cognitive psych: ch 2 textbook

What are levels of analysis?

The idea that a topic can be studied in different ways/at different levels, with each level adding to our understanding.

What are the levels of analysis for cognition?

Can be studied from broader to smaller physiological levels:
Whole brain → brain structures → neurons → chemical/electrical processes

Why do psychologists use different levels of analysis?

To get a more complete understanding of cognition by studying both behavior and the physiological processes behind it.

Example of levels of analysis in perception

Back: Seeing/hearing someone involves:
Chemical processes → neurons activated → brain structures activated → perception

Example of levels of analysis in memory

Back: An experience causes chemical and electrical activity that stores information in the brain; later, physiological activity retrieves the stored information, producing a memory.

What was the nerve net theory?

The early belief that the nervous system was one continuous, interconnected network.

Why did scientists originally think the nerve net was continuous?

Early microscopes and staining techniques could not show small details between cells.

What was the Golgi stain?

A: A staining technique using silver nitrate that stained fewer than 1% of neurons, making individual cells easier to see.

What is the neuron doctrine?

A: The idea that individual neurons are the basic building blocks of the brain and transmit signals through the nervous system.

What is the function of dendrites?

A: They receive signals from other neurons.

What is the function of the axon?

A: It transmits signals to other neurons.

What is another name for an axon?

A: A nerve fiber.

What is the general direction of information through a neuron?

A: Dendrites → cell body → axon → next neuron

What is a synapse?

A: The small gap between the end of one neuron's axon and another neuron's dendrite or cell body.

Are neurons connected randomly to other neurons?

A: No. Neurons form connections with specific neurons.

What are neural circuits?

A: Groups of interconnected neurons.

What are receptors?

A: Specialized neurons that receive information from the environment.

Q: Where are receptors found?

A: Sensory systems such as the eyes, ears, and skin.

What does −70 mV resting potential mean?

A: The inside of the neuron is about 70 mV more negative than the outside while resting.

When does a neuron remain at resting potential?

A: When it is not transmitting a signal.

What is an action potential?

A: A brief electrical signal that travels down the axon and transmits information.

What happens to the neuron's charge during an action potential?

A: It rises from about −70 mV to +40 mV, becomes negative again, and returns to resting potential.

About how long does an action potential last?

A: About 1 millisecond (1/1000 second).

What are microelectrodes?

A: Small electrodes used to record electrical signals from individual neurons.

What is a recording electrode?

A: An electrode placed inside or very near a neuron to detect its electrical activity.

What is a reference electrode?

A: An electrode placed farther away to provide a comparison for measuring electrical activity.

What happens when an electrical signal reaches the end of an axon?

A: It triggers the release of neurotransmitters.

What are neurotransmitters?

Chemicals that allow signals to cross the synaptic gap from one neuron to another.

What is firing rate?

A: The number of action potentials a neuron produces per second.

What does “quality across the senses” mean?

A: Different sensory experiences, such as vision, hearing, and smell.

What is an example of quality within one sense?

A: In vision: color, movement, shape, or facial identity.

What is the principle of neural representation?

A: Everything we experience is based on representations in the nervous system.

What are neural networks?

A: Interconnected brain regions/neurons that communicate with each other.

What are feature detectors?

: Neurons that respond to specific features of a stimulus.

What specific features can feature detectors respond to?

A: Orientation, movement, and length.

What is experience-dependent plasticity?

A: The structure of the brain is changed by experience.

How can feature detectors work together to represent an object?

A: Different neurons respond to different features, and their combined activity represents the whole object.

What do neurons at early levels of visual processing respond to?

A: Relatively simple features, such as oriented lines.

What do neurons at higher levels of visual processing respond to?

A: More complex stimuli, such as geometrical patterns, hands, and faces.

Localization of function

Specific functions are performed by specific regions of the brain.

Cerebral cortex

Thin outer layer of the brain involved in many cognitive functions

Subcortical regions

Brain regions located below the cerebral cortex

Neuropsychology

Study of how brain damage affects behavior and cognition.

Cortical equipotentiality

Old theory that the brain operates as an indivisible whole, rather than having specialized regions.

Broca’s area

Frontal lobe region involved in speech production.

Broca’s aphasia

Damage to Broca’s area → slow, labored, ungrammatical speech.

Broca’s patient “Tan”

Patient who could essentially only say “tan,” providing evidence for localization of speech production.

Wernicke’s area

Temporal lobe region involved in understanding language.

Wernicke’s aphasia

Speech is fluent but often meaningless/incoherent + difficulty understanding speech.

Broca vs. Wernicke

Broca = producing speech 🗣 / Wernicke = understanding speech 👂

Visual cortex

Located in the occipital lobe; responsible for vision.

Auditory cortex

Located in the temporal lobe; responsible for hearing.

Somatosensory cortex

Located in the parietal lobe; processes touch, pressure, temperature, and pain.

Frontal lobe

Coordinates sensory information and is involved in thinking and problem-solving.

Prosopagnosia

Inability to recognize faces, associated with damage to the lower temporal lobe.

Double dissociation ⭐

Damage to area 1 disrupts A but not B, while damage to area 2 disrupts B but not A → shows A and B use different mechanisms.

Fusiform face area (FFA)

Area in the fusiform gyrus/temporal lobe that responds strongly to faces.

Single-neuron recording

Records activity from individual neurons to determine what they respond to.

EEG

Measures electrical brain activity using electrodes on the scalp. Great temporal, poor spatial resolution.

Temporal resolution

How accurately a method tells us WHEN brain activity occurs

Spatial resolution

How accurately a method tells us WHERE brain activity occurs.

fMRI ⭐

Measures brain activity through changes in blood oxygenation.

Parahippocampal place area (PPA)

Responds strongly to places, scenes, and spatial layouts.

Distributed representation ⭐

A cognitive function/experience is represented by activity across many different areas of the brain, rather than just one area.

Localization vs. distributed representation ⭐

Localization: specific brain areas have specific functions. Distributed representation: a single experience/function can involve many brain areas working together.

Broca & Wernicke's original language idea

Broca = speech production / Wernicke = speech comprehension. This supported localization of function.

Wernicke's connectivity idea ⭐

Language depends not only on individual brain areas but also on connections between multiple brain regions.

Modern view of language processing ⭐

Language is distributed across many interconnected brain regions, not just Broca's and Wernicke's areas.

What are the 4 main principles of neural networks?

1. Structural pathways form the brain’s information highway.

2. Functional pathways serve different functions.

3. Networks operate dynamically.

4. The brain has resting-state activity

What is structural connectivity?

A: The brain’s physical “wiring diagram” created by nerve axons connecting different brain regions

What is a connectome

A: A map of the brain’s structural connections—its wiring diagram.

How can structural connectivity be measured?

A: Track-weighted imaging (TWI) detects water diffusion along nerve fibers to map neural pathways.

Is structural connectivity the same for everyone?

A: No. Structural connectivity maps can act like “fingerprints” that differ between people.

What is functional connectivity?

A: The extent to which activity in two brain regions is correlated.

What does highly correlated activity between two brain regions suggest?

A: They are likely functionally connected.

What is resting-state fMRI?

A: Measuring brain activity with fMRI while a person is at rest and not performing a cognitive task.

What is a seed location?

A: The brain region used as the starting point when measuring functional connectivity.