Transcript 意義影響運動知覺start

Chapter 8
運動知覺
（Perceiving
movement ）
• 運動知覺有多重要？
– 運動失認症（motion agnosia）
• 無法用茶壺倒茶
• 無法待在人多的地方
• 過馬路有困難
產生運動知覺的四種方式？
• 真實運動
– 閾值受周邊因子影響
1/6~1/3 VA / second
1/60 VA / second
Fig. 9-1, p. 196
Fig. 9-1a, p. 196
產生運動知覺的四種方式？
• 似動運動（apparent motion）
– Exner (1875)
– 電影/動畫/霓虹燈
– Wertheimer
• Phi phenomenon
• Magni-phi
• AM-illusory contour
Fig. 9-1b, p. 196
(No motion)
產生運動知覺的四種方式？
• 與視覺似動運動相近
– 刺激皮膚產生似動運動時，somatosensory
cortex之神經元也產生反應
皮質處理感官訊息時，不論何種感官，均傾向將連續的刺
激連結起來
– ISI<30ms, 無運動--同時on/off
ISI>30ms,部分運動
ISI>60ms, 連續運動
ISI>200~300ms, 無運動--先後on/off
（demo）
– 距離
觸覺的似動運動
產生運動知覺的四種方式？
• 誘發運動（induced movement）
– 周遭的運動引發自身運動的錯覺
• 如，坐在靜止火車中等待會車，相鄰車廂的移動引
發自身車廂移動的錯覺，demo
– 運動後效（motion aftereffect）
• 如瀑布錯覺（waterfall illusion），spiral motion
after effect（demo）
Fig. 9-1c, p. 196
• motion illusion
• Structure from motion
– 透過刺激的運動，使原本不清楚的結構（形狀）
變得清楚可辨
Figure 9.4 Setup similar to the one used by Wallach and O’Connell (1953) to demonstrate the kinetic depth
effect.
Fig. 9-5, p. 199
Fig. 9-3a, p. 198
Fig. 9-3b, p. 198
Fig. 9-3c, p. 198
觀看者運動或不運動的幾種狀況
Figure 8.8 In (a) and (b), Jeremy walks past as
Maria observes him. Maria perceives him as
moving in (a), when his image moves across her
retina, and in (b), when his image stays fixed on
her fovea. In (c), when Maria walks through the
environment, she perceives the environment as
stationary, even though its image is moving
across her retina. The text describes how the
stimulus information provided by the optic array
and global flow helps determine these
perceptions.
Motion of a Stimulus Across the Retina
• Aperture problem
– Activity of a single
complex cell does not
provide accurate
information about direction
of movement.
Figure 8.12 “Movement of Bar Across an Aperture” demonstration. See text for details.
框架問題（the aperture problem）
• Solution to aperture
problem
– Responses of a
number of directionally
selective neurons are
pooled
• This may occur in
the MT cortex (the
where/action
stream).
– Neurons on the striate
cortex respond to
movement of ends of
objects.
解決方式—統整不同區域的訊息
Module for
movement
perception
Figure 9.15 (a) Some of the nuclei in the dorsal and ventral streams. The MT cortex, which is a module for
movement perception, is in the dorsal stream, and the IT cortex, which is a module for form perception, is in
the ventral stream. (b) The location of the MT and IT cortex in the brain.
運動知覺的特徵偵測器
• V1複雜細胞之tuning curve
• 但是神經元是如何偵測運
動的？背後的神經迴路是
什麼？
• 偵測以後呢？
– MT--90%神經元具有方向選擇性，切除之影響猴子對運
動方向的偵測；方位選擇性並具有columnar structure
also 可由microstimulation的方法獲得類似結論
– MT神經元並與global motion的偵測有關
• 相關 0.8%-- baseline firing—chance detection
相關 12.8%--faster firing—highly accurate detection
Coherence of dot movement↑,
Firing of the MT neurons↑ & Judgment of movement accuracy↑
• Lesioning experiment
– Normal monkeys can detect
motion with coherence of 1 or 2%.
– Monkeys with lesions in MT cortex
cannot detect motion until the
coherence is 10 to 20%.
• Activating “preferred downward
direction neurons” made
monkey change judgment.
• Downward + Rightward
眼球移動的角色
Corollary discharge theory
• 運動知覺仰賴三種訊號
– 動作訊號（motor signal, MS）
– 附帶釋放訊號（corollary discharge signal, CDS）
– 影像移動訊號（image movement signal, IMS）
• 當CDS或IMS到達比較器（comparator）時，運
動知覺產生；但是當CDS與IMS同時到達比較器
（comparator）時，沒有運動知覺
Figure 8.18 According to the corollary discharge
model (a) when a motor signal (MS) to move the
eyes is sent to the eye muscles, so the eye can
follow a moving object, there is a corollary discharge
signal (CDS), which splits off from the motor signal.
(b) When the CDS reaches the comparator, it sends
a signal to the brain that the eye is moving, and
motion is perceived.
Figure 9.8 How inputs to the comparator (circle) affect movement perception. When the comparator
receives either the corollary discharge signal (CDS) alone, as in (a), or the image movement signal (IMS)
alone, as in (b), it sends a movement signal to the cortex, and movement is perceived. When the
comparator receives both the CDS and IMS signals, a movement signal is not sent to the cortex, and no
movement is perceived.
Figure 9.9 In all four examples shown in the figure, a signal is sent to the eye muscles, and a corollary
discharge is generated. However, no image movement signal is generated, so movement is perceived.
See text for details.
Fig. 9-10, p. 203
– 沒有IMS，但CDS引發運動知覺的可能方式 – 這些行為證據支持
corollary discharge theory
真實運動神經元
當眼球與刺激都運動時就不活躍
Fig. 8.23, p. 191
知覺組織與運動知覺
• 運動造成知覺組織
– Biological motion
• animal
• male vs. female
• Neurons in monkey’s
superior temporal
sulcus respond to
man walking forward
but less so for other
directions of walking
生物運動（biological motion）
http://www.biomotionlab.ca/Demos/BMLwalker.html
Fig. 9-17, p. 208
Figure 9.18 Frames from the stimuli used by Grossman and Blake (2001). (a) Sequence from the pointlight walker stimulus. (b) Sequence from the scrambled point-light stimulus.
• Determining whether
motion was biological
or scrambled
– Noise added led to
71% accuracy.
– Transcranial magnetic
stimulation (TMS)
applied only to STS
caused a decrease in
ability to detect
biological motion.
Biological motion
Scrambled stimulus
Biological motion
+ noise
Biological motion
+ noise
Biological motion
stimulus

• Other
neurons
respond to
point light
walker
• Also, for
human, PET
activity
increases in
STS when
presented
with man
walking
• 意義與運動知覺
– 意義影響運動知覺start
– 知識影響運動知覺
• 最短路徑規範（shortest path constraint）
– 即使兩個刺激的運動路徑有很多可能性，運動
知覺仍會採最短的路徑
– 長SOA(>200 ms）正常動作start
短SOA(<200 ms) 不可能動作start
– PET 研究發現，二者都有頂葉激發，但只有前
者有運動皮質的激發
• 顯示
– 視覺系統需要時間來處理複雜意義的刺激
– 人體有其特殊性（用其他類型刺激無法得到這
個結果）
運動知覺的智慧
• Visual heuristics, again
– 由於視覺刺激中的訊息往往不夠明確，所以視覺系統採用一
些捷徑來解讀刺激的特性
• 「運動朝同一方向進行」經驗法則
– 一個物體開始運動後會持續朝同一方向運動（格式塔定
律--good continuation）
– 「遮蔽」經驗法則
• 運動的物體落於同一位置時可能會被遮蔽
• Duck demo
• Finger demo
Fig. 9-22a, p. 210
Fig. 9-22b, p. 210
• Implied motion
– Representational momentum
Figure 8.28 Stimuli used by Reed and Vinson (1996) to demonstrate the effect of experience on
representational momentum. In this example, the test pictures are lower than the memory picture. On other
trials the rocket would appear in the same position as or higher than the memory picture.
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End
Figure 9.12 Stimuli used to study the neural response to movement: (a) oriented moving bars; (b) fields of
moving dots.
Figure 9.13 “Movement of Bar Across an Aperture” demonstration. See text for details.
框架問題（the aperture problem）
解決方式—統整不同區域的訊息
Module for
movement
perception
Figure 9.15 (a) Some of the nuclei in the dorsal and ventral streams. The MT cortex, which is a module for
movement perception, is in the dorsal stream, and the IT cortex, which is a module for form perception, is in
the ventral stream. (b) The location of the MT and IT cortex in the brain.
運動知覺的特徵偵測器
• V1複雜細胞之tuning curve
• 但是神經元是如何偵測運
動的？背後的神經迴路是
什麼？
• 偵測以後呢？
– MT--90%神經元具有方向選擇性，切除之影響猴子對運
動方向的偵測；方位選擇性並具有columnar structure
also 可由microstimulation的方法獲得類似結論
– MT神經元並與global motion的偵測有關
• 相關 0.8%-- baseline firing—chance detection
相關 12.8%--faster firing—highly accurate detection
知覺組織與運動知覺
• 運動造成知覺組織
– Biological motion
• animal
• male vs. female
• Neurons in monkey’s
superior temporal
sulcus respond to
man walking forward
but less so for other
directions of walking
生物運動（biological motion）
Fig. 9-17, p. 208
Figure 9.18 Frames from the stimuli used by Grossman and Blake (2001). (a) Sequence from the pointlight walker stimulus. (b) Sequence from the scrambled point-light stimulus.
• Other neurons
respond to point
light walker
• Also, for human,
PET activity
increases in STS
when presented
with man walking
• 意義與運動知覺
– 意義影響運動知覺start
– 知識影響運動知覺
• 最短路徑規範（shortest path constraint）
– 即使兩個刺激的運動路徑有很多可能性，運動
知覺仍會採最短的路徑
– 長SOA(>200 ms）正常動作start
短SOA(<200 ms) 不可能動作start
– PET 研究發現，二者都有頂葉激發，但只有前
者有運動皮質的激發
• 顯示
– 視覺系統需要時間來處理複雜意義的刺激
– 人體有其特殊性（用其他類型刺激無法得到這
個結果）
運動知覺的智慧
• Visual heuristics, again
– 由於視覺刺激中的訊息往往不夠明確，所以視覺系統採用一
些捷徑來解讀刺激的特性
• 「運動朝同一方向進行」經驗法則
– 一個物體開始運動後會持續朝同一方向運動（格式塔定
律--good continuation）
– 「遮蔽」經驗法則
• 運動的物體落於同一位置時可能會被遮蔽
• Duck demo
• Finger demo
Fig. 9-22a, p. 210
Fig. 9-22b, p. 210
• Implied motion
– Representational momentum
Figure 9.24 Stimuli used by Reed and Vinson (1996) to demonstrate the effect of experience on
representational momentum. See text for details.
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