Week Two Flashcards
Who discovered the brain’s electrical activity
Gustav Fritsch and Eduardo Hitzig (1870) electrically stimulated
Wilhelmina Wundt (1832-1920)
- Studied under Johannes Muller and Herman von Helmholtz at the University of Heidelburg
- They developed psychophysiology (precursor to todays cognitive neuroscience)
- First experimental psychology lab (Leipzig, 1876)
Alexander Bain (1818-1903)
- Originated the theory of psychophysical parallelism - brought the scientific method to psychology
psychophysical parallelism, in the philosophy of mind, a theory that excludes all causal interaction between mind and body inasmuch as it seems inconceivable that two substances as radically different in nature could influence one another in any way
Gustav Theodar Fechner (1801-1887)
-With Helmhlotz and Wundt, a founder of experimental psychology
- October 22, 1850 Fechner hd a dream that resulted in new approach to the study of the mind - that he called psychophysics
“In order that a sensation (S) increase in arithmetic progression, the stimulus (1) must increase in geometrical progression”. S= k log(1)
- In 1738 the Swiss mathematician Gabriel Cramer noted a similar relationship between the value (I) and utility (S) of money
19th century development
- theory of evolution
- Golgi stain
- the mirror galvanometer
- analgesics (pain remover) and anesthetics
- Electronics
- Artificial lights
- optical design and fabrication
- biochemistry
- publishing and broadcasting
7 factors affecting brain functions
- Genetics (prepares you)
- Nutrition
- Experience; brain has ways to store past experiences (may be able to recall a song that was playing at an important event)
~Episodic Memory (specific personal memories; eg: first kiss, someone’s birthday) - Infection / trauma
- drugs
- surgical intervention
- Electromagnetic energy: TMS, electrical pulse gets sent to the cortex allowing enough energy for movement to occur (eg; movement of arm)
Brain had no knowledge of itself, but has knowledge of everything else outside.
Divisions of the Nervous System (CPSA)
- Central Nervous System (CNS)
~Brain, Spinal Cord - Peripheral Nervous System (PNS)
~ Somatic nervous system (SNS)
~ Sensorimotor connections via spinal and cranial nerves - Autonomic nervous system (ANS)
~ Balances the internal organs through the parasympathetic and sympathetic nerves
~ Once you’ve damaged your spinal cord or brain there is no way to fix the damage
Anatomical Terms of Location
- Rostral (nose); right angel bend
- Caudal (tail)
- Dorsal (back)
- Ventral (belly)
- Coronal (XY plane)
Anatomical Terms of Location pt 2
- Axial (aka ‘transverse’ or ‘horizontal’ , XZ plane)
- Sagittal (aka ‘lateral’ YZ plans)
- Nucleus; cluster of cell bodies in the CNS; cluster of nerves, in the lateral side of the thalum
- Ganglion; cluster of cell bodies in the PNS
- Anterior or frontal
- Posterior (behind)
- Lateral (side)
- Medial (midline)
- Superior/ Inferior
Anatomical Terms of Location (structures) pt 3
- Structures in the same side are ipsilateral
- Opposite side: contralateral
- That lie in both hemispheres: bilateral
- that are close together are ‘proximal’ to another
- Far apart are DISTAL to one another
Frequently used terms
- Nerve: collection of neuron axons in PNS
- Tract: collection of neuron axons in CNS
- Efferent: directed away from the brain (motor nerves, eg; waving arm)
- Afferent; directed towards the brain (sensory nerves, eg; feeling the cool air when waving arm)
Convention for compound terms
Prefix = origin of nerve signal
Suffix = termination of nerve signal (eg; corticospinal tract)
Grey VS White Matter
Grey matter (normal) : nervous tissue that appears greyish due to the presence of unmyelinated neuronal cell bodies and axons. The neocortex is predominately grey matter
White matter: nervous tissues that appears light coloured due to the presence of myelinated axons. Neuronal tracts are typically white matter
Types of Neurons
SMI
- Sensory neurons: carrying information from receptors to the brain
- Motor neurons: carrying signals from the brain to the muscles
- Interneurons: which convent information between different types of neurons
5 type of Gila
- Astrocytes (star shaped): most abundant glial cell in the brain, closely associated with neuronal synapses. They regulate the transmission of electrical impulses within the brain
- Microgila: account for 10-15% of all cells found within the brain. they act as the first and main form of active immune defense in the CNS
- Ependymal cells: lines the CAF-filled ventricles in the brain and the central canal of the spinal cord. These are nervous tissue cells with a ciliated simple columnar form much like that if some mucosal epithelial cells
- Oligodendrocytes and Schwann cells: provide support and insulation to axons in the CNS of some vertebrates, equivalent to the function performed by Schwann cells in the PNS. They both do this by creating the myelin sheath, 80% lipid and 20% protein.
The neuron Doctrine
(Proposed by Wilhelm Waldeyer)
• Neural units: The brain is made up of individual units that contain specialized features such as dendrites, a cell body, and an axon.
-Neurons are cells: These individual units are cells as understood from othertissues in the body.
- Specialization: These units may differ in size, shape, and structure according to their location or functional specialization.
- Nucleus is key: The nucleus is the trophic center for the cell. If the cell is divided only the portion containing the nucleus will survive.
Nerve fibers are cell processes: Nerve fibers are outgrowths of nerve cells.
• Cell division: Nerve cells are generated by cell division.
- Contact: Nerve cells are connected by sites of contact and not cytoplasmic continuity.
• Law of dynamic polarization: There is a preferred direction for transmission from cell to cell.
• Synapse: A barrier to transmission exists at the site of contact between two neurons that may permit transmission.
Unity of transmission: If a contact is made between two cells, then that contact can be either excitatory or inhibitory, but will always be of the same type
The basic neuron: collects, integrate, conducts and communicates signals
Parts of neuron:
• Dendrite
• Hillock
*Soma
*Nucleus/organelles
*Axon
*Cytoplasm
• Terminal button
*Synapse
*Presynaptic membrane
• Postsynaptic membrane
How neurons differ
-Dendritic tree complexity
-Types of synaptic receptors
-Types of activating neurotransmitters
- Axonal length and cross-sectional area
-Arrangement of cell body to axon (e,B.unipolar, bipolar or multipolar)
- Spatial & temporal integration
-Physical size
- Degree of axonal myelination
CNS support and protection
Skill and vertebrae
- brain is enclosed in the neurocranium (posterior portion of the skill, aka “brain pain”)
- vertebral column: 33 articulating bones
Meninges: 3 meme brands enclosing the CNS
- Dura Mater (L. ‘Tough mother’ : outermost membrane next to skull)
- Arachnoid Mater (aka Arachnoid membrane, ‘spider-like mother: a highly vascularized layer)
- Pia Meter ( ‘soft matter’ : innermost membrane (next to CNS)
Cerebrospinal Fluid (CSF)
- Cushions and the brain and spinal cord
Meningeal Blood Supply
- Meningeal argues: mainly supply the dura region of the meninges
- Anterior meningeal artery: irrigates the meninges in the anterior cranial fossa
- Middle Meningeal Artery ^
- Posterior Meningeal artery ^
Intracranial Blood Supply
Left and right internal Carotid Arteries
- ascend in the neck to enter the skull through the carotid canal (temporal bone)
Left and right Vertebal Arteries
- ascend in the neck to enter the skull through the foramen magnum to supply blood to the brain parenchyma
Connect at the base of the brain and branch off into the: anterior, middle, and posterior cerebral artery
Meningeal Hematomas
Subdural hematoma; caused by bleeding of bridging veins across the subdural space (blood collects between the dura mater and the arachnoid space, resulting in increased intracranial pressure). According to UCLA’s Neurosurgery
Department, about 50 to 90 percent of those with acute subdural hematomas die from the condition or its complications
Epidural hematoma: caused by bleeding of meningeal arteries resulting in blood pooling between the dura mater and the skull.
Epidural hematoma presentation
Epidural hematoma presentation can include a brief loss of consciousness followed by a lucid interval lasting from minutes to hours. This is then typically
followed by headache, progressive obtundation (decreased responsiveness or altertness), an ipsilateral “blown pupil” and contralateral hemiparesis. If untreated “uncal herniation” can occur, leading to coma and respiratory arrest due to compression of the midbrain and the posterior cerebral artery.
Pterion
• One of the weakest parts of the skull
- Region on the lateral skull - at the junction of 4 skull bones (parietal bone, temporal bone, sphenoid bone and frontal bone)
- The anterior division of the middle meningeal artery runs under the
Pterion - Rapid acceleration/deceleration caused by traumatic blow to the pterion can rupture the MMA, causing an epidural hematoma…
Symptoms of intracranial hematomas: Subural hematoma
- slurred speech
- headache
- inability to speak
- loss of consciousness
- numbness
- seizures
- visual problems
- weakness
