Molekuláris bionika és infobionika szakok tananyagának komplex

Electrophysiological Methods for the Study of 

the Nervous- and Muscular-systems 

György Karmos, Balázs Dombovári 

István Ulbert 

Péter Pázmány Catholic University 

Faculty of Information Technology 

 Budapest, Hungary 

[karmos, dombovari]@itk.ppke.hu, [e-mail]  

Richárd Csercsa, Richárd Fiáth, 

Domonkos Horváth 

Institute for Psychology of the  

Hungarian Academy of Sciences 

 Budapest, Hungary 

[csercsa,fiath]@cogpsyphy.hu, 

[e-mail] 

The  course  makes  the  students  familiar 

with the topics of electrophysiology, the major 

recording  techniques,  and  the  relationships 

among  the  fields  of  bioelectromagnetism. 

They get acquainted with electrophysiological 

techniques  and  devices  used  in  neuroscience 

and in every day’s clinical practice. The great 

advantage of the electrophysiological methods 

is that we can study nervous and muscle func-

tion in intact organisms or with minimal dam-

age of the functioning tissue. Electrophysiolo-

gy is a broad area of biosciences. In the course 

we  deal  only  the  bioelectric  processes  of  the 

nervous  and  muscle  systems  since  they  are 

most interesting from the point of information 

technology.

The  first  lectures  basic  bioelectrical  phe-

nomena of nerve cells are discussed. When a 

nerve  impulse  travels  along  a  nerve  fiber  ac-

tion potential can be recorded. This bioelectric 

phenomenon is a concomitant of the biological 

process of the nerve conduction however at the 

same  time  the  potential  changes  play  active 

role in the spread of the excitation. This dual 

nature of bioelectricity is strongly emphasized.  

Connection  between  the  living  tissue  and 

the  recording  apparatuses  is  realized  by  the 

electrodes.  In  this  interface  connection  is 

formed  between  electron  conductor  and  elec-

trolyte  conductor.  Ideal  electrode  does  not 

exist  living  tissue  is  a  chemically  aggressive 

medium  for  electrodes:  there  is  always  a 

chemical  reaction  between  the  electrode  and 

the  tissue.  Critical  problem  of  electrophysio-

logical  electrodes  are  the  electrode  stability 

and  biocompatibility:  on  the  one  hand,  elec-

trodes  have  to  withstand  the  chemically  ag-

gressive living tissue, on the other hand, elec-

trode-caused  harm  to  the  living  tissue  has  to 

minimized.  Chronically  implanted  electrodes 

of different type pacemakers must operate for 

decades.

Recording  techniques  of  neuroelectric  sig-

nals  can  be  categorized  form  the  membrane 

potential of the single neuron recorded by in-

tracellular  microelectrodes  to  the  electroen-

cephalographic  activity  (EEG)  of  the  brain 

recorded by macroelectrodes on the scalp sur-

face. Lectures of the course offer detailed sur-

vey of in vitro and in vivo methods. Extracel-

lular  single  unit  recording  technique  earlier 

was  regarded  as  a  purely  research  method 

nowadays  it  is  applied  in  human  brain  com-

puter interfaces. Computer based multichannel 

EEG recording makes possible the mapping of 

brain processes with good time resolution and 

application  of  complex  mathematical  signal 

processing  methods  offers  possibility  the 

forewarning of epileptic seizures. Beyond the 

electrical activity noninvasive recording of the 

magnetic signals produced by the brain serves 

also as a diagnostic tool. Good spatial resolu-

tion  of  magnetoencephalography  makes  it  a 

good complement of EEG. 

Surface  recorded  brain  oscillations  time 

locked to sensory stimuli – called event related 

33

---

potentials (ERP) – became essential in study-

ing perceptional and other psychological phe-

nomena and serve as one of the a basic tools of 

cognitive  psychophysiology.  Recording  of 

early components of ERPs can be used as di-

agnostic method to reveal pathology of senso-

ry pathways even in unconscious patients e.g. 

the  objective  audiometry  using  the  brainstem 

auditory evoked potentials. One of the lectures 

of the course deals with the different forms of 

the ERPs. 

Recording  of  the  bioelectrical  activity  of 

striated muscles can be used for diagnosing of 

pathology  of  the  motor  part  of  the  nervous 

system as well as the  muscles themselves. In 

the clinical practice needle electrodes are used 

for  the  localization  of  pathological  changes. 

Surface electrodes are applied in psychological 

research  as  well  as  in  sport-  and  work-

physiology to analyze optimal performance of 

muscles.  The  lecture  dealing  with  electromy-

ography  describes  both  of  these  techniques 

and applications. 

Computer methods become more and more 

important in analyzing bioelectrical signals. In 

the last lecture of the course we give an over-

view  of  the  mathematical  methods  that  are 

used  for  electrophysiological  signal  pro-

cessing.

Understanding  of  brain  functions  and  pa-

thology  needs  collaboration  of  researchers  of 

different  disciplines.  Information  technology 

and bioengineering fields gain more and more 

importance  both  in  neuroscience  and  in  the 

related  clinical  areas.    At  the  same  time  bio 

inspired  solutions  become  essential  in  man-

made systems. In preparing the material of the 

present course we intended to give and over-

view of electrophysiological methods that may 

be useful for students with engineering as well 

as biological interest.

35

34

---