<P> Ethanol is the type of alcohol found in alcoholic beverages . It is a volatile, flammable, colorless liquid that acts as a central nervous system depressant . Ethanol can impair different types of memory . </P> <P> Alcohol acts as a general central nervous system depressant, but it also affects specific areas of the brain to a greater extent than others . Memory impairment due to alcohol has been linked to disruption of hippocampal function--in particular affecting gamma - Aminobutyric acid (GABA) and N - methyl - D - aspartate (NMDA) neurotransmission which negatively impacts long - term potentiation (LTP). The molecular basis of LTP is associated with learning and memory . Particularly, damage to hippocampal CA1 cells adversely affects memory formation, and this disruption has been linked to dose - dependent levels of alcohol consumption . At higher doses, alcohol significantly inhibits neuronal activity in the CA1 and CA3 pyramidal cell layers of the hippocampus . This impairs memory encoding since the hippocampus plays an important role in the formation of new memories . </P> <P> Alcohol acts as a positive allosteric modulator of GABA receptors, specifically type GABA . Upon activation, these GABA receptors conduct Cl -, resulting in neuronal hyperpolarization . This hyperpolarization decreases the chance of an action potential occurring and, thus, has an inhibitory effect on neurotransmission in the central nervous system . GABA receptor subtypes vary in their sensitivity to dosage of alcohol consumed . Furthermore, acute alcohol intake promotes GABAergic neurotransmission via presynaptic release of GABA, dephosphorylation of GABA receptors (increasing GABA sensitivity), and elevation of endogenous GABAergic neuroactive steroids . Protein kinase C (PKC) has been implicated in differentially modulating the response of the GABA receptor to alcohol, with effects depending on the PKC isozyme . Alcohol effects have also implicated protein kinase A in affecting GABA receptor function, such as promoting sensitivity . Enhancement of GABAergic transmission due to alcohol consumption can also be brought about by neuroactive steroids, such as allopregnanolone, which act as GABA receptor agonists . Chronic alcohol consumption and alcohol dependence are correlated with altered expression, properties, and functions of the GABA receptor that may contribute to alcohol tolerance . There is still much to be discovered about alcohol's specific and varying effects on the GABA receptor and its subtypes . </P>

What part of the brain is memory affected by alcohol