<p>Ohm's law famously states V=IR, the voltage change (V) across a resistor generated by a current (I) equals the current multiplied by the resistance (R).  </p>

<p>The resistor in this case is the cell membrane.  When an experimenter injects a known amount of current through an electrode, the voltage change that occurs is related to that current by the resistance of the cell membrane.  A high value indicates that the cell membrane does not let current pass easily so a given amount of current requires a large voltage changes.  </p>

<p>The size of the cell and the number of open ion channels affect the input resistance.  Larger size means lower resistance (more surface area for current to flow through) and more open ion channels means lower resistance (the conductance g=1/R increases when you open ion channels so the resistance decreases).  </p>

<p>As for relevance to neural computation, higher input resistance means that less synaptic input (current injection) can lead to larger voltage changes.  Manipulating input resistance (say by opening Cl- channels, which don't change the voltage of the cell much but do decrease the resistance) can change the responsiveness of the neuron to other inputs.  This phenomenon is called shunting inhibition.  </p>

CC BY-SA 3.0
2016-02-12T19:09:28.330Z
2016-02-12T19:09:28.330Z
honi
<p>For example, <a href="http://neuroelectro.org/ephys_prop/2/" rel="nofollow">this site gives a distribution of values of the input resistance of various cells</a>. The values are in MOhms. The definition says that "input resistance measured at steady-state voltage response to current injection".</p>

<p>How can its value be interpreted? What do high or low values indicate? Does it relate to other cell properties?</p>

<neuroscience><electrophysiology>
What is input resistance and how to interpret its values?
Justas
# What is input resistance and how to interpret its values?

(Asked by: username_0 on 2016-02-11)

For example, [this site gives a distribution of values of the input resistance of various cells](http://neuroelectro.org/ephys_prop/2/). The values are in MOhms. The definition says that "input resistance measured at steady-state voltage response to current injection".

How can its value be interpreted? What do high or low values indicate? Does it relate to other cell properties?

**Tags:** neuroscience, electrophysiology


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## 1 answers

### Answer by username_1 on 2016-02-12. Score: 3

Ohm's law famously states V=IR, the voltage change (V) across a resistor generated by a current (I) equals the current multiplied by the resistance (R).

The resistor in this case is the cell membrane. When an experimenter injects a known amount of current through an electrode, the voltage change that occurs is related to that current by the resistance of the cell membrane. A high value indicates that the cell membrane does not let current pass easily so a given amount of current requires a large voltage changes.

The size of the cell and the number of open ion channels affect the input resistance. Larger size means lower resistance (more surface area for current to flow through) and more open ion channels means lower resistance (the conductance g=1/R increases when you open ion channels so the resistance decreases).

As for relevance to neural computation, higher input resistance means that less synaptic input (current injection) can lead to larger voltage changes. Manipulating input resistance (say by opening Cl- channels, which don't change the voltage of the cell much but do decrease the resistance) can change the responsiveness of the neuron to other inputs. This phenomenon is called shunting inhibition.


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