sensory ino processing and sub-cortical systems

Question 1

what are the sub-cortical structures for sensory info processing?

Answer 1

superior colliculus and thalamus

Question 2

Torre, 1995 said what?

Answer 2

mechanisms of transduction and adaptations are v similar across senses

Question 3

what is selective adaptation?

Answer 3

neurons are tuned to properties of a stimulus firing.
sensory system is tuned to changes in stim, diminished sensitivity due to unchanging stimulation, causing neuron’s firing rate to decrease.

Question 4

what is sensory transduction?

Answer 4

conversion of a sensory stimulus from one form to another.

Question 5

vis and olfactory are what type of stim?

Answer 5

chemosensation; absorption of photon, binding of molecule.

Question 6

audition and vestibular systems are what type of stim?

Answer 6

mechanosensation/ direct activation

Question 7

what is the retino-collicular pathway?

Answer 7

retina- superior colliculus (SC)- pulvinar (in thalamus)- posterior parietal cortex (PPC)

Question 8

what is the retino-geniculate pathway?

Answer 8

retina- LGN (in thalamus)- V1- …
…dorsal stream brings you to PPC
…ventral stream brings you to infero-temporal cortex

Question 9

thalamocortical system?

Answer 9

primary sensory signals pass thro thalamus en route to cortex.
thalamus is the primary sight of relay of all sensory pathways, except olfaction.

Question 10

types of thalamic nuclei?

Answer 10

1) relay nuclei
2) association nuclei
3) non-specific nuclei

Question 11

what are relay nuclei?

Answer 11

receive very defined inputs and project this signal to functionally distinct areas in cerebral cortex.
- nuclei that relay primary sensations: VPL/ ventro posterolateral; VPM/ ventro posteromedial; LGN and MGN

Question 12

what are association nuclei?

Answer 12

receive input from cerebral cortex and project back to cerebral cortex in association areas where they appear to regulate activity.
largest of these is the pulvinar: vis perc. and eye movements

Question 13

what are non-specific nuclei?

Answer 13

intralaminar and midline thalamic nuclei. project broadly throughout cerebral cortex.
general functions: alerting and arousal

Question 14

what is thalamus?

Answer 14

site where sensory input gets modulated, and the site of relay from cerebellar and basal ganglia inputs go to cerebral cortex.

• feedback pathways/ cerebellum and basal ganglia respond to outputs from cerebral cortex
• limbic pathways/ make input to dorsal thalamus

all thalamic nuclei project to cerebral cortex, except reticular thalamic nuclei

all pulvinar region of thalamus= high-order relay of transferring info between cortical areas

Question 15

thalamocortical projections; Cappe 2009?

Answer 15

do diff modalities partly overlap in thalamus?
anatomical supports multisensory interplay in thalamus
measured PPC activation in macaque monkeys
- most sig. overlap across modalities was the medial pulvinar nucleus

Question 16

pulvinar thalamus nucleus; Berman and Wurtz 2008?

Answer 16

measured inputs from SC, and outputs to cortex of pulvinar nucleus (MT/ motion cortical region)
- neurons fire to inputs from SC to vis stim but do not fire before eye movement is made