tuning curve
describes what stimuli a cell likes to fire in response to
Does the RF change during different stimuli?
Moran & Desimone, 1985
record cell in monkey, find RF
effective and ineffective stimuli - place in RF
less firing when animal attends to ineffective stimulus (RF shrinks around location of attending)
competition within neuronal receptive field
Responses to the same stimulus with & without attention
train monkey to attend to location of RF and away
attended = more stronger firing
unattended = weaker firing
advantages of mice models
sophisticated cognitive abilities
small brain (multiple recordings)
2 photon imaging
transgenic mice
5CSRTT
5 choice serial reaction time task
touch panel when light comes on in 5 spatial locations
top down inputs from anterior cingulate cortex to V1 are needed only when task is attentionally demanding
silencing ACC-V1 inputs
use cre-dependent inhibitory DREADD and retro-AAV expressing Cre
eliminates top down projections - reduces accuracy
how does attentional modulation occur
disinhibtion
VIP interneurons inhibit SOM interneurons
Pyramidal neurons are activated
