NeuroSci 1
Terms
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- ontogonic approach
- developmental approach to understanding Brain/Behavior relationships (individual represents evolution of species) development of the human nervous system mimics evolutionary development
- Evolutionary Approach
- how is a structure similar of different to other species and how does this relate to differences in behavior
- philosophical approaches: Mind/Body Problem
- descartes: mind body probelm after disceting a human body how does eternal soul influence deterrorating structure
- Neruoscientists are Materialist
- the view that everything exists is physical and therefore knowable
- lesion studies
- damage to the brain: injury involving a brain part is a loss of that function
- ESB: Electrical Stimulation of the Brain
- Wilder Penfield activating electrical impulses to promote its function
- Pharmologically/ knockout
- inducing a chemical to see the chemical component involved in the brain functioning
- Imaging Tech: PET Scan
- Positron Emmission Therapy: a radio active substance is injected and detects around the brain can identify those regions with the highest radio activity (better at detecting lack of activity)
- Imaging tech: MRI
- magnetic resonance imaging: measures changes in plasma hemoglobin as they release oxygen can detect those brain areas with oxygen: can detect areas that are highlighted in the brain acording to cues
- Genes
- defined as units of heredity that maintain sturctural identity from one generation to another can know gene sequences but not functions yet genes represent expression of proteins
- chromosomes
- 23 pairs in humans deoxyribonucleic acid: sugar (deoxyribo) four flavors: aderyine guanine thymine cytosine
- enzymes
- proteins that regulate the activity of chemical reactions (-ase is always an enzyme)
- phenotype v genotype
- pheno: mainfestation of genetic expression geno: specifeic genes available for expression
- Soma
- cell body neculous genetic info
- dedrites
- spindle threads out of soma other neurons connect here
- axon
- long, carries electrical signals from the soma to the boutons
- terminal boutons
- specialized spot between receiving cell and fiving cell
- multi polar
- all directions off of soma
- Bipolar
- dedrites one side axon other
- unipolar
- dendrite and axon come out same side
- neuron doctrine
- Santiago and Golgi: Santi all neurons would stain if connected, chem transmission(unitary hypothesis). neurons are unitary and comm each other across synapse. golgi: reticular hypothesis continuous transmission belief of shared membrane (cytoplasm) electrical transmission
- glia
- neuroglia= nerve glue. three types asrocytes microglia oligodendrocytes(Cns)/Schwann cells(pns)
- Astrocytes
- have multiple end feet some contact blood vessels some contact neurons hold neuron in place control chem environment surrounding nourishes
- Microglia
- smallest glia cells perfrom phagocytosis principle immune system component
- Oligodendroglia
- wrap axon in asheath of myelin, wrap multiple axons found in cns schwann: wrap only single axon cell, in pns
- myelination
- increase the speed of comm saltatory conduction not all neurons are myelinated myelin is destroyed in MS
- BBB Blood Brain Barrier
- blood vessels throughout the body are leaky capillaries in the brain have specialized structures, astrocytic \"end feet\" and capillary \"tight junctions\"
- flow within a neuron is... flow between axons are...
- electrical axons: chemical
- (Resting)Membrane Potential
- charge differential across membrane (is when at rest). charge comes from ionic concentrations
- Equilibrium Potential
- the membrane voltage (difference in electrical potential) between the inside and outside of neurons at this point for that ion
- Equilibrium
- If the concentration gradient and the electrostatic gradient for a particular ion species are at equal strength and are pushing on opposite sides of the membrane the ions are at this
- nernst equation
- For any given ion you can figure out the voltage of the membrane at which the concentration gradient and the electrical gradient will be equal and opposite
- Sodium Potassium Pump
- moves three Na+ ions out and two K+ ions in, requires energy (ATP)
- tetrodotoxin
- Na+ inner channel blocker (elicites subthreshold)
- tetraethyl ammonium
- K+ outward current blocker
- Saltatory Conduction
- nodes of ranvier only place for escape (last longer larger change farther away)
- Synapses 3types:
- axon to soma: axosomatic axon to dendrite: axodendritic axon to axon: axoaxonic
- First Discovered NT
- Acetycholine
- Temporal Summation v Spatial Summation
- temp: one firing enough to elicite ap spatial: many imputs fire simultaneously
- receptor
- proteins on the cell surface that recognize specific neurotransmitters leading to postsynaptic response
- law of dynamic polarization
- communication goes one way dendrite, soma, axon
- EPSP
- Excitatory postsynaptic potential: depolarization, influx of Na+ (Ca++), glutamate (acetylcholine)increases likelihood of postsynaptic firing
- IPSP
- Inhibitory postsynaptic potential: decreases likelihood of firing, efflux of K+, hyperpolarization, GABA
- Metabotropic
- ex. Dopamine, Serotonin 2nd messenger signaling, slow (no immediate change that tells you what is happening)
- Ionotropic Effects (on postsynaptic neuron)
- fast, uses ipsp (gaba-chloride)and epsp (glutamate-sodium), regulated by a ligand selective to one or more ions
- Metabotropic Process
- NT binds to receptor, g-protein breaks off, activates adenalate cyclase increased levels, activates cyclic AMP, levels activate protein Kinase A
- Snare
- a.p. comes in activates ca++ channels activates Ca++ sensor (synaptotagim) changes shape of V-Snare (synaptobreun) proximity to T-Snare (syntaxin)hook and bind and dump NT (exocytosis)
- Snare clear away NT
- 1. reuptake 2. enzymatic degragation 3. diffusion
- Agonist
- mimics effects of a NT 1. Direct- bind to receptor, produce same effect 2. Indirect-doesn\'t bind, may just block it increases effect of NT
- Antagonist
- prevents/blocks effects of a NT
- Homeostasis
- the tendency for a biological process to be maintained with certain parameters
- Negative Feedback
- represents an ability to reduce excitability or NT release in response to overexcitability (autoreceptors)
- 3 Autoreceptors
- 1 NT decreases release (Ca++ channel blocked) 2 neruonal excitability decreases (Na+ channel blocked) 3. NT syntesis decreases
- Summation Process
- cumulative effects of input across dendritic tree may result in a suprathreshold membrane potential at the initial segment of athe axon
- Small Molecule Transmitter: Acetylecholine (ACh)
- involved in muscle contraction and regulation of the heart rate and respiration in the PNS and learning and memory in CNS does by depolarization implicated in Alzheimers Disease and Myasthenia Gravis Metabolized by acetylcholineste nicotine mimics NT in direct (Na+ ionotropic) muscanic (in shrooms) metabotropic
- Small Molecule Transmitter: Norepenephrine (NE)
- chemically realted to adrenaline, involved in arousal and attention, linked to activation of CNS, located in the Locus Coeruleus implicated in depresssion, metabolized by COMT and MAO
- Small Molecule Transmitter: Dopamine (DA)
- involved in intiation and control of voluntary movement motivation and reinfocement, located in the SUbstantia Nigra and Ventral Tegmental Area (midbrain), implicated in Parkinson\'s Disease, Schizophrenia, and Drug Addiction, L-Dopa sythetic precurser to dopamine-crosses BBB treats symptoms not disease, affects frontal lobe innervoice working memory, metabolized by COMT and MAO
- Small Molecule Transmitter: Serotonin (5-HT)
- regulation of mood appetitte aggression and impulse control, located in Raphe Nucleous (hindbrain), implicated in a lot of things but totally responsible for nothing- bulemia obesity depression bipolar, synthetic precurser is dietary tryptophan, SSRI\'s not associated with alot of adverse sideffects, LSD
- Small Molecule Transmitter: GABA
- primary inhibitory transmitter in the brain, promotes sedation, implicated in anxiety elilepsy and alcholism, too little GABA leads to seizures, benzodiazepine (ex. valium)
- Small Molecule Transmitter: Glutamate
- primary excitatory transmitter in brain, involved in learning and memory, implicated in epilepsy and neruotoxicity (hemmorage and stroke-due to max levels of Ca++), too much leads to seizures
- Peptides: Endoenous Opiates
- pain regulation, euphoric properties of heroin and morephine
- Gases: Nitric Oxide
- not released via synaptic vessicle, modulates response of neurons to other transmitters
- CNS Depressants
- disorientation impaired memory and judgment sleep death, facilitation of GABA receptor or lipid membrane, barbituates: phenobarbitol, alcohol, general anesthetic (gasses lipophilic), antianxiety agents (Diazepam)
- Psychomotor Stimulants
- increased arousal, psychomotor agitation, sleep disruptions, paranoi, hallucinations, and sizures, mechanisms include increased DA, cocaine, amphetamine and derivatives, caffine, nicotine, adenosine atnagonist (sleepyness, sedation)
- Mood Stabalizers
- Lithium- Bipolar, compliance problems don\'t want to loose manic stages
- anti-depressants
- MAO inhibitors- prevents metabolism of DA NE and 5-HT, TRicyclic Anti Depressants, Atypical Antidepresants- Zoloft
- Narcotic Analgesics
- Produces analgesia euphoria depressed respiration and nausea, mechanism of action includes modulation of nocicepton via activation of opiate receptors and subsequent modualtion of substance P 5-HT and NE ex. Morephine and Heroin Naltrexane (for oding)
- Anti psychotic Drugs
- decrease psychotic symptoms but with sedation and motor side effects blockaed of DA receptors is related to both the therapeutic efficacy and side effects, 1. Traquilizers 2. Neruoleptics (1 & 2 have adverse side effects on motor) 3. Atypical Anitpsychotics
- Psychedelic & Hallucinagenic Drugs
- 1. Anti-Cholinergic: Atropine, 2. Noradreneergic: Mescaline 3. Serotonergic: LSD, psilocybin 4. Anti- Glutamatergic: PCP, Ketanin (MDMA receptor antagonist) -affects CNS learning memory used in surgeries 5. THC marijuana
- hindbrain
- regulates basic motor functions, most primitive, first to develop in womb
- medulla oblongota
- respiration heart rate blood pressure
- pons
- axons cross from one side of the brain to the other, location of cranial nerves, connects with thalmus so you don\'t act out your dreams
- pariacquaductal Gray
- involved in processing of pain stimuli and relevant learned associates
- Raphe Nucleus
- involved in mood aggression and impuls control and contains NT serotonin
- Locus Coeruleus
- makes and releases NE, transmits info from the reticular formation to the rest of the brain via NT NE
- reticular formation
- a network of neurons threaded throught the hindbrain that relates function to arousal and attention
- Bell-Megendie Law
- the entering dorsal roots of the spinal cord carry sensory info in tot he brain the exititng venural roots carry motor info to muscles and glands
- Midbrain
- translates motor sensory info into action
- substantia nigra
- intiation of movement, death of these in parkinson\'s
- ventral tegmental area
- dopamine containing neurons involved in substance abuse
- tectum
- inferriof and superriof colliculi visual and audtiory attention respectively (extension of thalmus)
- thalmus
- the relay of sensory (except smell) info to and from cortex provide meaning to senses experience
- basal ganglia
- caudate putamen and globus pallidus initiation and control of voluntary movements (caudate aka dorsal straitum receives DA and is involved in PD degeneration linked to Huntington\'s Disease
- Limbic system
- motivation and emotion: hippocampus, amygdala, nucleous, accumbens, cingulate cortex
- Hippocampus
- learning and memory (new) ongoing events
- amygdala
- involved in emotional expression particularly to prior experience
- Nucleous Accumbens
- ventral straitum, behavioral activation and reinforcement learning receives DA and is implicated in addiction
- cingulate cortex
- links events to emotional behavior- frontal labotomy detect conflicts make sure youre operating according to super ordinate goals
- cuts: Sagital Plane coronal plane Horizontal plane
- Sag: disects into right and left corona: front and back horizon: upper and lower
- Nuraxis
- an imaginary line used and drawn through the center of the CNS between the front of the forebrain and bottom of the spinal cord locals described in relation to it
- stage 7: 15-17 Days
- specialties develop: sensitivity to environment neural development starts
- stage 10: 21-23 days
- entire development of nervous system is complete
- 16 days
- development beginning: neural plate- bunch of cells one cell thick one layer thicker towards middle, neural groove now has folded together => neural fold-> forming a tube->neural tube
- 24 Days
- neural crest cells will make up all the nervous cells in your system neural system neural system complete now will just get bigger add more cells
- Neural Tube Defects: Anencephaly Hyrdoencephaly Spina Bifida Encphealorde
- Anen: Brain does not develop Hydro: water brain Spina B: spinal fluid blocks bone development Encephea: tumor in back of head (=to spina b)
- founder cells
- divide and lead to cells of CNS
- symmetrical division
- (mitosis) division of founder cells => 2 identical founder cells
- asymmetrical division
- division of founder cell into a founder cell and a neuron
- apoptosis (falling away)
- a death of a cell caused by a chemical signal that actiates a genetic mech inside the cell aka \"programmed cell death\"
- Radial Glia
- special glia with fibers that protrude radially from the ventrical zone out to the cortex
- Fovea
- directly center back of you eyeball, central vision, different cells around area, veins don\'t cross it
- Optic Nerve
- Blind Spot
- Rods
- highly sensitive to light, 1 kind of photorecptor within them, only use at night/dimlight, absent at fovea
- cones
- 3 kinds of photorecptors provide for color vision, high concentration at fovea
- receptive field
- that portion of the visual field that derives the response of that cell not as high visual equity in perirphery
- Object Recognition
- takes place in inferior temporal cortex responses of cell in this area are \"tuned\" for complex objects: responses highest to actual objects, also face recognition very developed
- Visual Agnosia
- damage to particualr brain structure processing sp. type of visual processing
- Apperceptive visual agnosia
- inability to recognize objects
- Prosopagnosia
- lesion to a part of the inferotemporal cortex leads to an inability to recongnize faces
- akinetopsia
- inability to recognize movement
- vision: Dorsal Stream Ventral Stream
- Where? What?