BIO 348 Lecture 1 Notes PDF

Lecture 1: Brief history of neuroscience - As early as 3rd century BC, thought the consciousness was located in the heart and not the brain - Franz joseph gall: phrenology - Brain as the physical manifestation of the mind - Cerebral localization - brain is fu...

Lecture 1: Brief history of neuroscience - As early as 3rd century BC, thought the consciousness was located in the heart and not the brain - Franz joseph gall: phrenology - Brain as the physical manifestation of the mind - Cerebral localization - brain is functional specialized - Intellectual processes that are well developed manifest in anatomical enlargements of the brain (the humps that are felt around the brain - this is different for everyone) - Did not use scientific method - Consistent with modern understanding of brain function - However, there are different brain regions that have specific function - Phineas gage - His story showed that the brain is functionally specialized - His story helped give the knowledge of the frontal lobe and how it deals with personality (since his personality had completed took a 180º) Modern Neuroscience - Santiago Ramon y Cajal - The grandfather of modern neuroscience - Proposed The neuron doctrine - The nervous system is composed of individual cells - That there is a synapse between the cells - Golgi - Proposed The reticular theory - The nervous system is a syncytium - Meaning the cells shared the cytoplasm and they're all connected to one another - Golgi stain - Kandel - Proposed molecular basis for learning and memory Synapses identified in 1954: - Neuron doctrine proposed in 1890s - Observation of the gap between neurons in 1954 by electron microscopy (EM) - Evidence that neurons are individual cells was not obtained until ~ 60 years after Cajal proposed the neuron doctrine Basic neuroanatomy - 3 primary axes - Dorsoventral- vertical axis that runs from dorsum (back) to ventral (belly)  - rostrocaudal/anteroposterior - longitudinal axis that extends from rostrum (beak/front) to cauda (tail) - Mediolateral - horizontal axis that runs from the midline (medial) to the lateral margin of the animal - Axes shift in human brain - Dorsoventral - axis extends along the top (head)/ bottom (chin) - rostrocaudal/anteroposterior - axis extends from front(eyes) to back - Mediolateral - horizontal axis that runs from the midline (medial) to the lateral margin of the animal - Anatomical planes - Horizontal plane - dorsal to ventral - Coronal plane - anterior to posterior - Sagittal plane - medial cut normally, and sees all dorsal, ventral, rostraul, and caudal Two divisions of the vertebrate Nervous system - Central nervous system (CNS) - Brain and spinal cord - Peripheral nervous system (PNS) - Cranial nerves - Spinal nerves CNS: - 7 main regions of the CNS - Spinal cord - Medulla oblongata - Pons - Cerebellum - Midbrain - Diencephalon - Cerebrum - Further anatomical and functional specialization within each region - Simple behaviors are functionally localized in discrete brain regions Spinal cord: - Cervical - 8 segments - Largely review input from periphery of arms/forelimbs - Send output to the arms - Thoracic - 12 segments - Receive and send info from the trunk - Lumbar - 5 segments  - Receive and send info from legs - Sacral - 4 segments - Related with internal organs - Brain stem - Rostral to spinal cord - Medulla oblongata, pons, midbrain - Necessary passage for all ascending and descending tracts between forebrain and spinal cord - Modulates sensory, motor, and reflex behaviors (feeding, drinking, respiration) - Modulation of arousal, CNS activity - Medulla: - Regulates autonomic functions such as respiration, heart rate, and blood pressure - Prebotzinger complex - generates respiratory rhythm - Pons - Cranial nerve nuclei - Mediates sensory and motor control of head and neck - Midbrain - Voluntary motor control (substantia nigra) - Degeneration of cells in this area lead to parkinson's disease - Processing of auditory and visual information (superior and inferior colliculi) - The brainstem is the cite of cranial nerve nuclei - Nuclei ≠ cell nucleus - Nucleus refers to collection of neurons within a brain region - Cells within a given nucleus share the same projections or inputs - Cerebellum - Dorsal to brain stem - Motor control - modifies motor commands to adapt to desired output, accuracy of movement - Maintaining posture - Receives sensory information from the spinal cord, balance from vestibular organs in the inner ear, motor and sensory information from the cortex - Certain forms of learning - Diencephalon - Anterior to the cerebellum - 2 parts: thalamus and hypothalamus - Thalamus - Sensory relay center - Information from visual auditory and somatosensory pathways relay here on their way to the sensory cortices - Hypothalamus - Includes nuclei  - Integrates physiology and behavior - Regulates homeostatic behaviors, including feeding, thirst, regulation of sleep wake cycle, reproduction - Cerebrum - The Cerebral cortex - Higher order sensory and cognitive processing - Wrinkly part of the brain - More wrinkles mean complexity - Cortex is the site of higher order cognitive functions - hippocampus: learning and memory - amygdala: formation and storage of memories associated with emotion HM: The most important patient in neuroscience - Henry Molaison (HM) - Suffered from serious seizures - Surgeon removed the temporal lobes (which include the hippocampus) - This was the site where the seizures where being triggered - Found that after his surgery, he had anterograde amnesia - Found out that memory storage and memory formation are in two different places - Declarative memory (facts) - HM couldn't form these - Procedural memory (ex: playing the piano) - HM was able to perform procedural tasks - The cerebral cortex: - Sulci and gyri - nor random outgrowths - Are anatomically defined - Consistent across individuals - Serve as anatomical landmarks for specific brain regions - increase the Surface area of the cortex - Gyrus is at the top of the fold - Sulcus is at bottom of fold - Specifically associated with anatomical functions - Precentral gyrus - motor cortex: anterior to central sulcusGyrus that is posterior to central sulcus is somatosensory cortex - Frontal lobe: short term memory, planning, control of movement, executive planning/higher order processing - Temporal lobe: auditory information, learning and memory, emotion hippocampus is inside herr, and amygdala - Parietal lobe: sensory processing, language processing, encompasses somatosensory cortex - Occipital lobe: visual processng - White matter: - Axon tracts covered with myelin sheath  - Reach with glial cell bodies - Gray matter - Unmyelinated neurons Ventricles: - Carry fluid - Contain CSF - Provide protection by buffering the brain - Floats the CNS - Reduces weight of the brain and pressure at the base of the brain - Normally weighs 1300g - With CSF 25g - Removes waste from CNS to blood stream - Produced by choroid plexus - epithelial cells found in the lateral of the ventricles Meninges: - 3 layers - Dura mater (2 layers) - Arachnoid - Pia mater - Protect the CNS (since brain and spinal cord has meninges - Meningeal cells are fibroblasts - Bacterial meningitis results from bacterial infection and inflammation of meninges Extra credit: watch YT video on BBLearn and answer questions due 10/17