Lecture 4 Flashcards
the Somatosensory ASSOCIATION area is made up?
Brodmann’s areas 5 and 7
the Primary somatosensory are is made up of?
Brodmann’s Areas 1, 2, & 3
Bilateral excision in Somatosensory area I results in Astereognosis. A term that describes one’s loss of ability to do what?
judge shapes or forms
a Bilateral cut in the Somatosensory area I will preserve these senses but they will be poorly localized
Pain and Temperature
Removal of somatosensory II has no apparent effect on the response of neurons in?
Somatosensory area I
The somatosensory area II (SSAII) receives signals from?
- Brain stem, transmitted Up and bilaterally
- secondarily from SSAII (somatosensory area II)
- Visual, Auditory, and other sensory areas
these layers of the Somatosensory cortex send information through the corpus callosum to the opposite hemisphere
layers II and III
the Superficial layers of the SS cortex function in?
receiving input signals from lower brain centers
Axons from layer VI in the SS cortex project into this part of the Brain
Thalamus
large neurons from this layer in the SS cortex project to distant areas such as basal nuclei, brain stem, and spinal cord
layer V
Receptor potentials are created in response to membrane deformation caused by touch or pressure that will open these channels
Modality gated sodium channels
if the receptor potential is strong enough, through Summation, it may generate an action potential at the first?
Node of Ranvier on the primary sensory neuron
Primary neurons are?
first order neurons. they originate from peripheral receptors and enter the spinal cord or brain via Dorsal roots of spinal/cranial nerves
Primary neurons synapse in the spinal cord with?
secondary neurons
the cell bodies of Primary neurons are located in the?
Dorsal root ganglia
these neurons originate in spinal cord gray matter, travel through myelinated columns in the spinal cord, decussate, and synapse in the thalamus with Tertiary neurons
Secondary neurons
Tertiary neurons travel through internal capsule, which is a myelinated pathway between thalamus and basal nuclei, to synapse in?
the somatosensory cortex
this touch refers to the ability to distinguish two separate points as close as 2mm apart.
Two-Point Discrimination
two Point discrimination travels in the?
Dorsal column-medial lemniscal pathway
why is Lateral inhibition important in the Cerebral cortex?
blocks the lateral spread of excitatory signals, thereby increasing the degree of contrast in the cerebral cortex
Lateral inhibition occurs at these three sites
Dorsal Column nuclei
Ventrobasal nuclei of thalamus
somatosensory cortex
Peripheral sensory neurons originate from?
receptors in the periphery
the Dorsal Column-medial lemniscal pathway also carries these neurons
Primary neurons
Axons from the lower limbs travel in the medial portions of the two dorsal columns called the?
fasciculus Gracilis
