1.6 (Recording from the brain) Flashcards
What was the early approach to understanding the brain in philosophy and science?
Through structured introspection, based on thinking about thought.
What major shift occurred in the study of the brain in neuroscience?
The shift from introspection to observing neural dynamics and recording brain activity.
What is the ideal scenario for recording from the brain?
Recording all voltage changes in all neurons and levels of various chemicals.
What are the two primary compromises in brain recording methods?
Between spatial and temporal resolution, and the degree of intervention.
Describe an in vitro experiment for brain recording.
Brain slices from animals are kept alive in a controlled environment, allowing detailed voltage recordings from neurons.
What is the key difference between intracellular and patch clamp recordings in in vitro experiments?
Intracellular recordings puncture the neuron membrane, while patch clamp recordings seal onto the membrane without puncturing.
Why is the hippocampus commonly used in in vitro experiments?
Its laminar structure makes it easier to prepare and study.
What is the main limitation of in vitro recording methods?
Neurons are outside their natural environment, with damaged neurites and an abnormal chemical environment.
What distinguishes in vivo electrophysiology from in vitro?
In vivo electrophysiology is conducted in living, often awake animals.
How do high-density silicon probes improve in vivo recordings?
They provide multiple recording sites, allowing better accuracy through spike sorting.
What is the role of spike sorting in in vivo recordings?
Spike sorting algorithms assign spikes to individual neurons, despite the mixing of signals from multiple neurons.
What are place cells and how are they studied?
Neurons that fire in specific spatial locations, studied through spike recordings in animals exploring mazes.
What major limitation exists in in vivo electrophysiology regarding animal welfare?
It is an invasive procedure, raising ethical concerns.
What does calcium imaging measure in the brain?
Calcium ion concentrations using calcium-sensitive fluorescent proteins or dyes.
What is a notable constraint of calcium imaging in measuring neuron activity?
Calcium signals are slower than spikes, requiring deconvolution algorithms to interpret spike timing.
What is a ‘virtual reality’ experiment in calcium imaging for rodents?
The animal’s head is fixed under a microscope, with movement simulated through a wheel or ball.
What makes calcium imaging ideal for studying brain activity over time?
It can track the same neurons over successive days, useful for studying development and long-term processes.
What is the main principle behind Electroencephalography (EEG)?
Recording electrical activity from the brain through electrodes placed on the scalp.
Why is EEG considered to have poor spatial resolution?
The signals are a blend of multiple neural sources, resulting in a broad and noisy average.
What significant discoveries were made possible by EEG?
The identification of sleep stages and study of epilepsy.
What advantage does Magnetoencephalography (MEG) have over EEG?
MEG is less affected by skull and tissue interference, providing clearer signals than EEG.
What limitation does MEG face despite its advantages over EEG?
It is very costly and requires superconductors, making it less accessible.
How does Magnetic Resonance Imaging (MRI) produce images?
By using an oscillating magnetic field to alter atomic energy states, detected as radiofrequency emissions.
What is Diffusion Tensor Imaging (DTI) used for in MRI?
To map neuronal tracts, revealing brain connectivity.
