Mid-term Review (Chapter 3)

Neurons

nerve cells that constitute the basic building blocks of the nervous system 

Cell Body (Soma)

contains the structures needed to keep the neuron alive, and its nucleus contains genetic info that determines how the neuron develops and functions 

Dendrites

emerging from the soma (small branching fibres), receive messages from adjacent neurons 

Axon

extending from one side of the cell body is a singular axon, conducts nerve impulses to other neurons, muscles, or glands

Blood-Brain Barrier

specialized lining of cells in the brain's blood vessels that screen out foreign substances while letting nutrients pass through to neurons 

Resting Potential

internal difference of the sodium ions outside of a cell and the negatively charged protein ions inside the cell 

Action Potential

a nerve impulse resulting from the depolarization of an axon's cell membrane (opposites attract!) 

Depolarization

shift from negative to positive voltage (reversal process) 

All-or-None Law

the fact that an action potential is not proportional to the intensity of stimulation; a neuron either fires with maximum intensity or it does not fire

Action Potential Threshold

intensity of stimulation needed to produce an action potential 

Myelin Sheath

a fatty insulating substance on the axon of some neurons that increases the speed of neural transmission 

Synapse

microscopic space between neurons over which the nerve impulse is biochemically transmitted 

Synaptic Cleft

a tiny gap between the axon terminal of one neuron and the dendrite of the next neuron

Neurotransmitters

chemical substances that are released from the axons of one neuron, travel across the synaptic space, and bind to specially keyed receptors in another neuron, where they produce a chemical reaction that is either excitatory or inhibitory 

Receptor Sites

protein molecules on neurons' dendrites or soma that are specially shaped to accommodate a specific neurotransmitter molecule 

Synaptic Vesicles

chambers within the axon that contain the neurotransmitter substance

Glutamate

excitatory, particularly important role in mechanisms of learning and memory

GABA

inhibitory, important for motor control and the control of anxiety

Acetylcholine

excitatory, involved in memory and muscle activity

Dopamine

Excitatory, mediates a wide range of functions (motivation, reward, feelings of pleasure, voluntary motor control, control of thought processes

Serotonin

neurotransmitter that influences sleep, mood, eating, sexual behaviour 

Endorphins

neurotransmitter that reduces pain and increases feelings of well-being

Neuromodulators

neurotransmitter substances that are released by neurons and circulate within the nervous system to affect the sensitivity of many neurons to their natural transmitter substances 

Sensory Neurons

carry input messages from the sense organs to the spinal cord and the brain

Motor Neurons

transmit output impulses from the brain to the spinal cord to the body's muscles and organs 

Interneurons

(vastly outnumber the other two neuron types) perform connective and associative functions within the nervous system 

Central Nervous System

consisting of all the neurons in the brain and spinal cord 

Peripheral Nervous System

composed of all the neurons that connect the CNS with the muscles, glands, and sensory receptors 

Somatic Nervous System

provides input from the sensory receptors and output to the voluntary muscles of the body.

Autonomic Nervous System

stimulates the body's involuntary muscles (I.e. heart) and internal organs

Sympathetic Nervous System

subdivision of ANS, activation function on the body's internal organs, speeding up bodily processes and mobilizing the body

Parasympathetic Nervous System

subdivision of ANS, slows down bodily processes to conserve energy and reduce arousal 

Homeostasis

balanced or constant internal state

Transcranial Magnetic Stimulation (TMS)

procedure that uses a magnetic field to affect electrical activity in specific brain regions without surgery or other invasive actions 

Electroencephalogram (EEG)

device used to record simultaneous activity of many thousands of neurons through electrodes attached to the scalp 

Computerized Axial Tomography (CT)

method to scan brain with narrow beams of x-rays that are then analysed and combined by a computer to provide pictures of brain structures from many different angles 

Positron Emission Tomography (PET)

procedure that provides visual display of the absorption of a radioactive substance by neurons, indicating how actively they are involved as the brain performs a task 

Magnetic Resonance Imaging (MRI)

procedure that produces highly detailed image of living tissue based on the tissue's response to a magnetic field; can be used to study both structure and, in case of functional MRI (fMRI), brain functions as they occur 

Hindbrain

lowest and most primitive level of the brain 

Brain Stem

portion of the brain formed by the swelling of the spinal cord as it enters the skull; its structures regulate basic survival function of the body (I.e. heart rate and respiration) 

Medulla

brain stem that controls vital functions, heartbeat and respiration (medulla causes them to happen automatically), encountered after leaving the spinal cord 

Pons

lies just above the medulla, brain stem having sensory and motor tracts whose functions are involved in sleeping and dreaming

Cerebellum

convoluted hindbrain structure involved in motor coordination and some aspects of learning and memory 

Midbrain

lies above the hindbrain, involved in sensory and motor functions and in attention and states of consciousness

Reticular Formation

structure extending from the hindbrain into the midbrain, plays central role in consciousness and attention

Forebrain

brain structure above the midbrain, involved in higher-order sensory, motor, and cognitive functions. Made up of two large cerebral hemispheres (left and right) that wrap around the brain stem 

Thalamus

located above the midbrain, major sensory integration and relay centre in the forebrain, organizes inputs from sense organs and routes them to appropriate areas of the brain – functions as a filter, helping coordinate actions 

Basal Ganglia

made up of five distinct structures that are critical for voluntary motor control

Hypothalamus

below the thalamus, controls autonomic and hormonal processes, plays major role in many aspects of motivation and emotional behaviour

Limbic System

group of subcortical structures, involved in organizing many goal-directed and emotional behaviours

Hippocampus

structure responsible for formation and storage of memories

Amygdala

structure that helps organize emotional response patterns (aggression, fear). Primary alarm system that triggers "fight or flight response" 

Nucleus Accumbens

involved in reward and motivation 

Cerebral Cortex

outer covering of the brain, seat of higher-order sensory, motor, perceptual, and mental processes 

Frontal Lobe

front portion of cerebral hemispheres; Broca's speech production area, motor cortex, associative cortex (planning and problem solving)

Parietal Lobe

cerebral region behind the frontal lobe, contains somatic sensory cortex, Wernicke's speech comprehension area 

Occipital Lobe

rearmost portion of the cerebral cortex, contains primary visual sensory area

Temporal Lobe

portion of cortex below parietal lobes, major site of auditory input to the brain 

Motor Cortex

cortical area, located back of frontal lobes, controls voluntary movements on opposite sides of the body

Somatic Sensory Cortex

cortical strips in the front portion of parietal lobes, receives sensory input from various regions of the body 

Wernicke’s Area

area of left temporal lobe, involved in speech comprehension

Broca’s Area

region of left frontal lobe, involved in speech production

Association Cortex

areas of the cerebral cortex that do not have sensory or motor functions, involved in integration of neural activity that underly perception, language, and other higher-order mental processes. Acts as a bridge, connecting multiple specialized cortexes, linking sensory and motor input 

Mirror Neurons

important for observational learning, play a role in learning, copying movements, understanding language, social interactions 

Prefrontal Cortex

area of frontal lobe, just behind the eyes + forehead, involved in executive functions of planning, self-awareness, and responsibility 

Corpus Callosum

broad band of white, myelinated fibres connecting the left and right cerebral hemispheres, allowing the two hemispheres to communicate with each other 

Lateralization

the localization of a function in either the right or left cerebral hemisphere 

Aphasia

the loss of ability to understand speech or produce it 

Neural Plasticity

the ability of neurons to modify their structure and function in response to experiential factors of injury

Dominant Gene

a gene that, when present, will produce a particular characteristic 

Recessive Gene

a gene whose characteristic will be masked by a corresponding dominant gene; its characteristic will be expressed if the correspondent gene is also recessive, can still be passed onto offspring

Polygenic Transmission

a number of genes working together to create a particular phenotypic characteristic

Epigenetics

lasting changes in gene function caused by external or environmental factors without a change to the gene itself 

Concordance

the likelihood that two people share a particular characteristic 

Adoption Study

research method in behaviour genetics in which adopted people are compared on some characteristic with both their biological and adoptive parents in an attempt to determine how strong a genetic component the characteristic might have, questions nature vs. nurture

Twin Studies

a behaviour genetics method in which identical (monozygotic) and fraternal (dizygotic) twins are compared on some characteristic; this method is particularly informative if the twins have been raised in different environments