Nervous System

Question 1

Excitatory neurons:

Answer 1

These cells use glutamate and other excitatory neurotransmitters to communicate with other neurons, triggering action potentials in their targets.

Question 2

Inhibitory neurons:

Answer 2

These cells use GABA and other inhibitory neurotransmitters to communicate with other neurons, suppressing action potentials in their target cells.

Question 3

Motor and sensory

Answer 3

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.

Question 4

Astrocytes:

Answer 4

supporting cells in the brain; important for recycling neurotransmitters and controlling the interstitial environment.

Question 5

Microglia:

Answer 5

important for responding to injury and infection in the central nervous system

Question 6

The brainstem:

Answer 6

medulla, pons, and midbrain; regulates basic body functions like heart rate, respiration, etc

Question 7

The cerebellum:

Answer 7

The cerebellum: coordination of movement and balance.

Question 8

The diencephalon:

Answer 8

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.

Question 9

The cerebrum:

Answer 9

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.

Question 10

temporal lobe:

Answer 10

Temporal lobe: language comprehension, memory, hearing.

Question 11

frontal lobe

Answer 11

Frontal lobe: speech, movement, decision making.

Question 12

Dorsal horn:

Answer 12

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.

Question 13

Ventral horn:

Answer 13

Ventral horn: contains motor neurons that project axons to skeletal muscles in the periphery, causing them to contract.

Question 14

Somatic system

Answer 14

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

Question 15

Autonomic system

Answer 15

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.

Question 16

Information processing in the cerebral cortex

Answer 16

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

Question 17

Sensory homunculus

Answer 17

The primary somatosensory cortex is organized like a “map” of the body.

Question 18

Primary sensory cortex

Answer 18

Primary sensory cortex: receive sensory information from the environment; specialized by modality (e.g., visual cortex, auditory cortex, somatosensory cortex, etc.).

Question 19

Primary motor cortex

Answer 19

Primary motor cortex: initiates movements of contralateral body parts (left motor cortex controls right side of body).

Question 20

Association cortex

Answer 20

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.

Question 21

voluntary movement

Answer 21

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.

Question 22

Involuntary movement and the reflex arc

Answer 22

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.

Question 23

Lateralization of cortical function

Answer 23

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.

Question 24

laterialization of cortical function cnt.

Answer 24

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

Question 25

Electrophysiology and the different varieties

Answer 25

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.

Question 26

Electrophysiology 2

Answer 26

Electrophysiology: uses electrodes to stimulate and record from neurons

Question 27

Extracellular multi-unit recording

Answer 27

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.

Question 28

Patch clamping

Answer 28

Patch clamping: records pure signals emanating from a single cell.

Question 29

Local field potentials

Answer 29

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

Question 30

Electroencephalography (EEG):

Answer 30

Another kind of electrophysiology

Electroencephalography (EEG): non-invasively records electrical signals emanating from large areas of cortex using electrodes attached to the scalp.

Question 31

Neuropsychological lesion studies

Answer 31

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.

Question 32

Transcranial magnetic stimulation

Answer 32

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.

Question 33

Computerized tomography (CT):

Answer 33

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.

Question 34

Magnetic resonance imaging (MRI)

Answer 34

Magnetic resonance imaging (MRI): provides higher resolution images than CT; can also be used to study function (fMRI).

Question 35

Positron emission tomography (PET):

Answer 35

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.

Question 36

CT/MRI vs. fMRI/PET

Answer 36

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!!!!!

Question 37

What is true about the cerebrum and spinal cord respectively?

Answer 37

The cerebrum has white matter surrounded by gray matter, spinal cord is the opposite

Question 38

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.

Answer 38

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.