The Functional Observational Battery (FOB) is a comprehensive battery of behavioral tests and observations conducted in vivo to assess the neurobehavioral effects of drugs, chemicals, or other substances in animal studies. The FOB is typically performed in rodents (e.g., rats and mice) and is designed to detect changes in various aspects of behavior and neurological function. The specific assays included in the FOB may vary slightly depending on the research objectives and the guidelines of regulatory agencies, but here are common assays and observations that are typically performed as part of the FOB:

General Appearance and Behavior

Observation of general appearance, posture, and spontaneous activity to detect any overt signs of distress, sedation, ataxia, or abnormal behaviors. Here we look for overt signs of distress, sedation, ataxia, grooming behaviors, posture, and any abnormal behaviors. No specific apparatus is required for this assessment; observations are made in the animal’s home cage or testing environment. Cage side observations are standard.

Home Cage Observations

Assessment of behaviors in the home cage environment, including grooming, eating, drinking, and social interactions. Behaviors such as grooming, eating, drinking, social interactions, and any changes in activity. No specific apparatus is required but we recommend a Sociability Chamber; observations are made in the animal’s home cage.

Handling Response

  • Evaluation of the animal’s response to handling, such as resistance, irritability, or passivity, which can provide insights into stress or anxiety levels.
  • Data We Collect: The animal’s response to handling, including resistance, irritability, passivity, or any other reactions.
  • Apparatus/Equipment: Handling gloves or gentle handling techniques are used for the assessment.

Motor Activity:

  • Measurement of locomotor activity, including assessment of spontaneous movements in an open-field arena or activity cage.
  • Data We Collect: Measures of locomotor activity, including distance traveled, time spent moving, and speed.
  • Apparatus/Equipment: Activity monitoring systems, such as infrared motion sensors or video tracking systems, are commonly used in open-field or activity cage assays.

Exploratory Behavior:

  • Evaluation of exploratory behaviors, including time spent investigating novel objects or environments.
  • Data We Collect: Time spent investigating novel objects or environments.
  • Apparatus/Equipment: Novel object recognition arenas or open-field arenas with novel objects can be used to assess exploratory behavior.

Sensory and Reflex Responses:

  • Assessment of sensory responses, such as response to auditory, visual, or tactile stimuli, as well as measurement of reflexes like the startle reflex.
  • Data We Collect: Responses to sensory stimuli, including auditory, visual, or tactile reactions, as well as reflex responses like the startle reflex.
  • Apparatus/Equipment: Equipment may include devices for presenting sensory stimuli and recording responses, such as audiometers for auditory testing and acoustic startle response chambers.

Neurological Reflexes:

  • Evaluation of specific neurological reflexes, such as the righting reflex (ability to return to an upright position when placed on the side) and the hindlimb clasping reflex (abnormal hindlimb posture when suspended).
  • Data We Collect: Assessment of specific reflexes, such as righting reflex and hindlimb clasping reflex.
  • Apparatus/Equipment: No specialized apparatus is required for these reflex tests.

Motor Coordination and Balance:

  • Tests to assess motor coordination and balance, such as the rotarod test or beam walking test, which measure the animal’s ability to maintain balance and coordination while walking on a rotating rod or narrow beam.
  • Data We Collect: Performance on motor coordination tasks, including latency to fall or number of falls.
  • Apparatus/Equipment: Apparatus like rotarods for the rotarod test or balance beams for beam walking tests are used.

Muscle Strength and Tone:

  • Evaluation of muscle strength and tone using assays like the grip strength test, which measures the animal’s ability to grip a sensor or bar with its forelimbs.
  • Data We Collect: Grip strength measurements, typically recorded in grams.
  • Apparatus/Equipment: Grip strength meters or apparatus for measuring forelimb and hindlimb grip strength.

Sensorimotor Function:

  • Assessment of sensorimotor function, including tests for sensorimotor integration and coordination, such as the beam balance test or the pole test.
  • Data We Collect: Performance on sensorimotor tasks, such as latency to turn or climb down a pole.
  • Apparatus/Equipment: Apparatus like vertical poles for pole tests or narrow beams for beam balance tests.

Aggression and Social Behavior:

  • Observation of social interactions among animals, including assessments of aggression, dominance, and social hierarchy within a group.
  • Data We Collect: Observations of social interactions, including aggression, grooming, and social hierarchy.
  • Apparatus/Equipment: No specific apparatus is required; observations are made in a social group housing or testing environment.

Cognitive and Memory Function:

  • Assessment of cognitive and memory function using tasks like the Morris water maze or the novel object recognition test, which measure spatial learning and memory.
  • Data We Collect: Latency to find a hidden platform (Morris water maze) or time spent exploring novel objects (novel object recognition).
  • Apparatus/Equipment: Morris water maze, novel object recognition arenas, or other specialized apparatus for cognitive testing.

Emotional Behavior and Anxiety:

  • Evaluation of emotional responses and anxiety-related behaviors using assays like the elevated plus maze or the open field test.
  • Data We Collect: Time spent in open arms (elevated plus maze) or time spent in center zones (open field test).
  • Apparatus/Equipment: Elevated plus maze, open field arenas, or other equipment designed for assessing anxiety-related behaviors.

Pain and Sensitivity:

  • Assessment of pain responses and sensitivity to stimuli, including tests for thermal or mechanical pain thresholds.
  • Data We Collect: Thresholds for responding to thermal or mechanical stimuli.
  • Apparatus/Equipment: Equipment such as von Frey filaments for mechanical sensitivity testing or hot plates for thermal pain threshold assessment.

Autonomic Function:

  • Measurement of autonomic functions, such as heart rate and blood pressure, to assess the influence of the test substance on physiological responses.
  • Data We Collect: Physiological data, including heart rate and blood pressure.
  • Apparatus/Equipment: Physiological monitoring systems or telemetry equipment for collecting autonomic function data.

The specific battery of tests and observations within the FOB can be customized based on the research objectives and the particular behaviors and functions of interest. The FOB is a valuable tool for assessing the effects of substances on neurological and behavioral function in animals, providing insights into potential neurotoxicity or other adverse effects.


Comprehensive List of Apparatuses & Assays for FOB

General Activity and Behavioral Observations:

  • Open Field Test: Assess spontaneous locomotor activity and exploration.
  • Home Cage Activity Monitoring: Monitor spontaneous activity within the home cage.
  • General Observation: Record overall behavior, posture, and grooming.

Sensory and Motor Function:

  • Grip Strength Test: Measure forelimb strength using a grip strength meter.
  • Tail Suspension Test: Evaluate immobility and limb muscle tone.
  • Hindlimb Extension Reflex: Assess hindlimb strength and reflexes.
  • Paw Placement Test: Examine sensorimotor coordination and reflexes.

Neurological Reflexes:

  • Eyeblink Reflex: Assess the response to a mild air puff directed at the eye.
  • Acoustic Startle Response: Measure the startle response to a sudden loud noise.
  • Pinna Reflex: Observe ear twitch responses to gentle stimuli.

Cognitive and Memory Function:

Sensory Function:

  • Visual Placing Reflex: Test visual function by observing the response to visual cues.
  • Hot Plate Test: Measure thermal sensitivity and pain response.
  • Tail Flick Test: Assess thermal nociception by measuring the tail withdrawal reflex.

Emotion and Anxiety:

Social Behavior:

Motor Coordination and Balance:

  • Rotarod Test: Measure motor coordination and balance on a rotating rod.
  • Balance Beam Test: Assess balance and motor coordination on a narrow beam.
  • Grid Walk Test: Evaluate fine motor coordination on a grid.

Autonomic Function:

  • Blood Pressure and Heart Rate Monitoring: Assess cardiovascular function.
  • Respiratory Rate Measurement: Monitor respiratory function.
  • Body Temperature Measurement: Measure core body temperature.

Seizure and Convulsion Assessment:

  • Pentylenetetrazol (PTZ) Test: Induce and assess convulsions following PTZ administration.
  • Maximal Electroshock (MES) Test: Evaluate seizure susceptibility using electrical stimulation.

Sensorimotor Gating and Prepulse Inhibition:

  • Startle Response/PPI Test: Assess sensorimotor gating by measuring the response to a startling stimulus alone and with a preceding prepulse.

Neurological Scoring Scales:

  • Neurological Deficit Score: Evaluate neurological deficits using a standardized scoring system.
  • Gait Analysis: Quantify gait parameters using specialized equipment.

The selection of specific tests within the FOB may vary depending on the research objectives, the species of animals used (e.g., rodents, primates), and the particular neurological endpoints of interest. Researchers should consider the scientific rationale and regulatory requirements when identifying the appropriate FOB assessments in preclinical drug safety evaluations.