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The Brain in Two Pages 91/10/15 13:55:02 THE_BRAIN_IN_TWO_PAGES 1 NEOCORTEX --muscle length (muscle spindles) 1) excitatory cells (spiny--long range axons) --force exerted by muscle (golgi tendon organs) --pyramidal (many subclasses) 2) dorsal root ganglion cells => spinal cord, dorsal column nuclei --spiny stellate (only in layer 4) 3) spinal cord (dorsal horn) 2) inhibitory cells (no spines--local axons) --spinocervical: spinal cord => lateral cervical nucleus --basket (large) --spinothalamic: spinal cord => posterior nuclei, intralaminar nuclei --chandelier (small, synapse on pyramidal axons’ initial seg) 4) spinal cord (ventral horn) --double bouquet (very small, vertical) --pattern generators --clutch (very small) --motor neurons (synapse on muscles) 3) layers of the cortex 5) dorsal column nuclei --layer 1 (feedback input layer) --cuneate nucleus (hand and upper body) => ventrobasal thalamus --layers 2/3 (feedforward cortical output layer) --gracile nucleus (foot and lower body) => ventrobasal thalamus --layer 4 (feedforward input) 6) principal sensory nucleus of the trigeminal (face) --layer 5 (descending output => striatum, SC, pontine nuc., spinal crd) --also => ventrobasal thalamus --layer 6 (feedback output layer) 7) ventrobasal thalamus (= VPL + VPM) --entire body reprensetation CEREBELLAR CORTEX --projects to cortical areas 3b, 1, and 2 1) input axons (excitatory) 8) intralaminar nuclei (in dorsal thalamus) --mossy fibers from many sources 9) cortical areas list --climbing fibers from inferior olive --3a, 3b, 1, 2, 5, 7b, S-II, Ig, VS 2) inhibitory --Purkinje (output cells => three deep cereb. nuc.) AUDITORY SYSTEM--MAMMALS --basket, Golgi, stellate 1) hair cells 3) excitatory --separate receptor cells synapse on distal end of ganglion cells --granule cells (give off parallel fibers) 2) cochlear ganglion cells 3) cochlear nuclei BASIC PARTS OF THE BRAIN --posterior ventral (PVCN; branched endings) 1) spinal cord --anterior ventral (AVCN; calyces of Held) --dorsal horn (sensory) --dorsal (DCN) --ventral horn (motor) 4) lateral superior olive (LSO) 2) medulla 5) medial superior olive (MSO) --lateral half (sensory) 6) dorsal and ventral periolivary nuclei --medial half (motor) 7) medial nucleus of the trapezoid body (MNTB) 3) pons 8) nuclei of lateral lemniscus --ditto --dorsal (nLLd) ------------------------------------------------------------------- --intermediate (nLLi) the pons-midbrain junction --ventral (nLLv) (relative to body: crossed above, uncrossed below) 9) inferior colliculus ------------------------------------------------------------------- --central nucleus (ICc) 4) midbrain --external nucleus (ICx) --tectum (’roof’: superior & inferior colliculus) --dorsal nucleus (ICd) --tegmentum (’floor’: red nucleus, substantia nigra, midbrain retic. fm.) --medial nucleus (ICm) 5) thalamus 10) medial geniculate complex --epithalamus (e.g., habenula) --dorsal anterior (MGDA) --dorsal thalamus (e.g., dLGN) --dorsal posterior (MGDP) --ventral thalamus (e.g., subthalamic nucleus) --principal (MGP) --hypothalamus --magnocellular (MGM--only non-tonotopic nucleus) 6) forebrain 11) cortical areas list --pallium (neocortex, hippocampus, amygdala) --A-I, RL, CM, paAlt, A-II, Tpt, T1, T2, T3 --septum --basal forebrain (caudate/putamen, globus pallidus) AUDITORY BRAINSTEM--OWLS 1) cochlear nuclei SOMATOSENSORY SYSTEM --nucleus angularis (NA; amplitude path--like mammalian PVCN) 1) receptors --nucleus magnocellularis (NM; time path--like mammalian AVCN) --specialized distal ends of dorsal root ganglion cells --there is nothing like DCN in birds --pain, cold, heat (free endings) 2) nucleus laminaris (NL; time path--like mammalian MSO) --slowly adapting touch (Merkel, Ruffini) --first binaural nucleus --rapidly adapting touch (Meissner, Pacinian) --detects interaural time differences; phase ambiguity 91/10/15 13:55:02 THE_BRAIN_IN_TWO_PAGES 2 3) nuclei of the lateral lemniscus (VLVA, VLVP) --reticulospinal 4) inferior colliculus --vestibulospinal --ICc core (time pathway--characteristic delay columns; input from NL) --rubrospinal (crossed) --ICc medial shell (amplitude pathway; input from VLVP) --corticospinal (crossed) --ICx (space map--time, amplitude converge; input from both parts of ICc) 2) sensory info affecting motor outputs via the cerebellum --sensory cortex => pontine nuclei AUDITORY CORTEX--BATS --pontine nuclei => (crossed) cerebellar cortex 1) DSCF area (doppler shift constant frequency)--in area A-I --cerebellar cortex => deep cerebellar nuclei --expanded representation around 60 kHz --deep cerebellar nuclei => (crossed) red nucleus --amplitude vs. frequency map --red nucleus => (crossed) spinal cord --detect size, texture of object also 2) CF/CF area (const. freq./const. freq.) --deep cerebellar nuclei => ventrolateral thalamus (VL; not VPL!) --map of CF1 of outgoing vs. CF2,3 of echo --ventrolateral thalamus => motor cortex --detect relative velocity of target --motor cortex => (crossed) spinal cord --possible relation to formant perception in human speech 3) sensory info affecting motor outputs via the basal forebrain 3) FM-FM area (freq. modulated-freq. modulated) --sensory cortex => caudate and putamen --map of monaural delays between FM1 of outgoing & FM2,3,4 of echo --caudate and putamen => globus pallidus --detect distance of object also: caudate and putamen <=> substantia nigra --globus pallidus => ventrolateral thalamus VISUAL SYSTEM also: globus pallidus <=> subthalamic nucleus 1) retina --ventrolateral thalamus => motor cortex --photoreceptors (red, green, blue cones, rods) --motor cortex => (crossed) spinal cord --bipolar cells (ON, OFF, rod) 4) vestibulo-ocular reflex --ganglion cells --vestibular canals => vestibular nuclei => oculomotor neurons midget or X-cells (ON and OFF types) => LGN parvo 5) optokinetic nystagmus parasol or Y-cells (ON and OFF types) => LGN magno --retina => pretectal nuc. => vestibular nuclei => oculomotor nuc. W cells => LGN, superior colliculus 6) pursuit eye movements direction selective => pretectum --retina => LGN => visual cortex thorn cells => superior colliculus --visual cortex => pontine nuclei --horizontal cells (synapses with photoreceptors and bipolars) --pontine nuclei => flocculus --amacrine cells (synapses with bipolars and ganglion cells) --flocculus => vestibular nuclei 2) dorsal lateral geniculate nucleus (dLGN) --vestibular nuclei => oculomotor neurons --magnocellar layers (Y input) 7) orienting eye movements (subcortical pathway) --parvocellular layers (X input) --retina => superficial superior colliculus 3) input layers in area V1 --superficial superior colliculus => deep superior colliculus --layer 4C-alpha (magno/Y input layer) --deep sup. colliculus, frontal eye fields => saccade patt. generators --layer 4C-beta (parvo/X input layer) --saccade pattern generators => oculomotor neurons 4) secondary stage layers in V1 (horizontal movement pattern generator is PPRF) --layer 4B (magno pathway) (vertical movement pattern generator is riMLF) --layer 3 blobs (parvo blob pathway) 8) orienting eye movements (parallel cortical pathway) --layer 3 interblobs (parvo interblob pathway) --retina => LGN => visual cortex 5) area V2 --visual cortex => frontal eye fields --thick stripes (magno) --frontal eye fields => saccade pattern generators --thin stripes (parvo blob) --interstripes (parvo interblob) LIMBIC SYSTEM 6) higher areas in magno pathways 1) medial forebrain bundle axis --thick stripes => MT => MST => 7a --septum <=> hypothalamus <=> limbic midbrain --other areas in magno pathway: V3, VIP, PO 2) hippocampus 7) higher areas in parvo pathways --dentate gyrus (input from entorhinal) --thin and interstripes => V4 => PIT => AIT --CA3 and CA1 (place cells; input from dentate gyrus) --other areas in parvo pathway: VP, CIT, TF --subiculum (connections with entorhinal and hypothalamus) 8) visual areas list --entorhinal cortex (connections with tertiary cortex) --main input areas: V1, V2 --postsubiculum (head direction cells; vestibular & visual input) --’parietal’ areas: V4t, V3A, MT, MST, FST, DP, PO, PIP, LIP, VIP, MDP 3) amygdala --’temporal’ areas: VP, VOT, PITv, PITd, CITv, CITd, AIT, TF, TH --central nucleus (taste input) --corticomedial amygdala (limbic connections) MOTOR SYSTEM --basolateral amydala (tertiary sensory cortex connections) 1) four main descending pathways.
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