Monkey neuron activation is a fascinating subject for research. This article explores how the mirror neurons in the monkey brain enable us to understand the actions of others. You’ll learn how they work and how their responses vary based on cognitive challenges. Plus, you’ll get a sneak peek at video clips of the monkey’s reaction to different stimuli.
Video clips of monkey neuron activation
A recent study by Shepherd and Freiwald examined brain activity patterns in monkeys while they watched video clips of other monkeys. The researchers explored neural processes involved in generating appropriate responses to facial and vocal emotions. They also investigated how the social interaction network in monkeys works, comparing it to the human social communication network.
In the context of the study, a mirror neuron was a neuron that is activated when a monkey observes another individual performing a similar action. In turn, the response is modulated by prior knowledge of the object behind the screen. This phenomenon was studied by measuring regional blood flow in the rhesus monkey’s brain.
Several studies have shown that the mirror neuron is associated with a number of other neuronal regions. These include the Brodmann area BA 44, the pars opercularis, and the left inferior frontal gyrus. However, researchers are not sure how the system works.
Shepherd and Freiwald used functional magnetic resonance imaging to examine monkey’s brain activity when watching video clips of social interactions. The results show that social videos stimulate a large network of parietal and temporal areas, and that a mirror neuron is not the only brain region to light up.
Mirror neurons are known to be activated by transitive actions, such as kissing, but are not activated by intransitive ones. It is assumed that this is because the observed action has no direct matching mechanism. Consequently, these neurons have been labeled as “communicative mirror neurons”.
As for the fMRI, the most prominent single-trial response was the “social-interaction network” which includes parts of the medial prefrontal cortex. It is thought to be responsible for higher complex cognition, and is associated with personality traits in humans.
In addition to these functional characteristics, the social interaction network in monkeys also shares certain anatomical features with the theory of mind network in humans. It is possible that the social interaction network in primates is an evolutionary adaptation, and that it plays a key role in the human default mode network.
Ultimately, the results of the study showed that specific areas of the monkey brain were activated by videos of social interactions. These activations are similar to those found in recent functional magnetic resonance imaging studies.
LC neurons respond to nontarget stimuli
The locus coeruleus (LC) is a major norepinephrine (NE) source in the central nervous system (CNS). LC is responsible for attentional control of both top-down and bottom-up salience. LC also plays a key role in modulating arousal. Several studies have reported that LC neurons respond to nontarget stimuli with a phasic response. However, the link between LC activity and pupil size is not completely understood. Here, we investigate how the LC responds to task-relevant stimuli and how reward incentives affect pupil responses.
Pupil dilation is a reliable indirect marker of LC activity. Previous animal studies have shown short bursts of LC activity coinciding with pupil dilation. Furthermore, LC is believed to be the sole source of NE in the brainstem. This study addresses the relationship between LC activity and pupil dilation in monkeys.
A novel approach is used to examine this relationship. Single-cell recordings of LC neurons were performed in monkeys. Each neuron was fit to two reward conditions. Spike counts were recorded for both the small and large-reward blocks. The spike rates were smoothed with a 15 ms half Gaussian. To account for block-averaged single-received rewards, normalized mean pupil area was calculated during the sample stimulus period. For each block, the rate of the correct trials was calculated.
P3 is a prominent positive large-amplitude ERP component. Its peak latency is around 300 to 400 ms. Although it is similar to the LC-NE response, it is likely to be influenced by reward. These findings suggest that LC responses may be habituated with repeated exposure.
Reward history is the primary external motivator for monkeys. In order to study LC response to task-relevant stimuli, an explicit reward protocol was needed. Studies of reward delivery have focused on dopaminergic systems. But LC also has an intrinsic motivational function.
Previous studies have indicated that LC responds to low-probability, non-target stimuli with a phasic reaction. However, the behavioural significance of this response is important. If repeated exposure to a stimulus reveals no behavioural significance, it may be discarded. Similarly, physical salience may not be as important as low probability salience.
LC response variability based on cognitive difficulty
The LC is a complex neuronal machine that responds differently to task related processes. Despite the complexity, pupillometry is a simple and non-invasive procedure that can be used to measure a wide variety of brain states. Although the correlation between pupil size and LC activity is not perfect, the current study offers useful information to improve our understanding of the LC.
This study presents the first study to quantify the effect of cognitive difficulty on LC response variability. We examined the relationship between LC spiking and pupil dilation during a standard Sternberg task. LC spikes were quantified in a -2 to -4 s window from event onset. Pupil dilation was measured between two consecutive positive zero crossings of the slopes. However, the LC spiking signal was not significantly affected by the -1 to -3 s window.
Unlike in human subjects, the LC was recorded during quiet wakefulness. To quantify the effect of task and time pressure on LC spiking, we used a technique that combines measures of cognitive control with time-pressure manipulation. The results show that cognitive load is a major driver of LC response.
Although it may sound counter-intuitive, increasing the task difficulty increases the overall task demand. Moreover, n (the number of trials performed in a given session) increases with the task. Therefore, the Stroop effect can be seen as a reflection of increased task demands and demands on the mind. Interestingly, the peak LC spiking signal was smaller on the second day.
We have now trawled through the data to find that there are some important similarities between LC and pupillometry. For instance, the largest peak in the licking response was found within about 100 milliseconds of licking event onset. While this may seem like a trivial observation, the resulting spike was larger than if the task were left unassisted. Also, pupil dilation may be a good proxy for LC spiking.
Lastly, despite the plethora of studies, there are still gaps in the literature. The current study addresses a key question: Does pupillometry measure brain state akin to other brain state indicators?
Mirror neurons allow understanding of the meaning of another’s actions
Mirror neurons are the brain’s innate ability to detect and understand the intention of another person. Their activity is activated when the individual observes another person performing a goal-directed action.
These nerve cells are found in two areas of the brain, the inferior parietal lobe and the ventral premotor cortex. In humans, these areas correspond to Broca’s area. They are the result of a long evolution that has provided primates with a mechanism that allows us to recognize the intent of other people.
Although mirror neurons are important for the understanding of the intent behind other people’s actions, they are not the only mechanism for detecting and mirroring others’ behavior. Another mechanism involves the use of inhibitory interneurons to synchronize the somatomotor regions of the brain. This allows us to anticipate the movements of other people and make behavioral responses.
The mirror mechanism may also have evolved to allow for vicarious learning. By monitoring the actions of other people, we can see and hear the abstract meaning of those actions.
Mirror neurons in the human brain have been studied for over a century. They have been found in different parts of the insula and the premotor cortex. Some of them fire only when they observe the exact same action as the coded action. Others are more selective and respond to one specific frequency of sound.
One group of mirror neurons is located in the frontal cortex. When monkeys see another monkey making a hand or mouth movement, these neurons fire. They also activate when monkeys observe other people making a similar action.
A group of mirror neurons are also known as canonical neurons. These neurons are used to guide motor actions and are triggered by the sight of a graspable object. However, when the monkey does not actually grasp an object, the neurons do not fire.
The mirror neuron system has been studied by using fMRI. Children with autism have been shown to have reduced activity in their mirror neuron area. It is believed that this may be a key mechanism for social deficits.