Lecture 11 + Passingham Ch.2 Flashcards

Where is the Lateral Occipital Cortex (LOC) located and what stimuli does it increasingly prefer anteriorly?

The LOC is on the lateral section of the back of the brain; moving anteriorly, it increasingly prefers cohesive shapes over scrambled objects.

What property of the ventral visual stream allows object recognition regardless of size or position?

Invariance (size and viewpoint invariance).

What is the primary role of the Inferotemporal Cortex (IT)?

It is critical for object categorization and sensitivity to semantic meaning.

According to the hierarchical model, what is a superordinate category and how is it spatially represented in IT?

A superordinate category is something like animate vs. inanimate; it occupies areas larger than 1 cm in IT.

How are subordinate categories represented in IT compared to superordinate categories?

Subordinate categories are represented in smaller, distributed areas less than 1 mm in size.

According to Passingham, what cognitive process is required beyond recognition to “make sense” of perception?

Classification into categories (e.g., animate vs. inanimate).

What does the traditional encoding approach in fMRI measure, and why does it struggle with fine-grained distinctions (e.g., dogs vs. cats)?

It measures which specific brain regions activate to environmental stimuli; it struggles because there are no clear anatomical functional landmarks for highly specific objects.

What is the goal of Representational Similarity Analysis (RSA), and what does proximity in representational space mean?

RSA examines similarity patterns across voxels that mirror categorical/biological structures; objects close in representational space have highly correlated voxel activation patterns.

How did the 2012 Connolly & Haxby study evaluate the brain’s internal animal taxonomy, and what did it find about LOC organization?

They compared voxel activation patterns (RSA) across biological classes (bugs, birds, primates). Animal categories in LOC are organized along the medial-to-lateral axis.

Along the medial-to-lateral axis of LOC, where are inanimate objects represented, and which animal class is most similar to inanimate objects?

Inanimate or “not-like-me” objects are more medial; bugs (insects) are represented more similarly to inanimate objects.

What is the representational spectrum for animate objects in LOC, and how does adult categorization relate to development?

It ranges from “not like me” (insects) to “very like me” (primates/humans); this hierarchical structure mirrors biological class structures learned in childhood.

What is meant by perception as “controlled hallucination”?

Perception as unconscious inference or predictive coding.

What is the fundamental premise of predictive coding?

The brain is a prediction machine using internal models to infer causes of sensory sensations.

What is a generative model and what is prediction error?

The generative model is an internal representation used to generate predictions about sensory input; prediction error is the mismatch between top-down prediction and bottom-up sensory evidence.

What determines the final contents of perception in predictive coding?

The winning hypotheses that best minimize prediction error.

How does top-down processing help resolve ambiguity (e.g., duck/rabbit, orange vs. ball)?

It provides hypotheses and contextual cues from the generative model to disambiguate stimuli.

What is the feedforward (bottom-up) model of vision, and why is it insufficient?

Information flows from early areas (V1) upward, building objects from features; it is insufficient because the same sensory signal may have multiple possible causes.

How do predictive coding models interpret neurons in visual cortex?

Neurons represent probabilistic predictions rather than just static feature detection.

What happens if predictions perfectly match sensory input?

Prediction error is minimized or eliminated.

What is the difference between representational units and error units in hierarchical predictive coding?

Representational units carry top-down predictions; error units carry bottom-up mismatches.

What is the function of the Fusiform Face Area (FFA) and Parahippocampal Place Area (PPA)?

FFA is specialized for faces; PPA is specialized for houses and locations.

What did Egner et al. (2010) test regarding FFA activity, and what were the competing hypotheses?

They tested whether FFA reflects additive expectation and surprise (predictive coding) vs. purely face-feature sensitivity regardless of expectation.

If FFA only detects face features, what happens when a face is expected but a house is shown?

FFA activity would not increase because no face features are present.

What is Multi-Voxel Pattern Analysis (MVPA), and why can’t V1 distinguish animal categories with it?

MVPA examines activation patterns across voxels; V1 processes low-level features, not learned semantic categories like higher visual areas.

What is blindsight, and what does it demonstrate about V1?

Blindsight is accurate guessing without conscious awareness after V1 damage; V1 is necessary for visual awareness, even if information reaches cortex through other routes.

What is backward masking, and what happens in the brain when awareness occurs?

A target stimulus is quickly followed by a mask preventing awareness; when awareness occurs, activation extends beyond ventral stream to parietal and dorsal prefrontal cortex.

How does Ned Block distinguish phenomenal awareness from access awareness?

Phenomenal awareness is raw experience; access awareness is the ability to report that experience.

Which brain area is linked to phenomenal color awareness in synaesthetes?

Ventral visual area V4/V8.

Which stream underlies phenomenal visual awareness (eyes open/closed study)?

The ventral visual stream.

Why might parietal and prefrontal cortex not be necessary for phenomenal awareness?

Awareness can occur (e.g., synaesthesia, eyes open) without their activation; their activity may reflect reporting demands.

What is the salience network and its function?

It consists of the anterior insula and anterior cingulate cortex; it detects and responds to important/prominent events.

What is the role of the thalamus in consciousness?

It acts as a gateway relaying sensory information to the cortex.

How does propofol induce loss of consciousness?

It decreases activity in the thalamus, insula, and anterior cingulate cortex, making sensory areas unresponsive.

What is Chalmers’ Hard Problem of consciousness?

Why and how physical brain processes produce subjective experience.

Why does Passingham suggest the pain system is useful for studying awareness?

It is less abstract than vision and provides observable markers of feeling (e.g., whimpering).

What did Von Helmholtz mean by unconscious inference?

We infer causes of sensations via educated guesses based on sensory effects.

How does category specificity change along the ventral stream?

Processing becomes more invariant and category specificity increases.

What is the “access problem” in interpreting prefrontal activation?

Activation may reflect the need to report awareness rather than awareness itself.

What historical concept did Henri Bergson propose about development?

The élan vital (vital force).