B&C: Recording Neuronal Activity Flashcards
what was the most important advance in neurophysiology
the development of methods to record the activity of single neurons in laboratory animals.
What did this development allow?
Single-cell recording enabled research- ers to describe the response characteristics of individual elements.
How does single cell recording work?
a thin electrode is inserted into an animal’s brain. When the electrode is in the vicin- ity of a neuronal membrane, changes in electrical activity can be measured
Is it injected into or extracellularly and why?
Although the surest way to guarantee that the electrode records the activity of a single cell is to record intracellularly, this technique is difficult, and penetrating the membrane frequently dam- ages the cell. Thus singlecell recording is typically done extracellularly
What problem arises from injecting the electrode extracellulary?
There is no guarantee that the changes in electrical potential at the electrode tip reflect the activity of a single neuron. More likely, the tip will record the activity of a small set of neurons.
What can be done to resolve this?
Computer algorithms are used to differentiate this pooled activity into the contributions from individual neurons.
What is the primary goal of single-cell recording?
to determine what experimental manipulations produce a consistent change in the response rate of an isolated cell.
What kind of graph is used to display neuronal activity over time?
Histogram (Raster Plot)
What can be obtained from recordings obtained from a series of cells in a targeted area of interest?
a functional map can describe similarities and differences between neurons in a specified cortical region.
What is meant by a receptive field?
all visually sensitive cells respond to stimuli in only a limited region of space. This region of space is referred to as that cell’s receptive field.
How can these receptive field spatially relate to the external world
External space is represented in a continuous manner across the cortical surface: Neighbouring cells have receptive fields of neighbouring regions of external space
How are topographic representations referred to in vision?
retinotopic maps
How are these retinotonic maps similar to auditory cells?
auditory areas in the subcortex and cortex contain tonotopic maps, in which the physical dimension reflected in neural organization is the sound frequency of a stimulus, neighboring cells tend to be tuned to similar frequencies.
What else can tonotopic maps be referred to as?
cochleotopic because the cochlea
How may neuron function be better understood than simply the sum of its parts?
by iden- tifying the correlations in the firing patterns of groups of neurons rather than identifying the response properties of each individual neuron.
What did this lead neuroscientists to develop?
new techniques that allow recordings to be made in many neurons simultaneously— what is called multiunit recording.
When and why is single-cell recordings in humans utilised?
surgical procedures are required to treat cases of epilepsy or to remove a tumour intracranial electrodes may be inserted as part of the procedure to localise the abnormality in preparation of the surgical resection.
Where do people with epilepsy have electrodes placed and how does this assist neuroscience?
in the medial temporal lobe (MTL), where the focus of generalised seizures is most frequent. Many patients with implanted electrodes have given generously of their time for research purposes, engaging in experimental tasks so that researchers can obtain neurophysiological recordings in humans.
What have neuroscientists found out about MTL neurons in humans?
MTL neurons in humans can respond selectively to specific familiar images. (single neuron specifically for Jennifer Aniston and other specific actresses be it their name or picture etc)
