Bio - chem/phys

• - when the release of a NT causes an increase in activity of the neuron/tissue it’s being released to by causing the voltage of the post-synaptic cell to become more positive and closer to threshold for action potential

  • Example- Glutamate is an excitatory inhibitor, meaning that when released, it will cause increased activity and

Excitatory Post-Synaptic Potentials

most common inhibitory NT in the spine

glycine

when the release of a neurotransmitter causes the post-synaptic neuron (the neuron that responds to the NT) or tissue to be less active (making the neuron potential more negative/further from threshold potential for action potential)

• Example- GABA, when released or consumed (like from drinking alcohol), causes neurons responsible for balance and coordination to decrease their activity, which is why we become impaired when drinking alcohol (not me though, only heavy-weights here insert stupid emoji here, y’all stay safe out there)

Inhibitory Post-Synaptic Potentials

Hippocampus -

new explicit memories

a set of structures deep in the brain that are heavily involved in the formation and storage of implicit, procedural memories (motor skills and habits).

basal ganglia

the external ear that collects sound waves and funnels them into the ear

pinna

the ear drum, separates the outer from middle ear, vibrating as sounds hit them to transfer the vibrations into the middle ear

tympanic membrane

membrane covering up the opening of the cochlea that will transfer the sound vibrations to the cochlea

oval window

 spiral shaped inner ear structure filled with fluid that vibrates with the same frequency as the sound wave, causing vibrations in the basilar membrane

cochlea

membrane in the cochlea that vibrates due to the vibration of cochlear fluid, where different regions of the membrane will vibrate depending on the frequency of the sound wave

basilar membrane

 the sensory organ of the ear on the basilar membrane that contains auditory hair cells, which are mechanoreceptors that vibrate on the basilar membrane, activating the auditory nerve

organ of corti

mechanoreceptors on the Organ of Corti that are activated when a specific frequency is activated on the basilar membrane, leading to audition

auditory hair cell

 membrane above the hair cells that the hair cells vibrate against to stimulate action potentials

tectorial membrane

pathway of sound

Pinna (external ear) → External Auditory Canal → Tympanic Membrane → Ossicles → Oval Window → Cochlea → Basilar Membrane → Auditory Mechanoreceptors → Auditory Nerve → Brainstem → Thalamus → Temporal Lobe

the process of hearing, where mechanoreceptors of the ear are vibrated by vibrations caused by sound waves, creating the sense of hearing

audition

the pitch of a sound wave is determined by where on the basilar membrane the sound wave vibrates

place theory

 different parts of the basilar membrane are tuned to respond to specific frequencies

• Base = High Frequency

• Apex = Low Frequency

basilar tuning

groups of neurons take turns firing to encode really high frequencies, rather than one neuron firing over and over and over again

volley principle

when a set of sound locations produce similar timing and intensity cues, making it hard to know where exactly the sound came from

cone of confusion

a portion of the hypothalamus that helps the pineal gland regulate the circadian rhythm

SCN- suprachiasmatic nucleus

region of the basal ganglia largely responsible for reward and motivation, making it important in reinforcement

nucleus accumbens

region responsibility for initiating voluntary (skeletal) muscle movements, particularly done by the nucleus accumbens, also important in storing implicit memories

basal ganglia

• communicates with the basal ganglia to help coordinate voluntary movements, a substantial dopamine producer

  • Example- if inhibited, we’d have significantly less dopamine present for movement initiation and coordination, leading to tremors or difficulties getting up to walk, since the SN makes dopamine

Substantia Nigra-

• the area responsible for our feelings of reward by producing dopamine that is sent to the amygdala, also decreasing serotonin (dopamine up, serotonin down)

  • Example- if inhibited, we’d lose our reward and motivation pathways, leading to symptoms such as avolition and anhedonia, as well as less drive to eat, study, pursue goals, etc.

VTA

•  coordination of voluntary movements, posture, and balance, connecting visual information to the muscle movements that respond to that visual stimuli, motor learning (memorizing how to swim)

  • Example- if inhibited, we’d have poor coordination and balance, and our movements would be inaccurate for what we’re trying to do. You’d look drunk, basically.

cerebellum

• important for basic life functions and making sure you can stay alive

brainstem

• life support center, sets our breathing rate, heart rate, and blood pressure

  • Example- if inhibited, respiratory failure, dysregulated heart rate, can be super dangerous

medulla

• controls cycles! Controls sleeping/waking patterns, dreaming, and adjusts breathing patterns/cycles where needed

  • Example- if inhibited, you’d have weird sleep cycles, weird breathing patterns, etc.

pons

• voluntary movements, decision making, personality, and some memory formation

frontal lobe

• personality and decision making, helps coordinate memory formation, typically most easily understood by thinking of it as the actual conscious part of your brain (although that is a bit reductive)

  • Executive Functions- higher order thinking processes, for example: planning, organizing, inhibition, etc. that occur in the prefrontal cortex

prefrontal cortex

•  region of the frontal lobe responsible for speech conduction (actual production of the words you want to say to someone)

brocas area

• proprioception and somatosensation

• Proprioception- an awareness of where you and your body is relative to the space around you

  • Example- proprioception is knowing how to adjust your ass so that you sit on a chair properly, or that you know that there’s a pencil 6 inches to your right, stuff like that

• Somatosensory Cortex- where many senses, such as the various touch and taste senses, are processed

  • Somatosensation- the ability to detect and interpret sensory information from the skin, muscles, joints, tissues, etc. and process it in the brain, just the fancy word for using your senses

parietal lobe

responsible for hearing, language conduction 

Auditory cortex- area responsible for processing hearing

Wernicke’s area- region of the left temporal lobe that aids in understanding various forms of language, whether it’s actual words being spoken, writing, etc. 

Hippocampus- part of the limbic system that is located in the temporal lobe and responsible for memories, further explained in

temporal lobe

visual cortex, where visual information is processed

occipital lobe

processing spatial, more holistic information, emotion

right brain

controlling language, writing, speech, and more minute details

left brain

myelinated axons that connect the right and left brains, allowing them to communicate

corpus callosum

• neurodegenerative disease (breakdown of neurons) that leads to memory loss, cognitive decline, and behavioral changes caused by degradation of the neurons in the brain

  • What exactly happens- beta-amyloid plaques accumulates outside neurons and Tau protein clumps up on the inside of neurons, disrupting communication and eventually leading to cell death

  • Typically coincides with low amounts of ACh

alzheimers

• death of dopamine producing neurons in the substantia nigra of the midbrain, leading to poor voluntary movement

parkinsons

• uses magnetic fields and radio waves to detect hydrogen atoms present in the brain in that moment

MRI

• shows brain structure using X-rays from multiple angles to identify bleeding, tumors, fractures, etc.

CT/CAT san

structural brain scans -

CT/CAT + MRI

• sensory neurons that conduct information from the body to the brain

afferent

• motor neurons conduct information from the brain to the body

efferent

• reflexes that do not directly require executive processing by the brain, only involving the peripheral sensory afferent and motor efferent neurons

  • Example- knee-jerk response, where when a doctor hits your patella tendon, that sends an afferent signal to your spinal cord, where another PNS neuron immediately sends an efferent signal to the muscles to contract in reaction to the stretch of the patella tendon

monosynaptic reflex arc

•  reflexes that require CNS functioning in some way, requiring interneurons between the peripheral afferent and efferent neurons to carry information to the brain so the correct response can be sent out by the brain

  • Example- hand on a stove, if you put your hand on a stove top while it’s hot, it requires your brain to register that the stove is hot, and your brain will then tell you to remove your hand. Usage of brain = polysynaptic, which involves the CNS.  

polysynaptic reflex arc

• a tract of neurons from the brain to the spinal cord that causes voluntary movements in distal extremities, like hands and feet

  • Example- if you’re trying to type, information is going through the corticospinal tract from your brain to your fingers to allow you to type

Corticospinal Tract

• a tract of neurons that carries motor commands from the cortex to the brainstem to allow control over face, head, and neck muscles

Corticobulbar Tract

• involuntary muscle twitches due to unstable LMNs

fasciculation

rapidly increase heart rate, blood pressure, and respiration.

Catecholamines (epinephrine and norepinephrine)

Which brain structure produces the majority of the brain's acetylcholine supply?

basal forebrain

A patient has tremors, rigidity, and difficulty initiating movement. Which structure is deteriorating?

Substantia Nigra