lecture 10: invasive physiological research methods (animals)

2-deoxyglucose technique

2-DG; inject animal with radioactive 2-DG and allow it to engage in behavior of interest, animal is sacrificed and its brain is removed and sliced, brain slices are subjected to autoradiography to see where radioactivity accumulated and hence, which brain regions were most active during behavior

bregma

a point on the top of the skull often used as a reference point

types of optogenetics

chlamydomonas reihardti channelrhodopsin-2, natronomonas pharaonis halorhodopsin

in situ hybridization vs immunocytochemistry

detects: mRNA vs protein uses: nucleotide probes vs antibodies

disadvantage of gene knockout techniques

difficult to interpret results - most behavior is controlled by many genes and removing one gene may alter the expression of others, including compensation for missing gene

cerebral dialysis process

fine tube with a short permeable section is implanted in the brain, extracellular neurchemicals are continuously drawn off for analysis

invasive EEG recording

in lab animals, EEG signals are typically recorded through large, implanted electrodes

invasive recording methods

intracellular unit recording, extracellular unit recording, multiple-unit recording, invasive EEG recording

invasive physiological research methods

lesioning, electrical stimulation, recording methods, manipulating or measuring within the brain

intracellular unit recording

measures membrane potential of an individual neuron

extracellular unit recording

measures the firing of an individual neuron

multiple-unit recording

measures the firing of many neurons

manipulating or measuring within the brain

measuring in vivo chemical activity of the brain: 2-deoxyglucose (2-DG) technique

cerebral dialysis

microdialysis; method for recording changes in brain chemistry in live, behaving animals

optogenetics

neuro engineering tool that utilizes the properties of two light sensitive microbial opsin proteins to investigate neural function with cell-type specific, temporally precise, reversible neuromodulation

immunocytochemistry

procedure for detecting and locating individual proteins by tagging the protein of interest with a specific antibody

stereotaxic atlas

provides coordinates for locating structures within the brain

lesioning

remove, damage, destroy a part of the brain to observe impact on behavior

lesion warning

studies must be interpreted carefully because it is difficult to make small, precise lesions in the brain

gene knockout techniques

subject missing given gene can provide insight into what the gene controls

in situ hybridization

technique for locating a specific mRNA sequence in a portion or section of cell tissue

immunocytochemistry process

tissue is first incubated with a primary antibody specific for the protein of interest, tissue is washed and incubated with a tagged secondary antibody that binds to the primary antibody, tissue is washed again and viewed on microscope

electrical stimulation

used to activate a structure; may have the opposite effect of lesioning

stereotaxic instrument

used to hold head steady and guide the device to be inserted

stereotaxic surgery

used to position experimental devices

in situ hybridization process

utilizes specifically constructed probes containing a sequence complementary to the mRNA of interest, probes are tagged with a dye, fluorescence, or radioactivity to allow visualization and localization of the sequence of interest