Chapter 3 - The Brain Flashcards
Won't be on tests... but know it anyway
action potential
The all-or-none firing of a neuron that leads to the release of neurotransmitters.
activation function (as in neural networks)
A function that takes in the weighted sum of the previous layer’s inputs and returns the activation level of the node.
activation level (as in neural networks)
The numerical value of a node in a neural network.
aphasia
The loss of language comprehension or expression due to brain damage.
artificial neural network (ANN)
A type of machine-learning models based loosely on the brain consisting of layers of nodes connected by modifiable weights that determine their activations.
association neurons
Neurons that receive their inputs and send outputs to other neurons.
autonomic nervous system
A portion of the peripheral nervous system that connects to most organs in the body and regulates certain unconscious bodily functions.
axon
A projection of the neuronal cell body along which action potentials are propagated, terminating in the release of neurotransmitters
backpropagation
A technique for gradually changing the weights of a neural network in order to reduce the error
brainstem
A stalk-like structure at the base of the brain that connects it to the spinal cord and regulates involuntary functions like heart rate and breathing.
Broca’s aphasia
A form of aphasia typically due to damage to the inferior frontal gyrus that leads to slow and labored speech production.
central nervous system
A portion of the nervous system consisting of the brain and spinal chord.
cerebral cortex
A folded, layered structure that is the largest single structure and the most superficial portion of the human brain
cerebrum
The largest portion of the human brain, sitting at the top of the brain and consisting of the cerebral cortex and related structures.
cognitive neuroscience
A subfield of neuroscience that uses multiple tools to measure and analyze active brain processing in awake and (typically) healthy individual.
corpus callosum
A band of fibers that connect the right and left hemispheres of the cerebrum
contralateral
A spatial relationship between brain and body observed in vertebrates in which one side of the brain controls or receives input from the opposite side of the body.
dendrites
Branch-like projections that protrude from the cell body of a neuron and contain receptor sites to which neurotransmitters can bind.
distributed/population encoding:
A theory of neural representation in which complex patterns or objects are represented by the distribution of activation across many neurons.
electroencephalography (EEG)
A method that measures electrical activity due to neural or other processing at the surface of the scalp.
encephalization quotient (EQ)
A measure of actual brain size relative to the size that would be predicted based on body size alone. It is strongly correlated with intelligence.
error/loss (as in a neural network)
The difference between the observed output and the correct output of an ANN, used as a measure of its performance and minimized during training.
event-related potential (ERP)
Rapid changes in electrical potential, as measured by EEG, due to the onset of a stimulus.
excitatory
When the firing of a neuron causes a receiving neuron to fire more frequently.
fight or flight response
A sympathetic nervous system response that prepares the body with increased strength and stamina in response to a perceived threat.
fissure
A deep sulcus fold in the cerebral cortex.
functional localization:
The concept that certain cognitive functions reside in specific regions of the cerebral cortex.
functional magnetic resonance imaging (fMRI)
A technique in cognitive neuroscience for measuring ratios of oxygenated bloodflow in the brain in order to determine task-related neural activity.
functional near-infrared spectroscopy
A tool of cognitive neuroscience which uses near-infrared light in order to measure oxygenated vs non-oxygenated hemoglobin, a component of blood to derive the hemodynamic response.
glial cells
Cells within the nervous system that provide support to neurons.
gyri/gyrus
The “hill”-like projections of the folds of the cerebral cortex.
hemisphere
Each of the two halves of the cerebrum, divided into a left and right, and connected by the corpus callosum.
hidden layer
The intermediate layers between input and output in an ANN. The units in the hidden layer encode patterns in the input layer or in previous hidden layers.
hippocacampus
A complex structure which is involved in memory formation and is structurally an extension of the temporal lobe of the cortex and is involved in the formation of long-term memories.
hypothalamus
A small but highly complex cluster of neurons that lies in the center of the brain that regulates multiple involuntary behavioral functions.
inhibitory
When the firing of a neuron causes a receiving neuron to fire less frequently.
input layer
The first layer of an ANN. The activation level of each node in this layer is determined by values of the data itself.
lobes
The four anatomical divisions of the cortex that exist on each hemisphere.
motor neurons
Neurons whose output leads to activation of muscle fibers.
multivariate-pattern analysis (MVPA)
A data-analysis that uses machine learning to decode what task or stimulus a participating in engaging, based on the distribution of activity across the brain.
nerves
Bundles of connective tissue that allows neurons to communicate with one another and other parts of the body.
nervous system
A portion of the body consisting of neurons, nerves and glial cells whose function is to allow different portions of the body to communicate with one another.
neuroplasticity
The ability of the brain to reorganize the spatial arrangement of its function.
neurospsychology
The study of brain function and impairment due to brain pathology.
neurotransmitters
Chemical agents that serve as “messengers” between neurons.
output layer
The final layer of an ANN that represents the networks decision about the input.
parasympathetic nervous system
A subdivision of the autonomic nervous system that regulates certain bodily functions under conditions when immediate action is not needed.
peripheral nervous system
A portion of the nervous system consisting of all neurons, nerves and glial cells outside of the nervous system.
receptors
Sites on the dendrite of a neuron to which neurotransmitters can bind.
reflex action
The simplest form of autonomic behavioral responses in which he spinal chord generates the behavioral signal without the brain.
reuptake
A process in which neurotransmitters in the synaptic cleft are reabsorbed by a sending neuron
sensory receptors
Neurons that receive their activation from physical stimulation of the body
sparse coding
A theory of neural coding in which a complex pattern or object is encoded by the distribution of responses across a small set of neurons.
split-brain
Patients (typically epileptic) who have had their corpus callosum severed, disconnecting the two hemispheres of the cortex.
specificity encoding
A theory of neural coding in which a complex pattern or object is encoded by the response of a single neuron.
sulci/sulcus
The “valley”-like indentations of the folds of the cerebral cortex.
sympathetic nervous system
A subdivision of the autonomic nervous system that unconsciously regulates certain functions of the body to prepare for immediate action.
