Sensory Perception Cannabis

Sensory perception can be characterized as neurological processing of stimuli in one's environment. This stimulus is perceived through "senses" like touch or pain, vision, and hearing. These senses are vital in understanding environmental factors affecting a person, and their position in time and space. Healthy human beings process these stimuli in varied but similar ways, however, the fascination of the effects psychotropic drugs pose on altering these systems is becoming a popular subject of study.

This paper will examine one such drug, cannabis, and the potential effects it has on the human bodies sensory perception.

Specifically, how cannabinoids impact vision, hearing, and pain perception. Understanding how cannabis impacts the sensory perception of humans is an important subject of study, and this paper outlines several studies looking into these effects.

Cannabis has long since been classified as a highly dangerous substance, and as a result, little research has been conducted over the years regarding this substance, beneficial or detrimental. Consequently, little material exists regarding the therapeutic effects of the drug, in addition to the psychological side effects it poses.

The effects of chronic cannabis use has been known to impair executive functioning such as decision making, and concept formation, in addition to amotivational syndrome; in which a decreased drive, productivity, and planning take place. In addition, heavy use of the substance can pose a risk for the development of psychotic disorders later on in life. This result is due to the fact that the component Tetrahydrocannabinol (THC) of cannabis, that interferes with normal functioning of the brain.

Although cannabis has been known to cause potentially detrimental effects, it has been known to have beneficial properties as well. Studies have discovered that cannabis use activates pathways in the central nervous system that halt pain signals from being passed along to the brain. In addition, the use of THC on medical patients having difficulty maintaining a healthy appetite can greatly increase their consumption of food. This is due to the discovery that THC interacts with receptors in the hypothalamus which release the hormone, ghrelin. Ghrelin is an important hormone in stimulating hunger.

In addition, cannabidiol (CBD), a component of cannabis that does not result in a high, and has been proven to reduce anxiety and psychotic symptoms, and been shown to provide many beneficial properties. From reducing anxiety, to controlling pain, CBD is becoming known as a therapeutic substance in the medical field. The contrast of these two substances, THC and CBD, indicates that these properties of cannabis could provide many beneficial, in addition to detrimental effects.

One might wonder why the study of cannabis in association with sensory perception would be a worthwhile venture. Well, cannabinoid receptors are found in all different parts of the brain, and interact with receptors in the brain. Areas in the brain which govern one's senses bind with THC receptors, therefore resulting in altered perceptual grounding. Thus, an indepth look into the human bodies sensory systems in association with cannabis can provide greater insight of potential effects on the body.

The first sensory system of study is the visual system. The human visual system is a complex and important component of the body. The effects certain psychoactive substances such as cannabis can pose on visual processing while under the influence, in addition to the potential disturbance and impairments chronic use can pose on these systems, is not widely known.

Furthermore, the presence of cannabinoid receptors found in the visual system poses a serious question about the potential impacts. However, understanding the components of the human eye is important to comprehend the effects that cannabis can potentially have on visual processing. Specifically, the visual processing components that form stimuli into meaningful images, and the mechanisms in place to process this stimuli.

The contraction of the iris allows the eye adapt to changing conditions of light, while the lens focuses the light rays onto the retina. The retina which lines the back of the eye is where image formation takes place. It converts the image constructed by the light rays into nerve impulses. This process is driven by photoreceptors, specifically rods, which allow one to see shades of grey in low light conditions, and cones, which are sensitive to color in bright light conditions.

The retina is a vital component of visual processing, and is where the analysis of visual stimuli begins. Once the information is passed along from the photoreceptors to bipolar cells, these cells convey the information to ganglion cells which are responsible for transmitting an electrical impulse through the optic nerve.

The retina as described above is a critical component of visual processing, and the first research paper analyzed in this paper looks as cannabis and the visual system, specifically visual neural processing in the retina.. Dr. Denise A. Valenti, OD, FAAO exams visual neural processing of the retina, explaining how primary receptors such as CB1 have been shown in the central nervous system; importantly the retina. The paper discusses the quantity of cannabinoid receptors found throughout the retina, explaining that these receptors are found throughout many layers of cell structures.

As these receptors are found in the retina, the type of light activating these CB1 receptors changes the type of functional implications it has. For example, if the CB1 receptors are activated at night, the rod-cone gap junctional signally is increased, while if they are activated during the day, this is decreased. The implications of these findings affects scotopic vision as well as glare recovery.

The implications of scotopic vision means that while under the influence of cannabis, the cells in the retina are more sensitive to light during the nighttime. This is a result of the CB1 receptor protein binding to the psychoactive component of cannabis, THC, being found in higher levels in the visual cortex. Suggesting that cannabis effects on vision are greatly due to its actions of the retina cells. Therefore the enhancement of scotopic vision, or an enhancement in night vision, is increased due to the high quantity of CB1 receptors cells in the retina.

An additional study conducted by Schwizer, and colleagues examined the association between regular cannabis use and ganglion cell dysfunction. The study included 28 marijuana uses, and 24 non users, and examined the working retina comparatively between both groups to determine whether cannabis affects the functioning of ganglion cells, which as recalled from earlier in this paper transmits electrical impulses from eye to brain.

This electrical impulse was found to be delayed in cannabis using individuals, compared to non users. This delay in transmission of action potential was explained to support alterations in vision. However, the study did not fully examine the long term effects of chronic cannabis use, and the potential detrimental effects it can pose on vision. However, what each of these two papers do show, is the connection between cannabis receptors and visual processing, indicating a link between cannabis, and altered visual processing

In another study examining the endocannabinoid system in the retina, the physiological to practical and therapeutic applications are studied. Schizer and colleagues review the distribution of cannabinoid receptors in the retina and how they affect critical stages of terminal processing. The study explains that given the quantity and distribution of the cannabinoid system in the layers of the retina, it is surprising that only one study to date has delved into the impacts of cannabinoids on normal retinal function. Although it is known that there is a correlation, the implications of such a correlation has not been studied in depth.

Furthermore, the effects of cannabinoids are known to concern neurotransmitters expressed in the retina such as glutamate, GABA, and dopaminergic brain synaptic transmissions. Dopamine, expressed in the retina of humans is involved in light adaptation, according to the study, with the addition of glutamate affecting vertical transmission of the retina signal. The study goes on to desirebe that cannabis has the potential to alter the transmission of retinal information, however, the studies in which the evaluation of retinal function in association with cannabis are lacking.

In summation, it has been shown that cannabis, specifically cannabinoid receptors such as CB1 are widely found in visual system, particularly the retina. The impacts of this correlation, in order to be completely factual, needs more in depth credible research. However, the amount of cannabinoid receptors found in the retina, along with the effects of scotopic vision, glare recovery, and vertical transmission of the retina signal, suggest that cannabis effects the visual system greatly.

The next sensory system studied is the the auditory system. This system is a complex interplay of the dimensions of sound, and how we interpret that sound through audition. Again, in order to understand the implications cannabis poses on the system, it is vital to fully understand the functions. The auditory system is made up of two subsystems, the peripheral auditory cortex or dorsal stream, and the central auditory cortex or ventral stream.

The dorsal stream perceives sound location, and the ventral stream perceives particular complex sounds. When a general sound is perceived, the sound producing object vibrates, causing air molecules surrounding the object to condense and rarefy, and this is how we perceive sound.

The perception of music has been a popular subject of study in association with brain activation, and other potential effects it poses on the brain. It has been shown that the beat of music can sync with brainwaves, in addition to contributing to concentration in individuals listening to fast beats, and calmness in those listening to slower tempos. The activation of blood flow patterns in varying brain regions have been shown to be influenced by music.

These patterns have been shown to have similarities to the activity patterns induced by drugs. The auditory perceptual effects cannabis poses on musicians, and music listeners has been noted for many years, however, little research has been conducted on this phenomenon. This seems to be a common theme in the study of cannabinoids in association with human functioning. Research on stigmatized and controversial aspects such as drugs, seem to reflect societal prejudices, or values present in various research fields. However, auditory perception appears to be hold the largest effects of cannabis.

The effects cannabis has on altering auditory perception in association with music has been studied by Dr. Jorg Fachner at the University of Germany in the faculty of medicine. Dr. Fachner has studied an ethnomethodological approach to cannabis and music perception through the use of electroencephalography (EEG), a method reflecting direct neuronal activity, and brain mapping in naturalistic setting. The aims of Dr. Fechner's study was to examine the relationship of auditory changes from THC, the component in cannabis which results in the 'high' of using marijuana. The effects of this alteration of central processing data was observed through the EEG, where this data can be visibly displayed.

The study noted that cannabis intensifies processes of sensory perception through several aspects, the first being parietal and temporal EEG changes. The study found that over all regions near the skullcap were higher amplitudes in addition to frequencies. This finding showed that inhibited cerebrum and upper brain structure interactions were occuring. However, this was not the case in the midbrain, or other brain regions associated with emotional and memory processing.

In fact, these areas were shown to have slower frequencies, an indication of inhibited upper brain structures. The parietal lobes, and other areas that coordinate attention and perceptual processing were shown to display a distinct increase in amplitudes in the alpha band. This alpfa band increase indicates coordination of interactions between the upper brain structure and midbrain, designed to control cognitive functions. These increased frequencies, and amplities found in alpha are known to be found in those with high IQ's.

These findings correlate to temporarily intensified attention, as a result of hyperfocusing on musical notes. In addition, the study found that THC has a significant impact on cerebral processing music, and displayed the influence and enhancing effect it can have on acoustic perception. One common theme throughout the studies listed thus far is that they have studied the temporary effects of cannabis causes, rather than the long term effects. Dr. Fechner's study however, uncovered several important findings of the association between cannabis and enhanced sensory perceptions. Using the EEG to pick up on the Apha band changes in the brain was an important step to represent the neural correlate of hyperfocusing and music perception.

Somatosenses are those associated with feeling such as touch and pain. These senses come in several forms known as cutaneous senses, proprioception, kinesthesia, and organic sense. Cutaneous senses are senses such as pressure, vibration, heating or cooling, and pain. Proprioception is associated with one's awareness of their bodily position and posture, while kinesthesia is the perception one's bodily movement. Organic sense is sense modality that comes about from receptors located in the organs of the body. The most important somatosensory component when examining the effects of cannabis, is cutaneous senses due to the senses its component detecting aspects of pain.

The growing knowledge cannabis has in alleviating otherwise interactive pain has been spreading across the various fields of neuroscience and science in general. The study conducted by Michael C. Lee and colleagues on cannabis and amygdala activity contributing to pain perception looks into these effects.

The study discusses the benefits cannabis has shown to alleviate pain, however, explains that the basis for the relief offered by the substance is debatable. Thus, the studies goal was to examine THC on brain activity related to hyperplasia, and cutaneous on-going pain. The subjects were administered with THC, and although the amygdala was the area of interest, the whole brain was analyzed to identify where THC affected the brain activity.

The results showed that THC minimized the unpleasantness reported by subjects, on average. In terms of brain activity, the amygdala activity positively correlated to the reduction in pain of hyperplasia in drug-induced subjects. Furthermore, THC was proven to reduce connectivity functionally between the primary sensorimotor areas during the pain state, and the amygdala. The positive correlation between amygdala activity and THC in the system, advocates that dissociative effects of cannabinoids, specifically THC in the brain are effective in relieving pain in humans. Specifically, this suggests that the amygdala contributes to cannabinoid analgesia.

The sensory systems of humans are complex, and their functioning is vital for environmental interactions. CB1 receptors are found multiple layers of the retina indicating a strong correlation between cannabis, and visual alterations. The sensory perceptive enhancements to auditory acoustic sound is yet another compelling finding to suggest a significant correlation to the impacts cannabis poses on sensory perception. Finally, the therapeutic properties it suggests in accordance with pain management in medical settings. There is not doubt that the psychoactive substance, cannabis, greatly impacts the human sensory processing systems.

The common theme throughout this paper, however, is the lack of long term credible research studies delving into the effects chronic marijuana use has on sensory perception systems. If more research studies begin to look into the effects cannabis has on the human body, there is no doubt that these findings will produce answers to many questions. Neurological processing of one's environment is vital to living a healthy life, and if cannabis can alleviate a person's pain, alter their vision in the long term, or impact their auditory ability, this substance deserves a higher quality of quality research.

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