Nervous System COPY Flashcards
Excitatory neurons:
These cells use glutamate and other excitatory neurotransmitters to communicate with other neurons, triggering action potentials in their targets.
Inhibitory neurons:
These cells use GABA and other inhibitory neurotransmitters to communicate with other neurons, suppressing action potentials in their target cells.
Motor and sensory
Motor neurons: Located in the ventral horn of the spinal cord, these neurons synapse with muscle cells, causing them to contract.
Sensory neurons: Located in ganglia throughout the peripheral nervous system, these neurons fire action potentials in response to sensory stimuli and transmit this information to the brain and spinal cord.
Astrocytes:
supporting cells in the brain; important for recycling neurotransmitters and controlling the interstitial environment.
Microglia:
important for responding to injury and infection in the central nervous system
The brainstem:
medulla, pons, and midbrain; regulates basic body functions like heart rate, respiration, etc
The cerebellum:
The cerebellum: coordination of movement and balance.
The diencephalon:
Thalamus: a relay station for directing incoming sensory information to the appropriate brain region.
Hypothalamus: regulates the endocrine system and motivated behaviors like eating, drinking, and mating.
The cerebrum:
The cerebrum: critical for processing and perceiving sensory information, for initiating movements, and for cognitive processes like attention, learning and memory, and decision making.
Frontal lobe: speech, movement, decision making.
Parietal lobe: touch sensation, attention.
Occipital lobe: basic visual processing.
Temporal lobe: language comprehension, memory, hearing.
temporal lobe:
Temporal lobe: language comprehension, memory, hearing.
frontal lobe
Frontal lobe: speech, movement, decision making.
Dorsal horn:
Dorsal horn: contains neurons that receive sensory info from the periphery and transmit it to the brain.
IN SPINAL CORD
The spinal cord: Relays sensory and motor signals between the brain and the rest of the body.
Central gray matter (cell bodies) surrounded by white matter (axons).
Dorsal horn: contains neurons that receive sensory info from the periphery and transmit it to the brain.
Ventral horn: contains motor neurons that project axons to skeletal muscles in the periphery, causing them to contract.
Ventral horn:
Ventral horn: contains motor neurons that project axons to skeletal muscles in the periphery, causing them to contract.
Somatic system
Somatic system: conveys sensory information about the external environment to the brain (sensory division) and signals to skeletal muscles causing voluntary contraction (motor division).
PART OF PNS
Autonomic system
conveys information about the internal environment to the brain (e.g., blood pH, osmolarity, body temperature) and regulates the function of endocrine glands and other organs.
Autonomic system includes sympathetic and parasympathetic divisions:
PERIPHERAL NERVOUS SYSTEM
Sympathetic division: “fight or flight”; increases heart rate, respiration, and blood flow to muscles; relies on norepinephrine.
Parasympathetic division: “rest and digest”; decreases heart rate, respiration, increases blood flow to digestive tract; relies on acetylcholine.
Information processing in the cerebral cortex
The cerebral cortex is made up of millions of interconnected microcircuits—organized into six layers—that receive information, process it, and send outputs to other microcircuits.
Primary sensory cortex: receive sensory information from the environment; specialized by modality (e.g., visual cortex, auditory cortex, somatosensory cortex, etc.).
• Sensory homunculus: The primary somatosensory cortex is organized like a “map” of the body.
also:
Primary motor cortex: initiates movements of contralateral body parts (left motor cortex controls right side of body).
and Association cortex
Sensory homunculus
The primary somatosensory cortex is organized like a “map” of the body.
Primary sensory cortex
Primary sensory cortex: receive sensory information from the environment; specialized by modality (e.g., visual cortex, auditory cortex, somatosensory cortex, etc.).
Primary motor cortex
Primary motor cortex: initiates movements of contralateral body parts (left motor cortex controls right side of body).
Association cortex
Comprises 3⁄4 of the surface area of the cerebral cortex.
Receives projections from primary sensory areas and other association areas, integrating sensory information from multiple modalities.
Responsible for “higher-order” mental processes like decision making, attention, learning, and memory.
voluntary movement
Voluntary movement is initiated by neurons in the primary motor cortex.
Voluntary motor circuit: primary motor cortex → through internal capsular white matter tract, brain stem, and spinal cord → motor neurons in ventral horn of spinal cord → muscle.
Acetylcholine release at muscle triggers calcium influx and contraction.
Supplementary motor area, basal ganglia, and cerebellum contribute to the planning, coordination, and fine-tuning of movement.
Involuntary movement and the reflex arc
In a simple reflex, an external stimulus (e.g., doctor hits your knee with a hammer) triggers an involuntary muscle contraction (quadriceps contracts → knee jerks).
Only three neurons are required: sensory neuron → interneuron → motor neuron.
All three neurons reside in the spinal cord or periphery; brain is not required.
Therefore, reflexes are fast and involuntary.
Lateralization of cortical function
The left and right sides of the brain are specialized for performing some functions.
In most people, language processing occurs predominantly in the left hemisphere.
The right hemisphere is specialized for performing complex spatial processing and recognizing complex patterns.
These insights come from studies of patients whose corpus callosum—a white matter tract that connects the right and left sides of the brain—was surgically resected (cut) as a treatment for severe epilepsy.
Note that these studies do not support the popular misconception of an artistic, intuitive right brain competing with an analytical, rational left brain.
laterialization of cortical function cnt.
b/c no connection cn study left brain versus right brain, great for science
researches would put obbject in left visual field, goes to the right side of the brain what do you see? researchers asked image of cup processed in right side of brain, left side of brain is how you speak cannot say name, so cannot send info from R side of brain to left side of brain with language
tried to use as a treatment for severe epilsepy, where signaling spreads like wildfire and that is why they tried to use it as a treatment
Electrophysiology and the different varieties
Electrophysiology: uses electrodes to stimulate and record from neurons.
Extracellular multi-unit recording: an electrode in the extracellular space records signals from multiple
nearby neurons but can be difficult to dissociate the contributions of individual neurons.
Patch clamping: records pure signals emanating from a single cell.
Local field potentials: records changes in the electric field caused by the summed activity of many cells in the vicinity of an electrode.
Electroencephalography (EEG): non-invasively records electrical signals emanating from large areas of cortex using electrodes attached to the scalp.
Electrophysiology 2
Electrophysiology: uses electrodes to stimulate and record from neurons
Extracellular multi-unit recording
A kind of electrophysiology
an electrode in the extracellular space records signals from multiple nearby neurons but can be difficult to dissociate the contributions of individual neurons.
Patch clamping: records pure signals emanating from a single cell.
Local field potentials: records changes in the electric field caused by the summed activity of many cells in the vicinity of an electrode.
Electroencephalography (EEG): non-invasively records electrical signals emanating from large areas of cortex using electrodes attached to the scalp.
Patch clamping
Patch clamping: records pure signals emanating from a single cell.
Local field potentials
Local field potentials: records changes in the electric field caused by the summed activity of many cells in the vicinity of an electrode.
A kind of electrophysiology
Electroencephalography (EEG):
Another kind of electrophysiology
Electroencephalography (EEG): non-invasively records electrical signals emanating from large areas of cortex using electrodes attached to the scalp.
Neuropsychological lesion studies
studies the function of a given brain structure by testing for cognitive deficits in patients who have lesions in that brain structure; limited by the fact that most lesions encompass multiple brain structures and the damaged brain may re-wire itself to function differently than it did in a healthy state.
Transcranial magnetic stimulation
Transcranial magnetic stimulation: induces a temporary “lesion” by briefly inactivating a brain region through high-frequency magnetic stimulation; can also activate a brain region using low-frequency stimulation.
Computerized tomography (CT):
Computerized tomography (CT): Like a 3-dimensional X-ray, this method can provide detailed structural images of the human brain and is especially useful in clinical settings for diagnosing stroke and bleeding within the head.
Magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI): provides higher resolution images than CT; can also be used to study function (fMRI).
Positron emission tomography (PET):
Positron emission tomography (PET): relies on dye containing small amounts of radioactivity; can be used to assess blood flow, oxygen update, or glucose utilization in a localized area.
CT/MRI vs. fMRI/PET
USED FOR STRUCTURES
these are used fo show you the structure of the brain
fmri/pet show you the function not structure, active brain area has more glucose can be seen with PET
fMRI= shows activity of different areas of brain, so use fMRI and PET for function of brain, if asked thsi question mri would be the wrong anser!!!!!
What is true about the cerebrum and spinal cord respectively?
The cerebrum has white matter surrounded by gray matter, spinal cord is the opposite
Q48 AAMC Sample test
Study 1 is replicated with split-brain patients. Participants are presented with the target colors only in the left side of their visual field. This procedure would specifically allow the researchers to investigate whether:
A. the patients show CP in the absence of access to color names.
B. the corpus callosum plays a significant role in color processing.
C. the patients show CP in the absence of access to color perception.
D. the frontal lobe plays a significant role in the recognition of color.
Split brain experiment, target colors in leftside of visual field we know how there is this criss cross at optic chasm, left visual field goes to right visual cortex** so then there is this information that is there, a normal individual right side of braina dn left side of brain talking to eachother v easily corpus callusm
splint brain pts corpus callosum has been cut
-the key thing here is langauge generated in left side of brain, if informationc oming into brain on righ side, need information to come into left side of brain to talk abotu it where langauge genreates, cannot NAME the color becuase no connection btw R brain and L side of brain, allowing researchers to test* becuase split brain pts cannot name the colors but can still have ht ecolor peception in the absence of being able to talk about them**
Solution: The correct answer is A.
A. The information about stimuli presented to the left half of a split-brain patient’s visual field will be projected to the right hemisphere. The right hemisphere of a split-brain patient has no access to the left hemisphere, where linguistic abilities are lateralized. Thus, presenting the target colors to the left half of a split-brain patient’s visual field would allow the researchers to determine whether categorical perception occurs even in absence of linguistic information, including color names.
B. Although the split-brain patient’s corpus callosum has been severed, there has been no disruption of the visual pathways from either eye to the contralateral occipital lobe. Thus, processes involved in the detection and transmission of sensory information related to color are not expected to be affected.
C. Color information will not be absent. Although a split-brain patient’s left and right cerebral hemispheres are unable to communicate with one another, the visual pathways from either eye to the contralateral occipital lobe remain intact. Thus, there has been no disruption of the detection and transmission of sensory information related to color.
D. The split-brain operation, in which the corpus callosum is severed, does not involve disrupting the functions of the frontal lobes. It results in the two hemispheres being unable to communicate with one another.
