Exam 1 Anatomy Peripheral Nervous system sensory neurons motor neuron axons o Nerves sensory motor neuron axons Ganglia collections of neuronal cell bodies outside the CNS Functional and anatomical division of motor PNS into autonomic visceral and somatic divisions Central Nervous system Brain and Spinal Cord Various neuroatomical directions Dorsal top part Ventral bottom part Rostral towards top of the front head Caudal tail Superior top Inferior bottom Posterior backwards Anterior forward Planes of section Horizontal Saggital Coronal Lateral section is away from midline Medial section is close to midline Medial Sagittal Section Brainstem respiratory centers control of movement o Pons medulla midbrain Cerebellum control of fine movement Diencephalon o Thalamus sensory information processing o Hypothalamus hormonal control Corpus callosum anterior commissure o Tracts of white matter linking the cerebral hemispheres Cerebral cortex cerebral hemispheres Cortical lobes Occipital lobe vision Parietal lobe somatosensation Frontal lobe motor planning Temporal lobe hearing Coronal Sections Basal ganglia motor planning o Caudate o Putamen o Globus pallidus Grey matter of cerebral cortex rind Tracts of white matter neuron axons sending information to from the cortex Hippocampus memory Thalamus sensory information processing Amygdala emotional balance Ventricles spaces containing cushioning cerebrospinal fluid Knee Jerk Response Reflex hammer tap stretches tendon stretches sensory receptor in leg excites motor neuron in spinal cord interneuron in spinal cord interneuron inhibits motor neuron to flexor muscle flexor relaxes motor neuron synapses and excites extensor muscle extensor muscle contracts leg extends 3 neurons spinal interneurons sensory neurons motor neurons Action potential number of spikes firing rate Graded potential depolarization or hyperpolarization Comparison with computers A single neuron has a very slow rate of information output Since we are able to process information e g visual scenes as rapidly as most computers arrays of neurons in our brains must act as massively parallel processors of information Cytological stains for neurons Voltage senstitive dye used to measure firing activity when a neuron fires it Calcium imaging dye changes color depending on Ca concentration used to see changes membrane potential how much Ca is in the cell Nissel stains labels ER in neuronal cell bodies often shows up the division of parts of the CNS into layers due to differing cell density in each layer o Good for distinguishing tissues and layers within the NS but does not distinguish individual neuronal types well because it does not stain the axons and dendrite patterns Golgi stain randomly stains a few whole individual cells in a tissue entirely shows axon dendritic branching Fluorescent dyes Injection into cytoplasm or application onto membrane surface stains the whole of a particular cell useful after recording electrically from the cell through an intracellular micropipette Water soluble dyes used for injection into a neurons cytoplasm most cannot exit that cell o lipid soluble dyes placed on a neuron s membrane most cannot leave that cell s membrane GFP labeling good for tracing individual molecules and proteins Other Methods for labeling and staining neurons to show their structure and to distinguish different neuronal types Antibody labeling of proteins expressed only by a specific neuronal type Retrograde or orthograde transport of radiolabeled amino acids or fluorescent dyes along axons tracing of pathways of axons through the brain Non invasive methods for examining gross brain structure and function CT 3D Xray that rotates around patient s head anatomical does not detect function MRI detects energy emitted by spinning hydrogen nuclei in water molecules anatomical based off of distribution of water in different tissues NOT functional High resolution I e white matter has less water than gray matter CT and MRI are ANATOMICAL do NOT detect functional fMRI hemoglobin distorts MRI resonance properties of nearby H nuclei depending on whether it is loaded with oxygen or not shows active regions supplied with oxygen rich Hb takes awhile for it to show up SLOW Best resolution functional detects function PET scan incorporates unstable labeled positron atoms into molecules such as glucose and oxygen Detect emitted positrons with scanning detectors reconstruct location and density SLOW take seconds for uptake Poor resolution essentially replaced by fMRI Functional detects function fMRI and PET are both FUNCTIONAL however they are often too slow EEG detects electrical potential waves between points on scalp due to currents flowing through active brain tissues beneath Characterize gross functional state of brain seizures REM cycles fastest response to functional test Functional detects function SQUID MEG detects magnetic fields very rapid millisecond response to neuronal activity fastest response to functional test Temporal resolution as good as EEG Poor localization Functional detects function EEG and MEG are both FUNCTIONAL and FAST but have poor localizaiton 1873 Camillo Golgi The Golgi Stain a cytological stain that randomly stains whole individual neurons He came up w reticular theory all neurons are connected in the cytoplasm thru a neuron network 1906 Golgi Stain used extensively by Santiago Ramon y Cajal He came up w neuron doctrine that found that neurons are separate entities connected thru synapses used light microscopes and silver salts Charles Sherrington also promosed that neurons are individual entities in the nervous system no syncytium instead synapses between cells Cajal o Principal of dynamic polarization Information flows in a consistent way within each neuron From dendrites to the nerve axon terminal via the axon o Principal of Connectional Specificity No cytoplasmic connection between neurons Nerve cells do not form RANDOM networks Each cell makes precise connections with other neurons via synapses In general neurons have dendrites cell body axon synaptic terminal o Dendrites contain receptors for NTs or sensory receptor proteins o Axon terminal makes synaptic contact releases NTs onto dendrties of other neurons or onto muscle cells Ganglion cell retinal bipolar cell bipolar Retinal amacrine cell mesencephalic nucleus cells monopolar Cortical pyramidal cell cerebellar purkinje cell multipolar Where do neuroransmitters act on mesencephalic nucleus cells where do