Chapter 41: Somatosensory Cortex Flashcards
The central sulcus is between the _____ gyrus and the _____ gyrus.
- Precentral
- Postcentral
The precentral gyrus is on the posterior (caudal) edge of the _____ lobe.
- Frontal
The postcentral gyrus is on the anterior (rostral) edge of the _____ lobe.
- Parietal
The ventroposterolateral and ventroposteromedial nuclei of the _____ project to the primary somatosensory cortex in the _____ gyrus of the parietal lobe.
- Thalamus
- Postcentral
Brodmann divided the _____ into 3 vertical strips, numbered 3, 1, and 2 from the central sulcus to the postcentral sulcus.
- Postcentral gyrus
Area _____ is posterior to area 1, but area _____ is anterior to area 1.
- 2
- 3
The anterior to posterior sequence of Brodmann areas in the postcentral gyrus is _____, _____, _____.
- 3
- 2
- 1
Brodmann’s area 1, forming the central strip of the _____, receives discriminative touch sensations from area 3 anterior to it.
- Postcentral gyrus
Area 3 sends discriminative touch sensations to _____.
- Area 1
Area _____ infers texture from discriminative touch sensations.
- 1
Area 1 is only the _____ strip of the _____.
- Central
- Postcentral gyrus
Area 3 is _____ to area 1, mostly on the posterior wall of the central sulcus.
- Anterior
Posterior to area 1, area _____ receives pressure and tendon stretch sensation from area 3.
- 2
Area _____ infers size and shape from tendon stretch.
- 2
Injury to area 3 or area 2 causes astereognosis, the inability to recognize _____ and _____ with the eyes closed.
- Size
- Shape
Area _____ infers weight from tendon stretch and pressure.
- 2
Area 3 receives epicritic information from the _____ and _____ of the _____ and sends discriminative touch to area _____ and tendon stretch and pressure to area _____.
- VPL
- VPM
- Thalamus
- 1
- 2
Epicritic sensation is somatotopically arranged in areas _____, _____, and _____ on a map that parallels the somatopic map of the primary motor cortex on area 4.
- 3
- 2
- 1
Because the spinothalamic fibers cross in the _____ of the _____ and the medial lemnisci cross in the _____, the somatosensory cortex is concerned with the _____ side of the body.
- Anterior white commissure
- Spinal cord
- Medulla
- Contralateral
Brodmann area 5 is a small region in the posterior wall of the _____ sulcus and the adjacent _____ cortex posterior to the somatosensory cortex for the trunk, arm, and hand.
- Postcentral
- Parietal
Brodmann area 5 receives information about tendon stretch in the hand from area _____ and the neurons in the _____ of the thalamus that receive tendon stretch information about the hand.
- 2
- VPL
Area 5 projects to area 4 to assist in reaching and grasping movements of the _____.
- Hand
Although it is a sensory area, area _____ guides motor activity of the hand and arm through its projections to area 4 and its projections to internuncial neurons influencing lower motor neurons.
- 5
Some axons from neurons in area 5 project to the anterior horn of the spinal cord via the _____ tracts.
- Corticospinal
Like lesions of the _____, lesions in area 5 cause past-pointing, but they do not cause resolution of movement.
- Cerebellum (or pontocerebellum)
Like lesions of area _____ or _____, lesions of area 5 cause astereognosis.
- 3
- 2
Astereognosis is the inability to recognize _____ and _____ with the _____ closed.
- Size
- Shape
- Eyes
Area _____ is sometimes called the “hand manipulation area.”
- 5
Brodmann areas 1, 2, and 3 occupy the visible part of the _____ gyrus and its sidewalls.
- Postcentral
The _____ gyrus is often called the primary somatosensory cortex (S I).
- Postcentral
Discriminative touch, pressure, and tendon stretch reach consciousness in the _____ cortex.
- Primary somatosensory
Conscious proprioception is localized in the _____ cortex on the postcentral gyrus.
- Primary somatosensory
The _____ and _____ nuclei of the _____ project pain to Brodmann area 3 with the same somatotopic distribution as the epicritic sensations.
- Ventroposterolateral
- Ventroposteromedial
- Thalamus
Brodmann area 3 projects pain to Brodmann area 1 with the same somatotopic distribution as the epicritic sensations of _____ and _____.
- Touch
- Pressure
Pain is somatotopically distributed in both Brodmann area _____ and Brodmann area _____.
- 3
- 1
Brodmann area 1 is conscious of the _____ of pain but not of its intensity.
- Location
Pain is projected _____ from VPL and VPM to Brodmann area 3 to area 1.
- Somatotopically
The lateral fissure is the inferior boundary of the _____ cortex.
- Primary somatosensory
Somatosensory cortex extends onto the roof of the lateral fissure as the secondary _____ cortex (S II) which receives independent projections of pain from the VPL and VPM.
- Somatosensory
The _____ and _____ project pain onto a head to toe map extending from lateral to medial on
the _____ of the _____ just inferior to the postcentral gyrus.
- VPM
- VPL
- Roof
- Lateral fissure
Since protopathic sensations are localized from medial to lateral in the primary somatosensory cortex, the localization of _____ in the secondary somatosensory cortex is a mirror image of the map of the primary somatosensory cortex.
- Pain
One can draw a homunculus showing the localization of _____ in the secondary somatosensory cortex with its _____ in the depths of the fissure and its head next to the opening of the fissure.
- Pain
- Head
The head and throat areas of the primary and secondary somatosensory cortices meet where the _____ gyrus meets the _____ fissure.
- Postcentral
- Lateral
Because the secondary somatosensory cortex is much smaller than the _____, it localizes pain less precisely than the primary somatosensory cortex.
- Primary somatosensory cortex
The primary somatosensory cortex perceives the _____ of _____, but the intensity of pain is perceived in the secondary somatosensory cortex.
- Location
The secondary somatosensory cortex communicates the _____ of pain to the posterior insula and the contralateral secondary somatosensory cortex.
- Intensity
Pain is projected from both secondary somatosensory cortices to the posterior halves of both _____.
- Insulas
The _____ of pain is perceived unilaterally, but the _____ of pain is perceived bilaterally.
- Location
- Intensity
The posterior half of each _____ projects to the cortex of the ipsilateral anterior cingulate gyrus (Brodmann areas 24 and 32).
- Insula
The cingulate gyrus is part of the _____ system.
- Limbic
As part of the limbic system, _____ is responsible for most of the emotional component of pain.
- Anterior cingulate gyrus
The ventroposterolateral thalamus and ventroposteromedial thalamus send pain messages to the _____ cortex which records their intensity.
- Secondary somatosensory
The secondary somatosensory cortex sends pain messages to the contralateral _____ via the corpus callosum.
- Secondary somatosensory cortex
Each secondary somatosensory cortex sends pain messages to the posterior half of the ipsilateral _____.
- Insula
Each insula sends pain messages to the _____, which is responsible for most of the emotional aspect of pain.
- Anterior cingulate gyrus
Itching is projected from the _____ nucleus of the _____ to the secondary somatosensory cortex.
- Ventral posterior inferior
- Thalamus
Because it is projected only to the _____, itch is less well localized than pain.
- Secondary somatosensory cortex
The somatotopic arrangement of the primary somatosensory cortex on the _____ gyrus parallels the somatotopic arrangement of the _____ on the _____ gyrus.
- Postcentral
- Primary motor cortex
- Precentral
The secondary somatosensory cortex is somatotopically arranged on the _____ of the _____ with the _____ region in the depth of the fissure and the _____ region on the lateral edge.
- Roof
- Lateral fissure
- Foot
- Head
The _____ and _____ of the _____ project sensations from the _____ side of the body to both the primary and secondary somatosensory cortex.
- VPL
- VPM
- Thalamus
- Contralateral
The primary sensory cortex perceives the _____ of pain, but the secondary cortex perceives its _____.
- Location
- Intensity
Pain becomes suffering when the _____ sensory cortex projects it to the _____ half of the _____ which projects it to the _____ half of the _____.
- Secondary
- Posterior
- Insula
- Anterior
- Cingulate gyrus
Discriminative touch is appreciated in area _____ in the _____ of the postcentral gyrus.
- 1
- Center
Tendon stretch and pressure are appreciated in area _____ on the _____ edge of the _____ gyrus.
- 2
- Posterior
- Postcentral
Brodmann area 5 is the _____ which is _____ to the dorsal third of the _____ sensory cortex.
- Hand manipulation area
- Posterior
- Primary
Area 5 receives _____ information from the _____ and projects to the _____ guide movements of the _____ hand.
- Proprioceptive
- Primary sensory cortex
- Primary motor cortex
- Contralateral
The hand manipulation area projects to the primary motor cortex and to the _____ of the _____.
- Anterior horn
- Spinal cord
Two thirds of the corticospinal fibers come from the _____ and _____ cortex in the _____ lobe; one third come from the parietal lobe.
- Motor
- Premotor
- Frontal
One third of the cortical projections to the internuncials of lower motor neurons are projections from the _____ cortex that help to guide actions.
- Parietal
