Chapter 3 Key Terms Flashcards
Define “representation” and “process.” In the Sternberg memory paradigm, how were reaction time data used to investigate the mental processes underlying memory search?
Representation refers to how information is encoded and stored in the brain. Process refers to the operations the brain uses to manipulate that information. In the Sternberg task, an increase in reaction time with more items in memory indicated a serial search process.
What is “cognitive subtraction”? Give examples of how it is implemented in
behavioral and fMRI experiments.
Cognitive subtraction is a method where brain activity or behavior in a control task is subtracted from that in an experimental task to better isolate the cognitive process of interest. For example, in fMRI, brain activity during a general visual condition may be subtracted from activity during visual processing of specific image categories.
What are different ways that people’s brains might become damaged?
Brain damage can occur due to trauma, strokes, tumors, neurodegenerative diseases, or surgery
Define the terms “single dissociation” and “double dissociation” and give
examples from any area of cognitive neuroscience. What can we conclude from these dissociations? Why does a double dissociation provide stronger evidence than a single dissociation?
Single dissociation occurs when a lesion in one brain area causes a deficit in Task A but not B. Double dissociation is when lesions in one brain area cause a deficit in Task A but not B, and lesions in another area cause the reverse. Double dissociations provide stronger evidence as they demonstrate two cognitive functions are independently
localized to separate brain regions.
What is being measured in fMRI?
fMRI measures changes in blood flow related to neural activity.
What is a “receptive field”? What experimental procedure would you use to determine the receptive field of a neuron?
A receptive field is a specific area of sensory space that elicits a response from a sensory neuron when stimulated. To determine this, light or tactile stimuli could be
systematically applied while recording neuron responses.
What are the advantages and disadvantages of block vs. event-related designs in fMRI?
Block designs are simpler, providing strong signal-to-noise ratios by grouping similar trials together, but lack temporal resolution. Event-related designs allow finer temporal
resolution and analysis of individual trials but can have lower signal strength.
How do single-cell recordings and multi-unit recordings differ in their application and insight?
Single-cell recordings provide highly detailed information about individual neurons but are invasive and limited to small samples. Multi-unit recordings capture broader activity across neuron groups, offering insights into population coding.
What are the limitations of correlational methods like fMRI compared to causal
methods like TMS?
Correlational methods can identify relationships between brain activity and behavior but cannot confirm causality. Causal methods like TMS allow direct manipulation of brain activity to test specific hypotheses but are spatially limited and sometimes
invasive.
Cognitive subtraction
Add or remove a process from the processing stream; a way to manipulate cognitive processes. A research method used in neuroimaging studies where researchers subtract brain activity during a control task from brain activity during an experimental task to isolate the neural activity specifically related to a cognitive process of interest
Computational modeling
Computational modeling simulates brain functions to test theories, predict neural outcomes, and integrate experimental data. It allows hypothesis testing beyond
experimental limits, linking diverse data to explore cognitive mechanisms. It relies on data quality and assumptions, risking oversimplification; complex models can be hard to validate.
Correlational experiments
“Listening” to the brain by measuring brain activity while observing behavior. Methods include electrophysiology, ECoG, EEG/ERP, MEG, CT, PET, MRI, DTI, and fMRI.
Causal experiments
“Poking” the brain by interrupting or modifying
brain function to observe effects. It includes lesions, genetic manipulations, Deep brain stimulation (DBS), optogenetics, Transcranial magnetic stimulation (TMS)
Diffusion tensor imaging (DTI)
A type of MRI that maps the diffusion of water molecules in brain tissue, revealing the microstructural organization of white matter pathways. Used for Maps and characterizes white
matter tracts, helping to understand brain connectivity, cognitive functions, and neurological disorders. It offers unique insights into white matter pathways beyond standard MRI, aiding in the diagnosis of conditions like multiple sclerosis, stroke, and TBI. It is susceptible to motion artifacts and assumes uniform water diffusion, which may not always reflect the brain’s complex microstructure.
Electrocorticography (ECoG)
It captures electrical activity directly from the surface of the brain using electrodes placed on the cortex, offering high spatial and temporal resolution of brain activity. Used for Identifying epileptic
zones and mapping brain
functions during surgery. It provides high spatial and temporal resolution, making it ideal for precise functional mapping. However, it is highly invasive, requiring surgical exposure of the brain, so it is mainly used in clinical settings.
Electroencephalography (EEG)
It measures electrical activity through the scalp. Used for diagnosing epilepsy, sleep
disorders, and studying brain responses to cognitive and sensory tasks. It is non-invasive, affordable, and offers excellent temporal resolution for tracking rapid neural activity. It has limited spatial resolution and is vulnerable to artifacts from muscle movement, eye blinks, and external noise
Electrophysiology
It involves recording electrical activity from individual neurons (single-unit) or groups of neurons (multi-unit) in animals to understand neural behavior at a highly detailed level. It offers precise, real-time measurement of spiking activity with high resolution. However, it is invasive, limited human use, and may not fully capture broader neural circuits.
Event-related potential (ERP)
ERP refers to brain responses tied to specific sensory, cognitive, or motor events,
providing insights into brain function and timing. EEG signal changes that occur in response to specific events, such as sensory stimuli or cognitive processes. Due to their small magnitude, ERPs are extracted by averaging EEG data across trials, removing background noise and isolating the event driven response.
functional magnetic resonance imaging (fMRI)
It measures brain activity by detecting changes in blood flow, offering insights into the brain’s functional areas during tasks or rest. Used for studies brain activity linked to
cognitive processes by measuring blood flow
changes, identifying brain regions involved in tasks like decision-making and perception. It is non-invasive, high spatial resolution,
and safe for repeated use due to lack of ionizing radiation. However, it has limited temporal resolution compared to EEG; indirect measurement via BOLD response may not fully capture neural activity; requires stillness during scanning.
Neuroimaging
a group of medical imaging techniques used to visualize and study the structure and function of the brain and central nervous system.
BOLD
The fMRI detectors measure the ratio of oxygenated to deoxygenated hemoglobin; This is referred to as the blood oxygen level-dependent (BOLD) effect. The blood-oxygen-level-dependent (BOLD) signal, detected in fMRI, reflects changes in deoxyhemoglobin driven by localized changes in brain blood flow and blood oxygenation.
Hemodynamic
When a brain area is active, increasing the blood flow to that region provides it with more oxygen and glucose at the expense of other parts of the brain. The change of blood flow is known as a hemodynamic response.
Independent variables
It modifies aspects of the task to assess their impact on
performance (e.g., number of distractors in a visual search task). The independent variable is the one the researcher intentionally changes or controls.
Dependent variables
Such as reaction time (RT) and accuracy, measure cognitive processing. The dependent variable is the factor that the research measures. It changes in response to the independent variable; in other words, it depends on it.
Invasive experiments
Medical procedures that involve cutting skin or inserting instruments into the body, or animal experiments that cause pain or distress.
Noninvasive experiments
medical procedures or research that doesn’t involve breaking the skin or directly manipulating variables; Don’t require instruments to be inserted into the body
Are often part of routine disease diagnosis, monitoring, and treatment
Can help reduce pain associated with medical procedures
Examples include X-rays, CT scans, MRIs, and ultrasounds
Lesions
Lesions are damage or removal of specific brain areas to examine behavioral effects. They are used for studying the effects of brain damage on behavior and
cognition to infer structure-function relationships. They provide strong causal evidence linking brain regions to specific functions. It can reveal long-term functional consequences of brain damage. Natural lesions (e.g., stroke, trauma) offer insight into brain disorders from real-world clinical cases. However, they lack experimental control over lesion location and extent in natural cases. Brain plasticity can compensate for damage, complicating
interpretation. Ethical and practical limitations prevent intentional lesion studies in humans.
Case studies
- Leborgne (“Tan”) – Stroke: Loss of speech, linking
left frontal lobe to language. - Phineas Gage – TBI: Frontal lobe damage led to
personality and impulse control changes.
Henry Molaison (“HM”) – Neurosurgery: Hippocampal removal caused profound memory deficits.
Magnetic resonance imaging (MRI)
It provides high-resolution images of the brain’s structure and anatomy using
magnetic fields and radio waves, without exposure to ionizing radiation. Used for: MRI provides high-resolution brain images to study structure-function relationships, detect abnormalities, and map cognitive processes. It is Non-invasive, no radiation, and excellent spatial resolution for detailed brain mapping. However, it is expensive, time-consuming, and requires subjects to remain still in a confined space.
Mental Rotation Task
Task: Participants determine whether two images
match.
* Independent Measure: Degree of rotation between
the images.
* Dependent Measure: Reaction time (RT) to make a
decision.
* Requires: Mentally rotating images to assess
similarity.
* Effect: RT increases linearly with rotation angle.
* Main Idea: Mental transformations take time,
suggesting a continuous process.
Parametric Variation
Vary the amount of a given process; a way to manipulate cognitive processes. a research method where researchers systematically manipulate a specific variable (or “parameter”) within an experimental design to observe how it affects cognitive processes
Posner task
Task: Participants determine whether two letters belong to the same category.
* Independent Variable: Type of letter relationship (physical match vs. categorical match).
* Dependent measure: Reaction Time (RT)
* Requires: Recognizing letters across
transformations within a category
* Effect: Longer RT for accessing more
abstracted representations (non-physical).
* Main Idea: Response latencies reflect
increasing processing demands
Processes in terms of experimental tasks
How does the brain manipulate and transform this information?
Representations in terms of experimental tasks
How is information stored in the mind and brain?
Reaction time
This was discovered by Donders as he found a way to measure and investigate cognitive processes. Reaction time (RT) is a measure of the quickness with which an organism responds to some sort of stimulus. RT is defined as the interval of time between the presentation of the stimulus and appearance of appropriate voluntary response in the subject.
Serial Processing
- Step-by-step, sequential approach
- Slower, but systematic
- Recognizes processing bottlenecks
Parallel processing
- Multiple processes occur simultaneously
- Faster, but requires efficient resource allocation
- Key for complex, high-speed cognitive task
Single and double dissociation
Single Dissociation: One patient group is
impaired on Task A but performs normally on
Task B. Double Dissociation: Patient Group 1:
Impaired on Task A, normal on Task B. Patient
Group 2: Impaired on Task B, normal on Task
A. Double dissociations provide
stronger evidence for selective impairments,
supporting the idea that different cognitive
processes rely on distinct neural mechanisms.
Sternberg memory paradigm
Task: Participants see 1–4 letters (memory set), then a single probe letter and must determine if it was in the set.
* Independent Measure: Number of items in memory set (memory load).
* Dependent Measure: Reaction time (RT).
* Requires: Comparing sensory input (probe letter) with stored active memory.
* Effect: RT increases linearly with # of items in the set; “yes” and “no” RTs do not differ.
* Main Idea: The comparison process operates serially, not in parallel
Stroop task
The task is to name the color of the printed word,
ignoring its meaning. The independent measure is the relationship between word meaning and ink color. The dependent measure is reaction time. The effect of the task is slower to name colors for mismatched color-word pairs. It requires ignoring semantic meaning of
word. The main idea of the task is that Task-irrelevant information interferes with processing, demonstrating
cognitive control limitations.
Transcranial magnetic stimulation (TMS)
It uses magnetic fields to non-invasively stimulate or inhibit specific brain regions. Used for non-invasively stimulating or inhibiting brain regions to study neural function and treat conditions like depression. It is safe, reversible, and non-invasive.
Provides causal evidence of brain function in humans by
disrupting activity. It can be used repeatedly without long-term harm. It has limited spatial resolution—it cannot precisely target deep
brain structures. Effects are temporary and can be variable. Mechanisms of action remain unclear for some applications.
