📗 -> 06/04/25: NPB163-L18

Visual Attention
Final Review Slides

🎤 Vocab

❗ Unit and Larger Context

Today is more of a bonus lecture, where she goes over her old research but doesn’t expect us to know it for final

✒️ -> Scratch Notes

Recommends going over all material and making some personal notes/study guides.

Helps to organize what you do / do not know
Increase familiarity as you go

Visual Attention

What is it?

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Process by which visual information is organized / processed respect to behavior

Two Types

Stimulus Driven Attention and Goal Driven Attention

Stimulus Driven Attention

Two obvious examples:

Camouflage - Elude attention, blend in
Fashion - Capture attention, stick out

Why do different things stick out? What is salience?

This is in visual system
Activations in parallel for different features / dimensions
- Apple has very high salience in the color dimension
Different types of ‘salience’ compete in a winner take all salience map (feature independent)

Parietal cortex, Prefrontal cortex, Superior Colliculus all play a role in visual attention. Recordings show ‘salience’ activation in all
Normally, we see highly similar activation fields to isolated and unique stimulus, but after perturbation, of LIP, we see the receptive field change
- This tells us there is a causal infleunce here

What is the sensory epithelium of the visual system? How does the retina contribute to this?
Retina photoreceptors are already tuned to an area. This contributes to formation of retinatopic map

Sensory epithelium in auditory cortex:

?
Organization of auditory system?
Tonotopic

PFC area (frontal eye field, FEF):

Influence of stimulus driven attention on scanning eye movements

Goal-Driven Attention: Spatial Attention

Posner cueing task:

Classic paradigm for visual/spatial attention
Give cues, and measure RT performance
- Neutral cues (none), invalid cue (cue to wrong side), valid cue (cue to same side)
- Endogenous cue - Arrow right above fixation point
- Exogenous cue - Farther from fixation point

Neural Correlates

Robust attention-related ring rate modulations have been reported in higher-order visual cortical areas like V4, MT or MST. Attentional modulation in primary visual cortex (V1) is substantially weaker.
Spatial attention: responses to the same stimulus inside the receptive eld (RF) depending on whether attention is allocated inside or outside the RF:

Some of the effect can be described as a ‘gain change’

Responses to stimuli are increased, especially for preferred stimuli
- Observed in MST and V4

Goal-Driven - Thought to be Top-down, evidence from FEF being activated before similar activations in V4
Stimulus-Driven - Feed-forward

LFP - Voltage signal measured from extracellular space

Tied to oscillations
Gamma-band: Tied to synchronized population activity and …

…

When you stimulate superior colliculus / FEF you usually induce a saccade
Subthreshold stimulation administered (no direct saccades):

If you stimulate FEF:

If target is at MF (motor field?): sensitivity will increase
- Selective effect
If you measure selectivity at other locations, you will not see this effect

FEF causally related yippee

Administer the same experiment with superior colliculus (SC), and see similar effects

Example of Goal Driven:

Do a quick scan for red triangles:

Afterwards, asked about yellow circles. No clue, information not attended to.

Review

very sparse notes, we skimmed over a lot of it

Techniques

Recording

Invasive
Noninvasive
Manipulation of neuronal activity
Inactivation
Activation

Neural Codes

Single neuron vs Population

Takeaway of information theory:
- Entropy = Uncertainty of system
  - Bound to 0, log2(states)
    - 0 entropy: System determined
    - log2(states):
- Mutual information:
  - 0, entropy of system
  - Reduction in system uncertainty (things co-varying for example)
    etc. etc…

Visual System

Sensory epithelium:

Where is it in vision? RETINA!!
Development of map is due to the retinotopic organization of the retina. Adjacent positions in space associated with adjacent retinas

etc. etc…

Auditory System

Sensory epithelium:

Where is it in audition? ORGAN OF CORTI!!

synchronized code: low frequency when neurons can follow, high frequency they cannot and get misaligned

Sensory Systems – Feedback, Predictive Coding, Anticipating sensory consequences of own actions

Super important
Anticipating actions
Not just feedforward, but feedback signal shaping perception

Oculomotor System

Purpose of eye movements
6 different types, and their purposes
Muscles
Nuclei
Superior Colliculus

Know:
- An association area, subcortical
- Service sensorymotor integration
- Help to control eye movement
- Role in decisionmaking and attention
  Saccade generation (SC, FEF)
  Smooth pursuit
  VOR

Skeletal Motor System

…
pay attention to cortical movement control section
etc. etc…

in addition to that, talk about basal ganglia and cerebellum control…

Cerebellum

Basal Ganglia

4 nuclei:

STN, Striatum (caudate, putamen), Globus Pallidus (external, internal)

Striatum is the input

different theories…

🧪 -> Refresh the Info

Did you generally find the overall content understandable or compelling or relevant or not, and why, or which aspects of the reading were most novel or challenging for you and which aspects were most familiar or straightforward?)

Did a specific aspect of the reading raise questions for you or relate to other ideas and findings you’ve encountered, or are there other related issues you wish had been covered?)

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NPB163-L18