PSC 101 Unit 11 - High Level Processing

(11.1) What are the aspects of vision?

Object identity, size, movement, location, etc.

(11.1) How is vision organized hierarchically?

V1 is the first place of initial processing. Detailed representation is sent to neighboring regions to be processed with each area processing a different aspect of vision

(11.1) What is parallel visual processing?

The visual processing in different regions are done in parallel at the same time to process it as quickly as possible. Processes are recombined in higher cognitive areas for detailed representation

(11.1) What is serial processing?

Tasks happening one after the other like a relay race

(11.1) What are the 2 major visual pathways and what do they do?

Dorsal Stream (Where) and Ventral Stream (What) constantly communicate to create a holistic representation of vision

(11.2) What is the dorsal stream and where is it located?

Collection of brain areas in the parietal lobe that processes visual information for where things are and where/how things are moving.

(11.2) What is MT and what does it do?

Area in dorsal stream that processes how patterns can move and complex movements.

(11.2) What would happen if the MT was damaged?

Motion blindness or akinetopsia - objects appear to vanish when they start moving. Retina and V1 can still encode info but MT won't be able to do its job

(11.2) What is agnosia?

Person is able to see object/action but can't perceive the object/action

(11.2) What is MST?

Processes optic flow

(11.2) What is optic flow?

What you seen when you're moving forward; center of view is moving slowly while periphery moves more quickly

(11.2) What is the role of the parietal lobe? What happens if it is damaged?

Lobe responsible for spatial info, touch, attention, and eye movements. It receives info from visual areas in the occipital lobe. When it is damaged, the person is unable to process spatial info

(11.2) What is hemispatial neglect?

Damage to one of the parietal lobes causes the inability to process visual field information from the opposite/contralateral side of damage. Spatial info is not processed for that visual field.

(11.2) A person experiencing hemispatial neglect due to an injury to their left parietal lobe would most like be unable to...

Notice something on their right side

(11.2) A patient experienced severe head trauma. They have normal vision, but objects seem to disappear when they are being moved from one location to another. Which brain area was most likely damaged?

Parietal Lobe

(11.2) A patient experienced severe head trauma and now they are unable to see. They can't process visual information but their eyes are undamaged. They are aware of their blindness. Which brain area was most likely damaged?

V1 in Occipital Lobe

(11.2) What will a person with hemispatial neglect do when asked to copy a drawing?

They will only draw half of the drawing. If they have damage on their left parietal lobe, they won't draw the right half of the drawing as they won't see it.

(11.3) What is the ventral pathway and where is it located?

Collection of brain areas in the temporal lobe that processes what features things have and what those things are.

(11.3) What is the fusiform face area (FFA)?

Region of ventral stream that responds well to faces. Might also be a visual expert area and not just a face area. It does not respond to upside down faces

(11.3) What was found in the FFA experiment with macaque monkeys?

Strong response to monkey, human, and drawn faces but weak response to faces with errors and no response to non-faces

(11.3) What is prosopagnosia?

Face blindness caused by damage to FFA; inability to recognize faces

(11.3) What is object categorization?

The way we recognize what something is ; processed in ventral temporal cortex

(11.3) What is the grandmother cell?

Hypothesis of object recognition - theory that there's a single cell that encodes for a specific complex object. No longer widely supported since it's impossible for the number of neurons in the brain.

(11.3) What is the hierarchal coding hypothesis?

Hypothesis of object categorization - brain breaks down a visual object into each of its foundational components and feature selective cells in ventral temporal lobe respond to specific components

(11.3) How does hierarchal coding hypothesis use population coding?

Feature selective cells use population coding to combine their information to generate unique combinations of activated cells for each unique object. This allows for representation of complex images

(11.3) What is visual agnosia?

Inability to visually recognize objects, associated with damage to temporal or occipital lobes since ventral and dorsal streams work together

(11.4) What is modality?

Information processed by each sense in the sensory system such as sight, hearing, touch etc

(11.4) What are the visual system's (sight) cell type and what info does it encode?

Photoreceptors that encode light

(11.4) What are the auditory system's (hearing) cell type and what info does it encode?

Hair cells that encode sound or pressure waves in air

(11.4) What are the somatosensory system's (touch) cell type and what info does it encode?

Mechanoreceptors that encode pressure, vibration, temperature, pain

(11.4) What are the olfactory system's (smell) cell type and what info does it encode?

Chemoreceptors that encode chemicals in air

(11.4) What are the gustation system's (taste) cell type and what info does it encode?

Chemoreceptors that encode chemicals

(11.4) What is a topographic map?

Organized structure where each sensory system is organized based on how information is obtained. This map is maintained in their primary sensory cortex.

(11.4) Describe topographic organization

Each sensory system has their own primary sensory cortex where initial processing is performed. Organization is made of columns (specific spot in visual field)

(11.4) What is the structure of the somatosensory cortex?

All info is processed in primary somatosensory cortex (S1). Each column in a somatotopic map corresponds to a specific part of the body.

(11.4) What is the structure of the auditory cortex?

Primary auditory cortex (A1) organizes info in a tonotopic map where columns correspond with specific frequencies or tones of sounds with low to high organization

(11.4) What is the general rule of the sensory cortex?

Primary sensory cortex (V1, S1, A1) is mostly monomodal and concrete initial processing while high-level processing regions (FFA, VTL) are responsible for multimodal and abstract processing

(11.4) Which trait is shared by all sensory systems?

Specialized receptors, topographic organization, primary sensory cortices, columns to organize, and hierarchical structures

(11.4) What happens when information becomes more abstract?

Sensory systems will share the same brain areas to process that information