Homework and Textbook Content

Golgi Stain

1873 by Camilo Golgi, using silver nitrate to stain the neurons to see the detailed neuron structure

Fast Axonal Transport

Goes upto 400mm/day

Slow Axonal Transport

0.5 to 5mm/day

Anterograde Transports

Move substances from cell body to axon terminals (proteins, lipids)

Retrograde Transports

Moves substances from axon terminal to cell body

Enkephalingergic Neurons

Interneurons in the dorsal horn, connected to C axons, that releases enkephalin onto nociceptive terminals, inhibiting pain signals which can be controlled by the brain

Enkephalin Process

Binds to delta opioid receptors, opening K channels, hyperpolarizing, and reduces the flow of Ca in, making it harder for neurotransmitter release, reducing transmittance

Silent Synapses

Requires glutamate and depolarization to send signals because it only has NMDA receptors blocked by Mg

Glutamate released on silent synapses bind only to

NMPA receptors

Silent Synapses are common in development in the

Hippocampus, cerebral cortex, and spinal cord

NMDA Receptors are abundant in

Postnatal development in adults

Silent Synapses have an early stage in

Ongoing maturation of glutamatergic synapses

Recreational Cocaine use can

Silence glutamatergic synapses

Long Term Depression

Happens at synapses between Schaffer collaterals and CA1 pyramidal cells in the hippocampus when stimulated at 1 Hz for a long time that weakens a specific set of synapses by depressing EPSP for many hours

LTD and LTP

Can erase each other

Schaffer collateral CA1 synapses both require

Activation of NMDA glutamate receptors and entry of Ca into the postsynaptic cell

LTD happens from Ca signals by

Slowly, small rises of Ca leads to depression, large, fast increases of Ca triggers potentiation

LTD Activates

Phosphates PP1 and PP2B causing loss of synaptic AMPA receptor probably from internalization of receptors into sorting endosomes in the post synaptic cell like endocytosis of synaptic vesicle recycling

Slow Movement of Eyes Countering Turning Motion

• Tilting causing afferents on the side to turning motion increases firing rate

• Afferent on opposite side decreases firing rate

• The net difference in firing rates leads to slow movement of eyes

Fast Saccade

Rapid, automatic eye movement that shifts gaze from points to focus on object of interest

Physiological nystagmus

Adaptive process that allows to fixate on visual target with ongoing rotational movements of head and body

Spontaneous Nyastagmus

Silencing of output from damage to a side results in abnormal difference in firing rate between the two sides causing nystagmus with no head movements

Meniere’s Disease

One cause of acute unilateral vestibular dysfunction that initially affects one ear and progressive impacts both ears causing tinnitus and sensorineural hearing deficits

Vestibular Nerve Section

Unavoidable impact of surgical removal of vestibular Schwannoma

Spontaneous Nystagmus can slowly

Go away after unilateral vestibular nerve section from central compensation and placticity

Regular People with Water Irrigated in the Ears

Have spontaneous eye movement because convection currents in the canal and direct cooling of the nerve mimic rotational head movements away from the watered ear

People with Dysfunction of Cerebral Hemispheres with Water Irrigated in the Ears

No quick eye movements and response to cold water has slow movement component of the eyes to the side of the irrigated ears

Brainstem lesions involving

• Vestibular nuclei

• Connection from vestibular nuclei to oculomotor nuclei or peripheral nerves exciting these nuclei

Vestibular responses are changed or stopped

Fixed

Preserve the tissue by immersing it in a buffered solution

Section

Slicing preserved tissues into thin slices

Perceptual Repulsion Illusion

Senses misinterpret stimuli making them seem to push away from each other or from a reference point

Hermann Grid Illusion

Grey spot at intersections of white lines from lateral inhibition, exciting retinal neurons but suppressing adjacent ones, tricking the brain into seeing a grey dot where the lines meet

Linear Perspective

Parallel lines converge at a vanishing point on the horizon

Hearing Aid

Amplify sound input for patient

Cochlear Implant

Use a microphone to capture sound waves and convert them into electrical signals that stimulates the cochlea

Tinnitus

Perceiving sound in the head from no external input

Causes of Tinnitus

• Loud noises

• Medications

• Aging

• Ear wax

Barn Owls

Asymmetrical positioned ears with the left ear higher and right one lower to help determine interaural time difference

Muscle Spindle

Stretch sensing receptor made of interfusal muscle fibres in a capsule of connective tissue, innervated by alpha and gamma motor neurons to detect changes in muscle changes

Ia Afferent

Detects muscle stretch by elongating in the central region which depolarizes the Ia

Golgi Tendon Organ

Sensory receptor, encapsulated afferent nerve ending at junction between muscle and tendon

Ib Afferents

Detects muscle tension because force of contraction is transmitted through the tendon which compresses or deforms Ib and depolarizes it

Gamma Motor Neuron

Innervate contractile end of intrafusal muscles and maintain the baseline for muscle fibres

Why is the Aplysia gill withdrawal reflex is slow?

Axons aren’t myelinated

TGRA happens because

Associative LTP can’t occur between cortical neurons

Anterograde Amnesia happens because

No hippocampus and LTP can occur

What parts of Nervous System is affect by AD

Neuronal death in hippocampus, enthorhinal cortex, frontal lobe

Plaques

Abnormal proteins from amyloid precursor that disrupt cell function and neuronal death

Tangles

Clumps of tau protein that harm synaptic communication

Tau

Protein that stabilizes microtubules

Place Cells

Cells in the hippocampus that fires when it’s in a specific location within the environment

Grid Cells

Cells in the entorhinal that fires when in multiple specific locations in the environment

John O’Keefe

Discovered place cells

May-Britt and Edvard Moser

Discovered grid cells