Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
FOUNDATIONS OF SI
NEUROSCIENCE
| Term | Definition | Definition 2 |
|---|---|---|
| COMPONENTS OF THE NEURON | ● Soma or Cell Body ● Dendrites ● Axon ● Myelin Sheath ● Schwann cells | |
| Soma or Cell Body | ○ Where the nucleus of the cell is and where the main processing happens | |
| Dendrites | ○ Responsible for reaching out and making connections with other neurons | |
| Axon | ○ Long projections out of the cell body, responsible for propagating action potential | |
| Myelin Sheath | ○ Wraps around the axon | |
| Schwann cells | - produce myelin | |
| Gray Matter | A general term for neuronal cell bodies in the CNS; the cut surface of the brain appears gray at these sites | |
| Cortex | Thin sheets of neurons, usually at the brain surface and most often used in reference to the cerebral cortex, but there are other examples | |
| Nucleus | A clearly defined mass of neurons, usually fairly large and deeply placed in the brain | |
| Locus | Clearly defined groups of neurons, but smaller than a nucleus | |
| Substantia | A less well-defined group of neurons | |
| Ganglion | Applied to collections of neuros in the PNS | |
| White Matter | A general term for axon groups in the CNS; the cut surface of the brain appears white at these sites | |
| Tract | A collection of axons with a common origin and a common destination | |
| Capsule | A group of axons connecting the cerebrum and brain stem | |
| Commissure | A collection of axons connecting one side of the brain to the other | |
| Lemniscus | A "ribbon-like" tract | |
| Nerve | A bundle of axons in the PNS | |
| cell membranes of neurons | _________________ are able to transmit an electrical impulse, the action potential, along the length of the axon | |
| protein channels | This is possible because the cell membrane contains ______________ that allow ions to pass in and out of the neuron – changing its electrical charge | |
| action potential | When the electrical charge reaches a specific threshold, an _____________ is initiated and runs down the axon, causing the neuron to communicate with other neurons or with muscle tissue | |
| THE ACTION POTENTIAL | ● - 70 mV at resting state ● Stimulus increases the voltage, making it less negative ● Voltage has to reach -55 to reach the threshold where it will actually fire to create action potential | |
| THE ACTION POTENTIAL ● Hyperpolarization | - around 1 millisecond where a new action potential cannot happen | |
| Synapse | is the communication point between one neuron and another, or between neuron and muscle | |
| Action potential | causes the release of a neurotransmitter at synaptic cleft | |
| neurotransmitter | The _____________ has either an excitatory or inhibitory effect on the post-synaptic neuron (if it synapses on muscle, it’s always excitatory) | |
| Excitatory: | causes the electrical charge of the post-synaptic neuron to be MORE likely to reach a threshold for synaptic transmission – an EPSP occurs | |
| Inhibitory: | causes the electrical charge of the post-synaptic neuron to be LESS likely to reach a threshold for synaptic transmission – an IPSP occurs | |
| Neuron | receive multiple “messages” from other neurons; the EPSPs and IPSPs are summed to determine whether an action potential is reached | |
| Spatial: | action potential is reached due to simultaneous messages from other neurons | |
| Temporal: | action potential is gradually reached with repetition over time of messages from other neurons | |
| Temporal | Number of pre-synpatic neurons: One Time delay: Yes Effect on post-synaptic neuron: Action potential | |
| Spatial | Number of pre-synpatic neurons: Multiple Time delay: No Effect on post-synaptic neuron: Action potential | |
| CONVERGENCE OF NEURONS | ● Axons from a number of different neurons terminate on the same neuron ● Information from different sources converge on a single neuron ● Converging inputs change membrane potential and can facilitate or inhibit an action potential | ● Often seen in sensory systems ● Allows for localization of sensory inputs as well as sensory integration (within a single sensory system or across multiple sensory systems) |
| DIVERGENCE OF NEURONS | ● One neuron’s axon has terminal endings that terminate on many other neurons ● May promote or inhibit action potential of the neurons receiving the inputs | ● Can lead to fine sensory discrimination, or can lead to spreading of information to different parts of the CNS |
| SPEED OF CONDUCTION is influenced by: | ● Axon diameter: Larger => Faster ● Amount of myelin: More => Faster ● Myelin | |
| Myelin | = sheath of fat and protein that is wrapped around axon at intervals | |
| Classified by axon diameter, from largest to smallest: ● Cutaneous (tactile) | ○ A-beta (90 m/sec) ○ A-delta (45 m/sec) ○ C (non-myelinated, 2 m/sec) | |
| Classified by axon diameter, from largest to smallest: ● Proprioceptive | – the fastest conducting ○ Ia (130 m/sec) ■ We need very rapid adjustments to keep up with our changing environment ○ Ib (120 m/sec) ○ II (90 m/sec) | |
| Neurotransmitter: | chemical that is released by a presynaptic neuron and acts directly on the postsynaptic neuron | |
| Neuromodulator: | chemical released into extracellular fluid that adjusts the activity of many neurons | |
| NEUROTRANSMITTERS | ● Acetylcholine ● Amino Acids ● Amines ● Peptides ● Gases | |
| ACETYLCHOLINE (Ach) | ● Primary PNS neurotransmitter ○ Sometimes active in the CNS as well ○ Proprioceptive input - we get from acetycholine getting muscle to contract ● Released into synapse at muscle | ● Muscle tissue has ACh receptors ○ Muscle contraction ● Signals muscle contraction (excitatory) ● Cholinergic |
| AMINO ACIDS ● Glutamate | ○ Major excitatory neurotransmitter in CNS ○ Fast acting | |
| AMINO ACIDS ● Gamma-aminobutyric acid (GABA) | ○ Major inhibitory neurotransmitter, fast acting ○ In CNS, especially at interneurons in spinal cord | |
| AMINO ACIDS ● Glycine | ○ Inhibitory in brainstem and spinal cord | |
| AMINES | ● Derived from amino acids ● Slow acting neurotransmitters and modulators ● Produced in brainstem with wide areas of projection throughout cerebrum ● Include dopamine, norepinephrine, serotonin, histamine | |
| DOPAMINE | ● Produced in substantia nigra of midbrain ● Projects to basal ganglia, cortex, limbic system ● Parkinson’s disease: too little ● Schizophrenia: too much (among other things) ○ Note: some controversy about this ● Reward and pleasure pathways | |
| DOPAMINE SI importance: | provides intrinsic motivation | |
| NOREPINEPHRINE (NE) | ● Produced in reticular formation of brainstem, hypothalamus, and thalamus ● Widespread projection throughout CNS ● Also produced by neurons in autonomic nervous system and secreted by adrenal glands | ● Major influence on attention and vigilance, fight/flight reaction |
| NOREPINEPHRINE (NE) SI importance: | Arousal levels and modulation | |
| SEROTONIN | ● Fluctuates with sleep and wake cycles (low in sleep, high when awake) ● Affects mood and pain perception ● Contributes to arousal modulation ● Low levels associated with depression | ● Many medications block serotonin reuptake, so that it remains in synapses longer (SSRIs) |
| Peptides | ● Large molecules ● Function as hormones, neurotransmitters, or neuromodulators ● Several types ○ Substance P ○ Opioids | |
| Substance P | related to pain transmission | |
| Opioids | endorphins and enkephalins, which inhibit neurons involved in pain perception | |
| Neurons | receive multiple signals from other neurons; the EPSPs and IPSPs are summed to determine whether an action potential initiates | |
| Temporal: | action potential is gradually reached with repetition over time of messages from other neurons. | |
| Spatial: | action potential is reached due to simultaneous messages from other neurons. | |
| NEUROPLASTICITY | ability of the nervous system to respond to intrinsic and extrinsic stimuli by reorganizing its structure, function, and connections | |
| NEUROPLASTICITY ● Can be described at many levels: | molecular, cellular, neural systems, or behavior ○ Our brain is consistently changing from internal and external stimuli | |
| Molecular | - neurons may start to increase amount of neurotransmitters that they produce | |
| Cellular | - neurons produce more dendrites and make more synaptic connections | |
| Neural systems | - more patterns of neural firing more frequently | |
| Behavior | - Habitual and easy doing of tasks | |
| NEUROPLASTICITY ● Occurs during | development, in response to the environment, in support of learning, in response to disease, or in relation to therapy | |
| EARLY EVIDENCE FOR NEUROPLASTICITY ● Long Term Potentiation: | with repeated stimulation of a synapse, new dendritic spines and new synapse forms; | |
| EARLY EVIDENCE FOR NEUROPLASTICITY ● Habituation at a cellular level: | with repeated stimulus, reduced amount of neurotransmitter is released, and number of receptors decreases | |
| EARLY EVIDENCE FOR NEUROPLASTICITY ● Effects of enriched environments: | increased dendritic branching, more synapses per neuron, heavier and larger brain | |
| Central nervous system (CNS): | Neural tissue that is encased with the skull or within the vertebral column; includes brain and spinal cord | |
| Peripheral nervous system (PNS): | Neural tissue that is outside of the brain or vertebral column | |
| Central nervous system (CNS): | ● Brain and spinal cord ● Integrative and control centers | |
| Peripheral nervous system (PNS): | ● Cranial nerves and spinal nerves ● Communication lines between the CNS and the rest of the body | |
| Sensory (afferent) division: | ● Somatic and visceral sensory nerve fibers ● Conducts impulses from receptors to the CNS | |
| Motor (efferent) division: | ● Motor nerve fibers ● Conducts impulses from the CNS to effectors (muscles and glands) | |
| Autonomic nervous system | ● Visceral motor (involuntary) ● Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands | |
| Somatic nervous system | ● Somatic motor (voluntary) ● Conducts impulses from the CNS to skeletal muscles | |
| Sympathetic division | ● Mobilizes body systems during the activity | |
| Parasympathetic division | ● Conserves energy ● Promotes 'housekeeping" functions during rest | |
| GRAY MATTER | ● Areas of the CNS made up mainly of neuron cell bodies | |
| WHITE MATTER | ● Areas of the CNS made up of myelinated axons | |
| In PNS, white matter are | “tracts” | |
| In PNS, gray matter is | ?? | |
| SPINAL CORD | ● Contains afferent (ascending) sensory tracts ● And efferent (descending) motor tracts ● Coordinates simple reflexes of the extremities and trunk | |
| White matter outside: | Axons (nerve fibers) within pathways carrying sensory information up to the brain and pathways carrying motor commands down from the brain to peripheral nerves | |
| Gray matter inside: | Sensory and motor neuron cell bodies, glial cells (which support the health of neurons), and small fibers exiting to white matter | |
| Three sets of columns of white matter form the outer part of the spinal cord: | 1. Dorsal (posterior) columns 2. Lateral columns 3. Ventral (anterior) columns | |
| Dorsal (posterior) columns | ● Only sensory information | |
| Lateral columns | ● Sensory and motor pathways | |
| Ventral (anterior) columns | ● Mostly motor pathways, some sensory | |
| THE ANATOMICAL ORGANIZATION OF EACH MAJOR SENSORY OR MOTOR SYSTEM FOLLOWS 4 PRINCIPLES: | 1. Each system contains relay centers 2. Each system is composed of several distinct pathways 3. Each pathway is topographically organized 4. Most pathways cross the body’s midline | |
| Autonomic Nervous System | ● Involuntary regulation of visceral body functions ● Sympathetic and Parasympathetic components ● Conducts information related to the gut microbiome and interoception ● Under central control of the hypothalamus ● Strong influence of limbic system | |
| Involuntary regulation of visceral body functions | ○ Maintains homeostasis ○ Regulates circulation, respiration, digestion, metabolism, secretions, body temperature, and reproduction ○ Works closely with brainstem | |
| Sympathetic and Parasympathetic components | ○ Opposing actions are balanced to provide optimal organ function ○ Sympathetic - fight or flight ○ Parasympathetic - rest and ? ○ It’s not one or the other, they are both active | |
| Conducts information related to the gut microbiome and interoception | ○ Knowing when to go to the toilet, knowing if you’re full | |
| Sympathetic Nervous System | ● Adrenal medulla secretes epinephrine and norepinephrine ● Fight or Flight response | |
| Fight or Flight response: | ○ Pupils dilate ○ Heart rate rapid and blood pressure increases ○ Bronchi dilate ○ Blood vessels to muscles dilate ○ Blood vessels to skin constrict ○ Increased sweat (e.g., on palms) | ○ Hairs erect ○ Thicker saliva dry mouth ○ Blood flow to gut inhibited ○ Decreased peristalsis |
| Parasympathetic Nervous System | ● “Rest and Digest” | |
| Rest and Digest: | ○ Pupils constrict ○ Increased salivation ○ Reduced heart rate ○ Reduced respiratory rate ○ Constricts bronchioles ○ Increased esophageal peristalsis ○ Increased digestive secretion ○ Increased intestinal activity | |
| BRAINSTEM | ● Major sensory and motor pathways run through brainstem ● Contains major centers | |
| BRAINSTEM ● Contains major centers for: | ○ control of vital functions (breathing, eating) ○ background regulation of arousal (e.g., sleep-wake cycles) ○ sensory and motor functions of the face and head ○ balance and equilibrium | |
| Brainstem: Medulla | ● Cardiovascular and respiratory regulation ● Swallowing ● Some aspects of oral control for speech ● Head movement and some aspects of balance ● Visceral activity, especially gastrointestinal | |
| Brainstem: Pons | ● Tactile discrimination and pain sensations for face, mouth, tongue, and jaw muscles ● Taste ● Control of muscles of facial expression | ● Stable visual field in response to head movement ● Postural control and equilibrium ● Relay of vestibular and proprioceptive information to cerebellum |
| Brainstem: Midbrain | ● Orienting and alerting response to visual stimuli, especially in peripheral vision ● Orienting and alerting response to auditory stimuli ● Control of eyeball and eyelid movements ● Pupillary light reflex ● Proprioception of face and jaw muscles | |
| Cerebellum | ● Regulates and refines distal limb movements and postural control ● Indirect regulation of movement ● No direct output to spinal cord ● Lesions produce ipsilateral deficits | ● Lesions affect postural control or distal motor control, due to loss of accuracy and precise coordination of movements |
| Cerebellum ● Does this by: | ○ Receiving unconscious proprioceptive messages during action ○ Comparing these sensations to the intended movement, i.e., the motor command | ○ Then sending messages to the motor command centers of the cerebral cortex in order to adjust and refine the intended movement |
| Thalamus | ● Major structure in central area of brain called diencephalon | |
| Thalamus ● Major Functions: | ○ Receives and organizes all somatosensory and some vestibular information, then relays it to cerebral cortex – contributes to discrimination and perception | ○ Receives and organizes regulatory motor messages from cerebellum and basal ganglia, then relays them to cerebral cortex |
| Basal Ganglia | ● Regulates voluntary movement (indirectly) through inhibitory messages (“braking”) ○ But no direct afferent or efferent connections to the spinal cord ● Influences executive functions, motivation, and emotion | |
| Basal Ganglia ● Major Structures: | ○ Caudate ○ Putamen ○ Globus Pallidus ○ Subthalamic Nucleus ○ Substantia Nigra | |
| Basal Ganglia ● An interrelated network that communicates with: | ○ Thalamus ○ Motor areas of cerebral cortex | |
| BILATERAL PROCESSING IN THE BRAIN: CINGULATE GYRUS | ● Most activities require participation of two sides of the body ● This requires information to be relayed across the midline of the brain ● Bilateral integration is essential for bilateral motor tasks | |
| Limbic System | ● Interrelated network that connects with basal ganglia, hypothalamus, cerebral cortex, autonomic system, and HPA axis | |
| Limbic System ● Key structures | ○ Amygdala ○ Hippocampus | |
| Amygdala: | strong emotion and arousal (anger, aggression, anxiety, fear, sexuality), olfaction, plays role in addiction | |
| Hippocampus: | memory (especially long-term), regulation of emotion (inhibitory influence on amygdala) ■ Important for learning how to respond to different stimuli and associating specific stimuli with strong emotions | |
| Hypothalamus | ● Loose collection of nuclei and associated fiber paths in the diencephalon ● Interacts with autonomic nervous system, endocrine system, and motivation and drive behaviors | |
| Hypothalamus ● Major role in homeostasis | ○ Blood pressure and electrolyte absorption ○ Regulates body temperature ○ Regulates reproduction by endocrine control ○ Controls emergency response to stress by regulating blood flow | |
| HPA Axis | - Eliciting stress response that releases cortisol in our bodies ○ Sensory input can directly affect stress response | |
| Cerebral Cortex | ● Refined processing of somatosensory, visual, and auditory information for perception and planning ● Planned movement (as response to sensory | |
| Somatosensory | → Parietal lobe | |
| Auditory | → Temporal lobe | |
| Visual | → Occipital lobe | |
| Primary motor cortex (frontal lobe) | → specific motor commands | |
| Anterior portions of frontal lobe | → ideation and planning of action (praxis) | |
| Ideation | - Thinking of ideas of what to die, happens before making motor plan | |
| Parietal Lobe | ● Primary somatosensory cortex ● Secondary somatosensory cortex ● Parietal association areas | |
| Primary somatosensory cortex | ○ Receives somatosensory input from the body ○ Somatotopic organization: the sensory homunculus ○ Projects to multiple areas involved in motor control ○ S1 (?) | |
| Secondary somatosensory cortex | ○ Integrates information from multiple somatosensory sources ■ Provides basis for body schema and environmental awareness (body position) ■ Prop, tactile, etc. Gotten from the thalamus ● Parietal association areas | |
| Parietal association areas | ○ Integrate somatosensory with information from other sensory systems ■ Receives information from the occipital lobe (dorsal stream) to use in locating objectsand visually guiding action | |
| Homonculus | pic | |
| Occipital Lobe | ● Primary visual cortex receives visual sensations ● Location of primary visual information including color, recognition of motion, and distinguishing objects from background | ● Dorsal Stream: provides info to the parietal lobe to use in locating objects and forming visual perception ● Ventral Stream: provides information to temporal lobe for recognition and naming objects, faces, food, etc. |
| Secondary visual cortex | integrates visual details for perception (shape, form, distinguishing objects from each other and from background, depth perception) | |
| Visual association areas | integrate visual with other sensory information | |
| White matter pathways | bring visual input to other areas | |
| Dorsal stream | provides information to the parietal lobe to use in locating objects and guiding actions, especially with hands | |
| Ventral stream | provides information to temporal lobe for recognition and naming objects and things | |
| Temporal Lobe | ● Primary auditory cortex receives auditory sensations ● Secondary auditory areas integrate auditory sensations ● Association areas receive information from the occipital lobe for recognition of visual images and giving words to objects, faces, etc. | |
| Wernicke’s area | is specialized for integration of sounds for perception of speech and comprehension of language. | |
| Individuals with Wernicke’s aphasia | (due to a stroke affecting Wernicke’s area) may have fluent speech, but communication is affected because comprehension is impaired. These individuals often have difficulty naming objects. | |
| Frontal Lobe | ● Primary Motor Cortex ● Premotor and Supplementary Cortex ● Prefrontal Cortex | |
| Primary Motor Cortex | ○ Sends motor commands down the spinal cord to activate muscles ○ Neurons are arranged somatotopically in a motor homunculus | ○ Motor commands are influenced through communication with somatosensory cortex, basal ganglia, and cerebellum ○ Integrates all input before sending out to motor signal to body |
| Premotor and Supplementary Cortex | ○ Activation of movement patterns ○ Participates in planning, organizing, and executing complex bilateral movements | |
| Prefrontal Cortex | ○ Associated with ideation and anticipation of outcomes of actions ○ Supports strategic planning and regulation of responses (impulse control) ○ Broca’s area is specialized for production of speech | |
| Brodmann Numbers | ● 52 areas differentiated by variations in the cell layers ofthe cerebral cortex | |
| Brodmann Numbers ● Primary areas | ○ Motor 4, sensory 3-1-2, ○ auditory 41 and 42, visual 17 | |
| Brodmann Numbers ● Secondary association areas | ○ Motor 6 ○ Broca’s area for producing speech 44 ○ Wernicke’s area for comprehending spoken language 22 | |
| Brodmann Numbers ● Tertiary association areas | ○ Prefrontal, parietal association areas, temporal association areas | |
| Commissural Fibers: Corpus Collosum | pic | |
| Most Cognitive Processes Require Cross-Cortical Connections ● To hear and comprehend: | ○ Primary Auditory Cortex receives auditory input, then forwards the message to nearby association cortex: Wernicke’s area | |
| Most Cognitive Processes Require Cross-Cortical Connections ● To repeat the word: | ○ Wernicke’s area forwards the message to Broca’s area via the arcuate fasciculus ○ Broca’s area plans the speech action and relays the motor plan to Primary Motor Cortex (area 4) | ○ Area 4 sends motor commands to activate oral musculature to produce sequences of speech sounds |
| Lateralization and Specialization of Function | ● Both right and left hemispheres work together, one more dominant for each function | |
| For about 90% of the population, the left hemisphere specializes in: | ○ Language ○ Sequencing of movements ○ Detailed analytical abilities | ○ For most people with left hemisphere language specialization, the left hemisphere also specializes in hand skill (right-handedness) |
| For most people the hemisphere that does not specialize in language is specialized for: | ○ Emotional components of language (prosody) ■ Tone of voice, affect (temporal lobe) ○ Complex spatial orientation and detailed perception (including tactile, visual-spatial) | ○ Getting the big picture (“gestalt” processing) ■ We don’t perceive individual details, we recognize face as a whole ○ Recognition of faces |
Created by:
avemaria