T14, Brain machine interfaces (Joao Sanches)

Question 1

Most application of brain computer interfaces?

Answer 1

• to motor cortex

- to repair and help destroyed parts of the brain?

Question 2

joh Hopkins university and prosthetic arms?

Answer 2

A man could lift his arm up and down and also to grasp a boll etc.

Question 3

implanted BCI?

Answer 3

Brain Computer Interface (BCI) (Brain gate?)

• chip is inplantade just beneath scull
• mind can control video games etc.

Question 4

Additional arm on a monkey? university of pittsburg

Answer 4

the money could control his arm without knowing what he is doing. he learned how to think to move the arm.

Question 5

brain gate 2012 in browns university?

Answer 5

A handicaped person succeeded to make a robot puck up something to drink with her mind

Question 6

How can we “see” the brain working?

Answer 6

1. Direct measures
   - -> electrical activity
   - -> magnetic activity
   - -> metabolic activity
2. Indirect information
   - -> psysiological
   - -> behavioural

Question 7

Ways of measuring brain activity?

Answer 7

1. Electrophysiological
EEG
--> directly from cortex
ECoG
—> electrocorticography
Intracortical devices

2. Magnetic systems
   - MEG
3. Metabolic measures
   - fMRI
   - NIRS

Question 8

Neuronal electronic activity

Answer 8

Observing a great amount of cells not one cell

Question 9

EEG?

Answer 9

ON SCUL

1. Cap
   - -> wireless
2. Electrods on the head (not wireless)

Problem: Quality of the signal,

Question 10

Local field potential?

Answer 10

Possible to detect activation of electrosignal
- EcoG & LFP

we assume that what we are processing is a continuous signal, (signal train)

Question 11

typicle waves?

Answer 11

1. Oscillatory brain waves
   - with different frequencies, magnitude and phase

brainwave during REM sleep and awake is very similar

alpha waves, resting state for adult, dissapears when sleeping

Question 12

what is BCI?

Answer 12

• a pattern recognition problem
• an estimation/detection problem

E.G. ?

Question 13

typical pipeline processing?

Answer 13

1. user brain signal acquisition
   - -> without noice
2. Cerebral activity measurement
3. pre-processing
4. feature extraction
5. feature classification and post-processing
6. Device control

Question 14

Name a typical problem for BCI?

Answer 14

Detection part

if we example have an observation with noisy and missing data but are able to reconstruct what we know through inverting the problem

Direct problem:
x

Question 15

Definition of a well posed problem

Answer 15

1. solution exist
2. solution is unique
3. the solution depends continuously on the data
   - -> when you change slightly the data the solution should change slightly
4. can be problematic

Question 16

what is a non well posed equation called?

Answer 16

ill-posed

e.g. where is tracy?

Question 17

who talked about well popsed problems?

Answer 17

Jacques Hadamard

Question 18

optimization problems?

Answer 18

try to find the highest slope

Question 19

what is restauration/estimation?

Answer 19

just like rebuilding in old temple, it is not relality

prior information

Question 20

Prior information?

Answer 20

.

Question 21

Estimation/detection theory?

Answer 21

data (x) is not the reality, it is distorted and incomplete observations of the reality (theta)

several different observations can/could be generated from the same reality

• probability are used to model uncertainty on data x for reality theta

Question 22

How does a sensorimotor activity change the brain rhythms of my, beta and gamma?

Answer 22

my and gamma is displayed when a person is not engaged in processing sensorimotor inputs or in producing motor outputs.

• A volontär movement is results in a desynchronization in the mu and b bands