Cognitive Neuroscience - Exam One (Chapter Three)

Cognitive Psychology

The study of mental activity as an information processing problem. It focuses on how we form internal mental representations and how those representations are transformed and computed.

Chronometrics

A method that uses reaction time to study mental processes - useful for studying mental events that happen very quickly and efficiently

Serial Processing

Mental processing that happens one step or item at a time - the target does not just “pop out”

Parallel Processing

Mental processing in which multiple items or features are processed at the same time - EX: finding something red or horizontal can happen in parallel

Stroop Effect

A form of interference where the meaning of a word can interfere with responding to another feature, such as the ink color (the interference is reduced when the response is manual instead of verbal, and can also decrease with practice or a dual task)

Eye Tracking

A method that uses eye movements and gaze patterns to study mental processes

• Uses an infrared camera to track where someone is looking

• Can measure things like where they look, how often they make saccades, and whether they return to previously viewed locations

Computer Modeling

Using computers to represent and transform information in order to model human cognition

• Can be used to simulate human behavior

• Helps researchers examine mental representations and how information is transformed

Limitations of Computer Modeling

They are not fully biologically realistic, often small in scale, and focus on narrow problems rather than the full complexity of cognition

Extracellular Recording

A type of single cell recording where an electrode measures electrical activity outside the neuron - most common method and records action potentials (spikes)

Intracellular Recording

A type of recording where the electrode measures electrical activity inside the neuron - much more difficult and measures graded membrane potentials (shows how close the neuron is to firing)

Baseline Activity

The normal level of activity a neuron has before an experimental manipulation

• Neurons are constantly active

• Researchers compare changes from baseline to see whether something increases or decreases the firing rate

Receptive Field

The location in space where a stimulus can affect a neuron’s activity (neurons also have preferences for certain kinds of input)

Limitations of Single Cell Recording

• Limited spatial coverage

• A few neurons may not represent the whole brain region

• Usually not done in humans

• It is not causal - it records activity but does not prove the neuron caused the behavior

Complex Cell Preferences

Neurons in higher visual areas can respond preferentially to more complex features or patterns, rather than just simple visual input

Animal Lesions

A research method used to test whether a brain structure is necessary for a task

• If damaging a brain region impairs performance, that suggests the region contributes to the task

• It can be tricky because animals may compensate or the damaged area may only be a pathway to another region

Animal Lesion Techniques

Methods used to damage or temporarily disrupt specific brain tissue

Aspiration

Tissue destroyed by suction

Electrolytic Lesion

Uses electrical charge

Neurochemical Lesion

Targets specific cell types

Reversible Lesion

Temporarily disrupts function, such as through cooling or drugs

Genetic Manipulations

Researchers alter genes in animals to study how genetics affect the brain and behavior

• A major goal is to identify the genetic basis of brain disorders

• One common method is using “knockout” mice, where a specific gene is disabled or altered

Computed Tomography (CT)

A structural imaging method that uses X Rays from many directions to create brain images

• Different tissues absorb radiation differently

• More images = More radiation exposure

• Difference between this and X - Rays, is that with CT you get multiple X Rays combined making it three dimensional

Magnetic Resonance Imaging (MRI)

A structural imaging method that measures the properties of hydrogen spin in the body

Electroencephalography (EEG)

A method that records the brain’s electrical activity using electrodes placed on the scalp

Diffusion Tensor Imaging (DTI)

Uses MRI to measure the diffusion of water through axons

Why is diffusion relevant?

Measures movement of water through axons, to then map white matter pathways and connections between brain regions