Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning
Several models of heading detection during smooth pursuit rely on the assumption of local constraint line tuning to exist in large scale motion detection templates. A motion detector that exhibits pure constraint line tuning responds maximally to any 2D-velocity in the set of vectors that can be dec...
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Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnbeh.2013.00022/full |
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doaj-77ca8666d62149b2ae82310a7673bc332020-11-24T20:49:17ZengFrontiers Media S.A.Frontiers in Behavioral Neuroscience1662-51532013-04-01710.3389/fnbeh.2013.0002237606Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuningJacob eDuijnhouwer0Andre eNoest1Martin eLankheet2Albert eVan Den Berg3Richard J A Van Wezel4Richard J A Van Wezel5Rutgers UniversityRadboud UniversityWageningen UniversityDonders Institute for Brain, Cognition and BehaviourRadboud UniversityTwente UniversitySeveral models of heading detection during smooth pursuit rely on the assumption of local constraint line tuning to exist in large scale motion detection templates. A motion detector that exhibits pure constraint line tuning responds maximally to any 2D-velocity in the set of vectors that can be decomposed into the central, or classic, preferred velocity (the shortest vector that still yields the maximum response) and any vector orthogonal to that. To test this assumption, we measured the firing rates of isolated MT and MST neurons to random dot stimuli moving in a range of directions and speeds. We found that as a function of 2D velocity, the pooled responses were best fit with a 2D Gaussian profile with a factor of elongation, orthogonal to the central preferred velocity, of roughly 1.5 for MST and 1.7 for MT. This means that MT and MST cells are more sharply tuned for speed than they are for direction; and that they indeed show some level of constraint line tuning. However, we argue that the observed elongation is insufficient to achieve behavioral heading discrimination accuracy on the order of 1-2 degrees as reported before.http://journal.frontiersin.org/Journal/10.3389/fnbeh.2013.00022/fullOptic Flowmotion directionextrastriate cortexvisual motionarea MTarea MST |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jacob eDuijnhouwer Andre eNoest Martin eLankheet Albert eVan Den Berg Richard J A Van Wezel Richard J A Van Wezel |
spellingShingle |
Jacob eDuijnhouwer Andre eNoest Martin eLankheet Albert eVan Den Berg Richard J A Van Wezel Richard J A Van Wezel Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning Frontiers in Behavioral Neuroscience Optic Flow motion direction extrastriate cortex visual motion area MT area MST |
author_facet |
Jacob eDuijnhouwer Andre eNoest Martin eLankheet Albert eVan Den Berg Richard J A Van Wezel Richard J A Van Wezel |
author_sort |
Jacob eDuijnhouwer |
title |
Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning |
title_short |
Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning |
title_full |
Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning |
title_fullStr |
Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning |
title_full_unstemmed |
Speed and direction response profiles of neurons in macaque MT and MST show modest constraint line tuning |
title_sort |
speed and direction response profiles of neurons in macaque mt and mst show modest constraint line tuning |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Behavioral Neuroscience |
issn |
1662-5153 |
publishDate |
2013-04-01 |
description |
Several models of heading detection during smooth pursuit rely on the assumption of local constraint line tuning to exist in large scale motion detection templates. A motion detector that exhibits pure constraint line tuning responds maximally to any 2D-velocity in the set of vectors that can be decomposed into the central, or classic, preferred velocity (the shortest vector that still yields the maximum response) and any vector orthogonal to that. To test this assumption, we measured the firing rates of isolated MT and MST neurons to random dot stimuli moving in a range of directions and speeds. We found that as a function of 2D velocity, the pooled responses were best fit with a 2D Gaussian profile with a factor of elongation, orthogonal to the central preferred velocity, of roughly 1.5 for MST and 1.7 for MT. This means that MT and MST cells are more sharply tuned for speed than they are for direction; and that they indeed show some level of constraint line tuning. However, we argue that the observed elongation is insufficient to achieve behavioral heading discrimination accuracy on the order of 1-2 degrees as reported before. |
topic |
Optic Flow motion direction extrastriate cortex visual motion area MT area MST |
url |
http://journal.frontiersin.org/Journal/10.3389/fnbeh.2013.00022/full |
work_keys_str_mv |
AT jacobeduijnhouwer speedanddirectionresponseprofilesofneuronsinmacaquemtandmstshowmodestconstraintlinetuning AT andreenoest speedanddirectionresponseprofilesofneuronsinmacaquemtandmstshowmodestconstraintlinetuning AT martinelankheet speedanddirectionresponseprofilesofneuronsinmacaquemtandmstshowmodestconstraintlinetuning AT albertevandenberg speedanddirectionresponseprofilesofneuronsinmacaquemtandmstshowmodestconstraintlinetuning AT richardjavanwezel speedanddirectionresponseprofilesofneuronsinmacaquemtandmstshowmodestconstraintlinetuning AT richardjavanwezel speedanddirectionresponseprofilesofneuronsinmacaquemtandmstshowmodestconstraintlinetuning |
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