Reflexes and Reaction Times – Lab josh, nicole, cesar

Report Lesson Re±exes and Reaction Times – Lab Knee-jerk re±ex – Challenge All re±ex actions occur via a re±ex arc. The diagram below illustrates a simple monosynaptic re±ex arc. Label the components of the knee-jerk re±ex arc in the diagram. Dorsal root ganglion Motor neuron Muscle spindle Patellar tendon Quadriceps muscle Sensory neuron Stimulus Ventral horn Dorsal root ganglion Motor neuron Muscle spindle Patellar tendon Quadriceps muscle Sensory neuron Stimulus Ventral horn

Knee-jerk re±ex – Activity Knee-jerk re±ex – Analysis Record 0 0.2 0.4 Jendrassik Jendrassik   Latency – Normal (ms) Amplitude – Normal (mV) Latency – Jendrassik (ms) Amplitude – Jendrassik (mV) Record 1 13.3 0.02 12 0.07 Record 2 10.8 0.82 10.8 0.62 Record 3 10.8 0.12 10.8 0.11 Record 4 10.8 0.15 12 0.55 Record 5 10.8 0.70 10.8 0.75 Latency – Normal (ms) Amplitude – Normal (mV) Latency – Jendrassik (ms) Amplitude – Jendrassik (mV) Mean 11.30 0.36 11.28 0.42 Standard deviation 1.12 0.37 0.66 0.31 Tendon Tap EMG (mV) 3 4 5 7 8 9 10 11 1 0.8 0.6 0.4 0.2 0 1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 0 8

Withdrawal re±ex – Activity This image shows the projections of sensory and motor axons from the spinal column involved in the withdrawal re±ex. Use the labels to correctly identify the following actions. Brie±y describe the evolutionary advantage of a withdrawal re±ex. The withdrawal re±ex can stop an individual from further injuries. Extension of knee Extensor activation Flexion of knee Flexor activation Motor output Sensory input Extension of knee Extensor activation Flexion of knee Flexor activation Motor output Sensory input

The pupillary light re±ex – Challenge The pupillary light re±ex – Activity The consensual light re±ex involves a complex neural pathway, triggered when bright light enters the other eye. Use this image of the eye , to help you label the image below. Ciliary muscles Motor signal Optic disc Optic nerve Pons Response Sensory signal Ciliary muscles Motor signal Optic disc Optic nerve Pons Response Sensory signal

Reaction time: Visual cues – Analysis Reaction time: Prewarning – Activity Record 0.2 0.4 0.6 Visual Cues – Control (ms) Record 1 100 Record 2 310 Record 3 190 Record 4 460 Record 5 110 Mean 234.00 Standard deviation 151.76 Response (V) Stimulus 3 4 5 7 8 1 0.8 0.6 0.4 0.2 0 1.2 1 0.8 0.6 0.4 0.2 0 0 2

Reaction time: Prewarning – Analysis Reaction time: Predictable cues – Activity Record 0.2 0.4 0.6 Volunteer reaction times Visual Cues – Control (ms) Visual Cues – Prewarning (ms) Record 1 100.00 170 Record 2 310.00 130 Record 3 190.00 120 Record 4 460.00 110 Record 5 110.00 97 Mean 234.00 125.40 Standard deviation 151.76 27.76 Response (V) Stimulus 1 2 3 4 5 1 0.8 0.6 0.4 0.2 0 1.2 1 0.8 0.6 0.4 0.2 0 0 2

Reaction time: Distraction – Analysis Record 0.2 0.4 0.6 Volunteer reaction times Visual Cues – Control (ms) Visual Cues – Prewarning (ms) Visual Cues – Predictable (ms) Visual Cues – Distraction (ms) Record 1 100.00 170.00 150.00 240 Record 2 310.00 130.00 94.00 340 Record 3 190.00 120.00 48.00 300 Record 4 460.00 110.00 30.00 390 Record 5 110.00 97.00 34.00 280 Mean 234.00 125.40 71.20 310.00 Standard deviation 151.76 27.76 50.86 57.45 Response (V) Stimulus 1 2 3 4 5 1 0.8 0.6 0.4 0.2 0 1.2 1 0.8 0.6 0.4 0.2 0 0 2

Reaction time: Auditory cues – Activity Reaction time: Auditory cues – Analysis Mental arithmetic is an excellent distraction compared to other tasks. How did it change the latency of the volunteer's reaction? The latency of the volunteer's reaction time increased signi³cantly. Record 0.2 0.4 0.6 Response (V) Stimulus 1 2 3 4 5 1 0.8 0.6 0.4 0.2 0 1.2 1 0.8 0.6 0.4 0.2 0 0 2

Consider two volunteers: Liam is 1.8 m tall and Jacqui is 1.4 m tall. Which volunteer will have the faster ankle-jerk re±ex? Can you explain why? Jacqui should have a fast ankle-jerk re±ex because they are shorter, which might produce a quicker signal response. Having examined the di²erence in latency for re±ex and voluntary contractions, what do you think can in±uence the variability seen under these two conditions? The variability can be in±uenced by an individuals physical attributes. Depending on these characteristics an individual can have a bigger or smaller variability. One re±ex is also based on consciousness and unconsciousness of what is happening with the body. Your volunteer's reaction times Visual Cues – Control (ms) Visual Cues – Prewarning (ms) Visual Cues – Predictable (ms) Visual Cues – Distraction (ms) Auditory Cues (ms) Record 1 100.00 170.00 150.00 240.00 97.00 Record 2 310.00 130.00 94.00 340.00 230.00 Record 3 190.00 120.00 48.00 300.00 270.00 Record 4 460.00 110.00 30.00 390.00 230.00 Record 5 110.00 97.00 34.00 280.00 300.00 Mean 234.00 125.40 71.20 310.00 225.40 Standard deviation 151.76 27.76 50.86 57.45 77.59 Describe how the mean reaction times changed across the conditions. Which conditions caused the greatest increase and decrease in the mean reaction times of your volunteer? Based on the graph, distraction caused the greatest increase in mean reaction time and predictable caused the greatest decrease in mean reaction time.

Popup - Notebook Having carried out the activities under di²erent conditions to test reaction times in this lab, what do you think can in±uence the variability seen in the experimental method used today? Some in±uences can be due to volunteer error, depending on the subject, outside distractions, or the volunteer not having a clear mind. Re±ection notebook