Chapter 2 Flashcards
Cognitive neuroscience
the study of the physiological basis of cognition
Levels of analysis
a topic can be studied in a number of different ways that each contribute to our understanding
Neurons
small units in the brain that create and transmit information about what we experience and know
Nerve net theory
continuous, interconnected pathways for conducting signals uninterrupted through the network in all directions
Why was the nerve net described as continuous?
past staining techniques and microscopes couldn’t resolve small details due to the high density of the cells
Staining techniques used to study the nerve net
immersing a thin slice of brain tissue in a solution of silver nitrate (Golgi); using a Golgi stain on only some cells in a slice of brain tissue from newborn animals (Ramon y Cajal)
Neuron doctrine
individual cells called neurons, which are not continuous with other cells, transmit signals in the nervous system
Cell body
metabolic center of the neuron that contains mechanisms to keep the cell alive
Dendrites
branches out of the cell body to receive signals from other neurons
Axons or nerve fibers
long processes that transmit signals to other neurons
Synapse
small gap between the axon terminal or the end of a neuron’s axon and the dendrites or cell body of another neuron
Neural circuits
groups of neurons that form specific connections with one another
Receptors
neurons that are specialized to pick up information from the environment; also have axons
Microelectrodes (Adrian)
small shafts of hollow glass filled with a conductive salt solution that can pick up electrical signals at the electrode tip and conduct these signals back to a recording device
Resting potential
the inside of a neuron has a charge that’s 70 millivolts more negative than the outside; this difference continues as long as the neuron is at rest
Action potential
when a neuron’s receptor is stimulated, the charge inside the axon increases to +40 mV as the nerve impulse passes the recording electrode for about 1 ms, then returns to resting potential
What determines the intensity of a stimulus?
the rate of nerve firing or the number of action potentials travelling down an axon per second; the shape and height of an action potential remains constant
Principle of neural representation
everything a person experiences is based on representations in the person’s nervous system
Feature detectors
neurons that respond to specific stimulus features like orientation, movement, and length
Experience-dependent plasticity
the structure of the brain is changed by experience e.g. neurons in visual cortex respond only to vertical lines
Hierarchical processing
neurons in the visual cortex that respond to simple stimuli send their axons to higher levels of the visual system, where signals from many neurons combine and interact to respond to more complex stimuli
Sensory code
how neurons represent various characteristics of the environment
Specificity coding
an object can be represented by the firing of a specialized neuron that responds only to that object
Population coding
the representation of a particular object by the pattern of firing of a large number of neurons; large number of stimuli can be represented
Sparse coding
a particular object is represented by a pattern of firing of only a small group of neurons, with the majority of neurons remaining silent
Localization of function
specific functions are served by specific areas of the brain
Cerebral cortex
a layer of tissue ~3 mm thick that covers the brain
Neuropsychology
study of the behavior of people with brain damage
Cortical equipotentiality
idea that the brain operated as an indivisible whole as opposed to specialized areas
Broca’s area
area in the frontal lobe that is damaged in those who experience stroke; responsible for producing speech
Broca’s aphasia
slow, labored, ungrammatical speech caused by damage to Broca’s area
Wernicke’s aphasia
speech is fluent and grammatically correct but tends to be incoherent due to damage in Wernicke’s area located in the temporal lobe; unable to understand other’s speech due to inability to match words with meanings
Gyrus
ridge on the cerebral cortex
Sulcus
groove or indentation on the cerebral cortex
What happens when the occipital lobe is damaged?
blindness in the area of the visual space connected to the area of the occipital lobe that was damaged
Auditory cortex
located in the upper temporal lobe; receives signals from the ears
Somatosensory cortex
in the parietal lobe; receives signals from the skin for perceptions of touch, pressure, and pain
Frontal lobe
receives signals from all senses and is responsible for coordination and higher cognitive functions like planning, short-term memory, strategic thinking, judgement, social cognition, and movement
Prosopagnosia
caused by damage to the temporal lobe on the lower right side of the brain; inability to recognize faces but still able to recognize people through featural processing (e.g. voices, names, hair color, clothes)
Double dissociation
damage to one area of the brain causes function A to be absent while function B is present, while damage to another area causes the opposite (e.g. object and face recognition)
task-related fMRI
change in brain activity when a person engages in a specific cognitive task
Corpus callosum
fiber bundle of axons or commissures that connect the right and left hemispheres
Contralateral control
right hemisphere controls the left side of the body, and vice versa
Lateralization
certain functions are dominant in on hemisphere (e.g. language production on the left)
Brainstem
controls automatic processes that regulate basic life-support functions like breathing, heart rate, swallowing, sleep cycles; can result in coma or death if damaged; contains regions producing serotonin, norepinephrine, etc.
Cerebellum
for balance and coordination of voluntary movements, and performing high-level cognitive tasks
Layers in superior and inferior colliculus
shallow: relay centers for sensory information entering the brain; deep: motor activity like eye movement
Result of damage to superior and inferior colliculus
problems in hearing, seeing, and motor control
Forebrain
surrounds the midbrain and contains the cerebral; regulates higher mental processes and enables people to engage in complex learning, memory, thought, and language
Diencephalon
subdivision of the forebrain consisting of the thalamus and the hypothalamus
Thalamus vs. Hypothalamus
for salience and sensory relay; for body regulation (body temp, hunger, thirst, sexual behavior) and arousal
Salience
the degree to which attention is captured by a stimulus in the environment
Parts of the limbic system
basal ganglia, thalamus, hypothalamus, amygdala, hippocampus
Amygdala(s)
for salience, perception, learning, memory, and fear responses
Hippocampus
for spatial navigation, perception, memory: creating new memories, integration of new memories with existing memories
Basal ganglia
in the base of forebrain, top of midbrain; for action-selection, skill, motivation, reward
Temporal lobe
for hearing, language, and long-term memory
Parietal lobe
for processing touch information and complex sensory integration
Occipital lobe
for visual processing and visual pattern recognition
Connectome
the wiring diagram of the structure of the brain
Default mode network
responds when a person is not involved in specific tasks; implicated in mind wandering and creativity
Fusiform face area
for facial recognition; damaged in prosopagnosia cases; in the fusiform gyrus on the underside of the temporal lobe
Parahippocampal place area
activated when perceiving indoor and outdoor scenes through information on spatial layout
Extrastriate body area
activated by pictures of bodies and parts of bodies (but not by faces)
Distributed representation
many areas of the brain are involved in a particular type of cognition e.g. looking at faces
Neural networks
interconnected areas of the brain that can communicate with each other; related to distributed processing
Networks
structural pathways that form the brain’s information highway containing functional pathways that operate dynamically
Structural connectivity
how the brain is wired together; formed by nerve axons connecting different brain areas
Functional connectivity
the extent to which neural activity in two brain regions is correlated by using resting state fMRI data; correlated = functionally connected
Track-weighted imaging
technique for detecting brain pathways based on how water diffuses along the length of nerve fibers
