Could synchronized neuronal activity be imaged using Low Frequency Electrical Impedance Tom

Could synchronized neuronal activity be imaged using Low

Frequency Electrical Impedance Tomography (LFEIT)?

O. Gilad1a, L. Horesh a, G.M. Ahadzi b,a, R.H. Bayford b,a, D.S.Holder a

a Departments of Clinical Neurophysiology and Medical Physics, University College London

b School of Health and Social Sciences, Middlesex University, Archway Campus, London. ABSTRACT: Electrical impedance Tomography (EIT) has the potential to achieve non-invasive functional imaging of fast neuronal activity in the human brain, which is not currently possible with any other method. The mechanism for fast ( ~ 1ms) impedance changes is the opening of ion channels during neuronal depolarization; this results in cell membrane impedance decreases below 100Hz. Cable theory modelling and animal studies previously done in our group indicate cortical resistivity changes of the order of 1% during evoked responses. The purpose of this work was to quantify the expected voltage changes over the scalp during visual stimulation and Low Frequency EIT (LFEIT) measurement and to estimate the SNR that could be expected in real human measurements. Modelling was performed using a four layer anatomically realisti

c Finite Element Methods (FEM) mesh of the head. LFEIT recordings were made in a saline fille

d tank and human experiments during visual evoked responses. Th

e numerical simulations predicted that resistivity changes o

f 1% in the primary visual cortex translated into voltage changes of 0.001% on the scalp. In human scalp recordings, a sensitivity limit of 0.003% was reached after 10 minutes of averaging. Low SNR conditions obscured resistivity changes in most subjects but possible changes were observed in 28.5% of the experiments with the highest change of 0.01% with SNR of 4. The main factor limitin

g the SNR is the background electroencephalography (EEG) activity whic

h coexists within the same band of the LFEIT measurements. These experimental results are in broad agreement with the predictions but indicate that the measurement of fast impedance changes related to neuronal depolarization is not yet reliable.

Keywords: low frequency electrical impedance tomography, LFEIT, visual evoked potential, VEP.

1.INTRODUCTION

EIT has the potential to image fast neuronal activity in the human brain; this is not yet possible using any other method [1]. Our aim is to develop a non-invasive method for measuring resistivity changes related to neuronal activity. Studies into imaging of brain function require active and synchronised neuronal activity at a known brain region. This can be achieved by visual stimulation, such as a bright flash or pattern reversal checkerboard screen, which causes activity in the visual cortex. The brain activity generates potentials on the scalp at the back of the head known as Visual Evoked Potential (VEP).

1.1.Mechanisms for bioimpedance changes during normal functional brain activity

Slow changes: Active brain tissue draws more blood to compensate for the increased metabolic activity. The increase in blood volume causes local impedance changes of the order of 10% over tens of seconds and was demonstrated in our group during human VEP [2].

Fast changes: The change of resistive properties in individual neurones underlies all neural activity. When an action potential propagates along a nerve, ion channels in the cell membrane open to allow ions flow. The electrical resistivity of the cell membrane decreases during neuronal depolarisation, thus allowing external current to flow more freely through the cell [3]. These changes last tens of milliseconds and are maximal at frequencies below 100Hz. Membrane capacitance limits current from flowing into the cell at low frequencies whereas at high frequencies the current can flow through the membrane regardless of the state of ion channels. When the activity of a population of neurones displays spatial and temporal coherence such as in visual evoked response, it will be accompanied with resistivity change of the active tissue as a whole.

The magnitude of such fast changes has been investigated by modelling and animal studies in our group (Table 1). Mathematical modelling, based on cable theory, estimated local resistivity changes near DC to be 3.7% for peripheral nerve bundles and 0.06-1.7% for the cortex during Evoked Potentials (EP) [4,5]. These predictions agree with measurements done on crab peripheral nerve which showed a change of 0.5-1o.gilad@https://www.sodocs.net/doc/118228592.html, ; phone 44 2076790244; fax 442073809002; https://www.sodocs.net/doc/118228592.html,/midx-group/

1.0% change [5-7] and measurement on the surface of rabbit cortex during median nerve evoked response which showed a change of 0.01-0.03% [5,8]. In order to predict how such local changes are translated when measured on the surface of the scalp, Liston [4] initially estimated the boundary changes to drop to 0.006-0.17%. Ahadzi [9] then used realistic Finite Element Method (FEM) of the head and solution of the forward problem to quantitatively estimate the changes on the scalp when a 1% local resistivity changes occurred at the visual cortex during the VEP. Boundary voltage changes were estimated to be 0.02-0.04% for optimal four terminal resistivity measurements. These numeric predictions are further refined in the present study (see below). A desirable sensitivity for measuring those small resistivity changes on the scalp appears to be 0.01-0.001%.

Table 1. Summary of predicted and measured fast resistivity changes [%].

Experimental

FEM

Cable

Theory

Crab nerve ~ 3.7 - 0.5-1.0

rabbit cortex, EP 0.06-1.7 - 0.01-0.03

Human scalp, EP 0.006-0.17 0.02-0.04 -

1.2.Purpose and design

The purpose of this study was to quantify the expected voltage changes recorded on the scalp during visual stimulation producing Visual Evoked Responses (VER) recorded with Low Frequency EIT (LFEIT) measurement. In order to achieve this, we estimated the Signal to Noise Ratio (SNR) that could be expected in human measurements. We set out to quantify the signal and noise level when the measurement was performed with scalp electrodes during VEPs. Unfortunately, the EIT signal is contaminated and obscured by the VEP and background EEG signals within the same frequency band; the need to separate the different components of the recorded signal and to maximize the signal to noise ratio (SNR) poses a substantial signal processing challenge.

We refined the FEM simulations done by Ahadzi [9] for the prediction of voltage changes, implemented a prototype LFEIT and performed phantom and human experiments to validate the predictions.. We induced brain activity using VEP and applied a 1Hz square wave current synchronized to the visual stimuli. Resistivity changes were extracted by calculating the sum and difference between the two polarities and compared with a reference recording of current without VEP. Resistivity changes were expected to occur when the VEP showed a peak activity 100ms after stimulation (P100).

2.METHODOLOGY

FEM Simulations: we predicted the voltage changes using a four layers (brain, cerebrospinal fluid, skull and scalp) realistic head Finite Element Method (FEM) mesh (136,000 elements), for solution of the forward problem [10]. The primary visual cortex (V1 area) was also modelled (Fig 1). The refinements of the simulations described in [9] included 1) an array of 21 electrodes placed on the back of the head instead of 31 electrodes all over the head, 2) taking into account all possible current injection and voltage measurement pairs, and 3) using the true electrodes positions as placed on individual subjects. The boundary voltage predictions for the standing voltage and the voltage changes resulting from local resistivity change were compared to measurements done on a spherical saline tank and human subjects (see below). The FEM simulations also suggested the optimal placement of electrodes for the prototype system measurements.

Prototype system: Data acquisition for the human subjects was done using 21 standard Ag/AgCl EEG electrodes placed on the back of the head centred above the visual cortex (5cm above the inion of the occipital bone). The reference and ground electrodes for all channels were the standard EEG positions Fz (forehead) and Cz (vertex) respectively. In a typical recording session, 19 electrodes were used to record the voltage signals and 2 electrodes were used to inject current (Fig. 2). Signals were recorded with a SD128 EEG acquisition system (Micromed, Italy) with 16bit resolution, ±12.8mV extended dynamic range, 1024Hz sampling rate, high pass input filter of 0.15Hz (40 dB/decade), common mode rejection ratio > 105 dB @ 50 Hz and input impedance > 1000G?. 2Hz trigger pulses were produced by the same machine and recorded on a separate channel for later analysis. These pulses were used to trigger the visual stimulation and the square wave current source.

Fig.1.Realistic head mesh and the visual cortex (red). Fig.2.The experimental setup.

A current level of a 100-200μA bipolar square wave was injected at several pairs out of the 21 channels. The custom made constant current source was calibrated for baseline offset <1% prior to each experiment to prevent DC components. The current source was triggered by a DDU-315 unit (Digitimer, UK), which was set to 150ms delay between the current source and visual stimulation triggers.

Visual stimulation was triggered from the EEG system at a rate of 2 reversals per sec. A full field pattern reversal black/white checkerboard (Pattern 10, Micromed, Italy) was applied to the subject while seated 70cm from the stimulating screen in a dark room. The subject was requested to focus on a centred fixation yellow point on the screen. The check size was 41.7’ (60 minutes = 1o), field size 22ox17o (32x24 checks) and 100% contrast. Each stimulation session lasted 60sec to prevent the effect of accommodation to the stimulus.

At every 60sec session, 39-41 out of 60 square wave cycles were averaged after rejecting 30% of outliers ascribed to eye blinking, muscular and movement artefacts and discontinuous eye focus on the screen marker. Resistivity changes from the resulting signal were calculated by subtraction of the two polarity segments of the square wave.

Six normal subjects (1 male, 5 females) age 25-42 participated in this study. Control recordings were done before and after the resistivity change measurements including a) background EEG, b) visual stimulation without current and c) current without visuals stimulation. Two different current injection pairs were used consecutively in four subjects and one current pair was used in two subjects. One subject was repeated to confirm reproducibility of the results. Each injection pair session was repeated 10 times with and without visual stimulation to construct a grand average to reduce noise levels. The total number of grand average sessions across subjects which could be regarded as different experiments was 14.

The tank experiment was done with the same recording setup on a spherical tank (20cm diameter) filled with 0.2% saline and 31 Ag/AgCl 2mm diameter ball electrodes. Local resistivity changes of 19% in the visual cortex area were simulated using a sponge ellipsoid of volume 18.5 cm 3.

First order linear regression was used to compare the measured and predicted standing voltages and voltage changes for both tank and human measurements. Statistical values given below are the slope mean, standard deviation (SD) and correlation coefficient R.

3. RESULTS

The numerical simulation predicted that resistivity changes of 1% in the primary visual cortex translate into a maximal voltage change of 0.001% on the scalp. There was a significant correlation between predicted and recorded standing voltages for the tank with a slope of 1.02 ± 0.05 (Mean ± SD; R=0.98) and for the human measurements with a slope of 1.1 ± 0.4 (Mean ± SD, R=0.95) (Fig. 3). Voltage changes due to local resistivity changes were confirmed in the tank with a slope of 0.87 ± 0.40 (Mean ± SD; R=0.86). However, such comparison was limited by poor SNR for the human measurements. The main source of noise was the background EEG signal caused by spontaneous brain activity (~10μV), which coexisted within the same band of the LFEIT measurements. The sensitivity limit was 0.003% after averaging n=1000 stimuli (~10 min for 2 stim./s) for 10 minutes with another 10 minutes recording as reference.

A significant resistivity change was observed in 4 out of 14 grand averaged sessions (29%). These 4 sessions were recorded from 3 different subjects and the best case had a maximal change of 0.01% and SNR of 4 (Fig. 4a). Reproducibility could not be confirmed from a repeated recording for the same

subject. A normal VEP, containing the expected P100, was extracted during current injection (Fig. 4b).

4. DISCUSSION AND CONCLUSIONS

The FEM simulations were validated by comparing the predicted standing voltages with measurements from both tank and humans. The dispersion around a unity slope in a linear fit (Fig. 3) is most probably related to inaccurate registration of conductivities in the four layers of the mesh, and usage of a single standard head geometry in the mesh which did not take account of individual differences in anatomy, and no allowance for tissue anisotropy. Predictions for changes in boundary voltages are of the order of 0.001%, an order of magnitude less than the value reported previously [9]. This is related to the refinments we incorporated into our modelling study as described in the methods section. The sensitivity of the prototype system with our experimental protocol was 0.003% which is an order of magnitude better than the sensitivity of 0.03-0.06% we have reported previously [11]. Signal levels are proportionate to the level of current used. However, it is limited by safety issues and the possible effect of the current on changing the brain activity. The low SNR conditions obscured resistivity changes in most subjects. Yet, possible changes were observed in 28.5% of the experiments with the highest change of 0.01% with SNR of 4. These changes are delayed by 50ms from the P100 peak. The low SNR prevented statistical validations of significany and reproducability.

No reproducible fast impedance changes related to neuronal activity could be detected. It is just possible that some were at the border of detectability using this new approach. However, the long acquisition protocol limits the feasibility of designing imaging system at this stage. Work in progress is to examine the posibility of using Magnetoencephalography (MEG) methods to increase the sensitivity of the measurement side as the skull is transparent to magnetic fields.

Acknowledgments

This study was supported by the BBSRC and the Epilepsy Research Foundation.

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VEP. XII International Conference on Electrical Bio-Impedance and Electrical Impedance Tomography , p 279-282, Gdansk, Poland, June 2004. Stimuli Stimuli

P100a

b

Fig 3. Measured vs. predicted standing voltages for all

human subjects. Fig.4. Grand averaged a) resistivity changes for 15 measurement pairs and b) VEP for 19 channels.

感官动词和使役动词

感官动词和使役动词 默认分类2010-05-28 23:14:26 阅读46 评论0 字号：大中小订阅 使役动词，比如let make have就是3个比较重要的 have sb to do 没有这个用法的 只有have sb doing.听凭某人做某事 have sb do 让某人做某事 have sth done 让某事被完成（就是让别人做） 另外： 使役动词 1.使役动词是表示使、令、让、帮、叫等意义的不完全及物动词,主要有make(使,令), let(让), help(帮助), have(叫)等。 2.使役动词后接受词,再接原形不定词作受词补语。 He made me laugh. 他使我发笑。 I let him go. 我让他走开。 I helped him repair the car. 我帮他修理汽车。 Please have him come here. 请叫他到这里来。 3.使役动词还可以接过去分词作受词补语。 I have my hair cut every month. 我每个月理发。 4.使役动词的被动语态的受词补语用不定词,不用原形不定词。 (主)He made me laugh. 他使我笑了。 (被)I was made to laugh by him. 我被他逗笑了。 使役动词有以下用法： a. have somebody do sth让某人去做某事 ??i had him arrange for a car. b. have somebody doing sth.让某人持续做某事。 ??he had us laughing all through lunch. 注意：用于否定名时，表示“允许” i won't have you running around in the house. 我不允许你在家里到处乱跑。 ******** 小议“使役动词”的用法 1. have sb do 让某人干某事 e.g:What would you have me do? have sb/sth doing 让某人或某事处于某种状态，听任 e.g: I won't have women working in our company. The two cheats had the light burning all night long. have sth done 让别人干某事，遭受到 e.g:you 'd better have your teeth pulled out. He had his pocket picked. notes: "done"这个动作不是主语发出来的。 2.make sb do sth 让某人干某事 e.g:They made me repeat the story. What makes the grass grow?

感官动词的用法

感官动词 1.see, hear, listen to, watch, notice等词，后接宾语，再接省略to的动词不定式或ing形式。前者表全过程，后者表正在进行。句中有频率词时，以上的词也常跟动词原形。 注释:省略to的动词不定式--to do是动词不定式，省略了to,剩下do，其形式和动词原形是一样的，但说法不同。 see sb do sth 看到某人做了某事 see sb doing sth 看到某人在做某事 hear sb do sth 听到某人做了某事 hear sb doing sth 听到某人在做某事 以此类推... I heard someone knocking at the door when I fell asleep. (我入睡时有人正敲门,强调当时正在敲门) I heard someone knock at the door three times. (听到有人敲门的全过程) I often watch my classmates play volleyball after school. (此处有频率词often) （了解）若以上词用于被动语态，须将省略的to还原： see sb do sth----sb be seen to do sth hear sb do sth----sb be seen to do sth 以此类推... We saw him go into the restaurant. → He was seen to go into the restaurant. I hear the boy cry every day. → The boy is heard to cry every day. 2.感官动词look, sound, smell, taste, feel可当系动词，后接形容词。 He looks angry. His explanation sounds reasonable. The cakes smell nice.

英语中感官动词的用法

英语中感官动词的用法 一、感官动词 1、感官动词(及物动词)有：see/notice/look at/watch/observe/listen to/hear/feel(Vt)/taste(Vt)/smell(Vt) 2、连缀动词(含感官不及物动词) be/get/become/feel/look/sound/smell/taste/keep/stay/seem/ appear/grow/turn/prove/remain/go/run 二、具体用法： 1、see, hear, smell, taste, feel,这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……"。除look之外，其它几个动词的主语往往是物，而不是人。 例如：These flowers smell very sweet.这些花闻起来很香。 The tomatoes feel very soft.这些西红柿摸起来很软。 2、这些动词后面也可接介词like短语，like后面常用名词。 例如：Her idea sounds like fun.她的主意听起来很有趣。 3、这五个感官动词也可作实义动词,除look(当"看起来……"讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,此时作为实义动词讲时其主语一般为人。 例如:She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 4、taste, smell作不及物动词时,可用于"t aste / smell + of +名词"结构,意为"有……味道/气味"。 例如:The air in the room smells of earth.房间里的空气有股泥土味。 5、它们(sound除外)可以直接作名词,与have或take构成短语。 例如：May I have a taste of the mooncakes?我可以尝一口这月饼吗？taste有品位、味道的意思。 例如：I don’t like the taste of the garlic.我不喜欢大蒜的味道。 She dresses in poor taste.她穿着没有品位。 look有外观，特色的意思，例：The place has a European look.此地具有欧洲特色。 feel有感觉，感受的意思，watch有手表，观察的意思。例：My watch is expensive.我的手表很贵。 6、其中look, sound, feel还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。 例如：It looks as if our class is going to win.看来我们班好像要获胜了。 7、感官动词+do与+doing的区别： see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do表示动作的完整性，真实性；+doing 表示动作的连续性，进行性。 I saw him work in the garden yesterday.昨天我看见他在花园里干活了。(强调"我看见了"

感官动词的用法

1.感官动词用法之一：see, hear, listen to, watch, notice等词，后接宾语，再接动词原形或ing形式。前者表全过程，后者表正在进行。句中有频率词时，以上的词也常跟动词原形。 I heard someone knocking at the door when I fell asleep. (我入睡时有人正敲门) I heard someone knock at the door three times. (听的是全过程) I often watch my classmates play volleyball after school.(此处有频率词often) 若以上词用于被动语态，后面原有动词原形改为带to不定式： We saw him go into the restaurant. →He was seen to go into the restaurant. I hear the boy cry every day. →The boy is heard to cry every day. 2.感官动词用法之二：look, sound, smell, taste, feel可当系动词，后接形容词： He looks angry. It sounds good. The flowers smell beautiful. The sweets taste sweet. The silk feels soft. I felt tired. They all looked tired. 这些动词都不用于被动语态。如：The sweets are tasted sweet.是个病句。注意：如果加介词like,则后不可接形容词，而接名词或代词：

感官动词

感官动词的概念和相关考点 1、什么是感官动词？ 听觉：listen to、hear 视觉：look at、seem、watch 嗅觉：smell 触觉：feel、touch 味觉：taste 2、感官动词如何正确使用？ Tom drove his car away. →I saw him drive away. (全过程) 用法一：somebody did sth + I saw this I saw somebody do something. Tom was waiting for the bus. →I saw Tom waiting for the bus. (看不到全过程) 用法二：somebody was doing sth + I saw this I saw somebody doing something 练习： 一、句子翻译 1. I didn,t hear you come in. 2. I suddenly felt sth touch me on the shoulder. 3. I could hear it raining. 4. Listen to the birds singing. 5. Can you smell sth burning? 6. I found Sue in my room reading my letters. 二、灵活运用 1. I saw Ann waiting for the bus. 2. I saw Dave and Helen playing tenins. 3. I saw Clair having her meal. 三、选择最佳选项 1. Did anybody see the accident (happen/happening)? 2. We listen to the old man (tell/telling) his story from beginning to the end. 3. Listen! Can you hear a baby (cry/crying)? 4.—Why did you turn around suddenly? — I heard someone (call/calling) my name. 5. We watched the two men (open/opening) a window and (climb/climbing) through it into house. 6. When we got there, we found our cat (sleep/sleeping) on the table. 四、感官动词的被动语态 Oh，the milk is tasted strange.

感官动词用法

我们学过了五个与人的感觉有关的动词，它们是look，sound，smel l，taste，feel，我们可称之为“感官”动词。它们的用法有着许多相同点，但也有不同之处，现就此作一小结。 一、这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为“看/听/闻/尝/摸起来……”。除loo k之外，其它几个动词的主语往往是物，而不是人。例如：These flowers smell very sweet. 这些花闻起来很香。 The tomatoes feel very soft. 这些西红柿摸起来很软。 The music sounds beautiful. 二、这些动词后面也可接介词like短语，like后面常用名词。例如： Her idea sounds like fun. 她的主意听起来很有趣。 He looks like his father. 三、这五个感官动词也可作实义动词，除look（当“看起来……”讲时）只能作不及物动词外，其余四个既可作及物动词也可作不及物动词，其主语通常是人。例如： She smelt the meat. 她闻了闻那块肉。

I felt in my pocket for cigarettes. 我用手在口袋里摸香烟。 He tasted the soup and added some salt. Miss Wang asked us to look at the blackboard. 四、taste，smell作不及物动词时，可用于“taste / smell + of + 名词”结构，意为“有……味道 / 气味”。例如： The air in the room smells of earth. 房间里的空气有股泥土味。 The bread taste of sugar. 五、它们（sound除外）可以直接作名词，与have或take构成短语。例如： May I have a taste of the mooncakes？我可以尝一口这月饼吗？ May I have a look at your photo? 六、其中look，sound，feel还能构成“look / sound / feel + as if +从句”结构，意为“看起来/听起来/ 感觉好像……”。例如：

英语感官动词用法大全!

在基础英语写作中往往有学生对谓语的选用有一定困惑，其中就有一类特殊的动词：感官动词。今天就由来为大家把其用法进行一下总结： (A)感官动词(及物动词)有： see/notice/look at/watch/observe/listen to/hear/feel(Vt)/taste(Vt)/smell(Vt) (B)连缀动词(含感官不及物动词) be/get/become/feel/look/sound/smell/taste/keep/stay/seem/ appear/grow/turn/prove/remain/go/run 一、see, hear, feel, watch, look,这五个动词均可作 连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……" look之外，其它几个动词的主语往往是物，而不是人。 例如： These flowers smell very sweet.这些花闻起来很香。 The tomatoes feel very soft.这些西红柿摸起来很软。 二、这些动词后面也可接介词like短语，like后面常用名词。 例如： Her idea sounds like fun.她的主意听起来很有趣。 三、这五个感官动词也可作实义动词,除look(当"看起来……"讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,此时作为实义动词讲时其主语一般为人。(和1有区别) 例如: She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 四、taste, smell作不及物动词时,可用于"taste / smell + of +名词"结构,意为"有……味道/气味"。 例如: The air in the room smells of earth.房间里的空气有股泥土味。 五、它们(sound除外)可以直接作名词,与have或take构成短语。 例如: May I have a taste of the mooncakes?我可以尝一口这月饼吗? taste有品位，味道的意思 例：I don't like the taste of the garlic. 我不喜欢大蒜的味道。 She dresses in poor taste.她穿着没有品位。 look有外观，特色的意思 例：The place has a European look.此地具有欧洲特色。 feel有感觉，感受的意思 watch有手表，观察的意思 例：My watch is expensive.我的手表很贵。 六、其中look, sound, feel还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。 例如：

英语中的感官动词的用法

感官动词表示人的感官动作，可作完全及物动词或不完全及物动词，例如：see/look/watch/notice/observe, hear/listen to, taste, smell, feel/touch. 一、感官动词经常和情态动词can 连用，例如： hear: Can you hear that? 你能听到吗？ see: I can't see much. 我看不太清楚。 feel: I can feel the baby moving inside me. 我能感觉到婴儿在我体内移动。 二、感官动词用于进行时，表明主语或感知者集中在一个特别的对象上，是一种自愿的动作，常见的有listen to, look at, touch, smell 和taste，例如： listen to: He is listening to the radio. 他正在听收音机。 look at: They are looking at the picture. 他们正在看这幅画。 touch: She is touching her cat. 她正在抚摸她的猫。 smell: She is smelling the flowers. 她在闻花。 taste:

We are tasting champagne. 我们正在品尝香槟。 并不是所有的感官动词都可以用进行时，例如： 误：She was hearing a noise. 误：He was seeing a woman in the rain. 但当hear 在表达一种经历时，可以用进行时；see 在表达与人见面或是约会，可以用进行时，等等，例如： hearing: She was always hearing voices in her head. 她脑子里总有声音。 seeing: She is seeing the doctor. 她正在看医生。 He was seeing another woman. 他在和另一个女人约会。 三、感官动词的特殊用法 1、感官动词+ 宾语+ 不带to 不定式，例如： We heard you leave. 我们听见你走了。 解析：此句强调的重点是“We heard". I saw her go. 我看见她走了。 解析：此句强调的重点是"I saw" . 2、感官动词 + 宾语 + 动名词，例如： We heard you leaving. 我们听见你走了。 解析：此句强调的重点是“you leaving",相当于 We heard you when you

感官动词用法

“感官”动词用法小结 我们学过了五个与人的感觉有关的动词,它们就是look,sound,smell,ta ste,feel,我们可称之为“感官”动词。它们的用法有着许多相同点,但也有不同之处,现就此作一小结。 一、这五个动词均可作连系动词,后面接形容词作表语,说明主语所处的状态。其意思分别为“瞧/听/闻/尝/摸起来……”。除look之外,其它几个动词的主语往往就是物,而不就是人。例如: These flowers smell very sweet、这些花闻起来很香。 The tomatoes feel very soft、这些西红柿摸起来很软。 The music sounds beautiful、 二、这些动词后面也可接介词like短语,like后面常用名词。例如: Her idea sounds like fun、她的主意听起来很有趣。 He looks like his father、 三、这五个感官动词也可作实义动词,除look(当“瞧起来……”讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,其主语通常就是人。例如: She smelt the meat、她闻了闻那块肉。

I felt in my pocket for cigarettes、我用手在口袋里摸香烟。 He tasted the soup and added some salt、 Miss Wang asked us to look at the blackboard、 四、taste,smell作不及物动词时,可用于“taste / smell + of + 名词”结构,意为“有……味道/ 气味”。例如: The air in the room smells of earth、房间里的空气有股泥土味。The bread taste of sugar、 五、它们(sound除外)可以直接作名词,与have或take构成短语。例如: May I have a taste of the mooncakes？我可以尝一口这月饼不？May I have a look at your photo? 六、其中look,sound,feel还能构成“look / sound / feel + as if +从句”结构,意为“瞧起来/听起来/ 感觉好像……”。例如: It looks as if our class is going to win、瞧来好像我们班要获胜了It sounds as if the rain is very heavy、

英语中感官动词的用法

英语中感官动词的用法 二、具体用法： 1、see, hear, smell, taste, feel,这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……"。除look之外，其它几个动词的主语往往是物，而不是人。 例如：These flowers smell very sweet.这些花闻起来很香。 The tomatoes feel very soft.这些西红柿摸起来很软。 2、这些动词后面也可接介词like短语，like后面常用名词。 例如：Her idea sounds like fun.她的主意听起来很有趣。 3、这五个感官动词也可作实义动词,除look(当"看起来……"讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,此时作为实义动词讲时其主语一般为人。 例如:She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 4、taste, smell作不及物动词时,可用于"t aste / smell + of +名词"结构,意为"有……味道/气味"。 例如:The air in the room smells of earth.房间里的空气有股泥土味。 5、它们(sound除外)可以直接作名词,与have或take构成短语。 例如：May I have a taste of the mooncakes?我可以尝一口这月饼吗？taste有品位、味道的意思。 例如：I don’t like the taste of the garlic.我不喜欢大蒜的味道。 She dresses in poor taste.她穿着没有品位。 look有外观，特色的意思，例：The place has a European look.此地具有欧洲特色。 feel有感觉，感受的意思，watch有手表，观察的意思。例：My watch is expensive.我的手表很贵。 6、其中look, sound, feel还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。 例如：It looks as if our class is going to win.看来我们班好像要获胜了。 7、感官动词+do与+doing的区别： see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do表示动作的完整性，真实性；+doing 表示动作的连续性，进行性。 I saw him work in the garden yesterday.昨天我看见他在花园里干活了。(强调"我看见了"这个事实) I saw him working in the garden yesterday.昨天我见他正在花园里干活。（强调"我见他正干活"这个动作）

感官动词的用法

感官动词的用法 1.see, hear, listen to, watch, notice等词，后接宾语，再接省略to的动词不定式或ing形式。前者表全过程，后者表正在进行。句中有频率词时，以上的词也常跟动词原形。 注释:省略to的动词不定式--to do是动词不定式，省略了to,剩下do，其形式和动词原形是一样的，但说法不同。 see sb do sth 看到某人做了某事 see sb doing sth 看到某人在做某事 hear sb do sth 听到某人做了某事 hear sb doing sth 听到某人在做某事 以此类推... I heard someone knocking at the door when I fell asleep. (我入睡时有人正敲门,强调当时正在敲门) I heard someone knock at the door three times. (听到有人敲门的全过程) I often watch my classmates play volleyball after school. (此处有频率词often) （了解）若以上词用于被动语态，须将省略的to还原： see sb do sth----sb be seen to do sth hear sb do sth----sb be seen to do sth 以此类推... We saw him go into the restaurant. → He was seen to go into the restaurant. I hear the boy cry every day. → The boy is heard to cry every day. 2.感官动词look, sound, smell, taste, feel可当系动词，后接形容词。 He looks angry. His explanation sounds reasonable. The cakes smell nice.

感官动词用法

感官动词用法 (A)感官动词(及物)有： see/notice/look_at/watch/notice/observe/listen_to/hear/feel(Vt)/taste(Vt)/smell(Vt) (B)连缀动词(含感官不及物) be/get/become/feel/look/sound/smell/taste/keep/stay/seem/ appear/grow/turn/prove/remain/go/run 一、see, hear, feel, watch, look,这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……"。除look之外，其它几个动词的主语往往是物，而不是人。例如： These flowers smell very sweet.这些花闻起来很香。 The tomatoes feel very soft.这些西红柿摸起来很软。 二、这些动词后面也可接介词like短语，like后面常用名词。例如： Her idea sounds like fun.她的主意听起来很有趣。 三、这五个感官动词也可作实义动词,除look(当"看起来……"讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,其主语通常是人。例如: She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 四、taste, smell作不及物动词时,可用于"taste / smell + of +名词"结构,意为"有……味道/气味"。例如: The air in the room smells of earth.房间里的空气有股泥土味。 五、它们(sound除外)可以直接作名词,与have或take构成短语。例如: May I have a taste of the mooncakes?我可以尝一口这月饼吗？ 六、其中look, sound, feel还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。例如： It looks as if our class is going to win.看来好像我们班要获胜了 1. 在表示生理感觉的动词后的不定式不带to。这类词有：

英语中感官动词的用法

first 感官动词 1、感官动词(及物动词)有：see/notice/look at/watch/observe/listen to/hear/feel(Vt)/taste(Vt)/smell(Vt) 2、连缀动词(含感官不及物动词) be/get/become/feel/look/sound/smell/taste/keep/stay/seem/ appear/grow/turn/prove/remain/go/run 二、具体用法： 1、see, hear, smell, taste, feel,这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……"。除look 之外，其它几个动词的主语往往是物，而不是人。 例如：These flowers smell very sweet.这些花闻起来很香。 The tomatoes feel very soft.这些西红柿摸起来很软。 2、这些动词后面也可接介词like 短语，like 后面常用名词。 例如：Her idea sounds like fun.她的主意听起来很有趣。 3、这五个感官动词也可作实义动词,除look(当"看起来……"讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,此时作为实义动词讲时其主语一般为人。 例如:She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 4、taste, smell 作不及物动词时,可用于"taste / smell + of +名词"结构,意为"有……味道/气味"。 例如:The air in the room smells of earth.房间里的空气有股泥土味。 5、它们(sound 除外)可以直接作名词,与have 或take 构成短语。 例如：May I have a taste of the mooncakes?我可以尝一口这月饼吗？taste 有品位、味道的意思。 例如：I don’t like the taste of the garlic. 我不喜欢大蒜的味道。 She dresses in poor taste.她穿着没有品位。 look 有外观，特色的意思，例：The place has a European look.此地具有欧洲特色。 feel 有感觉，感受的意思，watch 有手表，观察的意思。例：My watch is expensive.我的手表很贵。 6、其中look, sound, feel 还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。 例如：It looks as if our class is going to win.看来我们班好像要获胜了。 7、感官动词+do 与+doing 的区别： see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do 表示动作的完整性，真实性；+doing 表示动作的连续性，进行性。 I saw him work in the garden yesterday. 昨天我看见他在花园里干活了。(强调"我看见了"这个事实)

广州小学英语感官动词用法

“感官”动词用法小结 主要的感官动词有：look，sound，smell，taste，feel 一、这五个动词后面接形容词作表语，说明主语所处的状态。其意思分别为“看/听/闻/尝/摸起来……”。除look之外，其它几个动词的主语往往是物，而不是人。例如： These flowers smell very sweet. 这些花闻起来很香。 The tomatoes feel very soft. 这些西红柿摸起来很软。 The music sounds beautiful. 这首歌听起来很动听。 用法的感官动词还有：hear, notice, watch, listen (to) 习题 ( )1.Don’t eat that meat. It smells______. A.dirty B.delicious C.bad ( ) 2. In the Science Museum, the children felt _____ to see so many ______ things. A.surprised; amazed B. surprising; amazing C. surprising; amazed D. surprised; amazing ( )3.I am eating cookies. Do you want to______one?

A.tastes B.taste C.tasting ( )4.Look! The butterflies are flying here and there. They look very______. A.beautiful B.beautifully C.beauty ( )5.That’s a good idea! It sounds______. A.interested B.interesting C.interest ( )6.Birthday cake is ready now, and it______nice.Would you like some? A.smells B.feels C.sounds ( )7.Oh, the vegetables have too much sugar.They taste______. A.salty B.hot C.sweet ( ) 8. ----Have you ever heard the song Welcome to Beijing? ---Yes, it _______ nice. A. hears B. sounds C. looks D. Listens ( ) 9. The girl's voice sounds_____. Maybe she can become a good singer when she grows up. A. sweet B. sweetly C. beautifully ( )10.The table______ very smooth.（光滑的） A looks B turns C feels D smells ( ) 11. Grandma, you must feel ________ after cleaning the house. Let’s take a rest. A. tired B. well C. good D. angry

感官动词的用法

感官动词的用法 1. see, hear, listen to, watch, notice 等词，后接宾语，再接省略to 的动词不定式或ing 形式。前者表全过程，后者表正在进行。句中有频率词时，以上的词也常跟动词原形。 注释: 省略to的动词不定式--todo是动词不定式，省略了to,剩下do，其形式和动词原形是一样的，但说法不同。 see sb do sth看到某人做了某事 see sb doing sth看到某人在做某事 hear sb do sth听到某人做了某事 hear sb doi ng sth听到某人在做某事 以此类推... I heard someone knocking at the door when I fell asleep. 我（入睡时有人正敲门, 强调当时正在敲门） I heard someone knock at the door three times. （听到有人敲门的全过程）I often watch my classmates play volleyball after school. 此（处有频率词often） （了解）若以上词用于被动语态，须将省略的to 还原： see sb do sth --- sb be seen to do sth hear sb do sth -- sb be seen to do sth 以此类推... Wesawhimgoi ntotherestaura nt. — Hewassee ntogoi ntotherestaura nt」hear the boy cry every day. —yThehbard to cry every day.

初中英语感官动词的用法

初中英语感官动词的用法 一、感官动词 1、感官动词(及物动词)有：see/notice/look at/watch/observe/listen to/hear/feel(Vt)/taste(Vt)/smell(Vt) 2、连缀动词(含感官不及物动词) ： be/get/become/feel/look/sound/smell/taste/keep/stay/seem/ appear/grow/turn/prove/remain/go/run 二、具体用法： 1、see, hear, smell, taste, feel,这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……"。除look之外，其它几个动词的主语往往是物，而不是人。 例如：These flowers smell very sweet.这些花闻起来很香。 The tomatoes feel very soft.这些西红柿摸起来很软。 2、这些动词后面也可接介词like短语，like后面常用名词。 例如：Her idea sounds like fun.她的主意听起来很有趣。 3、这五个感官动词也可作实义动词,除look(当"看起来……"讲时)只能作不及物动词外,其余四个既可作及物动词也可作不及物动词,此时作为实义动词讲时其主语一般为人。 例如:She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 4、taste, smell作不及物动词时,可用于"taste / smell + of +名词"结构,意为"有……味道/气味"。 例如:The air in the room smells of earth.房间里的空气有股泥土味。 5、它们(sound除外)可以直接作名词,与have或take构成短语。 例如：May I have a taste of the mooncakes?我可以尝一口这月饼吗?taste有品位、味道的意思。 例如：I don’t like the taste of the garlic. 我不喜欢大蒜的味道。 She dresses in poor taste.她穿着没有品位。 look有外观，特色的意思，例：The place has a European look.此地具有欧洲特色。 feel有感觉，感受的意思，watch有手表，观察的意思。例：My watch is expensive.我的手表很贵。 6、其中look, sound, feel还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。 例如：It looks as if our class is going to win.看来我们班好像要获胜了。 7、感官动词+do与+doing的区别： see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do 表示动作的完整性，真实性;+doing 表示动作的连续性，进行性。 I saw him work in the garden yesterday. 昨天我看见他在花园里干活了。(强调"我看见了"这个事实) I saw him working in the garden yesterday.昨天我见他正在花园里干活。(强调"我见他正干活"这个动作)